JPH01288168A - Picture processing system - Google Patents

Abstract

PURPOSE:To improve the gradation reproducibility and picture quality of a scenery or portrait picture by allowing an output picture element signal selection section to select and output an output picture element signal obtained through the addition of an additional data in response to the quantity of the signal change in the original reading between adjacent picture elements. CONSTITUTION:In case of reading an original where lightness and color are changed slowly as a scenery or portrait picture and an original read signal change is less between adjacent picture elements by an original read section 1, an edge detection section 10 outputs a small edge detection signal 22. In this case, an output selection section 11 selects the 1st output picture element signal 17 outputted from the 1st picture element selection section 5 and outputs the result as a selected output picture element signal 23 to a printer 12. The printer section 12 gives outputs dots of color members onto paper in nearly the order of a picture element having larger 1st additional data. Thus, in case of using a centralized dither pattern, isolated dots outputted onto the printer are reduced, a scenery or portrait picture is outputted from the printer section 12 with excellent gradation reproducibility and picture quality.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image processing system that outputs color or monochrome photographs or printed matter read by a scanner to a printer device that can originally only express the image by the presence or absence of color materials.

Conventional technology In recent years, the development of printer devices has been remarkable.
The recent trend is toward higher resolution, and printers are required to be able to output not only text information but also image information. In other words, it is a challenge to output documents such as text, photographs, and printed halftone photographs to a printer with good reproducibility. However, most of the printer devices described above can only control the presence or absence of color material dots for each pixel, and therefore a process is required to convert the document reading signal input from the scanner into the presence or absence of color material dots. becomes. Therefore, an image processing system has been announced that performs processing to convert text, photographs, and halftone dot manuscripts into dots and dots that can be output with good reproducibility when output to a printer. An example of the above-mentioned conventional image processing system will be described with reference to the drawings. Figure 2 shows
Conventional image processing system configuration (what is it? In FIG. 2, 31 is an original reading section, which optically reads an original and outputs an original reading signal 35 converted into a digital signal. 32 is an output pixel number calculation means, 1. An output pixel number signal 36 is output in response to the magnitude of the original reading signal 35. 33 is an output 11ii pixel selection section, which outputs an output pixel number signal 36 in response to the magnitude of the original reading signal 35.
5 is input, a plurality of original reading signals 350 are compared in size, and in response to the comparison processing results, an output pixel number signal 36 is generated.
The number of pixels indicated by is selected and output pixel signal 37 is output. Reference numeral 34 denotes a printer section that outputs coloring material onto paper in response to an output pixel signal 37.

The operation of the image processing system configured as above will be described below. First, read the original into the original reading section 3.
An output pixel number calculation means 32 calculates the number of pixels to be output to the printer in response to the magnitude of the original reading signal 35 and outputs it as an output pixel number signal 36. In addition, the output pixel selection section 33 selects the pixels of the number indicated by the output pixel number signal 36 from the pixels with the largest original reading signal 35 so that the printer outputs the color material, and outputs the output pixel signal 37. Then, the printer unit 34 outputs coloring material onto paper in response to the output pixel signal 37 (for example, see Nikkei Electronics Magazine, November 18, 1985, p. 130).Problems to be Solved by the InventionHowever, the above-mentioned configuration In this method, dots of coloring material are outputted onto paper in order from the pixel with the highest original reading signal, so that originals containing text or printed halftone photographs can be output to the printer with good reproducibility. However, for documents whose brightness and color change gradually, such as photographs of landscapes or people, there is not much difference in the magnitude of the document reading signal between pixels that are close to each other, so noise during document reading may cause the printer to Many isolated dots are output, where one pixel has color material that differs from neighboring pixels, resulting in a grainy image quality.In many printers, gradation reproducibility is affected by bleeding or blurring of color material. The problem was that it worsened.

In view of the above-mentioned problems, the present invention provides good gradation reproducibility and image quality not only for originals with text or printed halftone photographs, but also for originals with gradual changes in brightness and color, such as photographs of landscapes and people. An image processing system capable of obtaining printer output is provided.

Means for Solving the Problems In order to solve the above-mentioned problems, the image processing system of the present invention includes: an original reading unit that optically reads an original and outputs an original reading signal converted into a digital signal; an output pixel number calculation section that outputs an output pixel number signal whose size is proportional to the sum of the plurality of original reading signals as input; an integer greater than or equal to); an additional data storage unit for the original reading signal;
(K is an integer greater than or equal to 1 and less than or equal to N) additional data, and a plurality of N output pixel selection units that select the number of pixels indicated by the output pixel number signal in descending order of the first additional data addition signal and output the Xth output pixel signal; and the document reading unit. an N+1 output pixel selection unit that receives a signal as input, selects pixels of the number of pixels indicated by the output pixel number signal in descending order of the plurality of original reading signals, and outputs an N+1 output pixel signal; an edge detection section that receives a reading signal and outputs an edge detection signal in response to a difference value of the original reading signal; and an edge detection section that selects one of the N+1 output pixel signals in response to the magnitude of the edge detection signal. The apparatus includes an output selection section that outputs a selected output pixel signal, and a printer section that outputs coloring material onto paper in response to the selected output pixel signal.

According to the above-described configuration, the present invention first calculates the number of pixels to be output to the printer in response to the magnitude of the document reading signal by the output pixel number calculation section, and uses this as an output pixel number signal. Each of the N+1 output selection units outputs N+1 different output pixel signals. The N output pixel signals are N additional data addition signals obtained by adding N different additional data to the original reading signal, and each selects pixels of the number of pixels indicated by the output pixel number signal in descending order. This is what I did. Further, the N+1st output pixel signal is obtained by selecting pixels of the number of pixels indicated by the output pixel number signal in descending order of the original reading signal.

The edge detection unit is used for document parts where the document reading signal changes greatly between neighboring pixels, such as documents with halftone photographs of text or printing, or where the brightness and color change gradually, such as photographs of landscapes or people. An edge detection signal is output by detecting whether it is a document part where the change in the document reading signal is small between neighboring pixels, such as a document. Then, in response to the edge detection signal, the output pixel signal selection section selects the output pixel signal obtained by adding the additional data having a large value in the document portion where the change in the document reading signal between neighboring pixels is small. , the output pixel signal obtained by adding the additional data of a smaller value is selected as the change in the original reading signal becomes larger between neighboring pixels. Then, the N+1st output pixel signal is selected for the document portion where the change in the document reading signal is greatest among neighboring pixels.

Finally, the printer unit outputs dots of coloring material onto paper in response to the selected output pixel signal.

Therefore, in document parts where there is a large change in the document reading signal between neighboring pixels, such as a document with text or a halftone photograph from printing, dots of coloring material are outputted onto the paper in order from the pixels with the largest document reading signal, and A printed halftone photograph is output to a printer with good reproducibility. In addition, in document parts where the brightness and color change gradually, such as photographs of landscapes and people, and the change in the document reading signal between neighboring pixels is small, pixels with a large additional data addition signal, which is the sum of the document reading signal and additional data, Print dots of coloring material on paper. As the amount of change in the additional data becomes larger than the amount of change in the original reading signal, dots of color material are outputted onto the paper in the order of pixels with larger amounts of additional data.

For example, if data known as a dot-concentrated dither pattern as shown in Figure 3 is used as additional data, the number of isolated dots output to the printer will be reduced, and the brightness and brightness of photographs of landscapes and people will gradually change. Printer output with good gradation reproducibility and image quality can be obtained even for originals whose colors change.

Embodiment Hereinafter, an image processing system according to an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, 1 is a document reading section, 2 is an output pixel number calculation section, 3 is a first additional data storage section, 4 is a first additional data addition section, 6 is a first pixel selection section, and 6 is a first additional data storage section. a second additional data storage section, 7 a second additional data addition section, 8 a second pixel selection section, 9 a third pixel selection section, 10 an edge detection section, 11 an output selection section,
12 is a printer section, 13 is an original reading signal, 14 is an output pixel number signal, 15 is first additional data, 16 is a first additional data addition signal, 17 is a first output pixel signal, 18
is second additional data, 19 is a second additional data addition signal, 20 is a second output pixel signal, 21 is a third output pixel signal, 22 is an edge detection signal, and 23 is a selected output pixel signal.

The operation of the image processing system of this embodiment configured as described above will be described below.

First, the original is optically read in the original reading unit 1 and converted into an electrical signal by the photoelectric conversion circuit, and then converted into a digital signal that is an integer from 0 to 255, depending on the size of the electric No. 15. The original reading signal 13 is obtained.

The output pixel number calculation unit 2 calculates the sum of the original reading signals 13 of pixels belonging to a rectangular area consisting of 16 pixels of 4 pixels in the vertical and horizontal directions, and divides the sum by a constant 266, and uses the quotient as the output pixel number signal 14. Output. Output pixel number signal 14 is 0
An integer greater than or equal to 16 or less.

FIG. 3 shows the dither pattern used for the actual rollover, and the values obtained by multiplying the dither pattern in FIG. 3 by 16 are used as the first additional data 15, The values obtained by multiplying each of the patterns by eight are used as the second additional data 18. The first additional data 15 is stored in the first additional data storage section 3 and output to the first additional data addition section 4 . The first additional data addition unit 4 receives the original reading signal 13
and the first additional data 15 are sequentially added for each pixel, and a first additional data addition signal 16 is output.

The first output pixel selection unit 6 selects the number of pixels indicated by the output pixel number signal 14 as soon as the first additional data addition signal 160 of the pixels belonging to a rectangular area consisting of 16 pixels of 4 pixels in the vertical and horizontal directions is large. and outputs the first output pixel signal 1a. The second additional data 18 is stored in the second additional data storage section 6 and output to the second additional data addition section 7 . The second additional data addition section 7 sequentially adds the original reading signal 13 and the second additional data 18 for each pixel and outputs a second additional data addition signal 19. The second output pixel selection unit 8 selects the number of pixels indicated by the output pixel number signal 14 in descending order of the second additional data addition signal 190 of the pixels belonging to a rectangular area consisting of 16 pixels of 4 pixels in the vertical and horizontal directions. Second
The output pixel signal 2o is output. The third output pixel selection unit 9 selects the number of pixels outputted by the output pixel number signal 14 in descending order of the original reading signal 130 of the pixels belonging to a rectangular area consisting of 16 pixels of 4 pixels in the vertical and horizontal directions, and outputs the third output. The edge detection unit 1o that outputs the pixel signal 21 receives the original reading signal 13 and calculates the absolute value of the difference between the original reading signals of pixels adjacent to the left and right and the absolute value of the difference between the original reading signals of pixels adjacent to the upper and lower sides. If the sum is the edge amount of one pixel, 16
The total amount of edges is calculated for pixels belonging to a rectangular area made up of pixels and outputted as an edge detection signal 22. The output selection unit 11 compares the edge detection signal 22 with two threshold values stored in advance. If the edge detection signal 22 is smaller than either of the two thresholds, the first output pixel signal 1 is selected, and if the edge detection signal 22 is larger than either of the two thresholds, the third output pixel signal 21 is selected. However, if the edge detection signal 22 is smaller than one of the two thresholds and thicker than the other one, the second output pixel signal 20 is selected and the selected output pixel signal 23 is output. Printer section 1
2 outputs the coloring material to paper in response to the selected output pixel signal 23.

As described above, when the document reading unit 1 reads a document portion in which the document reading signal changes greatly between neighboring pixels, such as a document with halftone photographs of text or printing, the edge detection unit 10 detects a large value. An edge detection signal 22 is output. At this time, the output selection section 11 selects the third output pixel signal 21 output from the third output pixel selection section 9 and outputs it to the printer section 12 as the selected output pixel signal 23. Dots of coloring material are outputted onto paper in order from the largest pixel, and manuscripts with letters and printed halftone photographs are outputted from the printer section 12 with good reproducibility.

In addition, when the document reading section 1 reads a document portion such as a photograph of a landscape or a person whose brightness or color changes gradually and the document reading signal changes little between neighboring pixels, the edge detection section 10 detects a small value. An edge detection signal 22 is output. At this time, the output selection section 11 is connected to the first pixel selection section 5.
The first output pixel signal 1 outputted from the first output pixel signal 1 is selected and outputted to the printer section 12 as a selected output pixel signal 23. The amount of change in the document reading device 13 is determined by the first additional data 15
In most cases, the amount of change is small compared to the amount of change, so dots of the coloring material are outputted onto paper almost in order from the pixels with the largest first additional data 15. Therefore, if you use a concentrated dither pattern like the one shown in Figure 3, the number of isolated dots output to the printer will be reduced, and the brightness and color will change gradually, such as in photographs of landscapes and people. The original document is also output from the printer unit 12 with good gradation reproducibility and image quality.

Furthermore, when the document reading section 1 reads a document portion that is the boundary area between the photograph and the text, the output selection section 11 outputs the second output j plane pixel signal 2o output from the second pixel selection section 8. is selected and outputted to the printer unit 12 as a selected output pixel signal 23, so that color material dots are immediately output from pixels with a large second additional data addition signal 19, which is obtained by adding the second additional data 18 to the original reading signal 13. will be printed on paper. Since the amount of change in the original reading signal 13 is not necessarily smaller than the amount of change in the second additional data 18, output pixels are determined depending on the original reading signal 13 and the second additional data 18. Tip 9: For originals with little change in brightness or color, the pixels to be output to the printer are determined depending on the second additional data 18, and for originals in which brightness or saturation changes, the pixel to be output to the printer is determined depending on the original reading signal 13. Determine the pixels to be output to the printer. Therefore, as the second additional data 18 uses data known as a concentrated dither pattern shown in FIG. This will result in printer output suitable for this area.

Note that in this embodiment, the sum calculation section 2 and the edge detection section 10. The first output pixel selection section 6 and the second output pixel selection section 9 processed a rectangular area consisting of 166 pixels of 4 pixels in the vertical and horizontal directions as a unit. An area of 64 pixels (vertically and horizontally 8 pixels), 4 pixels vertically and 8 pixels horizontally
Any collection of adjacent pixels, such as a 32-pixel region, may be used as a unit of processing.

Furthermore, in this embodiment, the edge detection unit 10 calculates the sum of the absolute value of the difference between the document reading signals of the pixels adjacent to each other on the left and right sides and the absolute value of the difference between the document reading signals of the pixels adjacent to each other above and below.
Any device may be used as long as it can detect areas with large changes in brightness or saturation of the document, and for example, a filter known as a Laplacian filter may be used.

Further, in this embodiment, the number of additional data and the additional data adding section is two each, but it may be constructed using N additional data and additional data adding sections.

Effects of the Invention As described above, the present invention includes an output pixel number calculation unit that outputs an output pixel number signal that is the number of pixels to be output to the printer, N pieces of additional data, and addition of different additional data to the document reading signal. N output pixel selection units select the pixels of the number of pixels indicated by the output pixel number signal in ascending order of the additional data addition signal, respectively, and output the output pixel signal, and select the output pixels in descending order of the original reading signal. An N+1st output pixel selection unit selects the number of pixels indicated by the number signal and outputs the N+1st output pixel signal, and a part of the document where the change in the document reading signal between neighboring pixels is large or small. An edge detection section detects whether the document is a document portion and outputs an edge detection signal, and in response to the edge detection signal, outputs the N+1st output pixel signal for a document portion where there is a large change in the document reading signal between neighboring pixels. is selected, and as the change in the original reading signal becomes smaller between neighboring pixels,
An output selection section is provided that selects an output pixel signal generated from an additional data addition signal obtained by adding larger additional data to a document reading signal, and outputs a selected output pixel signal.

As a result, in document parts where there are large changes in the document reading signal between neighboring pixels, such as documents with text or halftone photographs of printing, dots of coloring material are output onto the paper in order from the pixels with the largest document reading signal. In document parts where the brightness and color change gradually, such as photos of people, etc., and the change in the document reading signal between neighboring pixels is small, dots of coloring material are outputted onto paper in the order of increasing dither pattern. In addition, in the case of a document at the boundary between a document with halftone photographs of text or printing and a document with gradual changes in brightness or color, such as photographs of landscapes or people, the additional data addition signal, which is the addition of the document reading signal and the additional data, may be large. Output dots of color material on paper from the pixel. This means that originals with halftone photographs of text and printing, originals with gradual changes in brightness and color such as photographs of landscapes and people, and originals with boundaries between the two types of originals have different reproducibility. You will get a good printer output of

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an image processing system according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a conventional image processing system, and FIG. 3 is an explanatory diagram of a dither pattern in this embodiment. 1... Original reading unit, 2... Output pixel number calculation unit, 3... First additional data storage unit, 4...
...First attachment, complete data addition unit, 5...First pixel selection unit, 6...Second additional data storage unit, 7
... second additional data addition section, 8 ... second pixel selection section, 9 ... third pixel selection section, 1o.
...Edge detection section, 11...Output selection section,
12...Printer section, 13...Original reading signal, 14...Output pixel number signal, 16...
...first additional data, 16...first additional data addition signal, 17...first output pixel signal,
18...Second additional data, 19...Second
additional data addition signal, 2o... second output pixel signal, 21... third output pixel signal, 22...
... Edge detection signal, 23 ... Selected output pixel signal, 31 ... Original reading section, 32 ... Output pixel number calculation means, 33 ... Output pixel selection section ,3
4...Printer section, 35...Original reading signal, 36...Output pixel number signal, 3γ...
...Output pixel signal. Name of agent: Patent attorney Toshio Nakao and one other person
1 Figure M 2 U:! '37 Figure 3

Claims (1)

[Claims] a document reading unit that optically reads a document and outputs a document reading signal converted into a digital signal; and a document reading unit that receives the document reading signal as input and outputs an output pixel number signal having a size proportional to the sum of the plurality of document reading signals. an output pixel number calculation section; an N additional data storage section (N is an integer of 1 or more) that stores and outputs additional data each consisting of a plurality of numerical values; N additional data adders that sequentially output added values with additional data (an integer less than or equal to N) as a K-th additional data addition signal; The pixels of the number of pixels indicated by the output pixel number signal are selected in descending order of the additional data addition signal.
N output pixel selection sections that output output pixel signals; and a plurality of output pixel selection sections that receive the document reading signal and select pixels of the number of pixels indicated by the output pixel number signal in descending order of the plurality of document reading signals. an N+1 output pixel selection section that outputs an N+1 output pixel signal; an edge detection section that receives the original reading signal and outputs an edge detection signal responsive to a difference value of the original reading signal; and a size of the edge detection signal. an output selection section that selects one of the N+1 output pixel signals and outputs it as a selected output pixel signal in response to the selected output pixel signal; and a printer section that outputs the coloring material onto paper in response to the selected output pixel signal. An image processing system comprising: