JPH06291973A - Picture reader - Google Patents

Abstract

PURPOSE:To detect a border line between a frame and a picture area with high accuracy by selecting picture data at a predetermined pitch of a lattice shape, storing the selected data to an edit RAM and comparing sequentially the selected data at an interval corresponding to sharpness of a border between a picture area and a frame area. CONSTITUTION:A picture signal read through preliminary scanning is fetched at an interval of 2mm and stored in an edit RAM. When a left side of a picture area is detected, data are sought in the X direction as to each line in the Y direction. In this case, data apart by two coordinates are sequentially compared. When a difference between two data exceeds at first a reference value, suppose that a position between the two coordinates is a frame object coordinate of the left side. The processing above is executed as to all lines in the Y direction. Since the interval of storage pitch of the edit RAM is spaced in this way, even when a border between the frame and the picture area is not clear and a density difference between adjacent picture data is small in the edit RAM, the border line between the frame and the picture area is surely detected with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for reading an original image such as microfilm to generate image data with a frame area removed and outputting the image data to a printer or the like.

[0002]

2. Description of the Related Art An image on a microfilm is projected on a screen and read by a photoelectric conversion element to obtain an image data.
There is provided an image reading device (reader scanner device) having a function of generating an image and outputting the image data to a printer to print an image on a sheet. .

In the above reader / scanner device, generally, the image data corresponding to the frame area of the microfilm is removed from the image data, so that the frame area becomes black solid on the paper. The function to prevent it from being printed out is added. This is not only because the solid black portion is unsightly, but also because of the demand for suppressing toner consumption in the printer.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
By removing the image data corresponding to the frame area of the microfilm from the data without excess or deficiency, there is no image loss,
In addition, in order to obtain a good print image in which unsightly black streaks are not formed around the image, it is necessary to accurately detect the boundary line between the frame area and the image area.

However, in the reader / scanner device, since the microfilm is projected and read on the photoelectric conversion element, the border between the frame and the image area becomes unclear due to the influence of the lens or the like, and the border becomes unclear. The line detection accuracy may deteriorate. In that case, a defect such as a defect occurring at the peripheral portion of the print image or conversely, unsightly black streaks are formed around the print image is likely to occur.

In Japanese Patent Publication No. 4-65371, (1) it is possible to prevent unsightly black streaks from being formed around a printed image by processing as a frame area slightly inside the detected boundary line. Disclosed is a device capable of selecting a mode and (2) a mode in which an area slightly outside the detected boundary line is processed as a frame area to obtain a print image without image loss. ing. In the mode (1), some image defects are likely to occur, and in the mode (2), black streaks are easily formed around the printed image.

According to the present invention, in the image reading apparatus, even when the boundary line between the frame area and the image area is unclear, the boundary line can be detected with high accuracy, thereby solving the above-mentioned problems. With the goal.

[0008]

SUMMARY OF THE INVENTION The present invention is an image reading apparatus for reading an original having a frame area around the image area and generating image data with the frame area removed; preliminary operation Data management means for selecting the image data read by the method at a predetermined grid-like pitch and storing it in the edit RAM; and the image data in the edit RAM for the image area and the frame area. Computing means for finding a coordinate group representing the boundary portion by sequentially comparing from line end side of each line forming the grid at intervals corresponding to the sharpness of the boundary portion of the grid; And a means for determining the frame area on the basis of the coordinate group thus created.

[0009]

The image data read out in pairs from the editing RAM by the calculating means has an interval corresponding to the sharpness of the boundary between the image area and the frame area, for example, the editing RA.
It is spaced from each other by twice the storage pitch of M. Therefore, the boundary between the frame area and the image area is unclear,
Even if the density difference between the adjacent image data in the edit RAM is small, the boundary line between the frame and the image area is surely and
It is detected accurately.

[0010]

Embodiments [1] Mechanism of Embodiment Device FIG. 23 is a schematic view showing a mechanism of a reader-scanner device 1 of the embodiment, and FIG. 24 is a system in which the reader-scanner device 1 is installed. It is a perspective view showing appearance.

The reader / scanner device 1 irradiates the microfilm set on the microfilm carrier 4 and projects the transmitted light on the screen 9 for viewing or the transmitted light. Is a device for generating image data by projecting light onto the photoelectric conversion element 12.

The reader / scanner device 1 includes a condenser lens 3 that collects light from a light source 2 and guides it to a microfilm, a projection lens 5 that guides light transmitted through the microfilm to a scanning mirror 7, and an image. It has a rotating prism 6.

When the power is turned on, the leader is set as the initial state.
The mode is set. Therefore, the light transmitted through the film from the projection lens 5 through the image rotation prism 6 and reflected by the scanning mirror 7 is further reflected by the reflection mirror 8 and reaches the screen 9, where the screen 9 is exposed. Projected on top.

When a reading mode is instructed from an operation switch or the like (not shown), the scanning mirror 7 is rotated, and the image on the microfilm is scanned with this rotation, and the photoelectric conversion element 12 is scanned. Are read line by line.
That is, in the reading mode, the film transmitted light reflected by the rotating scanning mirror 7 from the projection lens 5 through the image rotating prism 6 is further reflected by the reflecting mirror 10 and the reflecting mirror 11. Then, the photoelectric conversion element 12 is reached. The image signal generated by the photoelectric conversion element 12 is a sample hold circuit, an amplifier circuit, an A / D converter.
After being processed by a known image processing circuit having a computer, a comparator, etc., an optical disk storage device (not shown) or FIG.
No. 4 laser printer 20 or the like.

[2] Outline of Processing When a printout of a microfilm is instructed by an operation switch or the like (not shown), the reader / scanner apparatus 1 first performs a preliminary scan and then a main scan. Is done. That is, the processing is executed according to the procedure shown in the flowchart of FIG.

First, it is determined whether the microfilm is a negative film or a positive film (S1
1). This judgment is made by operating a switch (not shown)
If the positive is designated, it is performed based on the designation. If there is no designation from an operation switch (not shown) or the like, it is performed by comparing the lightness and darkness of the entire microfilm with a threshold value during prescan (preliminary scan). As shown in FIG. 2, in the negative film, the frame is a low density portion and the image area is a high density portion (hatched portion). The reverse is true for positive films. However, in the frame recognition process (S13) to be executed next, for example, in the case of negative film, the fact that the data changes from "small to large" at the boundary of "frame → image area" is used. I'm looking for a frame. That is, the negative /
The frame recognition process changes depending on the positive. Therefore, first, it is necessary to determine the negative / positive. When the negative / positive is unknown, both of them need to be detected and compared as shown in FIG. 3, resulting in a long processing time.

Next, frame recognition is performed (S13). Details of this frame recognition processing (S13) will be described later, but the outline of FIG.
The process is performed according to the procedure shown in the flowchart. First,
Candidate boundary lines between the frame and the image area, that is, coordinate groups presumed to constitute the upper, lower, left, and right boundary lines are detected from the upper, lower, left, and right sides (S21). Next, it is checked whether or not the detected coordinate groups are continuous, and if there are coordinates at positions far apart in the continuous coordinate group, the coordinates are corrected to positions on the continuous line (S23). Next, linear equations representing the upper, lower, left, and right boundaries are calculated (S25). This calculation is performed based on the continuous coordinate group having the largest number of coordinates among the continuous coordinates. Finally, the coordinates of the intersections (four corners) of the upper, lower, left, and right boundaries are calculated (S27), and the frame and the image area are identified.

When the frame recognition (S13) is completed in this way, next, an AE (automatic exposure) process (S15) is performed to set the light amount of the light source 2 during the main scan. This setting is performed based on only the data in the image area identified in the frame recognition process (S13). This enables optimum exposure control that is not affected by the frame.

After that, the image is output within the image output range set according to the mode, such as centering for printing on the central portion of the paper at the same size or full framing for printing by enlarging the output paper size. To print accordingly,
The main scan for the print operation is performed (S17).

[3] Details of Processing Next, details of the frame recognition processing (FIG. 15) will be described in the above step S2.
1, step S23, step S25, and step S27 will be described in this order.

[3-1] Search for candidates (S21) The photoelectric conversion element 12 is prescanned from the lower end side of the image.
The image signal read in step (1) is processed as described above to form image data, and then, as shown in FIG. 1, it is fetched at a pitch of 2 mm and stored in the edit RAM. For example, 400dp
If i, one dot is 63.5 μm, so 3
Captured every 1.496 dots. This edit RAM
As shown in FIG. 4, image data can be stored from the address (00,00) to the address (105,148). this is,
Since the A4 size is 210 x 297 mm, when storing at a 2 mm pitch as described above, (210/2 = 105,297 / 2 = 14
This is because 8).

A coordinate group which is presumed to constitute a boundary line between the frame and the image area (upper and lower left and right boundary lines), that is, a frame candidate coordinate group is detected based on the data of the edit RAM.
For example, in the case of detecting the frame on the left side of the image area as shown in FIG. 16, each line in the Y direction (the 0th line to the 148th line) has Xs as shown by a group of broken line arrows A in FIG. Data is searched for in the direction.

First, the coordinates of the left end of the line (X = 0
0) is used as a reference coordinate and the data is read out.
(S102). Further, the data of the second coordinate (X = 02 in this case) from the reference coordinate in the X direction is read (S10
3). Next, the two read data are compared (S
104). As a result, if the difference is less than or equal to a certain predetermined value (= reference value) (S105; NO), the reference coordinate is moved one coordinate in the X direction.
(S109: In this case, X = 01) After the data of that coordinate is read out (S102), the second coordinate (X = 03 in this case) in the X direction is read in the same manner as above. It is compared with the data (S
103, S104).

In this way, the reference coordinates are moved one by one in the X direction, and the comparisons are sequentially performed. As a result, when the difference between the two read data exceeds the reference value for the first time in the line (S105; YES), a certain position between the two coordinates (this certain position). Is determined as the frame candidate coordinates on the left side of the line and stored (S106).

Next, the object to be processed is moved by one line in the Y direction (S107), and the moved lines are sequentially compared from the left end side in the same manner as above (S102 to S104).
The frame candidate coordinates on the left side of the line after the movement are searched (S10
Five). Although not shown in the process of FIG. 16,
Even if the reference coordinate becomes the second coordinate from the right end as a result of the reference coordinate being moved in the X direction by searching as described above,
When the frame candidate coordinates on the left side have not been detected on the line, the processing target is naturally moved by one line in the Y direction.

In this way, all lines in the Y direction (0th line
When the search for the left-side frame candidates for lines (line to 148th line) is completed (S108; YES), the right-side frame candidate coordinates, then the upper-side frame candidate coordinates, and finally the lower-side frame candidate coordinates are
Sequentially searched.

The search for the frame candidate on the right side is performed by searching for data in the negative direction of X for each line in the Y direction as shown by the broken line arrow group B (FIG. 7). Each line in the X direction (the 0th line to the 10th line) is indicated by a group of broken arrows C
(5 lines) in the Y direction to search for frame candidates on the lower side by searching the data in the Y negative direction for each line in the X direction as shown by the broken line arrow D group. Each is done.

In this frame candidate search process (S21), the frame candidate coordinates are not searched by comparing the data of the reference coordinates with the data of the next coordinates, but as described above, I am looking for it by comparing it with the data of the next (skip one and the second) coordinates. This is because the density change at the boundary between the frame and the image area is comparatively gentle, and therefore a difference of the predetermined value (= reference value) cannot be obtained between the data of the adjacent coordinates. is there.

That is, the image data (image density) is defined by the border between the frame and the image area where the image changes from white to black on the screen.
Does not change rapidly, but tends to change gently as shown in FIG. For example, until the image density of 10 in the low density portion (frame) reaches 80 in the high density portion (image area), there is an interval of 2 pitches (4 mm), and the image density in the middle is 50.
Is. In addition, the characteristic that the change of the image data at the edge portion of the image is gentle in this way occurs in the defocused image, the sharpness of the lens, the positional relationship between the sensor and the edge, and the photometry. It may inevitably occur due to variations. Note that FIG. 5 shows that the density at the edge portion of the image (for example, the circle immediately above the shaded circle in the figure) is between white (frame portion) and black (image area portion). It is a thing.

Next, an example of a method for specifying the frame candidate coordinates will be described with reference to FIG. As described above, the density difference between the image data of the standard coordinates and the image data of the next and next coordinates (coordinates separated by 2 pitches = 4 mm) is the predetermined value which is the first predetermined value on the line. When (= reference value) is exceeded, a certain position between the reference coordinate and the next next coordinate is set as a frame candidate coordinate.

This certain position is shown in FIG. 13 as the reference coordinate, the coordinate next to the reference coordinate, and the coordinate next to the next coordinate.
It is specified based on one image data. That is, the density difference between the image data of the standard coordinate and the image data of the next coordinate, and the density difference of the image data of the next coordinate and the image data of the next next coordinate are calculated. Then, the certain position is specified based on the ratio of the two density differences. For example, in the example on the left side of FIG. 13, since the ratio of the density differences is “1: 1”, the intermediate position between the reference coordinate and the next next coordinate is set to the certain position. In the example on the right side of FIG. 13,
Since the density difference ratio is “3: 1”, the space between the reference coordinates and the next next coordinates is divided into four equal parts, and 1 is calculated from the reference coordinates.
The second division position, that is, the 0.5 mm position is specified as the certain position.

The reason why the frame position is precisely determined according to the densities of the three points is that the data for detection is 2 mm as described above.
This is because the pitch is relatively coarse and printing can be performed dot by dot, so it is meaningful to determine the frame position more precisely. Note that the process may be simplified by specifying the intermediate point between the reference coordinate and the next and next coordinates as the certain position instead of specifying the image density as shown in FIG. .

[3-2] Check for continuity (S23) With respect to the frame candidate coordinates found in step S21, the continuity is checked in order by the procedure shown in the flowcharts of FIGS. 17 and 18. To be done. Hereinafter, description will be made with reference to FIG.

First, the first data is used as a reference, and its coordinate value is compared with the coordinate value of the next data (S20).
3). As a result, if the difference between the X direction and the Y direction is 1 or less (2 mm or less), these two data are considered to be continuous (S204; YES) and saved (S241). , The continuous number is counted (S242). Further, the last data stored (in this case, the next data in this case) is used as a reference (S243) and compared in the same manner as above. That is, the coordinate value of this newly set data is compared with the coordinate value of the next data (S203) and processed in the same manner. For example, in FIGS. 8A to 8C, there are cases where the X direction is discontinuous but the Y direction is continuous. Also, ~ is the X direction and Y.
This is the case when the direction is continuous.

If the result of comparison is that the difference exceeds 1, (S204; NO), one is skipped and compared with the coordinate value of the next data (S205). As a result, if the difference is 2 or less (4 mm or less), it is considered that these data are continuous (S206; YES), and the data skipped above is compared. The coordinate is corrected to an intermediate coordinate between the two data (S221). After that, the data is saved (S241), the continuous number is counted (S242), and then the last saved data.
Is set as the reference (S243), and the processing similar to the above is continued based on the newly set data. For example, ~ in Fig. 8 is discontinuous, and ~ and the following ○.
The circled 10 is also discontinuous, but the circled 10 is Y
Since the difference in direction is 2, it is considered continuous (S206; YES),
It is corrected to the coordinates in the middle of 10 surrounded by ∘ and ○ (S221).

If it is determined that the data is discontinuous in step S206 (S206; NO), another one is skipped and the coordinate value of the next data is compared (S207). As a result, if two intermediate data items are skipped and compared and it is determined that they are continuous (S208; YES), these two intermediate data items are corrected in the same manner as described above (S231). ), Then
Data storage (S241), continuous count (S242), reference data
The update of the data (S243) is performed in the same manner as above. In this way, by correcting the coordinates of one or two data in the middle (see S221 and S231), there is an adverse effect when the frame candidate coordinates are erroneously detected due to scratches or dust on the microfilm. Is prevented.

On the other hand, if it is determined in step S208 that the data is discontinuous (S208; NO), the data up to the reference data is continuous, and the next data is no longer continuous. It is judged (S209). Therefore, the storage location of the continuous coordinate group is moved (S210), the data next to the reference data is set as the reference, and the new reference data is set.
A new continuous coordinate group is searched for based on the target (S211).

[3-3] Calculating linear equation (S25) From the plurality of continuous coordinate groups searched in step S23, the continuous coordinate group having the largest number of continuous lines is picked up and the continuous coordinate group is selected. Based on the procedure shown in FIG. 19, linear equations representing the boundaries between the frame and the image area are calculated for each of the upper, lower, left and right sides. However, if the number of consecutive picked-up continuous coordinate groups is less than a certain reference number, no calculation is performed on the sides of the consecutive coordinate group. This is because it is uncertain whether or not it is a true frame when the number of consecutive characters is too small. Hereinafter, description will be made with reference to FIG.

First, the maximum value, the minimum value, the difference, and the average value of the coordinates of the picked-up continuous coordinate group are calculated (S301). Here, when the linear expressions of the left side and the right side are calculated, the X coordinate is calculated, and when the linear expressions of the upper side and the lower side are calculated, the Y coordinate is calculated.

Next, it is judged whether or not the difference between the maximum value and the minimum value is 2 or less. If it is 2 or less (S302; YES), the linear expression is not calculated, and the coordinates of the average value of the side are calculated. Indicates the section of the side (S307). That is, the side is the edit R
It is treated as if it is not tilted with respect to the coordinates of AM. This is because, due to the configuration of the sensor and photometry, even if there is no inclination, a variation of about one coordinate will always occur. Therefore, if the difference is 2 or less, it is treated as if there is no inclination. It is designed to prevent black frames and defects.

On the other hand, when the difference exceeds 2, (S302; N
O), X of the fifth data from the beginning of the continuous coordinate group
・ Y coordinate and (S304), XY of the fifth data from the end
From the coordinates (S305), the linear equation of the side corresponding to the continuous coordinate group is calculated (S306). That is, the linear equation is not calculated based on the coordinates of both ends of the continuous coordinate group, but the linear equation is calculated based on the coordinates slightly inside. By doing so, it is possible to avoid the influence of the broken ear and the influence of the shift of the image edge at the time of photometry.

[3-4] Obtaining the coordinates of the intersection (S27) Based on the linear equation of each side calculated in step S25, the image area of the image area is processed by the procedure shown in the flowcharts of FIGS. The coordinates of the four corners are calculated. Hereinafter, FIGS.
The description will also be made with reference to.

When all the straight line equations indicating the upper, lower, left and right sides are obtained (S401; YES), the coordinates of the four corners are calculated from the intersections thereof (S402).

If only three sides among the upper, lower, left, and right sides are determined (S403; YES), the coordinates of two points are determined as the intersections of the linear expressions of the three sides (S411). The other two points can be obtained from the frame candidate coordinate group as the coordinates of the opposite ends of the two points obtained as the intersections (S412).

For example, the upper two points in FIG. 10 are respectively determined as the intersection of the left side and the upper side, and the intersection of the right side and the upper side.
For the other two points, the coordinates of the lower edge of the left side, and
It is obtained as the coordinates of the lower edge of the right side. Here, the coordinate of the end (lower end) on the opposite side is detected as a frame candidate coordinate of the side in the process of searching for a candidate (S21), and is necessary in the process of checking whether it is continuous (S23). In the coordinate group corrected as shown in FIG. 8 according to the above, the coordinate at the opposite end is referred to. The accuracy can be increased by checking whether the left side and the right side are parallel to each other.

If only two sides are obtained (S405; YE
S), different processing is performed depending on whether it is two parallel sides or two orthogonal sides. In case of two parallel sides (S
421; YES), as shown in FIG. 12, the coordinates of both ends thereof are respectively obtained from the frame candidate coordinate group (S422). Here, the coordinates of both ends are the same as the definition of "end" in "when three sides are determined". If there are two orthogonal sides (S42
1; NO), as shown in FIG. 11, the coordinates of one point are obtained as the intersection of the linear equations of the two sides (S423). Further, two points adjacent to this one point are respectively obtained from the frame candidate coordinate group as coordinates of the ends on the opposite side of the two sides (S424). Also, the remaining one point is
It is calculated based on the above three points (S425).

As described above, even when not all the sides are obtained, the four corners of the image area can be determined when the two sides or the three sides are obtained. The frame can be recognized even in the image.

It should be noted that only one side is obtained, or
If no side has been obtained (S405; NO), it is determined that there is no frame (S407). In this way, in this embodiment, the boundary line between the frame and the image area is determined.

[0049]

As described above, according to the present invention, even when the boundary line between the frame and the image area is unclear like the projection image of the microfilm, two image data to be compared and detected to detect the boundary line. Since the interval between the data is relatively long, it is possible to detect the boundary line reliably and accurately. Therefore, even on the printer side which performs printing based on the output data of the apparatus of the present invention, it is possible to prevent the occurrence of defects such as the formation of black streaks around the printed image and the loss of the peripheral edge of the printed image. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a reading pitch of data.

FIG. 2 is an explanatory diagram showing a state in which the density of a frame is reversed in a negative / positive film.

FIG. 3 is an explanatory diagram showing a determination method when the negative / positive is unknown.

FIG. 4 is an explanatory diagram showing coordinates on an edit RAM.

FIG. 5 is an explanatory diagram showing that the density difference between adjacent data is relatively small at the boundary between the frame and the image area.

FIG. 6 is an explanatory diagram showing that the density of data does not change abruptly but gradually rises at the boundary between the frame and the image area.

FIG. 7 is an explanatory diagram showing that the left side is searched from the left side, the right side is searched from the right side, the upper side is searched from the upper side, and the lower side is searched from the lower side when searching the coordinates forming the boundary line between the frame and the image area. .

FIG. 8 is an explanatory diagram of a method for determining whether or not the coordinate groups forming the boundary line are continuous.

FIG. 9 is an explanatory diagram of a method in which the inclination is 0 ° or 90 ° when the difference between the maximum value and the minimum value of the X or Y coordinates of the coordinate group forming one side of the boundary line is 2 or less. .

FIG. 10 is an explanatory diagram showing a method of obtaining coordinates of four corners of an image area when three sides of a boundary line are found.

FIG. 11 is an explanatory diagram showing a method of obtaining coordinates of four corners of an image area when two sides of a boundary line are found.

FIG. 12 is an explanatory diagram showing a method of obtaining coordinates of four corners of an image area when two sides of a boundary line are found.

FIG. 13 is an explanatory diagram of a method of accurately obtaining the position of a frame.

FIG. 14 is a flow chart showing the outline of the sequence of operations of the apparatus of the embodiment.
It is a chart.

FIG. 15 is a flowchart showing a procedure of processing for obtaining a frame.

FIG. 16 is a flowchart showing the procedure for searching for the coordinates forming the boundary line between the frame and the image area on the left side.

FIG. 17 is a flowchart showing a part of the procedure for determining whether or not the coordinate groups forming the boundary line are continuous.

FIG. 18 is a flowchart showing the rest of the procedure for determining whether or not the coordinate groups forming the boundary line are continuous.

FIG. 19 is a flowchart showing a procedure for calculating an expression representing a boundary line.
It is a chart.

FIG. 20 is a flowchart showing a procedure for obtaining coordinates of four corners of an image area.

FIG. 21 is a flowchart showing a procedure for obtaining coordinates of four corners of an image area when three sides of a boundary line are found.

FIG. 22 is a flowchart showing a procedure for obtaining coordinates of four corners of an image area when two sides of a boundary line are found.

FIG. 23 is a schematic view showing the mechanism of the device of the example.

FIG. 24 is a perspective view showing the external appearance of a system in which the apparatus of the embodiment is installed.

[Explanation of symbols]

 2 light source 7 scanning mirror 9 screen 12 photoelectric conversion element (reading element)

Claims (1)

[Claims] 1. An image reading apparatus for reading an original having a frame area around an image area and generating image data with the frame area removed, wherein image data read in a preliminary operation is read. Is selected at a predetermined pitch in a grid pattern and stored in the edit RAM, and the image data of the edit RAM is sharpened at the boundary between the image area and the frame area. And a coordinate group searched for by the calculating unit for calculating a coordinate group representing the boundary portion by sequentially comparing each line forming the grid from the line end side at intervals corresponding to An image reading device having means for determining the frame area based on the above.