JPH01184142A - Image processing apparatus - Google Patents

Abstract

PURPOSE:To reproduce a natural image using a memory having relatively small capacity, by providing a page memory having the region equal to the max. output region of a printer and another page memory storing image data with the gradation equal to the reproduction capacity of the printer and having a region smaller than that of the above-mentioned page memory and storing image data in either one of both page memories according to the kind thereof. CONSTITUTION:A document image (a) is stored in a page memory 13 in a color code state. This memory 13 has the region size equal to the output size of a printer and address signal AR2(xa, ya) of the memory 13 coincides with the coordinates AR(xc, yc) of an output image (c). A natural image (b) is stored in a page memory 11 at a unit of 8 bits with respect to each of R, G and B but has a region size smaller than the output size of the printer. Therefore, when the natural image (b) coincides with the document image (a) so that the origin thereof becomes the position of output coordinates (2000, 50), the conversion of AR1, (xb, yb)=AR(xc-2000, yc-50) is performed. By this method, the document image read from the memory is converted to an image signal by a decoder 14 and synthesized along with the natural image read from the page memory 11 in an image synthesizing part 15 to obtain a synthetic image (c).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image processing device that processes human image information.

[Conventional technology]

In recent years, as page printers such as laser beam printers (LBPs) have become cheaper, programming languages based on page description languages that can express various character fonts and graphics have been developed, and printers are also able to translate these page description languages. Functional devices are being developed. Po5tScript, developed by Adobe, is a typical page description language, and its specifications are (Adobe
e System Inc.:Po5tscrip
t Language: Reference M
annual Addison-Wesley, 19
85), (Adobe Systems Inc.:
PostScript Language: Tutori
al and Cookbook, Addison
- Wesley, 1985), (Page Description Language PDL
(Published by I-East Co., Ltd.).

On the other hand, printers have changed from conventional so-called binary printers, which express only black dots, to multi-value printers, which express one dot in multiple gradations, and color printers capable of color expression are being developed and put into practical use. .

Based on this background, printers compatible with page description languages that can handle multi-gradation images and color images such as photographic images have been proposed.

FIG. 5 is a functional block diagram of such a printer. Color image information described in a page description language by the host computer 1 is sent from the host computer 1 to the translation unit 3 via the communication unit 2 of the printer. The host computer 1 and the communication section 2 are connected through a standard interface such as GP-IB or 5CIS. The page description language sent to the translation section 3 is sequentially decoded by a microprocessor (not shown) on the translation section 3, and the results are given to the memory driver 4. The memory driver 4 stores pixel data R,
Record G and B respectively.

The page memory 5 is configured in a so-called bitmap format in which pixel positions on output paper correspond to each bit of the memory on a one-to-one basis, and one pixel has a number of bits corresponding to the expressive ability of the printer. For example, if the printer is capable of expressing 256 gradations for each of the R, B, and G signals, the page memory 5 has a depth of 8 bits per pixel for each color signal, and the total It has a depth of 24 bits.

The full-color image data developed on the page memory 5 is read out as a raster image by giving a raster scan address A synchronized with the recording section 7 as an address of the page memory 5 from the printer driver 6.

The printer driver 6 performs processing on the image data from the page memory 5 according to the recording section 7. For example, R-G
A complementary color MMC signal is generated from the B defect signal, or a miss signal is generated by performing UCR processing. The recording unit 7 can be implemented using various methods such as an electrophotographic method, a thermal transfer method, and an inkjet method.

In this way, it is possible to obtain a print image of a full-color image configured using the page description language on the host computer 1.

[Problem that the invention is trying to solve] However,
A page memory corresponding to such a color image has an enormous capacity.

For example, the color gradation per pixel is 8 bits for each RGB, a total of 2
4 bit resolution 400dpt (d.

A3 size (297x4
20mrr? ), the capacity of page memory 5 is approximately 7
It becomes 42M bits. This requires 742 IMbito DRAMs, and having one for each printer poses a problem in terms of cost and the like.

[Means for solving problems]

The present invention has been made in view of the above points, and includes a first page memory means having an area size equivalent to the maximum output area of a printer that stores pixel data in the form of a code;
and a second page memory means having a smaller area than the first page memory for storing pixel data in a gradation level equivalent to the reproduction ability of the printer. The present invention provides an image processing device that develops and stores image information in any one of the second page memory means.

〔Example〕

The present invention will be explained below using preferred examples.

FIG. 1 is a block diagram of an embodiment of an image reproducing apparatus to which the present invention is applied.

In the figure, blocks having the same numbers as those in the conventional block diagram of FIG. 5 have equivalent functions.

In FIG. 1, the memory controller 10 translates the page description language and expands the image information in the translation unit 3, and in the case of a multi-gradation image such as a natural image, addresses Adl corresponding to the pixel positions.
is stored in the page memory 11 for multi-tone images.

On the other hand, when the number of colors used in a page is limited, such as in a document image, the image signal is converted into a color code with a code length corresponding to the number of colors by the encoder 12, and the image signal is converted to a color code with the code length corresponding to the number of colors using the address signal Ad2. to be memorized. This page memory 13 has the same number of bits as the code length of the encoder 12 for each pixel.

At the time of output from the recording section 7, the rask address signal An from the printer driver 6 is appropriately converted by the image composition section 15 into address signals A R1 and A R2 for each page memory.

FIG. 2 is a diagram explaining the concept of address conversion during image composition. The image (a) in FIG. 2 is a document image and is stored in the page memory 13 in a color coded state. Address signal AR2 (Xs + 3
'a) is the output image (c) + 7) coordinates AR, (Xe,
yc). That is, the document page memory 13 has an area size equivalent to the output size of the printer. On the other hand, the natural image (b) is stored in the page memory 11 with a total depth of 24 bits, including 8 bits each for R, G, and B.

However, the area size is smaller than the printer's output size,
The address signal AR1 (xb I yb ) does not necessarily match the output coordinates AR.

Now, the origin of the natural image (b) is at the output coordinates (2000°50
), when merging with document image (a),
The printer driver 6 sequentially generates a rask address signal AII (xe, yc) synchronized with the operation of the recording section 7 to the page memory. Document page memory 13
Since both addresses match, it remains as is, that is, Al1(xa, ya) = AIl
It is sufficient to read by giving an address signal (xc, ye). On the other hand, since the coordinates do not match for the multi-tone image page memory 11, ARt(Xb + '
jb)=AR(Xc-2000, y, -50) to obtain an address signal.

The document image read out from the page memory 13 in this way is converted from a color code signal to an image signal by the decoder 14, and then combined with the natural image read out from the page memory 11 in the image forming section 15. A composite image (e) with an arbitrary positional relationship between the two is obtained.

Naturally, the image synthesis section 15 also includes a switching function for supplying only one of the image data as an output signal to the recording section.

[Other Examples] FIG. 3 shows a second embodiment of the invention.

This adds a function that allows image data to be directly written from an external image input device 20 such as a TV camera or image scanner without going through the host computer 1 to input image data into the page memory 11 for natural images. It is something.

In FIG. 3, the image switching section 21 has a function of switching between image data from the memory controller 10 and image data from the external image input device 20.

On the other hand, as for the memory address signal, the signal generated by the memory controller 10 may be shared. In this case, it is sufficient to add a function to the image switching section 21 to synchronize the image signal from the external image input device 20 and the address signal.

In this way, by providing a bus for manually transferring images directly to the page memory 11 for natural image scars, it is possible to expand the images to the memory at high speed and shorten the treatment time.

Furthermore, since the host computer is not used, the load on the storage device of the host computer can be reduced.

[Third example] FIG. 4 shows a third embodiment of the present invention.

By adding a function to change the magnification of the image data in the page memory 11 for small area multi-tone images to an arbitrary magnification when outputting,
The purpose is to obtain an image of any size as an output image regardless of the page memory area.

In FIG. 4, the scaling processing section 30 has two functions. One is a function that performs density conversion of image data according to instructions given to the image data.

The other function is to further convert the rask address data ARI converted by the image synthesis section according to the scaling factor.

The conversion is performed based on the following formula:

ARI'(Xb',yb') where n is the magnification, (x, y) are the coordinates of the origin in the output image, AR+'(Xb' + 3'b') is the address data in the page memory 11, (Xb, 3/
b) is the converted address data in the image synthesis unit 15, (x
c, yc) is the coordinate data of the output image from the printer driver 6.

By adding the function of scaling the image data from the page memory 11, which has a limited area, to an arbitrary magnification,
An output image of any size can be obtained regardless of the size of the area of the page memory 11.

However, in scaling, especially in enlargement processing in which the same image data is simply repeated during enlargement processing, deterioration of image quality becomes a problem when the enlargement ratio becomes large. Therefore, when enlarging, a reproduction image of good quality can be obtained by adopting an enlarging method that interpolates between pixels using an appropriate function.

Furthermore, since the scaling process is performed in synchronization with the recording operation of the printer during output, real-time processing is performed and no extra processing time is required.

In this way, even if a color printer that can interpret a page description language has tonality that can reproduce natural images, in actual applications the number of colors that can be used within one page is limited. . This is because in many cases, the means for generating images is a computer itself, and in order to generate an image using a number of colors close to that of a natural image, an enormous and complex program is required. For example, in the case of a document image, at most 8 to 16 colors may be sufficient.

Therefore, as the page memory 13 of a color printer,
By limiting the number of colors used within a page and storing them as color codes, the number of bits per page memory pixel can be limited.
The overall page memory capacity can be reduced. For example, if the number of colors used in the same page is 16, it can be expressed with 4 bits per pixel, and the capacity of the page memory 13 will be 1/6 of the conventional case with a depth of 24 bits. .

By converting the image signal back to the original image signal when outputting it to a printer, it is possible to output it in any color even if the number of colors is limited.

In addition, the number of colors should be limited when a computer uses image data obtained from an imaging device such as an image scanner or TV camera, or when an image is obtained through advanced image processing such as computer graphics. This is difficult, and the page memory for these image data must also have a number of bits commensurate with the printer's representation ability.

However, even in this case, the area is often limited by the number of pixels. For example, if a natural image is obtained with a TV camera, the number of pixels per page will be at most 1 million pixels, and even when generating image data using computer graphics methods, the amount of data will be limited due to the processing time. Naturally, there is a limit, and the upper limit can be considered to be around 1 million pixels. Furthermore, there is a limit to the storage capacity of the computer itself.

In other words, in the case of natural images, unlike document images, a large compression effect cannot be expected, so it is problematic for a computer to store image data of the entire area that can be expressed by a printer. The page memory 11 having a large size can be used in many applications even if it has an area smaller than the recording area of the printer, as shown in the configuration shown in FIG.

In this way, the page memory 13 of the printer has a limited number of colors used and compressed bit number in the depth direction for document images and graphic images, and the page memory 13 has a limited area for natural images. By having two types of page memories (No. 11), it is possible to configure a page printer that can handle almost all practical applications, even if the overall memory capacity is small.

According to some of the embodiments described above, the page memory of a page color printer is divided into a page memory that has the same area as the maximum area of the output image but has a limited depth by storing image data as a color code, and a page memory that has a limited depth by storing image data as a color code. There are two types of page memory, the depth of which has a number of bits depending on the printer's expressive ability, but a limited area. By using these properly depending on the type of image, you can achieve a large amount of memory with a relatively small capacity. Printers with similar capabilities and full page memory capacity are now possible.

Furthermore, by making it possible to directly write image data from the outside into a memory for small-area natural images, processing time can be shortened and the storage capacity of the host computer can be reduced.

Furthermore, by adding a function to scale the image data from the natural image memory to an arbitrary magnification, it is possible to obtain a natural image of any size as an output image without being limited by the size of the page memory. It has become possible.

〔effect〕

As explained above, according to the present invention, the first page memory means has an area size equivalent to the maximum output area of the printer that stores pixel data in the form of a code, and the pixel data is and a second page memory means having a smaller area than the first page memory which stores data with the same gradation, and depending on the type of input image information, one of the first and second page memory means is provided. Since the image information is developed and stored in the page memory means, an image processing apparatus capable of reproducing natural images can be constructed with a relatively small capacity memory means.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an image reproducing device embodying the present invention; Fig. 2 is a diagram illustrating address signal conversion during image synthesis; Fig. 3 is a diagram showing the configuration of a second embodiment; 5 is a block diagram showing a conventional configuration example, 1 is a host computer, 2 is a communication section, 3 is a translation section, 6 is a printer driver, and 7 is a recording section. , 10 is a memory controller,
11 is a page memory for natural drawings, 13 is a page memory for line drawings, and 15 is an image composition section.

Claims (1)

[Scope of Claims] First page memory means having an area size equivalent to the maximum output area of a printer for storing pixel data in the form of a code, and a tonality equal to the reproduction ability of the printer for storing pixel data. a second page memory means having a smaller area than the first page memory for storing the image information; An image processing device that develops and stores image information.