JPS61125282A - Shade removal method - Google Patents

Abstract

PURPOSE:To remove only the shade between adjacent pages generated when a book is copyed by detecting the positions, where the distance from the edge of an original receiving stage to the first white portion detected changes at the rate specified, as the beginning edge and ending edge and replacing the shade between both edges with a white signal. CONSTITUTION:A read signal, obtained by scan and exposure of a book original on the original receiving stage 1 from light source not shown in the figure, is recorded in a memory of a microcomputer not shown in the figure. The shade in the direction of scanning is detected, or the one in the direction of subscanning is detected if that shade does not exist. The shade removal process is done only when it is detected that either shade exists.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for removing shadows, and more particularly, to a novel method for removing shadows that are peculiar to those that occur when copying book manuscripts.

<Prior art> Conventionally, in order to prevent shadows from appearing in copied images and deterioration of image quality, the following methods have been used: ■ Limiting the average level of image reading signals and removing reading signals with a level below the average level. (Japanese Unexamined Patent Publication No. 57-887
(Refer to Publication No. 8), ■ Binarize the image reading signal, calculate the black level run length, and if the run length is greater than a predetermined value, the black level (by replacing the black level signal with the white level signal, Copy image with pasted shadows removed (7 things)
(Refer to Japanese Unexamined Patent Application Publication No. 147563/1983), ■ Copying in which parts other than the original are whitened by converting all the binary signals from the scanning start point to the point where the level first changes to the own level signal. There are image processing methods such as those for obtaining an image (see Japanese Unexamined Patent Publication No. 165065/1983).

However, the above item (■) is intended to ensure that the background of the copy is white even if the background of the original is a color other than white, and when copying a book manuscript,
It does not remove the shadow between two adjacent pages that occurs in a copy, but considering that this shadow usually has a density very similar to that of the original image, only two shadows are removed. I can't.

In addition, in the case of item (■) above, when the black level continues to exceed a predetermined amount, this part is determined to be a shadow and is expressed as white in the copied image, but for book manuscripts. When copying, the shadow between two adjacent pages that appears in the copy varies depending on the number of pages in the book manuscript, the configuration of the spine, etc. On the other hand, if you want to remove the above shape, you have to reduce the threshold for making the black level the white level,
If the threshold value is made small, there is a problem in that when a black level part exists over a fairly wide range, such as in a photographic image in a document, this black level part is set as the self level.

In addition, the above method (■) only covers the range from the scanning start point to the point where the level first changes to the own level, so when copying a book manuscript, the adjacent The shadow between the two pages cannot be removed or covered.

<Purpose> This invention was made in view of the above problems,
It is an object of the present invention to provide a shadow removal method that can reliably remove only the shadow between two adjacent pages that occurs in a copy when copying a book manuscript.

<Structure> In order to achieve the above object, the shadow removal method of the present invention detects the position where the distance from the edge of the document table to detecting and covering the first white part changes by a predetermined percentage or more. starting end,
1! It detects each edge as an edge and replaces the shadow between the two edges with a white signal.When copying a book, it detects the shadow between two adjacent pages in the copy. A high-quality copy can be obtained by detecting the shadow and coloring the part that should be a shadow in white.

However, if the starting and ending parts of the shadow are detected on the edge of the document placement table facing h, the shadow distribution can be detected with high accuracy, and By detecting the start and end of the shadow for at least one of the opposing edges, the shadow distribution can be detected with high accuracy regardless of the direction in which the book manuscript is set. ,preferable.

Furthermore, if the ranges of shadows detected for mutually opposing edges do not overlap, then within the intermediate range between the two ranges, the first white color from the edge of the document table in each of the above ranges is By replacing the range up to the detection of the white part with a white signal centered around the maximum distance until the white part is detected, the above type of detection can be performed with high viscosity even if the book original is set diagonally. It is possible and most preferred.

<Example> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings showing examples.

FIG. 1 is a diagram showing the relationship between the document mounting table (1) and the book document (2), and FIG. The area 1ii1i (3) corresponding to the shadow between the two pages extends perpendicularly to the sub-scanning direction (arrow X direction in the figure),
- Figure 8 shows a state in which the area 11i+31 extends at right angles to the main scanning direction (direction of arrow Y in the figure);
3 shows a state in which the region (3) extends obliquely with respect to both scanning directions.

Then, the above manuscript mounting table (1) ten book manuscripts (2)
is scanned and exposed using a light source (not shown), and the read signal obtained is recorded in the memory of a micro combi coater (not shown), etc.
Based on this read signal, the shadow area can be determined and the whitening process can be performed as follows.

FIG. 2 is a flowchart for performing the above-mentioned determination and processing, in which a shadow extending in the main scanning direction is detected in step (2), a judgment is made in step (2) whether or not there is a shadow extending in the main scanning direction, and a shadow extending in the main scanning direction is determined in step (2). If it doesn't exist, step■
Detect a shadow extending in the 01 scanning direction at step
It is determined whether a shadow extending in the sub-scanning direction exists or not, and only when it is determined that a shadow exists in any of steps (■), shadow removal processing is performed in step (2).

Therefore, as shown in FIGS. 1A and 1R, even if the edge directions of book manuscripts are different, shadow areas can be reliably detected and shadow removal processing (whitening processing) can be performed.

Figure 3 shows step ① above! This is a flowchart showing details of step 1, in which the read signal level is compared with a predetermined level set in advance from the main scanning start position in the main scanning direction, and a count is taken until the comparison result changes. . Then, in step (2), the ratio of the count value of the current line to the count value of the previous line is calculated, and in step (2), it is determined whether or not the F distribution is greater than or equal to a predetermined ratio.

If the above ratio is less than or equal to the predetermined ratio, in step (2), the line for comparing the read level and the predetermined level is shifted by one line in the sub-scanning direction (direction of arrow A1 in FIG. 1C), and in step 0, It is determined whether or not it is the final line in the scanning direction, and if it is not the final line, the determination and processing from step (2) onwards are performed again.

If it is determined in step (2) that the above ratio is greater than or equal to the predetermined ratio, then in step (2) the current line (C
The line indicated by the coordinate x 1 in the X-axis direction) is moved to the detection position at the end of the beam, and in step [phase], the sub-scanning direction is reversed (direction of arrow A2 in Fig. 1C), and step In step (2), it is determined whether or not sub-scanning has been performed twice, and if it has been performed only once, the determination and processing below in step (2) are performed again to determine the line as the detection position (Fig. 1C [11X
A line (indicated by coordinate x 2) in the axial direction is obtained.

If it is determined in step 2 that it is the last line, or if it is determined that sub-scanning has been performed twice in step [phase], the direction in which the +2 count is taken is reversed in step (1) from the other edge until the comparison result changes), line as the detection position (coordinate x 3 in the X-axis direction in Figure 1C)
line) is obtained, and in step 2, it is determined whether or not the detection position from both directions has been obtained. If not, the determination and processing below in step 2 are performed again to determine the detection position from both directions. A line (the line indicated by coordinates x 4 in the X-axis direction in FIG. 1C) is obtained, and if the line is obtained, the determination in step (2) in FIG. 2 is performed.

Further, regarding the details of the process in step (2) in FIG. The only difference from the flowchart in FIG. 3 is that the explanation is omitted.

FIG. 4 is a flowchart illustrating the process of step (J) in FIG. In other words, it is determined whether the ranges of the shadow existing regions detected from the mutually opposing ends of the document table (1) do not overlap or overlap, and only if post-processing is necessary. , in step [phase], post-processing for removing light is performed.

Therefore, if the ranges of shadow regions overlap, the shadows can be completely removed by preprocessing alone; if they do not overlap, preprocessing,
By performing post-processing, it is possible to completely remove the shine.

Figure 5 shows the process of step [phase] in Figure 4.
This is a flowchart that explains in detail, in step (2), the detection position (coordinates in the X-axis direction x1, ) as the starting and ending parts of the shadow, and in step [phase], set the ten raw material loading platform (1
) in the direction (y-axis direction) perpendicular to one edge of The signals are replaced, and in step 0 it is determined whether the count value of the current line is greater than the count value corresponding to the maximum position up to the current line, and if it is,
In step [phase], the count value of the current line is set to the maximum value of 1 to 1, and in step [phase], the line position is shifted by one line in the direction perpendicular to the direction of the step [phase], and in step 0, the current line It is determined whether the line corresponds to the end of the shadow, and if the line does not correspond to the end, the determination and processing in step [phase] and subsequent steps are performed again.

If it is determined in step (2) that the value of the current line is smaller, the determination and processing in step [phase] and subsequent steps are performed as is.

In addition, if it is determined in step 0 that the line corresponds to the terminal end, in step
value (coordinate y5 in the X-axis direction in Figure 1 C) and the line position corresponding to the maximum count value (coordinate y5 in the X-axis direction in Figure 1 C)
5) is recorded in a memory, etc., the scanning direction is reversed (opposite to the y-axis direction) in step [phase], and it is determined whether scanning has been performed twice in step O, and if scanning has been performed only once. If not, perform the determination and processing following step ① again, and calculate the maximum count value (coordinate y6 in the direction of the axis in Figure 1 C) and the line position M corresponding to the maximum count value (X in Figure 1 C). Record the coordinates in the axial direction x 6) in memory, etc., and
If the process has been repeated twice, the determination in step (2) in FIG. 4 is made.

FIG. 6 is a flowchart illustrating the process of step [phase] in FIG. 4. In step [phase], the two line positions recorded in step Let the coordinates in the direction x 5° x 6) be the start and end points, set the count value corresponding to one line position (coordinate y5 in the y-axis direction) as the maximum position in step [phase], and set a3 in step ω. 5 above
In the flowchart shown in the figure, the read signal level is
The read signal is compared with a predetermined level set in advance, and the read signal is replaced with the signal of the own level for the range from the maximum position to the change of the comparison unity, and in step [phase], the signal is replaced in the opposite direction to the step ω. (in the direction opposite to the y-axis direction), compare the read signal level with a preset predetermined level, The above read signal is replaced, and the line on which the read level and the predetermined level are compared in step (3) is shifted by one line in the direction (X-axis direction) perpendicular to the direction of step ω [present], and in step O, the line for comparing the read level with the predetermined level is shifted by one line. Determine whether or not is the end point set in step O, and if tJ is the end point, step ω
The following processing is performed, and if it is the end point, the determination and processing following step [phase] is performed.

The step [phase] is the other line position (coordinate in the X-axis direction ×
This step sets the count value (coordinate y6 in the y-axis direction) corresponding to step 6) as the maximum position, and then, in step [phase], it is determined whether or not the above determination and processing have been performed twice, that is, in FIG. Based on each count value (coordinate V5ry6 in the y-axis direction) corresponding to the two line positions (coordinate in the X-axis direction x 5° x 6) obtained in the flowchart, it is determined whether the above discrimination and processing have been performed or not. However, if it has been performed only once, the determination and processing from step ω is performed again, and if it has been performed twice, the shadow removal process is completed.

In the above embodiment, regardless of the orientation of the book original (2) set on the original placing table (1), when the book original is copied, the adjacent By replacing the reading signal of the area (3) corresponding to the shadow between the two pages with the white level signal, the above area (3)
) can be reliably removed. In addition, in the above explanation, the coordinate x 5° x 6 is actually the coordinate x
2. This will match x3.

However, if it is possible to control the direction of the book document placed on the document table (1) to a certain extent, it is possible to omit the process of removing shadows as shown in FIG. Various settings may be made within the scope of not changing the gist of
It is possible to make one change in history.

Effect> As described above, the present invention detects the position where the distance from the edge of the document U table until the first white part is detected changes by more than a predetermined rate, such as the starting edge and the ending edge of the shadow. Detect each,
I changed the shadow between both ends with a white signal, so
This has the unique effect of being able to reliably remove only the shadows between adjacent pages that occur when a copy of a book manuscript is obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the relationship between the document placement table (1) and the book document (2), and FIGS. 2 to 6 are flowcharts showing the shadow removal operation.
. (1)...Manuscript mounting table, (2)...Book manuscript,
(3)...area corresponding to the shadow

Claims (1)

[Claims] 1. The first white part from the edge of the document placement table The distance until detection is at least a predetermined percentage The changing position is the start and end of the shadow. and detect the shadow between the two ends. Shadow characterized by replacement with white signal Removal method. 2. About the opposite edges of the document table Detect the starting and ending parts of the shadow. A shadow removal method according to claim 1. 3. Opposing each other in the main scanning direction and sub-scanning direction For at least one of the edges, The above patent detects the start and end of a shadow A shadow removal method according to claim 2. 4. Shadows detected on mutually opposing edges If the ranges of do not overlap In the middle range between the above ranges, and the document mounting table in each of the above ranges. until the first white part is detected from the edge of The white area is centered around the maximum distance at Set the range until the minute is detected using a white signal. The claim described in claim 2 above which converts Shadow removal method.