JPH0898119A - Picture processor - Google Patents

Abstract

PURPOSE: To prevent the occurrence of a trapezoid distortion in a projected picture by averaging the added value of a result obtained by means of giving weight corresponding to a deformation coordinate position on a screen by a deformed original picture and to the coordinate position of the nearby picture element to respective pieces of picture data and calculating them so as to obtain picture data of the deformation coordinate position. CONSTITUTION: In a first projection picture projected on the screen by a projection lens to which a gate angle in a vertical direction is given and a second projection picture by the projection lens where an optical axis matches the normal of the screen, the deformation coordinate position on the screen by the deformed original picture is obtained by using a relation expression regulating the relative position relation of the coordinate position. When the obtained deformation coordinate position is within a picture frame, a signal processing operation part 10 reads picture data on four nearby picture elements in the deformation coordinate positions from memories 6-9 and obtains picture data of the deformation coordinate position by an operation for averaging the added value of the result obtained by giving weighing corresponding to a position difference between the deformation coordinate positions and the coordinate positions of the four nearby picture elements to picture data of the respective picture elements and operating them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, and more particularly to an original image forming section in which pixels are arranged in a predetermined two-dimensional arrangement mode in a projector such as a projector using a liquid crystal light valve. Even if the optical image of the original image formed on the surface is projected on the screen by a projection lens that has a vertical tilt angle, an image without trapezoidal distortion is displayed on the screen. The present invention relates to an image processing device used to generate an original image in a state in which it is distorted in a predetermined manner when the original image is distorted in a predetermined manner so as to be output. .

[0002]

2. Description of the Related Art Various types of image projectors (projectors) for projecting a large image on a screen have been put into practical use, and in recent years, they have been controlled by video signals (image signals). A projector is widely used in which the intensity of light from a light source is modulated using a liquid crystal light valve, and the light emitted from the liquid crystal light valve is imaged on a screen through a projection optical system and projected on the screen. It became so. By the way, when the projector is installed in such a manner that the optical axis of the projection optical system of the projector and the normal line of the center position of the screen coincide with each other, keystone distortion (keystone distortion) occurs in the projected image projected on the screen. Distortion) does not occur, but when a projector is installed in front of the screen and an image is projected on the screen, the optical axis of the projection optical system of the projector is set to the center of the screen. When the installation is performed so as to match the normal line, the presence of the projector may hinder the viewing of the projected image on the screen. So
It is common to install the projector at a position where the presence of the projector does not hinder the viewing of the projected image, for example, on the floor or on a ceiling, but even in that case, the projected image projected on the screen In order to prevent trapezoidal distortion from occurring, various methods using an optical solution or an electrical solution have been proposed in the past, and in many practical projectors, An optical solution is generally adopted as a means for preventing the trapezoidal distortion from occurring in the projected image.

[0003]

However, the projector in which the trapezoidal distortion is corrected by the optical solution has a problem that the cost becomes high. In addition, as an electrical solution for preventing the occurrence of trapezoidal distortion in the projected image, the one in which the image to be displayed on the pixel array of the liquid crystal light valve is previously distorted in advance is thinned by thinning out pixels. It is difficult to meet the demands for large screens and high image quality, and the emergence of image processing devices that can be effectively used to configure projectors that can project good projected images at low cost has emerged. I was asked.

[0004]

According to the present invention, an optical image of an original image formed on a surface of an original image forming portion in which pixels are arranged in a predetermined two-dimensional arrangement mode is vertically tilted. An original image forming section in which the first projected image projected on the screen when projected onto the screen by a projection lens having an angle is arranged with pixels in a predetermined two-dimensional array mode. When the optical image of the original image formed on the surface of is projected on the screen by the projection lens provided with the optical axis of the projection lens aligned with the normal line of the screen, it is projected on the screen. In order to form an image similar to the second projected image, the original original image, which should be used as the original image when projected on the screen by the projection lens having the above-described vertical tilt angle, is used. An image processing apparatus for generating a deformed original image in a state of being subjected to a predetermined deformation in advance, converting an image signal capable of forming an image of an image frame of a predetermined shape into a digital signal at a predetermined sampling period. Means for obtaining digital image data corresponding to a two-dimensional pixel array of the original image, means for sequentially storing the digital image data in an image memory, the first projected image, and the second projected image In both the projected image and the projected image, how the same portion of the same original image is different in the coordinate positions on the first and second projected images projected on the screen. Is used to calculate the modified coordinate position of the projected image on the screen by the modified original image and the calculation result for obtaining the modified coordinate position. The transformed coordinate position is In the case of a coordinate position outside the image frame in the screen image based on the original shape image, a means for setting the image data of the modified coordinate position to black data, and the modified coordinate obtained as the calculation result for obtaining the modified coordinate position. When the position is a coordinate position within the image frame of the screen image based on the modified original image, a two-dimensional pixel array of the original image having an image frame of a predetermined shape is scanned by 2 × 2 in the normal scanning direction. By the read operation performed in such a manner that the pixels are sequentially taken out, the neighborhood 4 of the modified coordinate position stored in the image memory is obtained.
A means for reading out the image data of the pixel from the image memory, weighting according to the positional difference between the modified coordinate position and the coordinate position of the individual pixel in the four adjacent pixels is given to the image data of each pixel for calculation. And an image processing apparatus comprising means for obtaining image data at the modified coordinate position by averaging the added value of the results, and, as described above, a predetermined modification to the original original image. An image processing apparatus for generating a deformed original image in a state where
Means for converting an image signal capable of forming an image of an image frame of a predetermined shape into a digital signal at a predetermined sampling period to obtain digital image data corresponding to a two-dimensional pixel array of the original image; A delay unit is used to scan a two-dimensional pixel array of an original image having an image frame of a predetermined shape in a normal scanning direction from time-series digital image data corresponding to the two-dimensional pixel array of the image. In the same manner as in the case where 2 × 2 pixels are sequentially cut out, the means for taking out the image data of 4 pixels simultaneously as the data to be signal-processed one after another, and the angle formed by the optical axis of the projection lens and the normal line of the screen in advance For each of the plurality of defined angles, the ratio of the horizontal lengths at the corresponding horizontal scanning line positions in the first projected image and the second projected image, which correspond to each other, data , The same portion of the same original image in both the first projected image and the second projected image is the first and the first projected images displayed on the screen. 2) By using the relational expression that defines the relative positional relationship of how different coordinate positions are present on both projected images, the modified coordinate position of the projected image on the screen is calculated by the modified original image. Means for preparing in advance the data of the ordinate value at the modified coordinate position, the data of the ordinate value at the modified coordinate position prepared in advance, and the previously prepared Of the abscissa value at the deformed coordinate position calculated based on the data of the ratio of the horizontal lengths at the corresponding horizontal scanning line positions corresponding to each other in the first projected image and the second projected image. Data and the data to be processed Means for performing arithmetic operations on the data, means for storing only effective image data in the first-in first-out memory among the operation results for each scanning line unit, and an image stored in the first-in first-out memory. A means for reading from the first-in first-out memory in a time relationship such that the image data of the central part of the data projects the pixel in the central part in the horizontal direction in the projected image, and storing it in the first-in first-out image memory. ,
An image processing apparatus comprising: means for reading image data from the first-in first-out type image memory in a time relationship such that the lower end position of the projected image becomes a predetermined position;
When an optical image of the original image formed on the surface of the original image forming section in which pixels are arranged in a three-dimensional arrangement is projected on a screen by a projection lens provided with a vertical tilt angle. The image frame shape of the first projected image displayed on the screen is an optical image of the original image formed on the surface of the original image forming part in which pixels are arranged in a predetermined two-dimensional arrangement mode. Is the image frame shape of the second projected image displayed on the screen when projected onto the screen by the projection lens provided in a state where the optical axis of the projection lens matches the normal line of the screen. Similarly, the original image should be used as an original image when projected on a screen by a projection lens that has a vertical tilt angle so that it becomes a rectangular image without trapezoidal distortion. hand An image processing device for generating a deformed original image in a state of being subjected to a predetermined deformation for converting an image signal capable of forming an image of an image frame of a predetermined shape into a digital signal at a predetermined sampling period and A means for obtaining digital image data corresponding to the two-dimensional pixel array of the image and a delay means from the time-series digital image data corresponding to the two-dimensional pixel array of the original image are used to obtain a predetermined shape. Regarding a two-dimensional pixel array of an original image having an image frame, image data of 4 pixels is simultaneously used as signal processing target data in a manner similar to the case where 2 × 2 pixels are sequentially cut out by scanning in the normal scanning direction. Means for taking out one after another, and the first projected image and the second projected image described above for each of a plurality of predetermined angles about the angle formed by the optical axis of the projection lens and the normal line of the screen. With images In the two projected images of the first projected image and the second projected image, the data of the ratio of the horizontal lengths at the successive horizontal scanning line positions corresponding to each other, Using the relational expression that defines the relative positional relationship of how the same portion of the original image of the above is at different coordinate positions on the first and second projected images displayed on the screen. Means for preparing in advance the data of the value of the ordinate at the modified coordinate position obtained by calculating the modified coordinate position of the projected image on the screen by the modified original image, and the previously prepared means. The data of the ordinate value at the modified coordinate position, the first projected image prepared in advance, and the horizontal direction at the corresponding horizontal scanning line positions corresponding to the second projected image. Deformation calculated based on the length ratio data Means for calculating the signal processing target data using the data of the abscissa value at the mark position, and first-in-first-out only effective image data among the calculation results for each scanning line unit. Of the central part of the image data stored in the first-in first-out type memory and the image data of the central part of the image data stored in the first-in first-out type memory. Provided is an image processing apparatus comprising a first-in first-out memory.

[0005]

An image signal capable of forming an image of an image frame of a predetermined shape is converted into a digital signal at a predetermined sampling period by an analog-digital converter, and a digital image corresponding to the two-dimensional pixel array of the original image. Generate data and store it in image memory. A projection lens provided in a state in which the optical axis located in the plane perpendicular to the screen in the vertical direction of the screen makes an acute angle with respect to the normal line of the screen, that is, a tilt angle in the vertical direction is given. The optical image of the original image formed on the surface of the original image forming portion in which the pixels are arranged in a predetermined two-dimensional arrangement parallel to the main plane of the projection lens by the projection lens on the screen. The first projected image displayed on the screen when projected, and the surface of the original image forming part in which the pixels are arranged in a predetermined two-dimensional arrangement parallel to the main plane of the projection lens. When the optical image of the formed original image is projected on the screen by the projection lens provided in a state where the optical axis of the projection lens coincides with the normal line of the screen, it is projected on the screen. Second In both the projected image and the projected image, how the same part of the same original image is different on the first and second projected images projected on the screen. Using a relational expression that defines the relative positional relationship of whether the image is in a position, an operation for obtaining the modified coordinate position of the projected image on the screen by the modified original image is performed.

If the modified coordinate position obtained as a result of the calculation for obtaining the modified coordinate position is a coordinate position outside the image frame in the screen image of the modified original image, the image data of the modified coordinate position is black. Set to data.
Further, when the modified coordinate position obtained as the calculation result for obtaining the modified coordinate position is a coordinate position within the image frame of the screen image of the modified original image, the original image having an image frame of a predetermined shape is With respect to a two-dimensional pixel array, the vicinity of the modified coordinate position stored in the image memory is obtained by a reading operation performed in such a manner that 2 × 2 pixels are sequentially taken out by scanning in the normal scanning direction. Four
The image data of the pixel is read from the image memory, weighted according to the positional difference between the modified coordinate position and the coordinate positions of the individual pixels in the four adjacent pixels, and weighted to the image data of each pixel, and the result is calculated. The image data at the modified coordinate position described above is obtained by averaging the added value of

An image signal capable of forming an image of an image frame of a predetermined shape is converted into a digital signal at a predetermined sampling period by an analog-digital converter and corresponds to a two-dimensional pixel array of the original image. The digital image data is generated, and the time-series digital image data is scanned by a delaying means in a normal scanning direction with respect to a two-dimensional pixel array of an original image having an image frame of a predetermined shape. 2x2
In the same manner as in the case of sequentially cutting out pixels one by one, image data of four pixels are simultaneously taken out one after another as data to be subjected to signal processing. A plurality of angles are determined in advance as the tilt angle of the projection lens in the vertical direction, and the first projected image and the second projected image correspond to each other at each of the angles. Data on the ratio of the horizontal lengths at the successive horizontal scanning line positions is stored, and in both of the first projected image and the second projected image, the same Using the relational expression that defines the relative positional relationship of how the same portion of the original image of the above is at different coordinate positions on the first and second projected images displayed on the screen. Then, the above-mentioned two types of data are stored in the memory in which the data of the ordinate value at the modified coordinate position obtained by calculating the modified coordinate position of the projected image on the screen by the modified original image are stored. Data to be read and subject to the above signal processing Performs signal processing using the signal processing.

That is, of the two types of data read from the memory, the data of the value of the ordinate at the modified coordinate position is used as it is for the arithmetic processing of the data to be signal-processed, Further, the data of the horizontal length ratio at the successive horizontal scanning line positions is used to calculate the data of the value of the abscissa at the deformed coordinate position, and thereby the data of the signal processing target described above is calculated. Perform arithmetic processing. Then, only the effective image data among the calculation results for each scanning line unit is stored in the first-in first-out memory. The image data stored in the first-in first-out memory is read out from the first-in first-out memory in a time relationship such that the image data in the central portion of the image data projects the central pixel in the horizontal direction in the projected image. Then, it is stored in the first-in first-out image memory.

Image data is read from the image memory from the first-in first-out image memory in a time relationship such that the lower end position of the projected image becomes a predetermined position. Based on the image data read from the first-in first-out type image memory described above, on the surface of the original image forming portion in which the pixels are arranged in a predetermined two-dimensional arrangement mode, a predetermined value is set in advance for the original original image. When a deformed original image in a deformed state is formed and the deformed original image is projected on the screen by a projection lens, it appears on the screen.
In the image frame having the same shape as the original image frame, a projected image similar to the original image is displayed.

Further, the image data stored in the first-in first-out type memory is used without using the first-in first-out type image memory described above. Image data read out from the first-in first-out memory in a time relationship such that the pixels are projected, the original original image is formed on the surface of the original image forming portion in which the pixels are arranged in a predetermined two-dimensional arrangement mode. On the other hand, when a deformed original image in a predetermined deformed state is formed in advance and the deformed original image is projected on the screen by the projection lens, an image having a rectangular image frame instead of a trapezoid is formed on the screen. The projected image can be displayed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The specific contents of the image processing apparatus of the present invention will be described in detail below with reference to the accompanying drawings. 1 and 2 are block diagrams showing schematic configurations of different embodiments of the image processing apparatus of the present invention, FIG. 3 is an explanatory view of a method of determining image data at a modified coordinate position, and FIG. 4 is a screen. On the screen when the original image is projected on the screen by the projection lens in the state where the normal line and the optical axis of the projection lens match, and the projection lens in which the tilt angle in the vertical direction is given FIG. 5 is an explanatory view of the shape of the projected image, and FIG. 5 shows an original image formed on the surface of an original image forming portion in which pixels are arranged in a predetermined two-dimensional arrangement parallel to the main plane of the projection lens. , An explanatory view with a projected image displayed on the screen when the original image is projected on the screen by a projection lens having a vertical tilt angle, and FIG. 6 is parallel to the main plane of the projection lens. And given The deformed original image formed on the surface of the original image forming portion in which pixels are arranged in a two-dimensional arrangement and a projection lens having a vertical tilt angle are used to screen the deformed original image. FIG. 7 is an explanatory diagram of a projected image displayed on a screen when projected onto the screen, and FIG. 7 is a side view showing a schematic configuration of the projector.

First, with reference to FIGS. 4 to 7, an image on the screen when an original image is formed on the screen by the projection lens with the optical axis of the projection lens aligned with the normal line of the screen is shown. The shape of the projected image and the projection lens provided in such a state that the optical axis located in the plane perpendicular to the screen in the vertical direction of the screen makes an acute angle with respect to the normal line of the screen, that is, in the vertical direction. Various matters related to the shape of the projected image on the screen when the image is formed on the screen by the projection lens having the tilt angle will be specifically described. FIG. 7 is a side view showing a state where a large image is projected on the screen by the image projector (projector).

In FIG. 7, reference numeral 13 is a projector, 14 is a light source, 12 is a portion for forming an original image to be projected on a screen (for example, a liquid crystal light valve), and 15 is a projection lens. Of the projection lens 15 is arranged concentrically with the image forming section 12 of the image forming section 12, and the main plane of the projection lens 15 is arranged in parallel with the original image forming surface of the original image forming section 12, and the light emitted from the light source 14 is emitted. , The screen 16 (or 1) by the projection lens 15 in the state where the intensity is modulated by the original image formed in the original image forming unit 12.
When the image is formed on 7), a projected image larger than the original image is projected on the screen 16 (or 17).

Reference numeral 18 in FIG. 7 denotes the optical axis of the projection optical system of the projector, and the screen 16 in FIG. 7 has its normal line 16n aligned with the optical axis 18 of the projection lens 15 described above. Screen 1 when installed in the state
6 and also the screen 17 in FIG.
Shows a screen tilted so that a vertical tilt angle θ is formed between its normal line 17n and the optical axis 18 of the projection lens 15 described above. Although the projected image projected on the screen 16 does not have a keystone distortion (keystone distortion), the projected image projected on the screen 17 has a trapezoidal distortion (keystone distortion) as illustrated in FIG. Stone distortion) occurs. That is, in FIG. 5, the cross-shaped figure 12f shown by the dotted line is the original image forming portion 1
2 is an example of the original image formed in FIG. 2, and the trapezoidal figure 17f shown by the solid line in FIG. The projected image projected on the screen 17 in the accompanying state is shown.

That is, even if the original image formed on the original image forming section 12 is the cross-shaped figure 12f shown by the dotted line in FIG. 5, the optical axis 18 of the projection lens 15 and the normal line of the screen The projected image projected on the screen 17 by the projection lens 15 in the state in which the tilt angle θ in the vertical direction is given so that a non-zero angle θ is formed therebetween is shown in FIG.
A trapezoidal figure 17f shown by a solid line in the figure is in a state with trapezoidal distortion, but as the value of the angle θ between the optical axis 18 of the projection lens 15 and the normal line of the screen changes, The state of the trapezoidal distortion of the projected image projected on the screen is changed. Then, as described above, between the optical axis 18 of the projection lens 15 and the normal line of the screen, 0
The original image is displayed on the screen 16 provided in such a manner that the angle θ not formed is formed, and the optical axis 18 of the projection lens 15 is aligned with the normal line of the screen. In order to be able to project the same projected image as the projected image obtained when the original image formed on the forming unit 12 is projected, As the original image to be formed, it is preferable to use a deformed original image in which the original image is previously deformed by a distortion opposite to the trapezoidal distortion that should be given to the original image when projected by the projection lens 15. Good.

In FIG. 6, a cross-shaped figure 12 shown by a dotted line
f is a figure of the original original image that should be formed in the original image forming section 12 like the figure 12f of the grid shown by the dotted line in FIG. 5, and the figure 12f of this original image is shown in FIG.
When projected by the projection lens 15 onto the screen 16 when the normal 16n of the screen 16 is provided so as to coincide with the optical axis 18 of the projection lens 15 as shown in Is projected as a projected image similar to the image shape 12f of the original image. Further, the trapezoidal figure 12fm shown by the solid line in FIG. 6 is formed on the original image forming portion 12 and the normal line 17
screen 1 provided in a tilted state so that an angle θ is formed between n and the optical axis 18 of the projection lens 15.
7 when projected by the projection lens 15 in the state where the tilt angle θ in the vertical direction is given as described above,
The figure has been deformed in advance so that it can be projected on the screen 17 as a projected image similar to the image shape 12f of the original image.

Further, a solid-lined figure 17fm shown so as to be in contact with the above-mentioned cross-shaped figure 12f shown in FIG. 6 (corresponding to the cross-shaped figure 12f shown by the dotted line It should be written as Figure 17fm, but since the content of the illustration becomes complicated when written in such a way, only the part of the image frame is described).
Causes the trapezoidal figure 12fm shown by the solid line in FIG. 6 to be formed in the original image forming portion 12 and the normal line 1 of the screen
7n and the optical axis 18 of the projection lens 15 forms an angle θ between the projection lens 15 and the projected image on the screen 17 (however,
It is shown as 1: 1).

The projection lens 15 can project a projected image without trapezoidal distortion on the screen 17 where an angle θ is formed between the normal line 17n of the screen and the optical axis 18 of the projection lens 15. In this case, the trapezoidal figure 12fm in FIG. 6 exemplifying the deformed original image formed and used by the original image forming unit 12 has the normal 16n of the screen on the optical axis 18 of the projection lens 15. An example of the image shape of the original image formed by the projection lens 15 on the original image forming unit 12 on the screen 16 provided so as to match the original image is used. It exists inside the figure 12f. The area of the trapezoidal figure 12fm shown by the solid line corresponding to the above-mentioned deformed original image becomes smaller as the angle θ between the normal line of the screen and the optical axis 18 of the projection lens 15 becomes larger.

That is, when the normal line of the screen and the optical axis 18 of the projection lens 15 coincide with each other and the angle θ between the two is 0, the image is formed in the original image forming section 12 and used. Even if the size of the frame of the original image is, for example, the entire cross-shaped figure 12f shown by the dotted line in FIG. 6, the normal line of the screen and the optical axis 18 of the projection lens 15 are used.
In the case where the angle θ between and is not 0, as the value of the angle θ increases, it is assumed that the area in the grid pattern 12f shown by the dotted line in FIG. 6 is gradually smaller. It is reduced to the trapezoidal area that is formed. By the way, when the original image forming unit 12 is constituted by a predetermined number of pixels arranged two-dimensionally like a liquid crystal light valve such as a liquid crystal panel, as shown in FIG. Since the number of pixels provided in the cross-shaped figure 12f shown by the dotted line is fixed, the number of pixels is determined according to the angle θ between the normal line of the screen and the optical axis 18 of the projection lens 15. The number of pixels included in the trapezoidal area indicated by the trapezoidal figure 12fm corresponding to the deformed original image formed in the grid pattern 12f indicated by the dotted line is the area of the trapezoidal area. Will be decided according to.

On the other hand, with the optical axis 18 of the projection lens 15 having an angle θ with respect to the normal line 17n of the screen 17, the deformed original image is projected onto the screen 17 by the projection lens 1.
6, when the deformed original image whose image frame is shown by the trapezoidal figure 12fm shown by the solid line in FIG. 6 is projected on the screen 17 by the projection lens 15, Since the projected image is enlarged to a state like the image frame 17fm shown by the solid line, the deformed original image formed in the original image forming unit 12 is a trapezoidal figure shown by the solid line in FIG. If the deformed original image is shown by the outer frame of 12 fm, the image frame shown by the outer frame of the grid pattern 12 f shown by the dotted line in FIG. 6 and the trapezoid shown by the solid line in FIG. Figure 12 fm
The pixels existing in the original image forming unit 12 corresponding to the portion between the modified original image and the image frame indicated by the outer frame of
The pixel area corresponds to a portion outside the image frame of the projected image on the screen, and the pixel area is an area in which black should be displayed.

As already described with reference to FIG. 6, the optical axis 18 of the projection lens 15 with respect to the normal line 17n of the screen 17
With the angle θ, the original image forming unit 1
The deformed original image formed in FIG. 2 is projected on the screen 17 by the projection lens 15, and the deformed original image whose frame is shown by the trapezoidal figure 12fm shown in FIG. When it is assumed that the projected image is enlarged in a state such as the image frame 17fm indicated by the solid line,
The pixel at the position P in the deformed original image whose image frame is shown by the trapezoidal figure 12fm shown by the solid line in FIG. 6 is enlarged to a state like the image frame 17fm shown by the solid line in FIG. It is displayed at the position P ′ in the pixel area in the projected image.

The above points can be understood by the following explanation. That is, the normal line 17n of the screen 17
With respect to the projection lens 15 such that the optical axis 18 of the projection lens 15 has an angle θ,
In the state where the image is given, the modified original image formed on the original image forming section 12 is projected onto the screen 1 by the projection lens 15.
When projected on 7, the trapezoidal figure 12 shown by the solid line in FIG.
The transformed original image whose frame is shown by fm is
A projected image projected on the screen 17 is obtained in an enlarged state such as an image frame 17fm shown by a solid line in FIG. As described above, the projected image projected on the screen 17 and the screen 16 provided in such a state that the normal 16n of the screen 16 coincides with the optical axis 18 of the projection lens 15 What is the projected image obtained by projecting the original image having the image frame formed by the cross-shaped figure 12f shown by the dotted line in FIG. 6 formed on the forming unit 12 onto the screen 16 by the projection lens 15? The projected image is a congruent figure. Then, the pixel at the position P in the deformed original image whose image frame is shown by the trapezoidal figure 12fm shown by the solid line in FIG. 6 is like the image frame 17fm shown by the solid line in FIG. The image is projected at the position P ′ in the pixel area in the projected image enlarged to the state.

The positional relationship between the position P and the position P'is described below with reference to FIGS. 4 (a) and 4 (b). 4A and 4B are original image forming units 1 in the projector 13 illustrated in FIG.
2, the projection lens 15, and the respective parts of the screens 16 and 17 are shown and the optical axis 18 of the projection lens 15 is shown as a horizontal horizontal line.
4A is a side view, and FIG. 4B is a plan view. Figure 4
As shown in (a) of FIG. 6, the screen 17 is provided so that the normal line of the screen coincides with the optical axis 18 of the projection lens 15, and the screen 17 is a plane perpendicular to the screen in the vertical direction of the screen. The optical axis 18 of the projection lens 15 located inside is provided in a state of being inclined by an angle θ with respect to the normal line of the screen 17. In FIG. 4, both screens 16 and 17 described above are shown.
Are shown as having the same position at their lower ends.

In FIG. 4, the optical axis 18 of the projection lens 15 is shown.
The image information projected on the point P on the screen 16 which is provided so as to be a plane perpendicular to is projected on a point P ′ where the straight line connecting the point P and the center of the projection lens 15 intersects with the screen 17. However, the angles α, γ, δ, θ and the distances L, Yb, V, Vn, Vm, X of the respective parts shown in FIG.
Using b, hn, hm, etc., the two points P,
The positional relationship (coordinates) of P'can be expressed by the following equations (1) and (2).

[0025]

[Equation 1]

As described above, the optical axis 1 of the projection lens 15
8 and the screen 16 provided so that the normal line of the screen coincides with the position of point P in the projected image projected by the projection lens 15, that is, the original image forming portion 12
The position of the point P in the screen 16 which is an image having a shape similar to the original image formed in the above, and the normal line of the screen with respect to the optical axis 18 of the projection lens 15 are provided with an angle θ. Since the relation with the point P ′ in the screen 17 on which the image information of the point P on the screen 16 is projected on a certain screen 17 is expressed by the equations (1) and (2), The above equations (1) and (2) are pixel positions (addresses) on the screen 17 when the original image is projected on the screen 17 without trapezoidal distortion.
Can be used to obtain the position (address) of the point P ′ described above with reference to.

By the way, as described above, the original image forming portion 12 is formed on the screen 17 which is provided with the normal line of the screen inclined by the angle θ with respect to the optical axis 18 of the projection lens 15. When the projected image without trapezoidal distortion is projected by the projection lens 15 on the screen 17 by the modified original image, the projected image on the screen 17 is a modified original image in a reduced state with respect to the original original image. Since the image is in a magnified state, as in the case where the liquid crystal panel is used as the liquid crystal light valve in the original image forming unit 12 described above, for example, the board shown by the dotted line in FIG. 6 is used. There are 2 pixels of a predetermined number in the figure 12f of the eye.
If the modified original image has a configuration that is arranged in a dimension, the deformed original image is located at a predetermined position in the grid pattern 12f shown by the dotted line in FIG. Of the predetermined number of pixels respectively provided, only the pixels in the area of the trapezoidal image frame indicated by the trapezoidal figure 12fm shown by the solid line corresponding to the deformed original image are reduced with respect to the original image. Is used as the deformed original image, and is enlarged and projected on the screen 17 by the projection lens 15 as a projected image having a rectangular image frame.

Therefore, by the pixels arranged two-dimensionally within the image frame indicated by the grid pattern 12f shown by the dotted line in FIG. 6, the grid pattern 12f by the dotted line shown in FIG. When a projected image having an image frame shape similar to the image frame shown by is projected on the screen by the projection lens 15, a projected image having the same image frame as the projected image formed on the screen is provided. In the case where the projected image is a deformed original image composed of only pixels in the area of the trapezoidal image frame indicated by the trapezoidal figure 12fm shown by the solid line in FIG. , The pixel area between the image frame shown by the cross-shaped figure 12f shown by the dotted line in FIG. 6 and the trapezoidal image frame shown by the trapezoidal figure 12fm shown by the solid line in FIG. Pair with the part outside the image frame of the formed projected image. The pixel regions.

By the way, one pixel has a one-to-one correspondence with the pixel data, and the pixel data is displayed in a unit. As is clear from the expressions (1) and (2) described above,
Since the relationship between the pixel at the position P and the pixel at the position P ′ illustrated in FIG. 6 cannot be generally expressed by the relationship of integer values, the dotted line in FIG. When a projected image having an image frame shape similar to the image frame shown by the grid pattern 12f shown in the drawing is projected on the screen by the projection lens 15, the same projected image as the projected image formed on the screen is displayed. The projected image provided with the image frame is screened by the projection lens 15 as a deformed original image composed of only the pixels in the area of the trapezoidal image frame shown by the trapezoidal figure 12fm shown by the solid line in FIG. When projected onto the screen, the same portion of the two projected images formed on the screen is projected corresponding to image data of different pixels. Therefore, the projected image projected by the modified original image on the screen has poor image quality.

FIG. 3 is a diagram of a pixel array used also for explaining the above-mentioned problems. In FIG. 3, # 11, # 12 ...
# 33, # 34, etc. exemplify a part of the pixel array on the screen when the array of pixels forming the original image having a two-dimensional array is projected on the screen without trapezoidal distortion. Yes, # 11, # 1 in FIG.
2, # 13, # 14 ..., # 21, # 22, # 23, # 2
.., # 31, # 32, # 33, # 34, etc. show pixel arrays in the respective row directions, and the pixel arrays # 11, # 21, # 31, ... In FIG. # 1
2, # 22, # 32 ..., # 13, # 23, # 33 ..., #
The array of pixels such as 14, # 24, # 34 ... Shows the pixel array in the respective column directions.

By the way, the point P'in FIG. 3 is the original deformation which is constituted only by the pixels in the area of the trapezoidal image frame shown by the trapezoidal figure 12fm shown by the solid line in FIG. The coordinates (address) on the screen 17 when the image is projected on the screen 17 by the projection lens 15 to which the tilt angle θ in the vertical direction is given are shown, and the coordinates of the point P ′ are shown. (Address) is on the screen when the array of pixels forming the original image having a two-dimensional array is projected on the screen without trapezoidal distortion by using the expressions (1) and (2) described above. Regarding the coordinates of the pixels in the pixel array of, the pixel # 11 in the upper left corner in FIG.
Is the origin of the coordinates, the coordinate value of the pixel # 11 described above is the integer part of the coordinates, and δX and δY shown in FIG.
Position (address) where is represented as the fractional part of the coordinate
This can be calculated using the equations (1) and (2).

As described above, the original image forming unit 12 has the structure shown in FIG.
When a deformed original image of a trapezoidal image frame indicated by a trapezoidal figure 12fm shown by a solid line is formed, a cross-shaped figure 12f shown by a dotted line in FIG. Regarding the pixels in the pixel area between the image frame shown and the trapezoidal image frame shown by the trapezoidal figure 12fm shown by the solid line in FIG. 6, P ′ described above using the equations (1) and (2) is used.
The position of P ′ calculated when the position of P is calculated is in the pixel area corresponding to the portion outside the image frame of the projected image to be formed on the screen by the modified original image. In this case, image data for expressing black is generated.

The horizontal scanning of the pixel array is started in a predetermined order from the pixel at the reference position in the pixel array of the original image forming section 12, that is, from the upper left corner of the original image forming section 12, and the vertical scanning is performed. According to the order such that the scanning of one image is completed at the lower right corner of the original image forming unit 12, the P'for the successive pixels is described.
As the position of P ′ is calculated, it is determined that the position of P ′ is within the image frame of the projected image to be formed on the screen by the modified original image. Above, it is assumed that it is # 11 shown in FIG. 3).
The position of is expressed by the integer part of the coordinate based on the coordinate value of the pixel # 11 and the decimal parts δX and δY of the coordinate shown in FIG.

When the position of the point P'is within the image frame of the projected image to be formed on the screen by the deformed original image as described above, the pixel of # 11 is set as the origin. , Four pixels # 11 near the point P'included as
Pixel data A, B, C, D in # 12, # 21, # 22 (four pixels # 11, # 12, # 21, # 22 surrounding the point P ') and the point P'. Using the above-mentioned coordinates δX and δY, the following equations (3) to (5): S1 = B · δX + A (1-δX) (3) S2 = D · δX + C (1-δX) (4) ) P's = S2.delta.Y + S1 (1-.delta.Y) (5) The image data P's at the point P'is obtained by calculation.

As described above, the position (address) of the pixel # 11 in FIG. 3 is calculated using the equations (1) and (2), and the pixel # 11 is set to the origin (0, 0) of the coordinates. As
Point P ′ that matches the value of the decimal part of the coordinates of the pixel # 11
Using the X coordinate δX and the Y coordinate δY of the image data and the image data A, B, C, and D of the four pixels # 11, # 12, # 21, and # 22 near the point P ′. (3)-(5)
When the pixel data P ′s at the point P in the deformed original image corresponding to the point P ′ on the screen is obtained by the formula, next,
The position (address) of pixel # 12 in FIG. 3 is calculated using equations (1) and (2) to calculate the position of point P ′ for pixel # 12, and that position is the transformed original image. If the pixel # 12 is within the image frame of the projected image to be formed on the screen, the pixel # 12 is set as the origin (0, 0) of the coordinate and the value of the decimal part of the coordinate of the pixel # 12 matches. X coordinate δX and Y coordinate δY of the point P ′ to be processed and four pixels # 12, # 13, # 2 in the vicinity of the point P ′.
Using the image data of # 2 and # 23, the above (3) to
Since the image data P's of the point P in the modified original image corresponding to the point P'on the screen is obtained by the equation (5), the pixel data of the point P'for the successive pixels are calculated in the same manner. Of.

The calculation of the pixel data of the point P'on the screen by the above equations (3) to (5) is performed as described above by the distance (coordinate position and the distance from four pixels near the point P '). However, the number of pixels used in the above calculation may be different depending on the position of the point P ′.
Either one case, two cases, or four cases, but in the present specification, the number of pixels used for the above calculation is one case, two cases, and four cases. In either case, it is described that it is performed based on the distance from four pixels in the vicinity of the point P ′. 1 and 2
FIG. 1 is a block diagram showing a schematic configuration of different embodiments of the image processing apparatus of the present invention. In each drawing, 1 is an input terminal of a video signal (analog signal), which is supplied to the input terminal 1. The video signal is converted into a digital image signal (digital image data) having a predetermined number of bits by the analog-digital converter 2. First, in the image processing apparatus shown in FIG. 1, 3 and 4 are selectors (data selectors, 5 is a control unit including an arithmetic unit, and 6 to 6).
Reference numeral 9 is a memory (random access memory), 10 is a signal processing operation unit, 11 is a digital-analog converter, and 12 is a modified original image signal generated by the image processing apparatus of the present invention. An original image forming unit on which an image is formed, 27 is a sync separation circuit, 28
Is an operation unit configured to include an information input unit.

The four memories 6 to 9 shown in FIG.
Is the number 4 near the particular point, like the point P'described above.
A random access memory (RAM) used to store four pixels in the vicinity of the specific point used when calculating pixel data of the specific point based on the distance from the specific pixel. Of the digital data output from the analog-to-digital converter 2, only the odd-numbered pixel data in the odd-numbered rows of the two-dimensionally arranged pixel array forming the image are stored in the memory 6 (in FIG. 3, # 11,
# 13, # 31, # 33 ...) is given by the selection operation of the selector 3 and stored.

In the memory 7, among the digital data output from the analog-digital converter 2, only the even-numbered pixel data in the odd-numbered rows in the two-dimensionally arranged pixel array forming the image (see FIG. # 3, # 12, # 14,
# 32, # 34 ...) are given by the selection operation of the selector 3 and are stored therein, and the digital data output from the analog-to-digital converter 2 constitutes an image in the memory 8. Only the even-numbered and odd-numbered pixel data (# 21, # 23, ... In FIG. 3) in the pixel array of the two-dimensional arrangement is given by the selection operation of the selector 3 and stored therein, and also in the memory. In FIG. 9, among the digital data output from the analog-digital converter 2, only the even-numbered pixel data in the even-numbered rows in the two-dimensionally arranged pixel array forming the image (# 22, # 24 ...) Is given by the selection operation of the selector 3 and is stored. The control unit 5 controls the switching operation of the selector 3 and the write operation and read operation of each memory.

The above-mentioned control unit 5 is composed of, for example, a microprocessor, a read only memory (ROM), a random access memory (RAM), a digital signal processor (DSP), a computing unit and the like. Then, in the control unit 5, the digital data corresponding to the pixels of the two-dimensional array in one image which is output from the analog-digital converter 2 is distributed to the four memories 6 to 9 in the distribution mode as described above. Control signals for causing the selector 3 to perform a selection operation such that the pixel data selected by the selector 3 are written in the corresponding memories (6 to 9). 4 pixels in the vicinity of the point P ′ at which it is necessary to perform a control operation to obtain the image data or to obtain image data from the pixel data stored in the above-mentioned four memories 6 to 9. A combination mode of data, for example, “# 11, # 12,
# 21, # 22 ","# 12, # 13, # 22, # 2 "
3 ","# 13, # 14, # 23, # 24 "... Performs a control operation for causing the respective pixels to be simultaneously read from the memories 6-9.

Further, the control section 5 is provided with a sync separation circuit 2 from the video signal supplied through the input terminal 1 described above.
The signal Sh of the horizontal scanning period and the signal Sv of the vertical scanning period, which are synchronously separated by 7, and the input means (for example, keyboard, mouse, switch, etc.) provided in the operation unit 28.
In addition, numerical information such as the angle value of the angle θ formed by the optical axis of the projection lens 15 and the normal line of the screen and the distance L (see FIG. 4) between the main plane of the projection lens 15 and the screen are also given. Has been. Then, the control unit 5 calculates the position of the point P ′ using the equations (1) and (2) already described for the sequential pixels. Further, the control unit 5 performs the operation of calculating the address value of the memory (6 to 9) corresponding to the position of the point P ′. The calculation of the address value of the memory (6 to 9) corresponding to the position of the point P ′ is performed, for example, by counting the sampling pulse supplied from the control unit 10 to the analog-digital converter 2 as the counted pulse. Is executed in the control unit 5 by using a counter for performing the above operation and an operation circuit for performing an address operation using a predetermined parameter with the count output value from the counter as the address value of the sequential pixel in each image.

That is, the signal Sh (horizontal synchronizing signal, horizontal driving signal) of the horizontal scanning period supplied to the input terminal 1 is
The address information of each row (horizontal scanning line) in the two-dimensional pixel array of each image is given, and the signal Sv (vertical synchronization signal, vertical driving signal) of the vertical scanning period is the total number of pixels in each image. It is used to reset the counter while the corresponding counting operation is performed on the counter. The count value output from the counter is a numerical value indicating the address value of each pixel in the two-dimensional arrangement mode for each one image, and the address value of each pixel is
# 11 used to distinguish each pixel in FIG.
It corresponds to # 12, # 13 ....

The count value output from the counter is
It is supplied to the address calculation circuit, and in this address calculation circuit, the angle value of the angle θ formed by the optical axis of the projection lens 15 set in the operation unit 28 and the normal line of the screen (the projection lens 1
5, the tilt angle θ in the vertical direction, and the projection lens 15
Distance L between the main plane of the screen and the screen (see FIG. 4)
Using parameters such as numerical values, etc., as parameters, the operation according to the equations (1) and (2) described with reference to FIG. 4 is performed to determine the position (address) of the sequential points P ′, Point P '
The position (address) of the information is given to the signal processing operation unit 10.

When the position of the above-mentioned sequential point P'is in the pixel area corresponding to the portion outside the image frame of the projected image on the screen, the signal processing arithmetic unit 10 separately performs a special arithmetic operation. No matter what, the digital-to-analog converter 11 converts the image data such that black is displayed corresponding to the position.
The operation just output to. When the positions of the above-mentioned sequential points P ′ are in the pixel area corresponding to the portion within the image frame of the projected image on the screen, the following equations (3) to (5) are followed. The image data obtained by performing the arithmetic operation is output to the digital-analog converter 11.

By the way, the image data of the four pixels used in the arithmetic operation performed in accordance with the equations (3) to (5) with respect to the sequential points P'is as described above with reference to FIG. , Four pixels # 11, # near the point P ′, for example
After the pixel data of the point P ′ is calculated based on the distances from 12, # 21 and # 22, for the point P ′ that needs to be calculated for the next image data, four points near the point P ′ are calculated. As a pixel of, based on the distance from the above four pixels,
Pixel data for the four pixels in the vicinity are given in (3)
~ The procedure of obtaining by the equation (5) is repeated for all pixels, but the pixel to be the origin of the image data calculation at the point P'where the image data calculation is to be performed is When the pixel is defined as the upper left pixel in the four pixels near the point P ′ and the above-mentioned four successive pixels are read from the memories 6 to 9 and the calculation is performed,
It is necessary that the above-mentioned arrangement relationship of the four pixels is a predetermined arrangement.

However, the pixel data stored in each of the above-mentioned four memories 6 to 9 is as described above.
The memory 6 has only the odd-numbered pixel data in the odd-numbered rows of the pixel array of the two-dimensional arrangement forming the image, and the memory 7 has the pixel data of the two-dimensional arrangement of the image forming the image. Only the even-numbered pixel data in the odd-numbered rows, only the odd-numbered pixel data in the even-numbered rows in the two-dimensionally arranged pixel array forming the image in the memory 8, and the image in the memory 9 Since only the even-numbered pixel data in the even-numbered rows in the two-dimensionally arranged pixel array, the pixel data stored in the above-mentioned four memories 6 to 9 has already been described with reference to FIG. A combination mode of four pieces of pixel data as described above, for example, “# 11, #
12, # 21, # 22 ","# 12, # 13, # 22,
By using the image data of each pixel in # 23 ”,“ # 13, # 14, # 23, # 24 ”..., the operations by the equations (3) to (5) are performed, and the image data of the sequential point P ′ is obtained. The arrangement relationship of the four pixels in sequence required for obtaining is determined by the selection operation of the selector 4 which performs the selection operation according to the control signal from the control unit 5.

When the operation speed of the multiplier used for the calculation in the signal processing calculation unit 10 does not reach the required image processing speed, it is used for the calculation (3).
The above-mentioned problem may be solved by applying a means of storing the calculation result for the fixed part in the equations (5) to ROM beforehand and processing it with a look-up table. The original image forming unit 12 supplied with the image signal output from the digital-analog converter 11 to which the calculation result of the signal processing calculation unit 10 is given is provided with the screen 1
The projection lens 15 provided in such a state that the optical axis 18 located in the plane orthogonal to the screen 17 in the vertical direction of 7 makes an acute angle with respect to the normal line of the screen 18, that is,
Projection lens 15 with vertical tilt angle
When the image is projected on the screen 17, a deformed original image is formed so that a projected image without trapezoidal distortion can be projected on the screen 17.

Then, the image signal generated by using the image processing apparatus of the present invention described with reference to FIG. 1 is supplied to the original image forming section 12 and the original deformation image formed in the original image forming section 12 is supplied. When an image is projected on the screen 17 by the projection lens 15 provided with a tilt angle θ in the vertical direction, the screen 17 has an image frame shape with no trapezoidal distortion, and The calculation of the pixel data of the point P in the deformed original image corresponding to the point P ′ on the screen is
Since the average value of the added values of the weighted values based on the distance (positional difference from the coordinate position) to four pixels near the point P ′ is calculated, the number of pixels is reduced. The deformed original image in the expanded state is enlarged on the screen 17
The projected image projected on top is a projected image of good quality with no sudden change in image content.

In the image processing apparatus of the present invention shown in FIG. 1, which has been clarified by the above description, the memories 6 to 9 are used.
Address input type random access memory (RA
M) is used, but as described above, it is necessary to simultaneously read pixel data for each pixel from the memories 4 to 6, that is, pixel data for a total of 4 pixels. Therefore, in the actual configuration of the device, two RAMs are prepared for each of the memories (6-9) in the above-mentioned four memories 6-9, and the two R
The AM is used by alternately switching between the write operation and the read operation. Therefore, as the memories 6 to 9 described above, it is necessary to use a total of eight RAMs for the configuration thereof, but now, the liquid crystal panel used as the original image forming unit 12 is 640 × 480 pixels. In the case of three colors of R, G, and B, assuming that the vertical scanning frequency is 60 Hz and the operation is performed with
2 Mbit high-speed (30 nanosecond or less cycle) RAM
Four will also be needed.

However, since the RAM capable of high-speed operation as described above is expensive at present even if it is in the future, there may be a problem that the cost becomes high in a device using a large number of expensive RAMs. The embodiment of the image processing apparatus of the present invention shown in FIG. 2 is an image processing apparatus having no problem in the image processing apparatus described above with reference to FIG. This figure 2
In the image processing apparatus shown in FIG. 2, the video signal (analog signal) supplied to the analog-digital converter 2 via the input terminal 1 of the input video signal has a predetermined number of bits by the analog-digital converter 2 (example shown in FIG. 2). Is converted into an 8-bit digital image signal (digital image data) and is supplied to the interpolation calculation unit 22, the latch circuit 20, and the delay circuit (1HDL) 19 for one horizontal scanning period. Further, the output of the latch circuit 20 is given to the interpolation calculation section 22. The digital image signal delayed by the delay circuit (1HDL) 19 for one horizontal scanning period is given to the interpolation calculation unit 22 and the latch circuit 21, and the output of the latch circuit 21 is the same as that described above. It is given to the interpolation calculation unit 22.

Therefore, the above-mentioned interpolation calculation unit 22 is
[1] At the present time, digital image data directly supplied from the digital-analog converter 2 (for example, # in FIG. 3).
22 pixel digital image data), [2] The latch circuit 20 delays the digital image output from the digital-analog converter 2 one sampling period before the current time by one sampling period. Digital image data in a given state (for example, digital image data of pixel # 21 in FIG. 3), [3] Digital image data output from the digital-analog converter 2 one horizontal scanning period before the present time. On the other hand, digital image data in a state where a time delay of one horizontal scanning period is given by the delay circuit (1HDL) 19 of one horizontal scanning period (for example, digital image data of pixel # 12 in FIG. 3), [3] One horizontal scanning period before the current time, with respect to the digital image data output from the digital-analog converter 2, the delay time of one horizontal scanning period is delayed. By (1HDL) 19, 1 together with the time delay of the horizontal scanning period is given, # 1 of the latch circuit 21 by one sampling period by the digital image data in a state in which the time delay is given (for example in Figure 3
Digital image data of one pixel).

That is, in the image processing apparatus shown in FIG. 2, the analog-digital converter 2 and the interpolation calculation are performed without using a large number of memories required in the image processing apparatus shown in FIG. Output from the analog-digital converter 2 every sampling period by a circuit arrangement including a delay circuit (1HDL) 19 for one horizontal scanning period provided between the unit 22 and the two latch circuits 20 and 21. Sequential pixels (for example, sequential pixels # 11 → # 12 → # 13 → # 14 → ... arranged sequentially on the time axis shown in FIG. 3).
# 21 → # 22 → # 23 → # 24 → ... # 31 → # 32
→ # 33 → # 34 → ... set of four pixels each (for example, four pixels “# 11, # 12, # 2”)
1, # 22 ","# 12, # 13, # 22, # 23 ",
4 corresponding to "# 13, # 14, # 23, # 24", etc.)
One image data can be supplied to the interpolation calculation unit 22 at the same time for each subsequent sampling cycle.

Further, in the image processing apparatus shown in FIG. 2, as described above, the arithmetic processing on the four image data supplied to the interpolation arithmetic unit 22 simultaneously at each successive sampling period can be easily performed. It can be done. That is, regarding the data required for the calculation operation in the above-described interpolation calculation unit 22, for example, focusing on the above-mentioned formula (1) used for the calculation, L in the formula (1)
The values of θ and Vm are values that are set to predetermined values, and since the values are fixed values when set to a predetermined value,
It can be seen that the value of Yb to be obtained by the calculation by the equation (1) has no relation to hn and is a function of Vn only.

The above means that the image data on one horizontal scanning line is on one horizontal scanning line in the modified original image even in the modified original image obtained by the interpolation calculation. Then, the deformed original image which has been distorted into a trapezoid in advance (12 fm shown by the solid line in FIG. 6)
Is formed in the original image forming unit 12, and when the deformed original image is projected on the screen 17 by the projection lens 15 having a vertical tilt angle θ, there is no trapezoidal distortion. Regarding the horizontal dimension of the deformed original image in the case where a projected image having a certain horizontal width is projected on the screen 17 for any part in the vertical direction of the projected image, the horizontal dimension is The value Dx of the ratio of the size of the largest part to the size of the part having the smallest lateral size is L, θ, V set as described above.
It is determined by the value of m, and the pixel array of each one row existing between two portions of the deformed original image, which has the largest lateral dimension and the smallest lateral dimension, The length is obtained by performing a proportional calculation depending on the position in the interval between the above two parts.

Therefore, for example, the value of Dx for each horizontal scan is stored in the ROM 25 in FIG. 2 for each of a plurality of predetermined tilt angles θ (θ1, θ2, θ3 ...), and the tilt angle θ In accordance with the set value, the value of Dx for each horizontal scanning line at the set tilt angle θ is read from the ROM 25 and given to the δX calculation unit 26, and the δX calculation unit 26 sequentially sets the pixel array of one row ( The value of δX in the successive horizontal scanning lines) is calculated and supplied to the interpolation calculation unit 22. Further, δ required for the calculation operation in the above-described interpolation calculation unit 22.
The value of Y is determined as a specific value for each pixel array (sequential horizontal scanning line) of one row in the image in correspondence with the set value of the tilt angle θ, and thus a plurality of predetermined tilt angles θ
For each (θ1, θ2, θ3 ...), a specific δY calculated for each row of the pixel array forming each image is
The value of δY corresponding to the set value of the tilt angle θ is stored in the ROM 25 in FIG. 2, is read from the ROM 25, and is supplied to the interpolation calculation unit 22.

As already described with reference to FIG. 6, since the transformed original image is transformed so that the screen is reduced, the points calculated by the equations (1) and (2) are used. Position of P '
The total number of pixels corresponding to (address) is smaller than the total number of pixels of the original image. Then, as described above, among the four image data that are simultaneously supplied to the correction calculation unit 22 every sampling period, the pixels that are not used as the image data of the projected image and should be discarded are shown in FIG. As is clear from the modified original image shown in FIG. 1, since it is known from the beginning, the calculation operation in the interpolation calculation unit 22 is not required for the four image data corresponding to that part. Therefore, the above δ which should be prepared in correspondence with the address of the pixel which is known to require no arithmetic operation as described above.
Special values (called skip data) are used for X and δY.

The calculation is performed in the interpolation calculation unit 22 as described above, and the calculation result for the pixel array of one row in the two-dimensional pixel array of the image (for each one scanning line unit in sequence) is obtained. Is stored in the first-in first-out line memory 23. That is, in the line memory 23, as described above, δX,
Interpolation calculation unit 2 using skip data with a special value of δY
The pixel data relating to the pixel calculated in 2 is not stored, but only the pixel data effective for forming the modified original image is stored in the state of being sequentially arranged. Therefore, the pixel data corresponding to the pixel array of one row in sequence (for each one scanning line unit in sequence) stored in the line memory 23 as described above is shown in the external shape shown by the solid line in FIG. Figure 12f
As shown by the length of the horizontal width in m, the image is stored in the first-in first-out type line memory 23 when it is read out from the line memory 23 although it is in a state of being reduced in the horizontal direction. The data is read out in a time relationship such that the image data of the central portion of the image is projected in the pixels of the central portion in the horizontal direction in the projected image, and the data is stored in the first-in first-out image memory 24.

In the first-in first-out type image memory 24, from the already-described first-in first-out type line memory 23,
Since the pixel data corresponding to the pixel array of one row in a row (for each one scanning line unit in a row) is supplied and stored, the external shape of the storage pattern in the first-in first-out image memory 24 is as shown in FIG. Although it becomes something like the figure 12fm shown by the external shape shown in the solid line inside, the image data stored in the first-in first-out image memory 24 is skip data with special values of δX and δY as described above. Only the pixel data effective for forming the deformed original image is stored in the state in which the pixel data regarding the pixel calculated by the interpolation calculation unit 22 is not stored in the state in which the pixel data is stored. , The vertical position of the projected image is shifted upward.

Therefore, when reading the image data from the first-in first-out type image memory 24, the image data is read out from the first-in first-out type image memory 24 in a time relationship such that the lower end position of the projected image becomes a predetermined position. To be read. As a result, the image data read from the first-in first-out image memory 24 causes the original image to be formed on the surface of the original image forming section 12 in which pixels are arranged in a predetermined two-dimensional arrangement mode. Then, a deformed original image in a predetermined deformed state is formed in advance, and the deformed original image is projected on the screen 17 by the projection lens 15 having a vertical tilt angle. In this case, a projected image similar to the original image will be displayed in the image frame having the same shape as the original image frame.

In the image processing apparatus shown in FIG. 2 described above, the image data output from the interpolation calculation section 22 is displayed using the first-in first-out line memory 23 and the first-in first-out image memory 24. Since the aspect ratio of the projected image was set to be proper, the projected image on the screen 17 is correctly projected as a circle if the original image is a circle, but the image frame has a trapezoidal distortion. Although not generated, a simple image processing apparatus may be desired in terms of price, in which an image in which a circle should be originally projected may be displayed as a vertically long circle. The image processing apparatus which meets the above-mentioned desire is a first-in first-out line memory 23 in the image processing apparatus shown in FIG.
Output from the original original image on the surface of the original image forming portion 12 in which pixels are arranged in a predetermined two-dimensional arrangement manner And the modified original image is projected on the screen 17 by the projection lens 15 having a vertical tilt angle. In that case, on the screen 17, an image frame is formed. Does not cause trapezoidal distortion, but a projected image is displayed in which an image in which a circle is originally projected is displayed as a vertically long circle.

[0060]

As is apparent from the above detailed description, the image processing apparatus of the present invention uses an analog-digital converter in a predetermined sampling period to generate an image signal capable of forming an image of an image frame having a predetermined shape. Is converted into a digital signal to generate digital image data corresponding to the two-dimensional pixel array of the original image and stored in the image memory, and the pixels are arrayed in a predetermined two-dimensional array mode. The optical image of the original image formed on the surface of the image forming portion is provided in such a state that the optical axis located in the plane perpendicular to the screen in the longitudinal direction of the screen makes an acute angle with respect to the normal line of the screen. Of the original image in which the pixels are arranged in a predetermined two-dimensional arrangement manner in parallel with the main plane of the projection lens by the projection lens which has a vertical tilt angle. Part of When the optical image of the original image formed on the screen is projected on the screen, the first projected image displayed on the screen when projected on the screen and the pixels in a predetermined two-dimensional array mode are arranged. The optical image of the original image formed on the surface of the arranged original image forming section is screened by the projection lens provided with the optical axis of the projection lens aligned with the normal line of the screen. In both the projected image and the second projected image displayed on the screen when projected onto the screen, the same portion of the same original image described above corresponds to the first image displayed on the screen.
A calculation for obtaining the modified coordinate position of the projected image on the screen by the modified original image is performed by using the relational expression that defines the relative positional relationship of how the coordinate positions are different on the second both projected images. , If the transformed coordinate position obtained as the calculation result for obtaining the transformed coordinate position is a coordinate position outside the image frame in the screen image of the transformed original image, the image data of the transformed coordinate position is changed to black data. If the deformed coordinate position set as a result of the calculation for obtaining the deformed coordinate position is a coordinate position within the image frame of the screen image of the deformed original image, the original image having an image frame of a predetermined shape The two-dimensional pixel array of is stored in the image memory by a reading operation performed in such a manner that 2 × 2 pixels are sequentially taken out by scanning in the normal scanning direction. The image data of the four pixels in the vicinity of the modified coordinate position that is present is read from the image memory, and weighting according to the positional difference between the modified coordinate position and the coordinate position of the individual pixel in the four adjacent pixels is weighted for each pixel. Image data at the above-mentioned modified coordinate position by an arithmetic operation for averaging the added values of the arithmetic results given to the image data of A converter converts the digital signal into digital signals at a predetermined sampling cycle to generate digital image data corresponding to the two-dimensional pixel array of the original image, and uses the delay means to convert the time-series digital image data. For a two-dimensional pixel array of an original image having an image frame of a predetermined shape, four images are simultaneously displayed in a manner similar to the case of sequentially cutting out 2 × 2 pixels by scanning in the normal scanning direction. Image data of the above is sequentially taken out as data to be subjected to signal processing, and the above-described first angle is set for each of a plurality of angles that are predetermined with respect to the angle formed by the optical axis of the projection lens and the normal line of the screen. Data on the ratio of the horizontal lengths at the corresponding horizontal scanning line positions in the projected image and the second projected image corresponding to each other is stored, and the first projected image described above is stored. In both projected images with the second projected image, how the same portion of the same original image described above is projected on both the first and second projected images displayed on the screen. Data of the ordinate value at the deformed coordinate position obtained by calculating the deformed coordinate position of the projected image on the screen by the deformed original image using the relational expression that defines the relative positional relationship of whether the coordinate position is different. And stored in memory Of the two types of data read from the memory, the data of the value of the ordinate at the modified coordinate position is used as it is for the arithmetic processing of the data to be signal-processed, and the sequential horizontal The horizontal length ratio data at the scanning line position is used to calculate the abscissa value data at the modified coordinate position, and the arithmetic processing is performed on the signal processing target data. Then, only the effective image data in the calculation result for each scanning line unit is stored in the first-in first-out memory, and the image data stored in the first-in first-out memory is the central portion of the image data. Image data is read from the first-in first-out type memory in a time relationship such that the pixel at the central portion in the horizontal direction in the projected image is displayed, stored in the first-in first-out type image memory, and is read from the image memory. The image data is read from the first-in first-out image memory in such a time relationship that the lower end position of the output image becomes a predetermined position, and the predetermined image data is read out from the first-in first-out image memory. On the surface of the original image forming part in which the pixels are arranged in a two-dimensional arrangement, the original original image is deformed in advance in a predetermined state. When an image is formed and the deformed original image is projected on the screen by the projection lens, a projected image similar to the original original image is displayed on the screen in the same frame shape as the original image frame. Or, without using the first-in first-out type image memory described above, the image data stored in the first-in first-out type memory, the image data of the central portion of the image data of the central portion in the horizontal direction in the projected image. Based on the image data read out from the first-in first-out memory in such a time relationship that the pixels are projected, the original image is formed on the surface of the original image forming part in which the pixels are arranged in a predetermined two-dimensional arrangement mode. On the other hand, when a deformed original image is formed in advance with a predetermined deformation and the deformed original image is projected on the screen by the projection lens, it is not a trapezoid on the screen. According to the present invention, the image data of the pixels of the projected image enlarged from the deformed original image in the reduced state is used for the neighborhood 4 because the projected image having a rectangular image frame can be projected. The weighting according to the positional difference between each pixel and the coordinate position of the individual pixel is given to the image data of each pixel by an operation of averaging the added value of the operation results to obtain a high quality image. The output image can be easily obtained, and the optimum state can be obtained depending on the angle formed by the optical axis of the projection lens with respect to the normal line of the screen, so it can be mounted on the floor or suspended from the ceiling. It is easy to do.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a different embodiment of an image processing apparatus of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of another embodiment of the image processing apparatus of the present invention.

FIG. 3 is an explanatory diagram of a method of determining image data at a modified coordinate position.

FIG. 4 is an explanatory diagram of a shape of a projected image on a screen in a state where a normal line of the screen is aligned with an optical axis of the projection lens and a state where the normal line of the screen is not aligned.

FIG. 5 shows an original image formed on a surface of an original image forming part in which pixels are arranged in a predetermined two-dimensional arrangement parallel to a main plane of a projection lens and a tilt angle in a vertical direction is given. It is explanatory drawing with the projected image displayed on a screen, when the said original image is projected on a screen by the said projection lens currently provided.

FIG. 6 shows a deformed original image formed on a surface of an original image forming section in which pixels are arranged in a predetermined two-dimensional arrangement parallel to the main plane of a projection lens and a vertical tilt angle. It is explanatory drawing with the projection image displayed on a screen, when the said deformation | transformation original image is projected on a screen by the given said projection lens.

FIG. 7 is a side view showing a schematic configuration of a projector.

[Explanation of symbols]

1 ... Input terminal, 2 ... AD converter, 3, 4 ... Selector, 5
... control unit, 6 to 9 ... memory, 10 ... signal processing operation unit, 1
1 DA converter, 12 ... Forming part of original image to be projected on screen (for example, liquid crystal light valve), 13 ... Projector, 14 ... Light source, 15 ... Projection lens, 16, 17 ... Screen, 18 ... Optical axis of projection lens 15 , 19 ... 1H delay circuit, 20, 21 ... Latch circuit, 22 ... Interpolation calculation unit, 2
3 ... Line memory, 24 ... Image memory, 2

Claims (3)

[Claims] 1. A projection in which an optical image of an original image formed on a surface of an original image forming portion in which pixels are arranged in a predetermined two-dimensional arrangement is provided with a tilt angle in a vertical direction. The first projected image displayed on the screen when projected onto the screen by the lens is an original image formed on the surface of the original image forming section in which pixels are arranged in a predetermined two-dimensional arrangement mode. The second projected image displayed on the screen when the optical image of the image is projected on the screen by the projection lens provided with the optical axis of the projection lens aligned with the normal line of the screen. To be a similar image, which should be used as an original image when projected on the screen by the projection lens provided with the above-mentioned vertical tilt angle, to the original original image,
An image processing device for generating a deformed original image in a state of being subjected to a predetermined deformation, wherein an image signal capable of forming an image of an image frame of a predetermined shape is converted into a digital signal at a predetermined sampling period to obtain an original image. Means for obtaining digital image data corresponding to a two-dimensional pixel array of an image, means for sequentially storing the digital image data in an image memory, the first projected image, and the second projected image. In both projected images with the image,
A relationship that defines the relative positional relationship of how the same portion of the same original image is at different coordinate positions on the first and second projected images displayed on the screen. The means for calculating the transformation coordinate position of the projected image on the screen by the transformation original image using the formula, and the transformation coordinate position obtained as the calculation result for obtaining the transformation coordinate position are based on the transformation original image. In the case of the coordinate position outside the image frame in the screen image, means for setting the image data of the modified coordinate position to black data, and the modified coordinate position obtained as the calculation result for obtaining the modified coordinate position are In the case of the coordinate position in the image frame of the screen image by the modified original image, the 2D pixel array of the original image having the image frame of the predetermined shape is sequentially scanned by 2 × 2 pixels in the normal scanning direction. Means for reading out image data of 4 pixels in the vicinity of the modified coordinate position stored in the image memory from the image memory by a read operation performed in such a manner as described above; Image data at the above-mentioned modified coordinate position is calculated by applying weighting according to the positional difference between the coordinate position of each individual pixel in the four neighboring pixels to the image data of each pixel and averaging the added value of the calculation results. An image processing apparatus comprising: 2. A projection in which an optical image of an original image formed on a surface of an original image forming portion in which pixels are arranged in a predetermined two-dimensional arrangement is provided with a tilt angle in a vertical direction. The first projected image displayed on the screen when projected onto the screen by the lens is an original image formed on the surface of the original image forming section in which pixels are arranged in a predetermined two-dimensional arrangement mode. The second projected image displayed on the screen when the optical image of the image is projected on the screen by the projection lens provided with the optical axis of the projection lens aligned with the normal line of the screen. To be a similar image, which should be used as an original image when projected on the screen by the projection lens provided with the above-mentioned vertical tilt angle, to the original original image,
An image processing device for generating a deformed original image in a state of being subjected to a predetermined deformation, wherein an image signal capable of forming an image of an image frame of a predetermined shape is converted into a digital signal at a predetermined sampling period to obtain an original image. A means for obtaining digital image data corresponding to the two-dimensional pixel array of the image and a delay means from the time-series digital image data corresponding to the two-dimensional pixel array of the original image are used to obtain a predetermined shape. 2 of the original image with a frame
With respect to a two-dimensional pixel array, a means for extracting image data of 4 pixels simultaneously as data to be signal-processed one after another in a manner similar to the case where 2 × 2 pixels are sequentially cut out by scanning in a normal scanning direction, and a projection lens The first projected image described above for each of a plurality of predetermined angles about the angle formed by the optical axis of and the normal line of the screen,
Both of the first projection image and the second projection image, which are data of the ratio of the horizontal lengths in the corresponding horizontal scanning line positions corresponding to each other in the second projection image, In the projected image, a relative positional relationship of how the same portion of the same original image is located at different coordinate positions on the first and second projected images displayed on the screen. Using a relational expression that prescribes, means for preparing in advance the data of the value of the ordinate at the modified coordinate position obtained by calculating the modified coordinate position of the projected image on the screen by the modified original image, The data of the ordinate value at the previously prepared modified coordinate position, the previously prepared first projected image, and the second projected image that correspond to each other Based on horizontal length ratio data at horizontal scan line position It is effective in the means for calculating the data for the signal processing using the data of the value of the abscissa at the deformed coordinate position calculated as above and the calculation result for each scanning line unit. Means for storing only the image data in the first-in first-out memory, and the image data in the central portion of the image data stored in the first-in first-out memory causes the pixel at the central portion in the horizontal direction in the projected image to be projected. The first-in first-out type image memory is read in such a time relationship that the first-in first-out type memory is read and stored in the first-in first-out image memory, and the first-in first-out image memory is arranged in such a time relationship that the lower end position of the projected image becomes a predetermined position. An image processing apparatus comprising means for reading image data from the image processing apparatus. 3. A projection in which an optical image of an original image formed on a surface of an original image forming portion in which pixels are arranged in a predetermined two-dimensional arrangement is provided with a vertical tilt angle. The image frame shape of the first projected image displayed on the screen when projected onto the screen by the lens has a predetermined 2
An optical image of the original image formed on the surface of the original image forming portion in which pixels are arranged in a dimensional arrangement is provided in a state where the optical axis of the projection lens is aligned with the normal line of the screen. The vertical tilt so as to form a rectangular image without trapezoidal distortion similar to the image frame shape of the second projected image projected on the screen when projected onto the screen by a certain projection lens. An image processing apparatus for generating a deformed original image, which is to be used as an original image when projected on a screen by a projection lens having an angle, and which is a modified original image in which a predetermined deformation is applied to the original original image in advance. A means for converting an image signal capable of forming an image of an image frame of a predetermined shape into a digital signal at a predetermined sampling period to obtain digital image data corresponding to the two-dimensional pixel array of the original image, The time-series digital image data corresponding to the two-dimensional pixel array of the original image is used in the normal scanning direction for the two-dimensional pixel array of the original image having the image frame of the predetermined shape by using the delay unit. And the angle formed by the optical axis of the projection lens and the normal line of the screen in the same manner as in the case of sequentially cutting out 2 × 2 pixels each by scanning For each of a plurality of angles predetermined with respect to the above-mentioned first projected image and the second projected image of the horizontal length at the horizontal scanning line position corresponding to each other. In both the ratio data, the first projected image, and the second projected image, the same portion of the same original image is projected on the screen. On the first and second projected images The ordinate at the deformed coordinate position obtained by calculating the deformed coordinate position of the projected image on the screen by the deformed original image by using the relational expression that defines the relative positional relationship of the different coordinate positions. Means for preparing in advance the data of the value of, the data of the value of the ordinate at the modified coordinate position prepared in advance, the first projected image prepared in advance, Using the data of the abscissa value at the deformed coordinate position calculated based on the data of the ratio of the horizontal lengths at the successive horizontal scanning line positions corresponding to each other in the second projected image, Means for performing an arithmetic operation on the data to be signal-processed, a means for storing only effective image data in the first-in first-out type memory among the arithmetic results for each scanning line unit, and the first-in first-out type memory. An image processing apparatus comprising means for reading from a first-in first-out type memory in a time relationship such that the image data of the central portion of the image data stored in the memory causes the pixels of the central portion in the horizontal direction in the projected image to be projected. .