JPH04865A - Method of processing picture - Google Patents

Abstract

PURPOSE:To prepare a histogram which is less influenced by a non-picture area on a screen by preparing the histogram in such a way that the screen is divided into small areas following a dividing pattern corresponding to the picture on the screen and weights are given to every picture element of each small area so that lighter weights can be given to small areas which are less in picture occupying area. CONSTITUTION:A picture processing section 42 fetches the density value D of a specific picture element from picture data (density values) stored in a picture storing section 41 and discriminates the small area to which the fetched picture element data belong, with the small area being formed by dividing a screen in accordance with a dividing pattern. The section 42 then finds the coefficient corresponding to the small area and calculates weighting frequency to the picture element data by multiplying the coefficient by the number of picture elements. Thereafter, the section 42 adds the weighting frequency to a histogram. The addition of the weighting frequency is performed against the density level frequency corresponding to the density value of the picture element data. By performing the above-mentioned process, the histogram is prepared by integrating weighting frequencies of picture elements in such a way that lighter weights given to small areas which are less in picture occupying area. Therefore, the influence to the histogram from a non-picture area becomes smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image processing method, and particularly to an image processing method for creating a histogram.

[Conventional technology]

In an image processing device such as a league printer, an image recorded on microfilm or the like is irradiated with light from a light source, and the light that passes through the image is magnified several times to several tens of times through a lens and projected onto a screen. .

The amount of light is detected by scanning the screen containing this projected image with an optical sensor such as a CCD, and the image is recorded on the recording material based on the image signal output from the optical sensor according to the detected amount of light. do.

In addition, in an image processing device such as a league printer, a histogram is created based on an image signal output by an optical sensor. This histogram is created by measuring the density of all pixels constituting the screen, and summing up the number of pixels having that density level for each density level, or calculating the ratio to the total number of pixels. This histogram is used for processing such as adjusting the amount of light detected by the optical sensor and determining whether the film on which the image is recorded is a negative film or a positive film.

[Problem to be solved by the invention]

However, conventional histograms are created with all pixels constituting the screen as targets. Therefore, if a non-image part such as a black frame around the image or a blank area is projected onto the screen, the pixels of the non-image part will be included in the histogram, making it difficult to create a histogram corresponding to the image. could not.

In order to solve this problem, it is possible to create a histogram by sampling the central part of the screen as a representative value of the entire image, but in the case of an image where two pages are recorded on one image plane, the central part of the screen Since non-image parts such as frames and blank areas are projected onto the image, it is not possible to create a histogram corresponding to the image. Further, in an image recorded with a newspaper or the like, a photograph may be placed in the center of the image, and in this case, it is not preferable to use the center as the representative value of the entire image.

The present invention has been made in consideration of the above facts, and an object of the present invention is to obtain an image processing method that can create a histogram that is less affected by non-image portions on the screen.

[Means to solve the problem]

In order to achieve the above object, an image processing method according to the present invention is an image processing method that detects the density of a screen containing an image with a sensor and creates a histogram of the image, and divides the image according to the image on the screen. A histogram is created by dividing the screen into small areas in a number of turns, reducing the weight of small areas where the proportion of images contained in each small area is small, and weighting each pixel in each small area. It is characterized by

[Effect]

In the present invention, the screen is divided into small areas according to the division method (turn) according to the image on the screen, and the weight of the small area where the proportion of the image contained in each small area is small is reduced. A histogram is created by weighting each pixel. Therefore, the weight is reduced for pixels in small areas where non-image areas occupy a large proportion, so a histogram that is less affected by non-image areas on the screen is created. be able to.

Therefore, for example, in the case of an image in which two pages are recorded in one image, the screen is divided using a division pattern in which the small area corresponds to the central area where the non-image part is projected, and the weight of the pixels in the small area is reduced. Since the histogram is created based on the images, it is possible to create a histogram with less influence from non-image parts.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a reader printer 10 to which the image processing method of the present invention can be applied. Konori-da printer 10
A screen 16 for projecting the image recorded on the microfilm 14 is arranged on the front surface of the casing 12 (right side in FIG. 1). Further, a line sensor 17 is arranged on the back side of the screen 16 along the vertical direction of the screen 16. Both ends of the line sensor 17 in the longitudinal direction are inserted into a guide shaft 19 extending in the lateral direction of the screen 16 . Thereby, the line sensor 17 is moved in the axial direction of the guide shaft 19 by the driving force of a driving means (not shown), and can scan and photometer the image projected on the screen 16.

A cartridge 18 containing a layered layer of microfilm 14 is loaded into a loading section 20 provided slightly below the screen 16, and the tip of the microfilm 14 inside the cartridge 18 is placed inside the device. is wound onto a take-up reel 22. Cartridge 1
A microfilm 14 is placed between the winder 8 and the winder 22.
A light source 24 is installed correspondingly. The light beam emitted from the light source 24 passes through image frames arranged along the optical axis, and is guided toward the screen 16 via an optical system composed of a lens 26 and a plurality of reflective mirrors 28. ing. Thereby, the image recorded on the microfilm 14 can be enlarged and projected onto the screen 16. A keyboard 92 is arranged near the screen 16. The keyboard 92 is connected to the control device 38 (see FIG. 2(B)), and the user specifies the image 1 to be searched, the division pattern described later, etc. by operating the keys.

The league printer 10 also includes a digital printer 32.
It is equipped with This digital printer 32 has the role of recording the image projected on the screen 16.

That is, due to the switching, the line sensor 17
The analog image signal output from the control device 38 (
The image data is converted into digital image data (see FIG. 2B) and subjected to image processing, and an image is recorded on a recording material (not shown) based on the processed image data.

FIGS. 2A and 2B show details of the loading section 20. Car) +J Tsuji 18 is the supply side reel 3
4 (hereinafter simply referred to as the reel 34) is the torque control section 36
A supply motor 40 connected to the control device 38 via
The rotating shaft 42 is connected to the rotary shaft 42 of the The supply motor 40 is rotated with a constant, weak torque in the direction of winding the microfilm 14 onto the reel 34 (in the direction of arrow A in FIGS. 2(A) and 2(B)). reel 34
The tip of the microfilm 14 wound up in layers is
The cartridge 18 is pulled out from an opening 44 provided in the cartridge 18 by the driving force of a loading roller of a loading mechanism (not shown), wound around guide rollers 46 and 48, and then wound onto the take-up reel 22. Film detection sensors 49 and 51 for detecting the presence or absence of the microfilm 14 are arranged near each of the guide rollers 46 and 48.

The outer periphery of an endless conveyor belt 52 is in contact with the shaft 50 of the take-up reel 22 . This conveyor belt 52 has elasticity and is wound around guide rollers 54, 56, 58. Further, the conveyor belt 52 is wound around a drive reel 66 attached to a rotating shaft 64 of a take-up motor 62 connected to the control device 38 via a speed controller 60. Therefore, the conveyor belt 52 is moved in the direction of arrow B in FIGS. 2A and 2B and in the opposite direction in accordance with the rotation of the drive wheel 66.

The microfilm 14 is transported between the conveyor belt 52 and the shaft 50.
It is held between the conveyor belt 52 and is wound onto the shaft 50 or pulled out from the shaft 50 according to the movement of the conveyor belt 52.

A driven roller 68 is in contact with the conveyor belt 50 .

This driven roller 68 is attached to a rotating shaft 72 of an encoder 70, so that the driving state of the conveyor belt 52 can be detected by the encoder 70 as a pulse number. Encoder 70 is connected to control device 38 .

A slit plate 74 is provided between the guide roller 46 and the guide roller 48 slightly closer to the guide roller 46 than the optical axis, and a pair of light-receiving elements 76 are provided corresponding to both ends of the microfilm 14 in the width direction. installed.

Corresponding to the light receiving element 76, an LED 78 is attached to the opposite side of the microfilm 14, and the light receiving element 76 receives the light emitted from the LED 78 and transmitted through the microfilm 14. The light receiving element 76 and the LED 78 are each connected to the control device 38.

There are blip marks 8 on both ends of the microfilm 14.
0 is assigned, and the presence or absence of the blip mark 80 can be detected based on a change in the amount of light received by the light receiving element 76.

The distance M between the light receiving element 76 and the optical axis is constant (75 mm in this embodiment).
After detecting the image frame 14A specified in 6, it can be positioned to a position along the optical axis by moving it by the dimension M.

The control device 38 includes a conversion section 39, an image storage section 41, and an image processing section 42. The converter 39 converts the analog image signal (photometric value) output from the line sensor 17
is converted into digital image data corresponding to the pixels of the image and output to the image storage section 41. The image storage section 41 is composed of a plurality of storage devices such as image memories, and stores the image data output from the conversion section 39 and the image data after image processing in correspondence with pixels. The image processing section 42 reads the image data stored in the image storage section 41, performs various image processing including creation of a histogram according to the image processing method of the present invention, and writes the data into the image storage section 41. Further, the image storage unit 41 of the control device 38 stores screen division patterns as shown in FIGS. 5(A) and 5(B). Figure 5 (A) shows a screen division pattern for creating a histogram when one page's worth of images is projected at the center of the screen, and Figure 5 (B) shows two screen division patterns.
This is a screen division pattern for creating a histogram when images for pages are projected. The control device 38 is configured to perform processing using one of the above-mentioned division patterns specified by the user operating the keyboard 92.

Further, each of the small regions divided by each division pattern is given a coefficient for weighting.

This coefficient is determined so that the weight of a small region in which the proportion of the image contained in each small region is small becomes lighter, that is, the numerical value decreases. For example, in the division pattern shown in FIG. 5(B) that is specified when two pages of images are projected onto the screen, the non-image portion is included in the small area corresponding to the projected central portion of the screen. occupies a small proportion, and the coefficient assigned to this small area is the smallest "1" among the coefficients assigned to each small area. Control device 38
The image storage unit 41 stores this coefficient in association with each small area.

Next, the operation of this embodiment will be explained.

First, the image search operation by the league printer 10 will be described.

When the cartridge 18 is loaded (determined, for example, by the on/off state of a microswitch, etc.), the loading mechanism operates, and the outer circumferential loading roller of the microfilm 14 comes into contact with the microfilm 14 to pull out the leading end. The pulled-out microfilm 14 passes through guide rollers 46, 48, reaches the winding wheel 22, and is connected to the conveyor belt 52 and shaft 5D.
sandwiched between. As a result, microfilm 1
4 is wound up by a predetermined amount onto the shaft 50, the movement of the conveyor belt 52 is stopped and the conveyor belt 52 enters a standby state.

Here, if you specify an image frame using the keyboard 92,
The take-up motor 62 is driven, the conveyor belt 52 is moved, and the microfilm 14 is taken up onto the shaft 50 at the same time.

In the light receiving element 76, when the microfilm 14 is transported, the L
Each blip mark 80 passing between the ED 78 and the light receiving element 76 is counted. When a predetermined number of counts have been made, the light receiving element 76 transports the light by the distance between the detection point and the optical axis, and the drive of the take-up motor 62 is stopped. Thereby, the positioning of the designated frame on the optical axis is completed, and the image transmitted by the light source 24 can be projected onto the screen 16.

Next, the process of creating a histogram by image processing according to the present invention on an image projected on the screen 16 will be explained with reference to the flowchart of FIG.

In step 100, photometry of the image projected onto the screen 16 by the line sensor 17 is performed.

This is done by moving the line sensor 17 in the axial direction of the guide shaft 19 while the image is projected onto the screen 16. In step 1O2, the analog image signal (photometric value) input from the line sensor 17 into the control device 38 is logarithmically converted in the converter 39, and then digitally converted to digital image data corresponding to the density value of each pixel. Convert to In step 104, the image data converted in step 102 is made to correspond to n pixels and is stored in the image storage unit 4 as image data D1...D.
1 image memory.

In step 106, it is determined whether a division pattern has been specified. When the image is projected onto the screen 16, the user checks the image and operates the keyboard 92 to designate a division pattern. At this time, if one page worth of images is projected on the screen 16, the image pattern shown in FIG. 5(A) is designated, and if two pages worth of images are projected on the screen 16, the 5. Specify the division pattern shown in Figure (B). In the determination at step 106, if a division pattern is not specified, step 106 is repeated until the division pattern is specified. Once the division pattern is designated, the process moves to step 108, where the designated division pattern and the coefficients assigned to each small area are read out and taken into the image processing section 42.

Hereinafter, in steps 110 to 116, a histogram is created using the image processing method of the present invention. That is, in step 110, the density value of a specific pixel is read out from the image data (density value) stored in the image storage section 41 and taken into the image processing section 42. In step 112, it is determined to which of the small areas divided by the division pattern the pixel data captured in step 116 belongs,
Find the coefficient corresponding to the small area, and multiply this coefficient by the number of pixels (in this example, since 1 pixel is processed, t, number of pixels = 1)
), and calculates the weighted frequency (relative frequency) of the pixel data.

In step 114, the weighted frequency of the pixel data obtained in step 112 is added to the histogram. This weighted frequency addition is performed for the frequency of the density level corresponding to the density value of the pixel data.

By performing the processing of steps 110 to 114 on all pixels, the histogram shown in FIG. 7 can be created. In step 116, it is determined whether processing has been completed for all pixels on the screen. Fourth
As shown in the figure, in this embodiment, the image data is processed in correspondence with the scan lines on the screen 82 (in the direction of arrow C in Figure 4), and after the processing for one scan line is completed, the process is performed on the next scan line. Move (in the direction of the arrow in FIG. 4) and perform the same processing. If the processing for all scan lines has not been completed, the process returns to step 110, and steps 110 to 116 are performed according to the processing order.
Repeat to create a histogram. When the processing for all scan lines is completed, the histogram creation ends.

Through the above processing, a histogram is created in which weights are reduced for small regions in which the proportion of images included in each small region is small, and weighted frequencies of pixels are integrated. As a result, compared to the case where a histogram is created without weighting as in the past (see Figure 6), the histogram created by the image processing method of the present invention has an image area that is different from a non-image area such as a frame. The frequency of becomes relatively large. Therefore, the ratio of the frequency of the non-image portion to the frequency of the entire screen becomes small, and the influence from the non-image portion is reduced.

In this way, in this real right, the screen is divided into small areas using a division pattern that corresponds to the image on the screen, and each small area is Since the histogram is created by weighting each pixel, it is possible to create a histogram that is less influenced by non-image areas on the screen.

In addition, when performing processing such as adjusting the amount of light detected by the line sensor 17 and determining whether the film on which the image is recorded is a negative film or a positive film using the histogram created in this embodiment, the influence from the non-image portion Since it is possible to use a histogram with a small number of errors, processing can be performed more accurately.

In addition, in this embodiment, two types of patterns shown in FIGS. 5(A) and 5(B) are shown as screen division patterns.
The present invention is not limited to this, for example, the area of the small region may be further reduced, and a division pattern corresponding to the case where an image of three or more pages is projected onto the screen may also be used. .

Further, in this embodiment, the photometric values output from the line sensor 17 are converted into density values, but it is also possible to convert them into brightness values and create a histogram.

Furthermore, the histogram created by the image processing method of the present invention can be used for processes other than adjusting the amount of light detected by the line sensor 17 and determining whether the film on which the image is recorded is a negative film or a positive film. Not even.

〔Effect of the invention〕

As explained above, in the present invention, the screen is divided into small areas using a division pattern according to the image on the screen, and each small area is Since the histogram is created by weighting each pixel in the area, it is possible to create a histogram that is less affected by non-image areas on the screen.
This excellent effect can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a league printer according to this embodiment,
Figure 2 (A) is a perspective view of the vicinity of the cartridge loading section;
Figure (B) is a schematic block diagram of the vicinity of the cartridge loading section;
FIG. 3 is a flowchart explaining the operation of this embodiment, FIG. 4 is a conceptual diagram explaining the processing order, and FIG. 5 (A)
and (B) are conceptual diagrams showing the division pattern of this embodiment and the coefficients given to each small area, FIG. 6 is a diagram showing a histogram created without weighting, and FIG. 7 is a diagram showing the histogram created without weighting. FIG. 3 is a diagram showing a histogram created by weighting. IO... League printer, 17... Line sensor, 32... Digital printer, 38... Control device, 39... Conversion section, 41... Image storage section, 42... Image processing section . 10th: Ready/Return 17: Line sensor 32: DIGITAL L-FLINK diagram (A) (B) diagram

Claims (1)

[Claims] (1) An image processing method that detects the density of a screen containing an image using a sensor and creates a histogram of the image,
The screen is divided into small regions using a division pattern that corresponds to the image on the screen, and weights are applied to each pixel in each small region by reducing the weight of the small regions in which the proportion of the image contained within each small region is small. An image processing method characterized by creating a histogram.