JPH07131742A - Image correction device for projection display - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an image correction device for a projection display capable of significantly shortening the adjustment time by automatically performing various corrections such as convergence, geometric distortion, brightness and focus. . [Structure] A test signal generating circuit 3 for generating a mountain-shaped test signal at a predetermined position of a light source of a display device, and the test signal is supplied to a projection magnifying display device 1 to pick up an image projected on the light source. Image pickup element 4, a calculation circuit 5 for calculating a display position / tilt error for each color from the head value and the inclination from the image pickup signal whose inclination from the image pickup element 4 is a straight line, and a calculation circuit 5
And a correction waveform creating circuit 6 for creating the convergence, geometric distortion, and gamma correction waveform of the correction area corresponding to the display area of the test signal from the output of 1., and the projection enlargement display device 1 is automatically driven by this correction waveform. It is a configuration to correct to.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for performing various corrections on a projection display, and more particularly to an image correction apparatus for a projection display that automatically performs various corrections such as convergence, geometric distortion, brightness and focus. Is.

[0002]

2. Description of the Related Art Generally, in a projection type display (video projector) for enlarging and projecting in a screen by using three projection tubes that emit three primary colors, an incident angle (hereinafter referred to as a concentration angle) with respect to a screen of the projection tube is Calling is different for each projection tube, so color shift, focus shift on the screen,
Deflection distortion and luminance change occur. These various corrections adopt a method in which an analog correction waveform is created in synchronism with the horizontal and vertical scanning periods, and the size and shape of this waveform are changed for adjustment, but there is a problem in terms of correction accuracy. is there. Further, since various corrections are manually observed by visually observing deviations on the screen, there is a problem that adjustment time is required.

Therefore, as a method with high convergence accuracy, a digital convergence device described in Japanese Patent Publication No. 59-8114 and a method for automatically correcting deflection distortion are disclosed in Japanese Patent Publication No. 3-38797. Tokkyo 1-4
The automatic convergence correction device disclosed in Japanese Patent No. 8553 discloses a method for detecting a convergence error and a correction method therefor.
Japanese Patent Laid-Open No. 63-48987 discloses a convergence error correction method disclosed in Japanese Patent No. 549993 and a method for automatically detecting and correcting a convergence error of a projection display.
The method disclosed in the convergence error correction apparatus for a projection display of Japanese Patent Publication is disclosed.

FIG. 36 shows a block diagram of a conventional automatic convergence correction device capable of automatic correction. As shown in FIG. 36, in order to adjust the convergence of the color image display device, a region obtained by dividing the entire display screen of the image display device 101 into positive integers N and M in the horizontal and vertical directions is formed, and each region is formed in a matrix. A low-frequency signal in which the display signal waveform of each color in the area is line-symmetrical in the horizontal and vertical directions is supplied from the signal generator 102 to the image display device 101 through the signal switch 103.

Further, a signal from the image pickup device 104 for picking up the display screen of the image display device 101 is sent to the image processing device 10.
In order to calculate the horizontal and vertical barycentric position of the signal for each region, the signal converted into the digital signal introduced into the image processing apparatus 105 is subjected to interpolation processing to obtain the threshold value. And the low-frequency signal waveform is approximated by a quadratic equation to obtain the barycentric position for each region. Next, calculate the centroid error value between each color,
The convergence of the image display device 101 is automatically adjusted based on this center-of-gravity error value.

FIG. 37 shows a block diagram of a conventional image correction apparatus capable of various automatic adjustments. The projection device 111 is a projector for each color, that is, an R projector 112, a G projector 113, and a B projector.
The projection K device 114 is included, the light of each color is projected on the projection screen 115, and the images of the projectors 112 to 114 are formed on the projection screen 115. At this time, the auxiliary screen 116 is installed on the non-imaging surface, the non-imaging image on the auxiliary screen 116 is detected by the photosensor 114, and the convergence error information existing in this image is detected as described in FIG. Is calculated by calculating the matrix center-of-gravity error value, and the convergence error on the projection screen 115 is calculated from the convergence error information existing in this non-imaged image, whereby the convergence of the projection display is automatically adjusted.

[0007]

However, in the correction device having the conventional structure as described above, the image pickup means for detection can be incorporated in the display device to perform an integrated automatic correction. Since only the static convergence correction can be adjusted, there is a problem that complicated adjustment and time are required to adjust the entire screen.

Further, since the barycentric position of the low-frequency signal waveform in the area obtained by dividing the entire display screen in the horizontal direction N and the vertical direction M is calculated by the quadratic approximation, complicated processing is required in the image processing section. Therefore, there is a problem that the circuit scale becomes very large and the adjustment time becomes very long.

Further, since the image processing is performed by the low frequency signal which is line-symmetrical to the angled waveform, there is a problem that the position detection sensitivity and the accuracy of each level change due to the image receiving gamma characteristic of the image display apparatus and the correction accuracy is lowered. Had.

In view of the above points, the present invention directly captures an optical image of a projection optical system to calculate an error value for each color, and corrects the convergence, geometric distortion, brightness, and focus of the entire screen by this calculation signal. It is an object of the present invention to provide an image correction apparatus for a projection display that can significantly reduce the adjustment time by creating a correction waveform for the above and automatically correcting it.

[0011]

According to a first aspect of the invention, generating means for generating a mountain-shaped test signal at a predetermined position of a light source of a display device, and supplying the test signal from the generating means to the display device, An image pickup means for picking up an image projected on the light source, a detection means for detecting a leading value and a tilt from an image pickup signal from the image pickup means whose inclination is a straight line, and an output for each color for each color. Configuration comprising calculation means for calculating display position / tilt error, and creation means for creating convergence, geometric distortion, gamma correction waveform of a correction area corresponding to the display area of the test signal from the output signal of the calculation means Is.

According to a second aspect of the present invention, image pickup means for picking up the light source image of the display device, calculating means for calculating an error value for each color from the output signal of the image pickup means, and convergence by the output signal of the calculating means. This is a configuration including a creation unit that creates a correction waveform for correction.

According to a third aspect of the invention, a display means for projecting and enlarging and displaying the light source image on a screen by using a light source and a projection optical system in which peripheral regions having different light emission characteristics are provided, and the light source image. Image pickup means for picking up an image, and calculation means for calculating an error value for each color from an output signal of the image pickup means,
And a creating means for creating a correction waveform for correcting the convergence based on the output signal of the calculating means.

[0014]

According to the first invention, the mountain shape test signal of the light source image of the projection optical system is directly picked up to calculate the error value for each color, and the convergence signal, the geometric distortion and the brightness of the entire screen are calculated by the calculated signal. Since the correction waveform for correcting the error is automatically created and corrected, various complicated adjustments are unnecessary and the adjustment time can be significantly shortened.

According to the second aspect of the invention, the light source image of the projection optical system is directly picked up to calculate the error value for each color, and a correction waveform for correcting the convergence is automatically created by this calculation signal. Since it is corrected in this manner, a test signal for detection is unnecessary and real-time automatic adjustment can be realized.

According to the third aspect of the invention, the light source image displayed on the light source in which the regions having different emission characteristics are provided at the predetermined peripheral positions is directly imaged to calculate the error value for each color, and the convergence signal is used to calculate the convergence. Since a correction waveform for correcting the error is automatically created and corrected, a test signal for detection, an image outer frame signal, and the like are unnecessary, and thus real-time automatic adjustment can be realized with a simple configuration.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram of an image display device of a projection type display according to the first embodiment of the present invention, FIG.
Shows the configuration in the first embodiment of the present invention.

In FIG. 1, 1 is a projection magnifying display device for magnifying and projecting light source light from a CRT of three primary colors of light with a lens, 3 is a test signal generation circuit for generating a test signal for detection, and 2 Is a screen for displaying image light, 4 is an image pickup element for picking up image light directly from a light source, and 5 is a calculation circuit for calculating an error value for each color based on an output signal from the image pickup element 4. Reference numerals 6 and 6 denote correction waveform generation circuits for generating correction waveforms for convergence, geometric distortion, luminance, and focus from the output signal from the calculation circuit 5, and the correction waveforms from the correction waveform generation circuit 6 are used for the projection enlargement display device 1 Is driven to make various corrections.

The configuration of the image correcting apparatus for the projection type display of the present embodiment having the above-described configuration will be described below with reference to FIG. FIG. 2 shows a transmissive screen 11
2A and 2B are configuration diagrams in the case of a rear projection type video projector using the above, FIG. 2A shows a set configuration, and FIG. 2B shows an optical configuration.

In FIG. 2, the image light which is the light source from the CRT 8 is enlarged and projected by the lens 9 and is transmitted through the screen 1.
1 is enlarged and projected. The mirror 7 provided between the screen 11 and the lens 9 is an optical reflection means for shortening the depth of the set having an integral structure. Since the image light on the CRT surface is directly detected, the image light is picked up by the image pickup device 4 installed on the image forming surface above the screen 11.

As shown in FIG. 2 (b), the image light from the CRT 8 and the lens 9 is projected at a right angle to the display surface of the screen 11, but the image sensor 4 installed on the left side of the screen 11 causes the CRT surface to move. The image light is directly captured and the image light is detected. The image pickup device 4 is installed so as to be inclined with respect to the screen surface 11, and an image of the CRT tube surface is picked up.

Next, in order to explain in detail the method of detecting the image light on the CRT screen and creating various correction waveforms,
The block diagram of FIG. 3, the display screen diagram of FIG. 4, and the operation waveform diagram of FIG. 5 are used. First, in FIG. 3, a synchronization signal is input to the input terminal 15, a deflection circuit 18 creates a correction current for raster scanning the screen, and this correction current is supplied to the deflection yoke 26 to control scanning. There is. The video signal from the input terminal 14 is input to the video circuit 17, and various kinds of signal processing and amplification for driving the cathode electrode of the CRT 8 are performed. The synchronizing signal from the input terminal 15 is supplied to the test signal generating circuit 25, and the nine square test signals shown in FIG. 4 are projected on the CRT8 screen.

Generally, the relationship between the input signal voltage (E) and the light emission output (L) of a CRT such as a projection tube can be approximated by the equation L = kEr, and the input signal voltage (E) and the light emission output (L) are both logarithmic. In terms of scale, gamma (γ) has its inclination, which is the gamma (γ) characteristic of the CRT.
Generally, the gamma characteristic of a CRT is γ = 2.2. From the above, the gamma characteristic 2.
The converted data of No. 2 is written, and the quadrangular pyramid test signal shown in FIG. 5 is generated. The test signal is supplied to the switching circuit 16 in the display device, switched to the video signal from the input terminal 14, and supplied to the video circuit 17 so that the test signal is displayed on the screen 11.

First, the case of adjusting the convergence and the geometric distortion of the first adjustment item will be described. CRT8
Image light in the shape of a quadrangular pyramid as shown in FIG. 5 is obtained on the tube surface.

The frequency band of the quadrangular pyramid-shaped test signal shown in FIG. 5 is a low-frequency signal component of 1 MHz or less, so that there is a correlation as shown in FIG. 5 regardless of whether the image is formed or not. A photoelectric conversion signal whose slope changes almost linearly is obtained.

In the present embodiment, for the sake of easy understanding,
The case where the photodiode 13 which is low in price and slow in response speed is used as the image pickup element will be described. However, even in an image pickup device such as an expensive CCD camera, since it is a test signal of a low frequency component as described above, high precision detection and correction are required. It goes without saying that it can be realized.

Image light from the surface of the CRT 8 is picked up by the photodiode 13. The photoelectric conversion signal from the photo diode 13 is supplied to an analog / digital converter (hereinafter referred to as A / D) 21 for image processing, and the information on the test signal display screen shown in FIG. 5 is converted into a digital signal. It The digital signal from the A / D 21 is the frame memory 2
2 and the display information is stored. Data corresponding to each adjustment area is extracted and read out from the frame memory 22, and is supplied to the CPU 23 to detect the position of the center of gravity and calculate an error value.

In the CPU 23, the photodiode 13 having a slow response speed and the sampling frequency of the A / D 21 are 14.
High-precision position detection is required even in a system with low detection accuracy processed at about 32 MHz.
In FIG. 6A, the sampling frequency fsap = 14.3 in A / D21.
The photoelectric conversion signal converted at 2 MHz (sampling period 70 ns) is shown. The center of gravity position, which is the apex of the photoelectric conversion signal at this time, exists at the sample point S7.

FIG. 6B shows the case where the position of the center of gravity, which is the apex of the photoelectric conversion signal, exists between the sample points S6 to S7. In this case, since the sample points are coarse, highly accurate position detection cannot be performed. Therefore, highly accurate position detection is performed by calculating the barycentric position by linear approximation from the voltage of the sample point near the barycentric position.

As shown in FIG. 6C, the linear approximation data of the data D4 to D6 of the rising sampling points S4 to S6 of the photoelectric conversion signal and the falling sampling points S9 to S6 of the photoelectric conversion signal.
By calculating the intersection of the straight line approximation data of the data D9 to D7 of S7, it is possible to calculate the center of gravity position with high accuracy even in a system with coarse detection accuracy.

Next, the block diagram of FIG. 7 and the operation waveform diagram of FIG. 8 will be used to describe the operation of detecting the position of the center of gravity in detail. The CPU 23 includes a center-of-gravity position detector 72, an error value calculator 73, a difference filter 70, and a linear region detector 71, and detects the center-of-gravity position and calculates the error value. Figure 8
The solid line in (a) shows the actual test signal, and the broken line shows the sampling signal by A / D.

As can be seen from FIG. 8A, the rounding of the apex portion of the test signal occurs due to the low sampling frequency, and when the barycentric position is obtained from the output signal of the A / D 21 as described above, the actual barycentric position is obtained. Although the position is the point A, the point A ′ is mistakenly determined to be the center of gravity of the test signal. In order to eliminate such a detection error, the position of the center of gravity is calculated. The calculation of the position of the center of gravity is performed by extending the linear portion excluding the rounded portion and setting the intersection of the extended portions as the position of the center of gravity. That is, on the data, the test signal data as shown by the solid line in FIG.

To detect the position of the center of gravity, the data is divided into areas corresponding to each of the test signals shown in FIG. 4, and the arithmetic processing for detecting the position of the center of gravity is performed on each area. By performing the arithmetic processing by dividing into such regions, parallel arithmetic processing such as pipeline processing can be performed.
Although the following description of the arithmetic processing is performed only for one area, the same arithmetic processing is performed for other areas.

As the first step of the arithmetic processing, the operation of detecting only the linear portion of the test signal data is performed excluding the rounding area by sampling. This converts the image data of the test signal into digital data by A / D21,
This data is passed through the difference filter 70 to detect the difference signal. When the image data of the test signal shown in FIG. 8A is input to the differential filter 70, the output data is as shown in FIG. 8B. Further, from the output data, the linear area detection unit 71 detects the data difference signal, that is, the periods A and B in which the slope of the test signal is constant. Here, the period when the slope is 0 is ignored. Hereinafter, only the image data within the periods A and B are valid and the position of the center of gravity is calculated.

The position of the center of gravity is calculated by extending the linear periods A and B on the data and using the test signal at this intersection as the center of gravity. In calculating the position of the center of gravity as shown in FIG. 8B, the data DA (corresponding address nA) from the highest vertex of the linear part A, the inclination of the linear part A is α, and the highest vertex of the linear part B is If the data DB (corresponding address nB) and the gradient of the linear portion A are β, the center of gravity position x can be determined by the following equation. x = nA + (DB−DA−β · (nB−nA)) / (α−
β) Thus, by determining the position of the center of gravity by linear extrapolation,
For example, even if A / D sampling is rough, the position of the center of gravity can be detected with high accuracy.

FIG. 9A shows an address map of the position of the center of gravity when image processing of 380,000 pixels is performed. In this way, 768 points in the horizontal direction (x1 to x768) and 493 points in the vertical direction (y
1 to y493). FIG. 9B shows a partially enlarged view of the address map when the barycentric position (black circle ●) of the test signal is calculated. As shown in FIG. 9B, the barycentric position is (x = 12.7, y = 11.1.
It is represented by 3). The coordinate data corresponding to the addresses of x and y becomes the data of the position of the center of gravity.

Next, a method of calculating the error value will be described. When calculating the convergence error, the G signal is treated as a reference signal as shown in the waveform diagram of FIG.
The error value of the signal is t1 in the left direction and the error value of t2 is in the right direction for the B signal.

Further, when the geometric distortion error is calculated, as shown in the waveform diagram of FIG.
Is treated as a reference signal, and an error value of t3 for the R signal, t4 for the G signal to the left, and t5 for the B signal to the left is calculated. The calculation of the barycentric position and the error value is managed by the information corresponding to the address of the sample point.

As described above, the data in which the position of the center of gravity and the error value are calculated by the CPU 23 are supplied to the correction signal generating circuit 24, and the correction signal for correcting the convergence and the geometric distortion is generated, and the data is displayed in the display device. It is supplied to the convergence correction circuit 19, the deflection circuit 18, the video circuit 17, and the focus circuit 20.

Next, in order to explain in detail the operation of the method of creating the convergence correction waveform in the correction signal creating circuit 24 shown in FIG. 3, the block diagram of FIG. 11 and FIGS.
The corrected waveform diagram of FIG. 14 and the operation waveform diagram of FIG. The correction signal generating circuit 24 shown in FIG. 3 includes a correction waveform generating circuit 28 for generating a basic correction waveform, a correction control circuit 29 for controlling the correction waveform, and various correction waveforms from the correction control circuit 29. It is composed of a correction signal generation circuit 30 for generating the correction signal of.

The horizontal synchronizing signal and the vertical synchronizing signal from the input terminals 33 and 34 are supplied to the correction waveform generating circuit 28. The correction waveform generating circuit 28 has at least 12 types of basics necessary for the convergence correction shown in FIGS. Correction waveform (WF1 ~
WF12) is generated. The correction waveform generation circuit 28 is
For example, a correction waveform composed of a plurality of Miller integrating circuits and synchronized with the input synchronizing signal is created. The correction waveform from the correction waveform generating circuit 28 shown in FIGS. 12 and 13 is a multiplication type D /
It is supplied to the reference potential terminals of the A converters 35 to 46. The correction data is stored in the memory 31 and is supplied to the serial data creation circuit 32 through the CPU 23.

In the serial data creating circuit 32, the CPU 2
A serial signal as shown in FIG. 14 is created on the basis of the control signal from 3. The serial signals shown in FIG. 14A are address signals (A3 to A0) and data signals (D7 to D).
0) is multiplexed, and the multiplication type D /
The A converters 35 to 46 are selected, and then the amplitude control is performed by the data signal. Further, clock signals and load signals for reading in synchronization with the serial data of FIG. 14A are shown in FIGS. 14B and 14C. Multiplier type D / A converter 35-
46, the load signal of FIG. 14 (c) is LOW, and
The clock signal 4 (b) is set to input data at the positive edge.

The three serial signals shown in FIG. 14 are supplied to the input terminals of the multiplying D / A converters 35 to 46, and the twelve basic correction waveforms (WF) from the correction waveform generating circuit 28 are supplied.
The polarities and amplitudes of 1 to WF12) are controlled. Multiplying type D /
Amplitude-controlled signals from the A converters 35 to 46 are supplied through resistors to an inverting amplifier circuit 47 composed of operational amplifiers, which adds and amplifies twelve kinds of correction waveforms and outputs to the output terminal 48, for example, red ( An R) horizontal direction (H) convergence correction signal can be created and supplied to the convergence correction circuit 19 shown in FIG. 3 for correction.

FIG. 15 shows a relational diagram of the movement on the screen of the correction change by the correction waveform of the analog system. As shown in FIG. 15, convergence correction can be automatically performed by calculating the barycentric positions of the screen center and the peripheral portion.

Generally, in the convergence correction of a video projector using three projection tubes that emit three primary colors,
Since it is necessary to correct the RGB of the three primary colors and the horizontal and vertical directions, it is necessary to control at least 12 × 6 = 72 systems.
A total of 100 lines of control are required for geometric distortion and other corrections.

Further, regarding the geometrical distortion correction of the screen amplitude and the deflection distortion in the deflection circuit 18 and the brightness correction in the video circuit 17 and the focus correction of the focus circuit 20, the same correction waveforms are created, and the description thereof will be omitted.

The photodiode 13 and A / D shown in FIG.
No. 21 has a limited operation dynamic range, so that FIG.
As shown in (a), correction is performed so that the relationship between drive voltage and screen brightness changes in proportion, and the detection sensitivity and accuracy at all gradations are made constant to perform highly accurate position detection and level detection. Is. In this way, by creating a test signal corresponding to the image receiving gamma of the image display device, the detection sensitivity and accuracy in all gradations are made constant, and highly accurate position detection and level detection are realized, and the barycentric position is calculated. It is possible to simplify the approximate calculation processing for. Although the image receiving gamma of the image display device has been corrected on the test signal generation side, it is sufficient that the gamma correction exists in the loop of test signal generation-image display-imaging-centroid position detection.

Next, in order to explain the case of adjusting the brightness of the second adjustment item (white balance adjustment),
16 and 17 are used. Similarly to the above-mentioned convergence and geometric distortion adjustment, when performing the brightness adjustment, the test signal generation circuit 25 supplies the brightness adjustment test signal to the switching circuit 16 during the automatic adjustment, and the display screen shown in FIG. Is projected. The window signal shown in FIG. 17 (a) is a test signal for highlight / low light and uniformity adjustment, and the square pyramidal signal shown in FIG. 17 (b) is a test signal for gamma adjustment.
Image light of each test signal is obtained on the RT tube surface.

The image light on the CRT tube surface is picked up by the photodiode 13. The photoelectric conversion signal from the photodiode 13 is supplied to the A / D 21 for image processing, and the information on the test signal display screen shown in FIG. 17 is converted into a digital signal. The digital signal from the A / D 21 is supplied to the frame memory 22 to store display information.
The data from the frame memory 22 is extracted and read out from the data corresponding to each adjustment area, and is supplied to the CPU 23 to calculate the level and inclination of each area and the error value of each color. The calculation signal from the CPU 23 is supplied to the correction signal creating circuit 24 to create various kinds of correction signals, and is supplied to the video circuit 17 of the display device for automatic white balance (highlight / gamma / lowlight) and uniformity. The brightness correction is performed.

With respect to the automatic brightness correction, the block diagram of FIG. 18 will be used to explain the operation thereof in detail below. Figure 1
8 shows a detailed block diagram of the video circuit 17 shown in FIG. Video signal from input terminal and test signal generation circuit 25
The test signal from is supplied to the switching circuit 55 for signal switching. The signal from the switching circuit 55 is a gain control circuit 56.
Is supplied to the clamp circuit 57 for gain control for contrast and highlight drive adjustment.

In the clamp circuit 57, the direct current is reproduced and is supplied to the uniformity correction circuit 58. The uniformity correction circuit 58 performs uniformization correction on the brightness of the central portion and the peripheral portion of the screen, and supplies it to the gamma correction circuit 59. The gamma correction circuit 59 corrects the change in the RGB emission characteristics of the 7-inch projection tube shown in FIG. 21 and supplies the corrected output to the video output circuit 60. The video output circuit 60 amplifies the CRT to a state where it can be driven and applies it to the CRT afterward.

Before the description of this embodiment, gamma correction in the case where saturation of the phosphor occurs will be described with reference to the emission characteristic diagram of FIG. FIG. 19 shows red, green, and blue (hereinafter R,
It is a light emission characteristic diagram of R, G, and B of a video projector which displays a large screen using a 7-type CRT (abbreviated as G and B). As can be seen from FIG. 19, for the linear characteristic of G,
It can be seen that the emission characteristic of B has a non-linear region from a certain level of the beam current. The cause of the non-linear region is the saturation of the B phosphor in the large current region. As can be seen from this figure, this non-linear characteristic due to saturation is canceled to make it linear as shown by the dotted line in FIG. 19, and in order to keep the chromaticity constant in all areas from low brightness to high brightness, gamma It needs to be corrected.

Now, the operation of the embodiment of the brightness correction configured as shown in FIG. 18 will be described below. To explain this operation, the adjustment order table of (Table 1) and FIGS. 16 and 17 are used together.

[0054]

[Table 1]

(Table 1) is a table showing the adjustment order of the brightness adjustment. In the adjustment order, the low brightness is detected first and the low light is adjusted, and the high brightness is detected second, and the highlight is highlighted. Adjustment, the third is to detect the medium to high brightness due to phosphor saturation, and adjust the gamma, and the fourth is to detect the high brightness again to correct the change in the highlight at the time of gamma adjustment, and then highlight the highlight again. Adjustment, last whole screen (center and periphery of screen)
Uniformity adjustment for screen uniformity is performed by detecting medium to high brightness.

As can be seen from Table 1, the low light, gamma, and highlight adjustments can be made only by detecting the brightness in the center of the screen, but the uniformity adjustment requires the brightness detection in the center and the peripheral part of the screen. Therefore, when the low light, uniformity, and highlight adjustments are performed, the window-shaped test signal shown in FIG. 17A for each gradation is provided at, for example, 9 places in the central portion and the peripheral portion of the screen as shown in FIG. When generating and performing gamma adjustment, generate a quadrangular pyramid-shaped (ramp-shaped signal, etc.) test signal shown in FIG.
The level and tilt of the image light on the T-tube surface is detected. In the case of gamma correction, the slope of the B ramp signal is controlled so as to be linear.

FIG. 20 is an input / output characteristic diagram showing the test signal level for each adjustment item. In this way, the test signal of the level corresponding to each adjustment mode is generated. For example, a test signal having a level of 10 to 20 V for low light adjustment, 50 to 100 V for gamma adjustment, 100 V for highlight adjustment, and 50 to 60 V for uniformity adjustment is displayed on the display screen.

First, the case of adjusting the white balance will be described. What is white balance adjustment? C
The color balance for each gradation due to the emission characteristics of the RT is adjusted. The test signal of each gradation shown in FIG. 20 is projected on the screen 11, and the level amount of each gradation is detected by the photo diode 13. It The signal photoelectrically converted by the photodiode 13 is supplied to the A / D 21, and the information on the test signal display screen is converted into a digital signal. A / D
The digital signal from 21 is supplied to the frame memory 22 to store display information.

Data corresponding to each adjustment area is extracted and read from the data from the frame memory 22, and the CPU 2
3, the level is detected and the inclination error value is calculated. The error value signal from the CPU 23 is the correction signal generation circuit 2
4 is supplied. In the correction signal generation circuit 24, as shown in FIG. 20, a low level control signal is supplied as a black level signal (10 to 20%), and an intermediate to white level signal (50 to 100).
%) For the gamma control signal and the white level signal (100%)
Creates a control signal for highlighting.

The low light control signal is supplied to the clamp circuit 57 to control the cutoff of the RGB signals for driving the CRT. Further, the gamma control signal is supplied to the gamma correction circuit 59 which is configured by the approximation of the broken line of several points, and the gamma correction circuit 59 shown in FIG.
As shown by the broken line, the saturation characteristic of the B phosphor is corrected. In addition, the highlight control signal is supplied to the gain control circuit 56 to control the amplitude of the RGB signals that drive the CRT, whereby the white balance can be automatically adjusted.

Second, the case of adjusting uniformity will be described. Uniformity adjustment is a CRT
The brightness balance in each part of the screen due to the optical system (lens or screen) is corrected, and the same operation as described above is performed, as shown in FIG.
The uniformity control signal is generated at 0 to 60%). The uniformity correction signal is supplied to a uniformity correction circuit 58 composed of an analog modulator that creates a modulated video signal by multiplying the video signal and the correction signal, and the CRT
By controlling the amplitude of each part of the RGB signal that drives the, it is possible to automatically adjust the uniformity for displaying a uniform screen.

[0062]

[Table 2]

Next, the operation control table (Table 2) is used to describe the level detection method. CR in the solid line in Fig. 20
8 shows the emission characteristics of T. Since the image receiving gamma coefficient is 2.2, comparing the luminance change amounts of the low drive voltage and the high drive voltage shows that the higher the drive voltage, the higher the sensitivity. This has a great influence on the CPU, the frame memory, and the number of quantization bits of D / A and A / D. That is, the amount of change in luminance per bit is small at a low drive voltage, but the amount of change in luminance per bit becomes very large at a high drive voltage, and the detection sensitivity in all gradations changes, so highly accurate detection and correction are possible. In addition to this, a quantization bit number of 10 bits or more is required. Therefore, as shown by a broken line in FIG. 22, correction is performed so that the relationship between the drive voltage and the screen brightness changes in proportion to make the detection sensitivity and accuracy in all gradations constant and perform highly accurate level detection. .

Generally, the number of quantization bits required for white balance adjustment and gamma correction is 10 bits (1024
Gradation) is required. Therefore, in this embodiment, by performing the gain and the image receiving gamma in the A / D front stage for each adjustment mode, the processing with the quantized bits of 8 bits is possible. As shown in the operation control table of (Table 2), during low light adjustment, as shown in FIG. 20, the gain of the A / D front stage is increased to detect the range of the low luminance region (10 to 30 V), The gamma correction coefficient (without gamma correction) indicated by the solid line in FIG. 20 is set, and during highlighting and gamma adjustment, the gain of the A / D front stage is reduced to detect the range of low to high luminance region (10 to 100 V).
The gamma correction coefficient (with gamma correction) indicated by the broken line in FIG.
At the time of uniformity adjustment, the range of the middle luminance region (10 to 60 V) is detected with the gain of the A / D front stage as the middle level, and high-accuracy level detection is realized as the gamma correction coefficient (with gamma correction) indicated by the broken line in FIG. There is.

As described above, the brightness correction such as white balance and uniformity is automatically corrected from the data whose level is detected.

Next, in order to explain the case of adjusting the focus of the third adjustment item, the relationship diagram between the display screen and the operation waveform of FIG. 21 will be used. Also in the case of performing the electric focus adjustment, the focus adjustment test signal is supplied from the test signal generation circuit 25 to the switching circuit 16 during the automatic adjustment as in the convergence adjustment described above, and the screen 11 is displayed.
The test signal shown in FIG. 21 (a) is projected on the image, and the quadrangular pyramid photoelectric conversion signal as shown in FIG. 21 (a) is picked up by the photodiode 13 and supplied to the A / D 21 to be converted into a digital signal. To be converted. The digital signal from the A / D 21 is supplied to the frame memory 22 to store display information.

The data from the frame memory 22 is read out by extracting the data corresponding to each adjustment area.
The data for which the level of the high frequency component and the error value are calculated are supplied to the correction signal generating circuit 24, and the correction signal for correcting the focus is generated and supplied to the focus circuit 20 in the display device. It Since the CPU 23 detects the level of the high frequency component, a signal as shown in FIG. 21 (b) is obtained, and the correction waveform shown in FIG. 21 (c) at which the level of each correction region becomes the maximum value is calculated. ing.

By driving the focus circuit 20 based on this correction data, as shown in FIG.
A photoelectric conversion signal whose focus is adjusted in the peripheral portion is obtained from the photodiode 13. In this way, the high frequency component of the pattern signal at each adjustment point on the screen is detected, and the correction amount that maximizes the high frequency component is extracted.

Next, in order to describe the installation position of the photodiode in detail, the optical configuration diagrams of FIGS. 22 and 23 are used. In FIG. 2, the case where the image light of the CRT 8 tube surface is picked up from the screen 11 surface which is the image forming surface of the projection optical system has been described, but in FIG. 22, it is formed on the non-image forming surface of the mirror 7 provided between the CRT and the screen. CR with image sensor 4 installed
FIG. 23 is an optical configuration diagram when imaging the image light of the T8 tube surface.
Then, the image sensor 4 is installed on the non-imaging surface at the tip of the lens 9 and C
The optical block diagram at the time of imaging the image light of RT8 tube surface is shown. In FIG. 2, the case where the image pickup device is installed outside the display screen because the screen 11 is the image forming surface has been described, but in FIGS. 22 and 23, the image pickup device is provided in the effective image area because it is the non-image forming surface. It is detecting. This is because it is a non-imaging surface and is not so affected by the displayed image.

[0070]

[Table 3]

Table 3 shows a comparison table of the detection methods of the screen surface of FIG. 2, the mirror surface of FIG. 22 and the lens tip of FIG. As shown in (Table 3), in the first screen surface detection method, it is possible to automatically adjust all fluctuations of the projector drive system, the projection optical system, and the mechanical system with one image sensor, and the second With the mirror surface detection method, it is possible to automatically adjust the fluctuations of the projector drive system and some projection optical systems with one image sensor, and with the third lens tip method, three image sensors corresponding to each light source are used. It is possible to automatically adjust the fluctuation of the projector drive system.

[0072]

[Table 4]

As shown in Table 4 showing the factors of each variation, the first drive system variation is a variation due to the temperature characteristics of the CRT gun center and the color misregistration correction drive circuit and a color shift due to the geomagnetism. The chromaticity, that is, the color reproducibility of low light, changes due to the change in the cutoff voltage of the CRT. The second variation of the projection optical system is the geometric distortion due to the mirror deformation, the color shift, and the focus due to the temperature characteristics of the lens.
Blurring occurs, and as the third mechanical system variation, geometric distortion and color misregistration due to chassis deformation occur.
Among them, the low light fluctuation in the CRT in the drive system is improved by detecting the cathode current and performing the cutoff adjustment, and the defocusing due to the lens temperature characteristic in the projection optical system is improved by adopting the glass material. It is possible, but geometric distortion (deflection distortion) and color shift (convergence)
Is a very important factor.

The selection of these methods is determined by which item among the fluctuations of the drive system, the projection optical system, and the mechanical system is to be automatically adjusted. In this embodiment, all the fluctuations can be automatically adjusted. The case of a simple screen surface detection method has been described.

As described above, geometric distortion, convergence,
Although the white balance and focus correction items have been described in detail, the adjustment flowchart of FIG. 24 is used to explain the mutual relationship and the adjustment order.

First, the display device and the image correction device for the automatic correction are initially set, and the focus correction is performed second. The reason for this is that the saturation characteristic of the B phosphor largely depends on the focus characteristic. This is because

Third, white balance correction at the center of the screen, that is, low light, highlight, and gamma correction is performed. Fourth, white balance correction for the entire screen, which is uniformity correction, is performed. This is a correction mode for level detection.

Fifth, the display area of the screen size and screen phase displayed on the image display device is corrected, and sixthly, the correction areas are sequentially set to correct the geometric distortion (deflection distortion). Seventh, in the same manner as above, correction areas are sequentially set to perform convergence (color misregistration) correction. The above is the correction mode in the position detection of image information, and if it converges, the correction is completed.

Since the accuracy of the position of the center of gravity depends on the linearity of the test signal, geometric distortion and convergence correction are executed after gamma correction in tilt and level detection.
Highly accurate correction can be realized.

As described above, according to the present embodiment, the mountain shape test signal of the light source image of the projection optical system is directly picked up to calculate the error value for each color, and the convergence signal or the geometry of the entire screen is calculated by this calculation signal. By creating a correction waveform for correcting the distortion and the brightness and automatically correcting the waveform, various complicated adjustments are not required, and the adjustment time can be significantly shortened.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 25 is a block diagram of an image correction device for a projection type display according to the second embodiment of the present invention.

In FIG. 25, reference numeral 75 is a calculation circuit for calculating an error value for each color from the output signal from the image sensor 4, and reference numeral 76 is a correction for creating a convergence correction waveform from the output signal from the calculation circuit 5. This is a waveform generation circuit, and the correction waveform from the correction waveform generation circuit 6 drives the projection enlargement display device 1 to perform various corrections. It should be noted that the same operations as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In order to explain the operation of this embodiment, the block diagram of the calculation circuit 75 and the correction waveform forming circuit 76, the display screen diagram and the operation waveform diagram of FIG. 27 are used in FIG. FIG. 27A shows a light source image projected on the surface of the CRT 8 of the projection magnification apparatus 1, and an image 73 (solid line) is projected in the effective display area 74 (broken line) of the CRT 8. The light source image light from the CRT 8 is received by the photodiode 13 and is shown in FIG.
Is converted into an electric signal shown in. The image pickup signal from the photodiode 13 is band-limited by the LPF 77 and is shown in FIG.
As shown in, the boundary area in the display area is converted into a waveform that changes with an inclination.

The band-limited signal from the LPF 77 is subjected to primary differentiation processing by the differentiating circuit 78 to become a signal which changes at the display area boundary line shown in FIG. 27 (d). The primary differential signal from the differentiating circuit 78 is processed for the center of gravity position as described in FIG. 7, and the center of gravity position signal shown in FIG. 27 (e) is obtained from the center of gravity position detector 72. The error value detection unit 73 detects an error value for each color from the detection signal from the center-of-gravity position detection unit 72, and the error signal is supplied to the static convergence circuit 79 to correct the static convergence. This static convergence correction can be realized by controlling the serial data of the multiplication type D / A 43 corresponding to WB8 described in FIGS.

In the present embodiment, the LPF 77 and the differentiating circuit 7 are described in order to make the detection of the display area boundary line easy to understand.
Although the case where 8 is a separated structure has been described, the same structure can be used because the band is generally limited in the differential processing. Thus, in this embodiment, as described in Table 4, CR
CRT by detecting the display area boundary line of the light source image of the T8 tube surface
This is to automatically adjust static color misregistration (convergence) due to changes in the gun center and changes due to the temperature characteristics of the drive system.

Next, in order to describe in detail the detection control method for automatically adjusting the static convergence by detecting the display area boundary line, the block diagram of FIG. 28 and FIG.
The operation waveform diagram of is used. FIG. 29A shows a light source image projected on the surface of the CRT 8 of the projection magnification apparatus 1, and an image 73 (solid line) is projected in the effective display area 74 (broken line). The light source image light from the CRT 8 is received by the photodiode 13 and converted into electric signals shown in FIGS. 29 (b) (c) (d).

The image pickup signal from the photodiode 13 is L
The band-limiting and differentiating circuit 78 performs a first-order differentiation process in the PF 77 to convert the boundary area in the display area into a waveform that changes with an inclination as shown in FIGS. 29 (e) (f) (g), and this signal is converted into A / Analog / digital conversion is performed at D21. The band-limited signal from the LPF 77 is supplied to the average value detection circuit 61 to detect the average value of the image pickup signal. A /
For example, the LSB bit signal of the 8-bit digital signal subjected to the differential processing from D21 and the detection signal from the average value detection circuit 61 are supplied to the detection control circuit 62, and whether the differential signal is generated at a predetermined position or an imaging signal. It is determined whether or not the average value of APL is 50% or more, for example, to determine whether or not it is in a detectable state.

Therefore, as the detection result from the detection control circuit 62, a detection control signal indicating that the detection operation is stopped in FIGS. 29 (b) and 29 (c) and the detection operation is started in FIG. 29 (d) is obtained. It is supplied to the CPU 23 for detecting an error value and the detection operation is controlled. That is, the presence or absence of the differential signal at the display area boundary line and the average value of the image pickup signal are automatically subjected to the detection control and the automatic adjustment is performed.

Next, how the display area boundary line is set will be described below. The setting in the image display area 73 shown in FIG. 29A is generally determined by a blanking signal (BLK is omitted hereinafter). When the display area boundary line is detected as in the embodiment of the present invention, BLK
Signal jitter and stability are required. Generally, the phase and the period of the BLK signal are set by a mono-multivibrator, etc., but the stability is inferior. Therefore, a BLK signal with high stability and no jitter is created by using a digital counter method. Can be created. The display area boundary line can be detected using this BLK signal.

As described above, the light source image of the projection optical system is directly picked up to calculate the error value of the display area boundary line for each color,
Since the correction waveform for correcting the convergence is automatically created and corrected by this calculated signal, a test signal for detection is not necessary, and pseudo real-time automatic adjustment can be realized.

Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 30 is a block diagram of an image correction device for a projection type display according to the second embodiment of the present invention.

In FIG. 30, reference numeral 65 denotes a light source image in which a region 66 having different light emission characteristics is provided in the peripheral portion of the light source, and 63 denotes an error value for each color from the output signal from the region 66 having different light emission characteristics from the image sensor 4. A calculation circuit for calculation, 64 is a correction waveform creation circuit for creating a convergence correction waveform from the output signal from the calculation circuit 63, and the correction waveform from the correction waveform creation circuit 64 drives the projection enlargement display device 1. Then, various corrections are performed. It should be noted that components that perform the same operations as those of the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted.

[0093]

[Table 5]

Before describing the operation of this embodiment, Table 5 is used to describe in detail how to provide regions having different emission characteristics in the peripheral portion of the light source. As shown in (Table 5), methods of providing regions having different emission characteristics can be broadly classified into signal generation and phosphor system. As a signal generation method, detection can be performed by displaying lamp signals of a mountain shape, a quadrangular pyramid shape, a horizontal / vertical bar, and a horizontal / vertical bar on the peripheral portion of the CRT tube surface. Further, as a phosphor system, a P47 phosphor having a short wavelength different from the phosphors of the three primary colors can be applied for detection.

In order to explain the operation of this embodiment in the case of the signal generation system, the display screen diagram and the operation waveform diagram of FIG. 31 are used. The calculation circuit 63 and the correction / correction waveform creation circuit 64
Since the configuration is the same as the configuration described in FIG. 7 and FIG. 25, detailed description will be omitted. FIG. 31 (a) shows a lamp signal in the upper left peripheral portion of the light source image 65 on the CRT8 tube surface of the projection magnification display device 1, a bar signal in FIG. 31 (b), and a mountain shape signal in FIG. A display screen diagram and a waveform diagram of each signal when the emission characteristics are controlled are shown.

As shown in FIG. 31, the signal projected on the peripheral portion of the screen is received by the photodiode 13, and this signal is A /
It is converted to a digital signal at D21. The converted digital signal passes through the frame memory 22 and is supplied to the center-of-gravity position detector 72 and the error value detector to calculate an error value for each color. The correction data based on the calculated signal is supplied to the static convergence correction circuit 79 to correct the static convergence. This static convergence correction can be realized by controlling the serial data of the multiplication type D / A 43 corresponding to WB8 described in FIGS.

Next, in order to describe the phosphor system in detail, the block diagram of FIG. 32, the operation waveform diagram of FIG. 33, and the spectral characteristic diagram of FIG. 34 are used. FIG. 33 (a) shows a screen view when the light source image 65 is applied on the surface of the CRT tube and the index fluorescent material having the spectral characteristics shown in FIG. 34 is applied to the peripheral portion. The index phosphor is irradiated with a certain amount of electron beam. The light source image 65 is received by the photodiode 13 after being filtered by the color filter 81 for extracting only the wavelength component of the index phosphor, and FIG.
Imaging signals having different phases of (e) and (e) are obtained.

This image pickup signal is binarized by the binarization circuit 82 and supplied to the time-voltage conversion circuit 83. The time-voltage conversion circuit 83 converts the time from the reference signal shown in FIG. 33C to the rise of the image pickup signal into a voltage. The time-voltage conversion circuit 83 is composed of, for example, a ramp signal generation circuit, and since the time constants are the same, (d) in FIG. 33 (b).
The voltage V1 of FIG. 33 (e) is the voltage V2 of FIG. 33 (e). This means that the voltage changes according to the time from the reference signal of FIG. 33 (c), and the timing of each color is detected from this voltage information to detect the static convergence deviation. is there. Time
The voltage from the voltage conversion circuit 83 is supplied to the level detection circuit 84 through the A / D 21 to detect the voltage level, and this detection signal is supplied to the error detection circuit 73.

The error detection circuit 73 calculates an error value for the reference G signal. The correction data based on the calculated signal is used as the static convergence correction circuit 85.
Is supplied to the device and static convergence is corrected. For example, in the case of the reference G signal in FIG. 33 (b), feedback control is performed so that the voltage V2 shown in FIG. 33 (f) becomes equal to V1.

Next, in order to explain the method of masking the phosphor, the display screen and operation waveform diagram of FIG. 35 are used. As in the case of FIG. 33, the light received by the photodiode 13 is received.
Imaging signals of different phases (b) and (e) can be obtained. This image pickup signal is binarized by the binarization circuit 82 and supplied to the time-voltage conversion circuit 83. Since the time-voltage conversion circuit 83 converts the time from the reference signal shown in FIG. 35C to the fall of the image pickup signal into a voltage, the voltage V1 in FIG. In e), the voltage V2 of (f) is obtained.

The voltage from the time-voltage conversion circuit 83 is A /
It is supplied to the level detection circuit 84 through D21 to detect the voltage level, and this detection signal is supplied to the error detection circuit 73. The error detection circuit 73 calculates an error value for the reference G signal shown in FIG. 35 (b), and the correction data for making the voltage V4 shown in FIG. 35 (f) equal to V3 is the static convergence correction circuit. The static convergence is fed back to 85 and feedback-controlled to automatically correct it.

As described above, according to this embodiment, the light source image displayed on the light source provided with the regions having different light emission characteristics at the predetermined peripheral positions is directly imaged to calculate the error value for each color. Since the correction waveform for correcting the convergence is automatically created by the signal and the correction is performed, the image outer frame signal and the like are not necessary, so that the complete real-time automatic adjustment can be realized with a simple configuration.

In this embodiment, the image display device using the CRT has been described for easy understanding, but it goes without saying that other display devices are also effective.

Further, in the present embodiment, the case where an integral type or a two-body type video projector is used as the projection enlargement display device has been described, but a projection type display device other than that may be used.

In this embodiment, the case where the photodiode is used as the image pickup device for detecting the image light has been described, but other CCD cameras, two-dimensional or one-dimensional type cameras are used.
It may be a dimensional detection element.

In this embodiment, the case where the communication signal between the correction circuit and the projection enlargement display device is the correction waveform signal for correcting the drive circuit in the display device has been described. It may be a control signal for controlling.

In this embodiment, the image receiving gamma of the image display device has been described as being corrected on the test signal generation side. However, gamma correction is performed in the loop of test signal generation-image display-imaging-centroid position detection. Needless to say, the existence of.

Further, in the first embodiment, the case where the position of the test signal displayed on the image display device is detected as the quadrangular pyramid mountain shape signal has been described, but other mountain shape may be used.

In the first embodiment, the case where the screen is divided and the convergence correction is performed in an analog manner has been described. However, another method may be used as long as the convergence adjustment is effectively performed.

In the first embodiment, the horizontal and vertical barycentric position of each area is calculated by linear approximation from the conical photoelectric conversion signal whose rising and falling are substantially linearly changed from the image pickup means. Although the case has been described, the calculation may be performed by non-linear approximation as long as simple approximation is possible.

Further, in the second embodiment, the case where the display area boundary line is detected by the differential processing of the image signal is described, but the detection may be performed by other methods.

Further, in the third embodiment, the case where the detection position in the peripheral portion of the screen is performed on the upper and left sides of the screen cross is described, but the detection may be performed at other peripheral position.

Further, in the third embodiment, the case where the regions having different light emission characteristics are provided by various test signals, application of index phosphor such as P47, or the mask of the phosphor has been described, but other methods are used. Good.

Further, in the third embodiment, the case where the regions having different light emission characteristics are set in the same direction as the scanning of the display device has been described, but they may be set in an oblique direction or a combination thereof.

[0115]

As described above, according to the first aspect of the present invention, the mountain shape test signal of the light source image of the projection optical system is directly picked up to calculate the error value for each color, and the calculated signal is used to display the entire screen. Since the correction waveforms for correcting the convergence, geometric distortion, and luminance are automatically created and corrected, various complicated adjustments are unnecessary and the adjustment time can be greatly shortened.

Further, with a quadrangular pyramid-shaped photoelectric conversion signal whose slope changes almost linearly, the head value and the slope are calculated and various correction waveforms are calculated to obtain a highly accurate correction with a simple detection system. Can be realized.

Further, according to the second invention, the light source image of the projection optical system is directly imaged to calculate the error value for each color, and the correction waveform for correcting the convergence is automatically created by this calculation signal. Since it is corrected in this manner, a test signal for detection is not necessary, and pseudo real-time automatic adjustment can be realized.

According to the third aspect of the invention, the light source image displayed on the light source provided with the regions having different emission characteristics at the predetermined peripheral positions is directly imaged to calculate the error value for each color, and the calculated signal is calculated. Automatically creates and corrects the correction waveform to correct the convergence, so it is possible to realize complete real-time automatic adjustment with a simple configuration because the image outer frame signal is unnecessary, and its practical effect. Is big.

[Brief description of drawings]

FIG. 1 is a block diagram of an image correction apparatus for a projection type display according to a first embodiment of the present invention.

FIG. 2 is an optical configuration diagram for explaining the operation of the embodiment.

FIG. 3 is a block diagram for explaining the operation of the embodiment in detail.

FIG. 4 is a display screen diagram for explaining the operation of the embodiment.

FIG. 5 is an operation waveform diagram for explaining the operation of the embodiment.

FIG. 6 is an operation waveform chart for explaining the operation of detecting the position of the center of gravity of the embodiment.

FIG. 7 is a detailed block diagram for explaining the operation of the position of the center of gravity of the embodiment.

FIG. 8 is an operation waveform diagram for explaining the operation of detecting the position of the center of gravity of the embodiment.

FIG. 9 is a display screen diagram for explaining the operation of detecting the position of the center of gravity of the embodiment.

FIG. 10 is an operation waveform diagram for explaining an error value calculation operation of the embodiment.

FIG. 11 is a detailed block diagram of correction waveform creation according to the embodiment.

FIG. 12 is an operation waveform diagram for explaining an operation of creating a correction waveform in the embodiment.

FIG. 13 is an operation waveform chart for explaining an operation of creating a correction waveform according to the same embodiment.

FIG. 14 is an operation waveform diagram for explaining a positive operation of the correction waveform creation in the embodiment.

FIG. 15 is a diagram showing a relationship between a correction wave and a correction change for explaining the operation of the embodiment.

FIG. 16 is a display screen diagram of a display device for explaining the brightness correction operation of the same embodiment.

FIG. 17 is an operation waveform diagram for explaining the brightness correction operation of the same embodiment.

FIG. 18 is a block diagram for explaining the operation of the video circuit of the embodiment.

FIG. 19 is a characteristic diagram for explaining a gamma correction operation of the same embodiment.

FIG. 20 is a characteristic diagram for explaining the brightness correction operation of the same embodiment.

FIG. 21 is a correspondence diagram of a display screen and an operation waveform showing the focus correction operation of the same embodiment.

FIG. 22 is an optical configuration diagram for explaining the operation of the same example.

FIG. 23 is an optical configuration diagram for explaining the operation of the example.

FIG. 24 is a flowchart for explaining the adjustment order of the operation of the embodiment.

FIG. 25 is a block diagram of an image correction device for a projection type display according to a second embodiment of the present invention.

FIG. 26 is a block diagram for explaining the operation of the embodiment.

FIG. 27 is a diagram showing a display screen and operation waveforms for explaining the operation of the embodiment.

FIG. 28 is a block diagram for explaining the operation of the embodiment.

FIG. 29 is a diagram showing a display screen and operation waveforms for explaining the operation of the embodiment.

FIG. 30 is a block diagram of an image correction device for a projection type display according to a third embodiment of the present invention.

FIG. 31 is a diagram showing a display screen and operation waveforms for explaining the operation of the embodiment.

FIG. 32 is a block diagram for explaining the operation of the embodiment.

FIG. 33 is a diagram showing a display screen and operation waveforms for explaining the detection operation of the embodiment.

FIG. 34 is a spectral characteristic diagram of the index phosphor of the same example.

FIG. 35 is a diagram showing a display screen and operation waveforms for explaining the detection operation of the embodiment.

FIG. 36 is a block diagram of an image correction apparatus for a conventional first projection type display.

FIG. 37 is a block diagram of a conventional image correction device for a second projection display.

[Explanation of symbols]

 1 Projection Enlargement Display Device 2 Screen 3 Test Signal Generation Circuit 4 Imaging Device 5, 75, 63 Calculation Circuit 6, 76, 64 Correction Waveform Creation Circuit 13 Photodiode 21 A / D 22 Frame Memory 23 CPU 24 Correction Signal Creation Circuit 25 Test signal generation circuit 65 Light source image 66 Area with different light emission characteristics 70 Differential filter 71 Linear area detection unit 72 Center of gravity position detection unit 73 Error value calculation unit

Claims (7)

[Claims] 1. A display device for projecting and enlarging and displaying a light source image on a screen using a projection optical system, signal generating means for generating a mountain-shaped test signal at a predetermined position of the light source, and the signal generating means. An image pickup means for supplying a test signal from the means to a display device to pick up an image projected on the light source, and an image pickup signal from the image pickup means whose inclination is a straight line. Error calculating means for calculating a position / tilt error, and correction waveform creating means for creating a convergence of the correction area corresponding to the display area of the test signal from the output signal of the error calculating means, geometric distortion, and a gamma correction waveform, An image correction apparatus for a projection display, characterized in that the display device is corrected by the correction waveform from the correction waveform creating means. 2. The signal generating means is adapted to output at least one pattern having a quadrangular pyramid shape when the display screen is the bottom surface and the signal level direction is the height direction. 1. The image correction device for a projection display according to 1. 3. The image correction apparatus for a projection display according to claim 1, wherein the error calculation means obtains the position of the leading value from the linear portion of the image pickup signal by approximate calculation. 4. A display means for projecting and enlarging and displaying a light source image on a screen by using a projection optical system, an image pickup means for picking up the light source image, and an output signal from a peripheral portion from the image pickup means for each color. Error correction means for calculating the display position error and correction waveform creation means for creating a correction waveform for correcting the convergence by the output signal of the error calculation means. An image correction device for a projection display, characterized in that the display device is corrected. 5. The image correction apparatus for a projection display according to claim 4, wherein the error calculation means obtains an error value according to the detection signal of the display area boundary line of the image pickup signal and the average level. 6. Display means for projecting and enlarging and displaying a light source image in which areas having different light emission characteristics are provided at predetermined peripheral positions, image pickup means for picking up the light source image, and output of the peripheral portion from the image pickup means. An error calculating means for calculating a display position error for each color from a signal, and a correction waveform creating means for creating a correction waveform for correcting convergence by an output signal of the error calculating means are provided. An image correction device for a projection display, wherein the display device is corrected with the correction waveform of 1. 7. The image of a projection display according to claim 6, wherein the error calculating means obtains an error value from image information having different light emission characteristics due to projection of a test signal, coating of a different kind of fluorescent substance, or blocking of a fluorescent substance. Correction device.