JPH02195776A - Method and device for inspecting color image - Google Patents

Abstract

PURPOSE:To perform the inspection of the quantity of color slippage suitable for real human vision by finding the maximum quantity of slippage between colors separated most at distance and a color with the maximum quantity of color slippage, and evaluating a color image by the maximum quantity of slippage and the color with the maximum quantity of color slippage. CONSTITUTION:An arithmetic processing unit 78 performs the setting of threshold values CT, MT, YT, and KT for the binarization of each image signal from each profile of cyan, magenta, yellow and black, and that of the central positions C*, M*, Y*, and K* of a line consisting of each color material. Next, the unit 78 calculates d0...d3 in equation I by using the central positions C*, M*, Y*, and K* of each line. A color with the maximum quantity of slippage Slipping from a black color material which becomes reference based on the value (d) is found. Then, the maximum quantity d0 of slippage and the color CC with the maximum quantity of slippage can be found. Furthermore, the unit 78 calculates the quantity H of evaluation of color slippage based on the maximum quantity d0 of slippage and the color CC with the maximum quantity of color slippage. The quantity H can be obtained from equation II, and the value of the quantity H is visualized by an output device 83.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] This invention relates to color image inspection for inspecting the quality of □particularly color images among the quality of images reproduced by copying machines, printers, printing machines, etc. The present invention relates to a method and apparatus, and particularly relates to a color image inspection method and apparatus capable of determining the amount of color shift as one of the inspection items for color reproducibility.

[Prior Art] In offices, various information devices output graphic information such as text and images. A typical example of this is a copying machine that copies original documents. A copying machine forms an electrostatic latent image on a photosensitive drum, reads image information using an image sensor such as a COD, and develops the image using a developing device, or uses a recording head such as a thermal head. Images are reproduced on paper.

When designing such information devices or shipping these information devices from a factory, the reproduced images are inspected. There are two types of such tests:

(1) Inspection of whether the information equipment operates normally according to predetermined procedures and reproduces images.

(2) Inspecting whether the quality of the reproduced image is acceptable in the market or within the specifications established at the time of equipment design.

For example, in the case of a copying machine, the inspection items include the position of the image relative to the copied paper, the density of the image relative to the original, and the resolution. The inspector uses a scale, magnifying lens, measuring device, or visually to check whether each process of the copying machine is working properly and that there are no errors in image reading or toner image transfer position. Determine whether or not. In the case of copying machines, the latter inspection is also performed by an inspector. That is, the quality of the image is determined by the inspector directly comparing the image transferred to the paper with the sample.

In conventional inspections as described above, the inspector is the main person, so
There were the following problems.

(1) Measured values or test results changed due to different testers.

(2) Measured values or test results changed even by the same tester due to familiarity with the test or due to the psychological influence of the test subject tested previously.

(3) Measured values and test results also changed due to physical and mental fatigue of the examiner.

In order to avoid such drawbacks, an image inspection device that automatically performs inspection has been proposed (Japanese Patent Application Laid-Open No. 103-1989).
45 and JP-A-59-10346).

This image inspection apparatus is provided with a table on which an object to be inspected having an image is positioned and placed.

The object to be inspected is set on this table, and the detection section is placed opposite to it. Then, the detection data output from this detection section is supplied to a data processing section, and the position, density, and resolution of the image are digitized based on the detection data.

However, in this proposed image inspection apparatus, since the detection section sequentially detects several predetermined patterns, only standardized inspections can be performed. For example, it is assumed that for a certain information device to be inspected, only density inspection is required, and for other information devices, resolution inspection is required at many locations of the object to be inspected. Since the proposed image inspection apparatus performs a standardized inspection on all objects to be inspected, the former information equipment is subjected to unnecessary inspections, which wastes inspection time. Furthermore, with the latter type of information equipment, there was a risk that the inspection points would be insufficient.

Of course, the latter inspection can be accomplished by incorporating a program that performs many inspections at many locations on the object to be inspected, but such image inspection equipment requires simple inspection. There is a problem in that the object to be inspected is inspected more inefficiently.

Above, we have explained intra-membrane image inspection, but recently, color copying or color recording has become common.
Image inspection of these items is also required. When the object to be inspected is a color image, colors other than predetermined colors are reproduced by mixing several colors.

In other words, when reproducing a color image in a device such as a xerographic copying machine (electrostatic copying machine) or a thermal transfer type recording device, generally, when reproducing a color image, the three color materials of cyan, magenta, and yellow, or ink ( An image is formed using four color materials including black.

FIG. 27 is for explaining this principle. After image information on a document (not shown) is selectively absorbed by a filter (not shown) on the photosensitive drum 301,
Slit exposure is performed in the direction shown by arrow 302. Although not shown, a charge corotron (charger) is arranged around the photosensitive drum 301, and an electrostatic latent image is formed by this exposure operation. The formed electrostatic latent image is developed by a developing device 303 to form a toner image.

This toner image is transferred to a recording paper 305 wrapped around a transfer drum 304 disposed close to the photoreceptor drum 301.
transcribed into. For this purpose, a transfer device 306 is used.

When performing color recording, the above-mentioned filters are sequentially set to desired ones, color materials are selected correspondingly, and toner images of one color are transferred onto the recording paper 305.

When color reproduction is performed by sequentially overlapping color materials in this way, the amount of color shift becomes a problem as one of the factors that influences color reproducibility. In other words, if color misregistration occurs in the process of reproducing each color, the quality of the image will deteriorate significantly, especially in line drawings and text areas.

For example, blue characters are reproduced by a subtractive color mixture of magenta and cyan, but if the positions of these two colors shift during the recording process, the characters become blurred and extremely difficult to read. Further, in the case of a pattern image, the influence of the positional shift (11) appears on the reproduced pattern itself, and there is a problem that accurate color reproduction cannot be performed.

Therefore, the amount of color shift has been conventionally measured for reproduced images. Conventionally, such color shift has been measured using a method in which a color image of the object to be inspected is enlarged and projected using a microscope, and an inspector directly reads the color shift.

As described above, when the inspector himself visually inspects the images, there is a problem in that inspection errors are likely to occur, as described above.

Therefore, in order to solve the above problem, the proposed image inspection device described above should detect the density of the three primary colors in addition to the detection of black and white density, thereby making it possible to perform unique inspections of color images such as color shift. It is considered. However, when measuring color shift by simply detecting the density of each of the three colors, the influence of unnecessary absorption of the coloring materials used appears, making it impossible to accurately determine the recording position of each coloring material.

For example, the yellow coloring material actually used includes not only yellow but also magenta and cyan to a small extent. Therefore, 1. When trying to detect the color separation density of blue to test yellow color, the two colors magenta and cyan contained at the same time in the color material have absorption in the blue region, and the magenta color and cyan color The cyan color portion will also be detected at the same time. As a result, it is no longer possible to ideally separate only the yellow color portion from other colors. In this way, simply extending the proposed image inspection device described above for three colors will not be able to completely separate the cyan, magenta, and yellow images, and the relative error in the recording position of each color material will increase. The inspection of the "color shift amount" will be incomplete.

Therefore, the present applicant has developed an automatic color image inspection system that solves the above problems, allows the inspection contents to be freely set according to the object to be inspected, and can accurately inspect the amount of color shift. We have already proposed the device
Publication No. 3673).

This automatic color image inspection device includes an inspection object holding means for holding an inspection object having an image composed of a plurality of inspection patterns, and a supply supply for supplying the inspection object to the inspection object holding means. means for selecting a pattern to be inspected from among the objects to be inspected held in the object to be inspected holding means; Alternatively, the optical density measuring means detects the density of a predetermined chromatic color, the moving means moves the optical density measuring means to an image reading position, and the data obtained from the optical density measuring means is used to determine the color of a color image. The image forming apparatus is configured to include a color shift amount detection means for determining the shift amount.

In this device, as shown in FIG. 28, the maximum value max(dl, dl, dl, dl,
2, d3) can be detected and color image inspection can be performed automatically.

[Problems to be Solved by the Invention] However, the above prior art has the following problems. That is, in the case of the color image automatic inspection apparatus described above, the maximum value of the amount of color deviation of the image is detected by the color deviation amount detection means, and the color image is inspected based on this maximum value of the color deviation amount. ing.

However, as a result of researching the correlation between the amount of color shift measured as described above and the feeling of color shift felt when viewing an actual color image, the inventors found that It was found that there is a difference between the visual sense of color shift and the visual sense of color shift.

In other words, it has been found that even if the maximum value of the amount of color shift is the same, the impact on human vision differs significantly depending on which color out of cyan, magenta, yellow, or black is shifted the most. For example, as shown in FIG. 29A, if magenta, yellow, and black overlap each other, and only cyan is shifted from these colors by a distance equal to the maximum shift amount dO, the color The deviation will be the most noticeable. In comparison, as shown in Figure 29B,
Even if the natural maximum dO of color shift is the same, if cyan, yellow, and black overlap each other, and only magenta is shifted from these colors by a distance equal to the maximum shift dO, then , the color shift is standard and noticeable. Furthermore, as shown in Figure 29C, even though the maximum color shift ff1dO is the same, cyan, magenta, and black overlap each other, and only the yellow color overlaps with these colors by a distance equal to the maximum shift 1ndo. If there is a shift, the color shift will be the least noticeable.

Therefore, there is a problem in that if only the maximum value of the amount of color shift in a color image is detected, it is not possible to detect a color shift matrix that accurately corresponds to human vision.

[Means for Solving the Problems] Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to improve the amount of color shift that more accurately corresponds to human vision. An object of the present invention is to provide a color image inspection method and apparatus that enable inspection.

That is, the color image inspection method according to the present invention reads a specific inspection pattern on an object to be inspected, detects the optical density of this inspection pattern as the density of an achromatic color and a predetermined chromatic color, and then detects the optical density of the achromatic color. Based on the density peak position and the predetermined chromatic color optical density peak position, determine the maximum amount of deviation between the colors that are the farthest apart from each other among achromatic colors and the specified chromatic color, and the color with the largest amount of color deviation. The color image is evaluated based on these maximum deviations and the color with the largest amount of color deviation.

Further, the color image inspection method according to the present invention is an optical density detection method that reads a specific inspection pattern on an object to be inspected and detects the optical density of the read inspection pattern as the density of an achromatic color and a predetermined chromatic color. The peak position of the achromatic optical density and the peak position of the predetermined chromatic color optical density detected by the optical density detection means are determined, and the colors that are the most distant from each other among the achromatic color and the predetermined chromatic color are determined. color shift amount detection means for detecting the maximum shift amount of , and the color with the maximum color shift m, and the color shift amount detected by the color shift amount detection means and the color with the largest color shift amount. The system is configured to evaluate color images.

For example, black is used as the achromatic color.

Further, as the predetermined chromatic color, for example, cyan, magenta, and yellow are used, but the present invention is not limited thereto, and it goes without saying that other chromatic colors may be used. Further, the number of chromatic colors is not limited to three.

Furthermore, the amount of color shift mentioned above takes into consideration, for example, the amount of shift of other colors such as cyan, magenta, and yellow with respect to black, but is not limited to this (but is not limited to this). Of course, the amount of deviation between the two colors may also be used.

[Function] According to the color image inspection apparatus according to the present invention, as explained in the configuration of the color image inspection method, a specific inspection pattern on the object to be inspected is read, and the optical density of this inspection pattern is adjusted to an achromatic color. and the predetermined chromatic color concentration, and then based on the peak position of this achromatic color optical density and the predetermined chromatic color optical density peak position, the distance is the farthest between the achromatic color and the predetermined chromatic color. Find the maximum amount of deviation between colors and the color with the largest amount of color deviation,
A color image is evaluated based on these maximum deviation values and the color with the largest color deviation 1.

As described above, in the color image inspection method and apparatus according to the present invention, the maximum deviation between colors that are the farthest apart from each other among achromatic colors and predetermined chromatic colors and the color with the largest amount of color deviation are determined. Since the color image is evaluated based on these maximum color shift stones and the color with the largest color shift, simply find the maximum value of the color shift amount and evaluate the color image based on this maximum color shift amount. It also detects the color with the largest amount of color shift that has a greater impact on the human eye, and evaluates the color image including this, so it automatically evaluates color images that are closer to human vision. can be done.

[Example] The present invention will be explained below based on the illustrated embodiments.

Outline of the Apparatus FIG. 1 shows the appearance of a color image inspection apparatus according to an embodiment of the present invention. This color image inspection apparatus includes an inspection section 1, a computer section 2, and a printer section 3.

Of these, the inspection section 1 is a section that continuously inspects copy paper 4 as an object to be inspected. The inspection section 1 includes a supply tray 5 and a discharge tray 6. When inspecting a copying machine, set the desired chart in the copying machine,
The copy sheets 4 thus obtained are stacked on the supply tray 5 as shown. The copy sheets 4 are fed into a cylindrical chart holder 8 one by one by a feed roller 7. The surface of the chart holder 8 is covered with an insulating film, and the copy paper 4 is electrostatically attracted to this surface by a charging operation by an electrostatic charge supply device (not shown). In this state, the image inspection of the copy paper 4 as the object to be inspected is performed. The copy paper 4 that has been inspected is peeled off from the chart holder 8 by a peeling mechanism that will be described later. The peeled copy sheets 5 are sequentially discharged onto the discharge tray 6.

An operation display panel 9 is arranged in this inspection section 1.
Disposed here are a power switch 11, a movement key 12 used when manually specifying the pattern of the object to be inspected, and a display 13 that displays density data as a measurement result.

The computer section 2 can be configured by a commercially available computer, and performs the identification of inspection items, processing of data such as concentration data, and various displays. This part includes a keyboard 15 as an input means, a CRT 16 as a display means,
It is equipped with a disk drive device 17 etc. for driving a floppy disk, and a CPLI (central processing unit) etc. for data processing is installed inside.

The printer section 3 is a section that outputs test results, etc.
In this embodiment a dot printer is used.

FIG. 2 shows an outline of the inspection section of this color image inspection apparatus. A shaft 21 for rotating the feed roller 7 of the inspection section 1 receives driving force from a feed roller drive motor 23 via a chain 22 . The supply tray 5 is adapted to be given a force to move upward by the excitation of a solenoid (not shown), and at the time of this excitation, the top layer surface of the copy paper 4 as the object to be inspected comes into contact with the feed row 57. When the feed roller 7 rotates by a predetermined amount in this state, only one sheet of copy paper 4 in the uppermost layer is fed out. Prior to this feeding, the surface of the chart holder 8 is uniformly charged by a charging mechanism (not shown). As a result, the fed-out copy paper 4 is electrostatically attracted to the chart holding section 8.

The rotation of the cylindrical chart holder 8 in the circumferential direction (Y-axis direction) is performed by the driving force of a chart holder drive motor 26 connected to a decelerator 25 .

In this embodiment, the outer diameter of the chart holder 8 is 162 mm.
．． 77 mm, the step angle of the chart holder drive motor 26 is 1.8 degrees, and the reduction ratio of the reducer 25 is 1/25.
It was set at 6. As a result, the chart holder drive motor 26
By driving one step, the chart holding section 8
The surface of will move by 10 μm in the Y-axis direction.

Control of the rotational position of the chart holder 8, that is, control of the position in the Y-axis direction, is performed using the point detected by the 7-point sensor 28, which is a notch 27 provided at the end of the cylinder, as a reference point.

A ball screw 32 rotated by an X-axis stepping motor 31 is arranged above the chart holder 8 so that its axis is parallel to the rotation axis of the cylindrical chart holder 8. The Y-axis direction movement hole 34 of the optical head mounting block 33 is threadedly engaged with the ball screw 32. Therefore, when the X-axis striving motor 31 rotates, the two
It is guided by two guide bars 35 and 36 to move in the X-axis direction.

In this embodiment, the pitch of the ball screw 32 is 5 mm.
It is. By setting the step angle of the X-axis stepping monitor 31 to 0.72 degrees, the optical head mounting block 33 moves by 10 .mu.m in the X-axis direction by driving one step. Two limit switches 3 in the X-axis direction
7.38 is arranged, and the optical head mounting block 3
The movement of 3 [is designed to limit the surrounding area.

A density detection section 41, which will be described next, is attached to the optical head attachment block 33. A magnifying eyepiece lens 42 is also attached to the density detection unit 41, and the position of the image captured by the objective lens 43 can be checked during focus adjustment and especially during manual operation.

In addition, in the color image automatic inspection apparatus of this embodiment, the density detection section 41 has a diameter of 10 μm in both the X-axis direction and the Y-axis direction.
Although it is designed to move at a pitch, it may be set at a finer pitch than this. In this case, for example,
The pitch of the ball screw 32 in the axial direction and the reduction ratio in the Y-axis direction may be made finer.

FIG. 3 shows the optical structure of the optical head.

The concentration detection section 41 includes a tungsten lamp 51 for illumination. The light emitted from the tungsten lamp 51 is focused by the illumination lens 52 and
The measurement site 53 is illuminated. The reflected light from the measurement site 53 is collected by the objective lens 43 and semi-transparent 11 (
The beam is split into two directions by a prism 54 equipped with a beam stabilizer.

One of the split lights is reflected by a mirror 55 and passes through a measurement field of view adjustment mechanism 56 . Here, the measurement field of view adjustment mechanism 56 has an aperture plate 59 and a field lens 61 disposed in the optical path.

The aperture plate 59 is a plate provided with a rectangular opening as shown in FIG. In this 50 μm x 2500 μm opening area, an image of the measurement site on the copy paper is formed with a 5-fold magnification. The short side on the chart, that is, on the copy paper 4 in this example, is 10 um,
The light beam reflected from the rectangular area (FIG. 4) with a long side of 500 μm passes through this opening to the photomultiplier tube 5 described above.
8. The direction of the opening of the aperture plate 59 can be set to an arbitrary angle in units of 1 degree by an aperture plate rotation step motor 62.

The light that has passed through the measurement field of view adjustment mechanism 56 reaches the filter unit 66 after its infrared wavelength component is cut by the color correction filter 57 .

The filter unit 66 includes seven types of color filters 68-1 to 68-7 and one type of light shielding filter 6 around a cylinder 67.
9 are arranged one type each at 45 degrees 1ljF]. The rotary solenoid 70 transmits a driving force to the cylinder 67 via gears, ratchets, and stoppers (not shown), rotates the cylinder 67 at an angle of 45 degrees as one step, and sets the filter unit 66 at a predetermined position. In this state, the light that has passed through any one of the color filters 68-1 to 68-7 is incident on the photomultiplier tube 58, and the optical density is measured.

By the way, the light-shielding filter 69, which plays the role of completely blocking the incidence of light beams to the photomultiplier tube 58, is prepared for the initial setting of the filter unit 66. That is, at the point in time when the cylinder 67 rotates and the light shielding filter 69 is placed opposite the color correction filter 57, no light rays enter the photomultiplier tube 58. This state becomes the initial position of the filter unit 66, and a desired color filter is set for selective absorption of light by performing predetermined step operations. Further, the signal level is also adjusted based on the output of the photomultiplier tube 58 in the initial state in which the light shielding filter 69 is disposed opposite the color correction filter 57.

Now, as the seven types of color filters 68-1 to 68-7, the following filters are used.

Color filter 68-1...Red filter manufactured by Kodak Corporation RATTEN #25 color filter 68-2...Green filter manufactured by Kodak Corporation -RATTEN #58 color filter 68-3...Blue filter manufactured by Kodak Corporation WRATTEN #47 color filter 68-4...B/II filter made by Fuji Film Co., Ltd. SP 18 color filter 68-5...red filter made by Toshiba Glass Co., Ltd. L-63 color filter 68-6...green Filter manufactured by Toshiba Glass Co., Ltd. KL-54 Color filter 68-7... Green filter manufactured by Toshiba Glass Co., Ltd. [-44 Here, the color filter 68-4 is a visual filter, and the output of the photomultiplier tube 58 is This is to change the wavelength characteristics to match human visual perception. Therefore, this filter 68-4 is inserted before the photomultiplier tube 58 when measuring optical density in black and white.

In addition, in this filter unit 66, two sets of color separation filters 681 to 68-3.6 are provided for each of the two color separations.
8-5 to 68-7 are available. One of the filters 68-1 to 68-3 is for a wide band, and the other filter 68-5 to 68-7 is for a narrow band. These can be used selectively depending on the inspection item, and depending on the device, only one set of filters and visual filters may be provided.

The other light branched by the prism 54 has its traveling direction changed by the roof-shaped prism 64, and forms an erect image on the observation screen 65.

The image of the measurement site 53 thus formed can be enlarged and observed using the magnifying eyepiece 42.

Circuit Configuration of the Device (Principle Configuration of the Device) Before specifically explaining the device, the fundamental configuration of the circuit will be explained.

The following FIG. 5 shows an outline of the circuit configuration of the automatic color image inspection apparatus. This device is equipped with external signal input means 72 for instructing desired inspection items.

The measurement control means 73 is configured to set the position and type of the pattern to be inspected and the inspection processing procedure according to the inspection item indicated by the external signal input means 72. The pattern information storage means 74 stores the pattern to be inspected within the object to be inspected, and the processing procedure storage means 75 stores the inspection processing procedure for the pattern to be inspected. The measurement means 76 scans the surface of the object to be inspected under the control of the measurement control means 73 and detects the image density. Arithmetic processing means 7
8 is a processing procedure instructed by the measurement control means 73 to perform arithmetic processing on the data obtained from the measurement means 76. The test results obtained thereby are outputted by the output means 8.3.

The output means 83 is typically the printer section 3 shown in FIG. 1, but the test results can also be displayed on the CRT screen of the computer section 2.

The operation of this automatic color image inspection device will be explained in more detail. In the color image automatic inspection apparatus, the type of the object to be inspected and the inspection items are encoded by the external signal input means 72 during inspection. The chart code 84 for identifying the chart copied to the object to be inspected and the inspection item code 85 representing the inspection item are transmitted to the measurement control means 7.
Sent to 3. The measurement control means 73 sends the chart code 84 to the pattern information storage means 74. The pattern information storage means 74 outputs a representative point position 87 representing the pattern to be inspected included in the chart represented by the chart code 84. Pattern code 86 also includes information representing the color of each pattern. The pattern code 86 is sent to the processing procedure storage means 75 together with the inspection item code 85, and the image density detection format 88 corresponding to the inspection item and pattern to be inspected and the arithmetic processing code 89 representing the arithmetic processing procedure are read by the measuring means 73. It will be complicated.

At this stage, ■ the type of pattern to be inspected required for inspection, ■
The positional information of where the pattern exists on the copy paper, the method of detecting the image si for the pattern, and the method of calculating and processing the results corresponding to the inspection items are stored in the measurement control means 73 as a code. It will be set in a formatted state.

Among these pieces of information, the representative point position 87 representing the coordinates of the position where the pattern exists and the image density detection format 8
8 is sent to measuring means 76.

The measuring means 76 moves to the representative point position 87 instructed by the measurement controlling means 73, and detects the image density to be measured according to the image density detection format 88.

The detection results are output to the arithmetic processing means 78 as a concentration sequence 91. At the end of the density data string 91, an end signal 92 is added to instruct the start of arithmetic processing.

Upon receiving the end signal 92, the arithmetic processing means 78 executes the arithmetic processing code 89 previously supplied from the measurement control means 73.
Based on this, the corresponding calculation processing routine is selected. Then, this arithmetic processing routine is loaded into an internal arithmetic processing routine memory area. The arithmetic processing means 78 includes
The density data string 91 described above is stored in the density data string memory area. The arithmetic processing means 78 processes this concentration data string 91 using the routine loaded into the arithmetic processing routine memory area, and supplies the results corresponding to the test items to the output means 83 as test results.

The output means 83 will output this content.

The image density detection and density data arithmetic processing operations described above are sequentially performed for all patterns to be inspected that are preset in the measurement control means 73. Arithmetic processing means 73
performs arithmetic processing on each pattern, and
It also performs statistical processing of the arithmetic processing results corresponding to all set patterns to be inspected. In this way, the inspection results for the object to be inspected are obtained.

(Configuration of External Signal Input Means) Next, the configuration of the external signal input means will be explained using FIG. 6.

The external signal input means 72 includes encoding means 101. The chart name 102 and test item 103 input by the operator are encoded by the encoding means 101. When the code type discrimination means 104 receives the coded information, it separates it into a chart code and a test item code. Then, it is outputted as a chart code 84 and a test item code 85 via the code control unit 105.

(Structure of Pattern Information Storage Means) FIG. 7 shows the structure of the pattern information storage means. The pattern information storage means 74 supplies the chart code 84 to the pattern information storage position retrieval means 107. The pattern information storage position search means 107 searches for the position of the pattern to be inspected, and searches the pattern information storage unit 1.
08 as a pointer 109.

FIG. 8 shows the contents of the pattern information storage section. The pattern information storage unit 108 stores as data the pattern codes of all the objects to be inspected in the corresponding chart and the representative point positions of the patterns represented by these pattern codes, using the chart code as a key. There is. In this figure, for example, for chart code “Xxx”, there are three pattern codes a1
A and b are available. This means that the chart specified by this chart code “Xxx” has pattern code a,
This means that two types of patterns specified by b are displayed, and the coordinates of the three patterns in total are as shown in the representative point position. Note that the pattern codes a and b are coded taking into account the color represented by the pattern.

Here, the pattern represented by the pattern code a is, for example, the resolution measurement pattern ( (not shown) is used. In this test chart, this pattern is placed in the upper left or lower right part. Also, the pattern represented by pattern code b is
This is a pattern for density measurement in the electrophotographic society test chart. In this test chart, various density samples are displayed in a row at the bottom, forming a pattern for density measurement. In this way, test charts expressed in black and white are often used in color inspections, but if the reproducibility of mixed colors itself is listed as an inspection item, then the The chart will be used.

The pattern information means 110 includes the pattern information storage section 108
The pattern information storage location retrieval means 10 retrieves the contents stored in
The data is read from the position indicated by the pointer 109 output by No. 7. The read contents are all pattern codes related to one chart code indicated by the pointer 109 and their representative point positions. The combination of the pattern code 86 and the corresponding representative point position 87 is sequentially read out under the control of the measuring means 73 shown in FIG. 5 and sent into the measuring control means 73.

(Configuration of processing procedure recording means) Next, the contents of the processing procedure storage means 75 are shown in FIG.

The processing procedure recording means 75 is supplied with an inspection item code 85 and a pattern code 86. Among these, the test item code 85 is detected by the test item code detection means 112.
The pattern code 86 is detected by the pattern detection means 113. The detection result of the inspection item code detection means 112 is outputted as a first pointer 114 to the processing code storage means 115, and
The detection result No. 13 is also output to the processing code storage means 116 as a second pointer 115.

FIG. 10 shows the contents of the processing hood storage means. The processing code storage means 116 stores (1) an arithmetic processing code, (2) a pattern code, and (3) an image density detection code for each inspection item code. The first pointer 114 output from the above-mentioned test item code detection means 112 specifies the test item code for specifying the test item. And pattern detection means 11
The second pointer 115 outputted by No. 3 selects the arithmetic processing code in that test item code.

In the example shown in FIG. 10, for the pattern specified by the pattern code "a", image density detection specified by the image density detection code "I" and calculation processing specified by the calculation processing code "A" are performed. The code content specified by the two pointers 114 and 115 is
It is temporarily stored in a storage area within the processing code storage means 116.

Returning to FIG. 9, the explanation will be continued. Inspection means grinding means 11
7 reads out the image density detection code 118 stored in the processing code storage means 116. In the example of FIG. 10 described above, the image density detection code 118 is "A'°. Then, using this as a base, the third pointer 119 as address information is outputted to the inspection procedure storage means 121.

FIG. 11 shows the contents of the inspection procedure storage means. The inspection procedure storage means 121 stores image density detection formats for each image density detection code. There are multiple sets of image density detection formats, each of which is stored in block units. The contents of these block units are, for example, (1) measurement start position, (2) direction, (3
) interval, (4) total number of points, (5) slit direction, and (6) filter set.

Here, (1) the measurement start position is shown as a position as a representative point. As described above, the representative point is indicated by the coordinates that serve as a reference for each pattern, whereas the counter representative point is the difference between the coordinate value of the starting position when scanning the pattern and the coordinate value of the representative point. (2) The direction is the direction of scanning, and there are two types of directions: the X-axis direction and the Y-axis direction. (
3) Interval is the sampling interval for concentration detection, and (4) Total number of points is the total number of sampled data. (5) The slit direction refers to the direction of the opening of the aperture plate 59 shown in FIG. In this embodiment, the opening is initially set parallel to the X-axis or rotated by 90 degrees from the X-axis.

Further, this opening is set to a desired rotational position in one-degree increments during measurement. By setting this angle, it is possible to effectively measure diagonal lines and the like.

Finally, (6) filter set refers to the light shielding filter 69 or 7 in the filter unit 66 shown in FIG.
This is a signal for selecting the types of color filters 68-1 to 68-7. This signal causes one or more of the red, green, and blue color filters and white/black filters to be selected. If the signal for this filter set selects multiple filters, the filters listed above (1
) to (5) are output to the code output means 1 the number of times.
22 to the measuring means 76. Measuring means 76
Then, the filter unit 66 is set at the desired filter position in response to this, and the operations determined in (1) to (5) above are repeated.

The third pointer 119 specifies the image density detection code. In the example shown in FIG. 11, the image density detection code “
"A" is selected.The first code output means 122
The image density detection format 88 selected by the pointer 119 is read out and supplied to the measurement means 76 under the control of the measurement control means 73 shown in FIG. On the other hand, the second code output means 123 reads out the processing code 89, and similarly supplies it to the arithmetic processing means 78 under the control of the measurement control means 73.

(Configuration of measurement means) The following FIG. 12 shows the contents of the measuring means.

The measuring means 76 can be roughly divided into three parts: an image density detection section, a detection aperture control section, and a moving section. The measuring means 76 moves over the object to be inspected (in this embodiment, the copy paper 4 on which the chart has been copied) based on the image density detection format 88 supplied from the measurement control means 73, and measures the image density in a predetermined format. Image density will be detected. That is, the image density detection format 88 (see FIG. 11) supplied from the measurement control means 73 is supplied to the data sampling control section 131, and based on the format 88 decoded here, the image density detection section and the detection aperture control section , and the moving part will be controlled accordingly.

By the way, the data sampling control section 131 knows the current position of the light receiving means 133 based on the data 133 obtained from the drive control section 132. Therefore, the data sampling t) control unit 131 determines the amount by which the light receiving means 133 should be moved by comparing it with the measurement start position obtained from the image density detection format 88. The obtained data regarding the movement port etc. is sent to the movement control unit 132.

The drive control unit 132 determines the amount of movement in the X-axis direction and the distance between movements in the Y-axis direction based on the data 134, and outputs an X-axis direction drive signal 135 and a Y-axis direction drive signal 136 corresponding to the number of pulses. The X-axis direction drive signal 135 is
The Y-axis direction drive signal 136 is supplied to the axis stepping motor 31, and the Y-axis direction drive signal 136 is also supplied to the chart holder drive motor 26 (see FIG. 2), which also serves as a stepping motor.

As already explained, the concentration detection section 41 (FIG. 2) is moved in the X-axis direction by the X-axis stepping motor 31.

Furthermore, the chart holding section drive motor 26 rotates the chart handling section 8 on the drum in the Y-axis direction, and the receiving optical film 133 consisting of the photomultiplier tube 58 and the like moves to a desired measurement position. .

The data sampling control unit 131 then decodes the image density detection direction, sampling interval, total number of sampling points, slit direction, and filter set. First, the aperture direction is compared with the current aperture direction, and an angle signal 138 representing the comparison result with the designated angle is output.

Angle signal 138 is provided to an angle signal generator 139.

The angle signal generator 139 is connected to the aperture plate rotating step motor 6.
2 (see FIG. 3) is supplied with a control unit @141 to rotate the aperture plate 61 by a desired angle.

Next, the data sampling control unit 131 compares the filter position indicated by the filter set with the currently set filter position, and outputs a filter switching signal 140 to set the filter at the designated filter position. The filter switching signal @140 is provided to a switching pulse generator 142. A switching pulse generator 142 supplies a pulse signal 1 to a rotary solenoid 70 for driving filter switching.
50 and filter 69 in filter unit 66
．． A desired one among 68-1 to 68-7 is inserted into the optical path.

When the setting of the light receiving means 133 is completed as described above,
The data sampling control section 131 sets the total number of points obtained from the image density detection format 88 in a counter (not shown) within the control section. Then, the image density detection direction and the sampling interval are outputted to the drive control section 132 as data 134 and set.

The drive control section 132 moves the concentration detection section 41 or the chart holding section 8 by a predetermined amount in accordance with the instructed detection direction.

By the way, the detection output 14 output from the light receiving means 133
3 is amplified by an amplifier 144 in the image density detection section, its output 145 is logarithmically converted by a logarithmic converter 146, and a converted output 147 is supplied to an A/D converter 148. A/D
The converter 148 includes an A/D signal generator 149 and an A/D signal 151 for specifying the time at which A/D conversion is performed.
is being supplied. A/D signal signal generating section 149 - A supplied from the data sampling control section 131
The A/D signal 151 is generated by the /D start signal 152, but the A/D start signal 152 is the data sampling I
The output of a counter (not shown) in the control unit 131 is used.

That is, this counter is preset with a count value corresponding to the measurement start position, and the light receiving means 1
As 33 begins to move, the count increases. When the count value of the counter reaches the preset value, the A/D
A start signal 152 will be output. When the A/D conversion is completed, the A/D signal generation section 149 completion signal 153
Output. When the data sampling control section 131 receives the end signal 153, it manages the above-mentioned counter and instructs the drive control section 132 to move the light receiving means 133, and if necessary, starts the next A/Dr at a predetermined timing.
The NI start signal 152 will be output. In this way, it becomes possible to manage the sampling interval of concentration data.

On the other hand, the A/D converter 148 converts the conversion output 147 from analog to digital based on the A/D signal 151. Converter density data 154 is sequentially stored in an image density buffer 155. The stored concentration data 154 is supplied to the arithmetic processing means 78 as a concentration data string 91, and is subjected to arithmetic processing.

Now, when the sampling of the concentration data progresses and the built-in counter counts a certain value as the final value, the data sampling control section 131 outputs an end signal 156 to the measurement control means 73.

When the measurement control means 73 receives this end signal 156, the measurement control means 73 converts the data for the next block into the image density format 8.
8 and is supplied to the data sampling control unit 131.

In this way, concentration data is collected for each part to be measured.

(Configuration of arithmetic processing means) FIG. 113 shows the configuration of the arithmetic processing means. The calculation processing means 78 includes a calculation control section 161.

The calculation control unit 161 is supplied with the calculation processing code 89 from the measurement control means 73 .

The arithmetic processing code 89 is a code representing the arithmetic processing procedure. The arithmetic control unit 161 decodes the arithmetic processing code 89 and supplies the result as an arithmetic processing code 162 to the arithmetic processing address search means 163.

The arithmetic processing address search means 163 uses this arithmetic processing code 162 to search the arithmetic processing storage section 164. The arithmetic processing storage unit 164 stores arithmetic processing data groups necessary for various tests. After moving the pointer 165 to the start address of the corresponding memory area by searching, the arithmetic processing address search means 163 sends an end signal 166 to the arithmetic processing section 161. Arithmetic control unit 161
receives the termination signal 166 and generates a start signal 167, which is supplied to the loader starter 168.

When loader starter 168 receives activation signal 167, it generates load signal 169.171.

Then, a pointer 165 in the arithmetic processing storage section 164
A series of arithmetic processing contents 172 shown in and the density data string 91 stored in the image density buffer 155 (see FIG. 12) of the measuring means are loaded into the working area 174. After loading, the loader starter 168 supplies a start signal 175 to the working area 174 to activate it and transfer control to the working area 174 itself.

Along with this, the working area 174 contains the concentration data string 91.
The desired arithmetic processing is performed on the data. The result is stored in the calculation result output buffer 177 as the calculation result 176. The output means 83 shown in FIG. 5 inputs this stored content as an inspection result 93 and visualizes it.

Optical Measuring Measurement Details In one embodiment of the color image inspection method according to the present invention, a color image inspection is automatically performed by the color image inspection apparatus configured as described above. In this color image inspection apparatus, the copy paper 4 is first held in the chart holding section 8, and after its position is determined, the density of each pattern is measured. Therefore, next, positioning with respect to the copy paper 4 will be explained, and then the density measurement work and the color shift amount measurement work for each pattern will be explained.

(Positioning for each measurement site) In order to measure an image from a copy sheet on which a chart has been copied, the objective lens 43 of the optical head must correctly capture the target measurement site. by the way,
If the density detection unit 41 side is unilaterally set at a predetermined coordinate position, the desired position on the copy paper 4 is ±
An error of about 5 mm will occur. This is due to the following reasons.

(1) Misalignment that occurs when a chart is copied using a copying machine.

In addition to alignment errors (registration deviations) between the copy paper 4 and the photosensitive drum of the copying machine and magnification setting errors, there are also skews when the copy paper 4 is transported inside the copy machine. Contains errors caused by (rotation).

(2) Misalignment when setting the chart in the chart holder 8.

This is a deviation that occurs when the copy paper 4 sent out from the supply tray 5 is set in the chart holder 8, and is caused by an error in the setting of the supply tray 5 or a misalignment of the copy paper 4 when it is sent out. Applicable.

In this embodiment, the target position can be reached with an accuracy of ±Q, 5 mm. For this reason, as shown in FIG. 14, the chart 1 used in the automatic color image inspection device is
91 has position detection patterns 192 at three locations, for example.
~194 were placed.

The coordinates of these position detection patterns 192 to 19'4 are known by the color automatic inspection device for each type of chart. These patterns 192-19 on the chart 17-
The coordinate values of 4 are called real coordinate values, and these are (x
, Yl, ×2. Y2,x3°Y3).

The device calculates these actual coordinate values (X, Y4, X2゜Y
, The coordinate values of these position detection patterns 192 to 194 on the copy paper 4 are (x, yl, x2゜'12, X3, V3
). The pattern to be measured on the copy paper 4 (Xo.

The actual position (X, Yo) corresponding to the coordinates of y ) is calculated, and the intensity detecting unit 41 is caused to reach the target image area using this coordinate value (X, Yo).

The position detection pattern does not need to be placed in three places on the copy paper; for example, by placing it in two places,
It is possible to understand the rotation and positional shift of the Furthermore, by arranging more points, it is possible to grasp the elongation of each portion of the copy paper 4, and it is possible to further improve the accuracy of reaching the measurement site.

(Pattern Scanning) FIG. 15 shows a certain pattern for density measurement. In this pattern 221, a point 223 is a representative point, and a point 224 is a detection start point in the X-axis direction.

The detection starting point 224 is expressed as a relative coordinate value with respect to the representative point 223. If this pattern 221 is to be scanned also in the Y-axis direction, a starting point different from point 224 may be prepared for this purpose.

As described above, in the automatic color image inspection apparatus of this embodiment, a rectangular area of 10 μm x 500 μm on a copy sheet is set as a reading range at one time. The reading mode is determined by the image density detection format shown in FIG. That is, in this example, the point 224 is the measurement start position, and the measurement direction is the X-axis direction. The measurement interval, ie, the sampling width, is determined depending on the purpose of measurement and the like. The color image automatic inspection device of this example has an opening of 10 μm x 5
Since the area is a rectangular (rectangular) area of 00 μm, the area of one concentration detection in the X-axis direction is 10 μm. Therefore,
When the copy paper 4 is scanned all over in the X-axis direction, the measurement interval is 10 μm.

FIG. 16 shows the scanning situation in this case. By setting the sampling width to be smaller than the visual resolution in this way, it is possible to extract data representing a fine image state that almost matches the human visual sense. Regarding this, as an effect of the color image inspection apparatus of this embodiment,
I will explain later.

Of course, measurement does not necessarily require sampling at the same width as the short side of the rectangular area in which optical density is to be detected, and can be freely set using the image density detection format. Therefore, depending on the inspection item, it is possible to scan the image roughly.

When scanning in the Y-axis direction, the slit direction is normally set to the XV*force direction. As a result, in the case of this embodiment, it is possible to sample an image with a width of 10 μm. As already explained, in this embodiment, the concentration detection section 41 is moved in the X-axis direction or Y@force direction in units of 10 μm by stepping the X-axis stepping motor 31 or the chart holding section drive motor 26 one step at a time. be able to.

(Inspection of color shift m) Now, pattern 2 as the object to be inspected shown in FIG. 17A
Assume that 21 is a pattern in which each of the color materials cyan, C, magenta, M, yellow, Y, and black are arranged adjacent to each other in order on a straight line. At this time, an enlarged schematic view of the object to be inspected in the pattern shown in FIG. 17 is as shown in FIG. 17 as an example.

The color shift cans to be inspected in FIG. 17B are do to d3. That is, cyan colorant 225, magenta colorant 2
26. To find not only the maximum deviation fddo between the colors that are the farthest among the relative distances between the center positions of the lines of the yellow coloring material 227 and the black coloring material 228, but also the relative position of each coloring material. The distance d1 between the two colors centered on the reference position (in the example of FIG. 17B, the position of the black coloring material),
Also find d2 and d3. This makes it possible to automatically detect not only the maximum deviation amount but also which color has the largest deviation amount in order to evaluate color deviation. Therefore,
Even if the dO value is the same, the color with the largest color shift has a large impact on the evaluation of color shift, so by detecting the color with the largest color shift, it is possible to more accurately estimate the amount of color shift. Evaluation becomes possible.

In the color image inspection method of this embodiment, in order to inspect such color shift, the color shift inspection is coded in the inspection item code AA shown in FIG. 10, and the pattern 221 described above is coded as the pattern code. coded as a in Furthermore, four color filters are coded as a filter set in the image density detection format corresponding to the image density detection code "I" shown in FIG. 11.As a result, in this color shift matrix inspection, The image density detection operation is repeated a total of four times for each color material of cyan, magenta, yellow, and black while sequentially switching to the designated four color filters.

This will be explained in detail with reference to a flowchart for inspecting the amount of color shift shown in FIG.

First, the measuring means 76 shown in FIGS. 5 and 12 sequentially scans the pattern 221 according to the image area detection format, and sequentially inspects the density data string for the four colors (
Figure 18 Step ■). Then, the result is sent to the arithmetic processing means 78 via the image density buffer 155.

This situation is shown in FIG. 19a. In this FIG. 19a, cyan of the image shown in FIG. 17, ! zenta, yellow,
For each black color material, cyan has a red separation density of 231. Magenta has a green resolution density of 232, and yellow has a blue resolution density of 2.
33. Black represents a pronoisle in which the visual density was sequentially scanned at a pitch of 10 μm.

The arithmetic processing means 78 calculates threshold levels C, .
The settings of M□, Y, K and the center position of the line made of each color material C*, M1Y*,
Set K* (step ■ in Figure 18).

First, threshold level CSM SY,,T K is determined by the following equation (1).

TH,=(DATA-DATAHIN,)1
)4AX ix o, 5+D
ATAHINH (1) where 1=1.2.3.4, TH1=C, TH-M, TH=Y 1TH4
=T 2T 3TK□.

This determined threshold level CT, M, ,Y
The 19th
As shown in the figure, * is determined at the center positions C*, M*, and Y* of each coloring material for each line.

Next, the arithmetic processing means 78 calculates the following values using the center positions C****M, Y, and K of each line (Step 2 in FIG. 18).

d 1 =Y*-* d2-M*-* d3-C*-* d O-max (I C*-M*I, * * 1M -Y I IY*-M*l, dll ,1d
21.1d31) Furthermore, based on the above (jl, d2, d3), find the color with the largest deviation from the standard black coloring material (first
Figure 8 Step ■).

In this embodiment, when dl, d2, and d3 all have the same sign, the color corresponding to the maximum value among Idl+1d21d31 is selected. Also, dl, d
If 2 and d3 have opposite signs, select the color with the largest positive and negative values.

For example, dl-50μm, d2-10μm.

If d3-30 μm, yellow color corresponding to dl is selected. Also, dl=50μm, d2-10μm, d
If 3=-30 μm, yellow color corresponding to dl and cyan color corresponding to d3 are selected.

In this way, the maximum deviation amount dO and the color CC with the largest color deviation peak are determined. The output means 83 visualizes these deviations IdO and colors CC as necessary.

Furthermore, the arithmetic processing means 78 calculates a color shift evaluation IH based on the maximum shift mdO and the color CC with the largest color shift layer. Here, H is given by the following formula, and is a value for evaluating how the color shift of a color image affects human vision.The closer this value is to 1, the more color This accurately corresponds to the impression of color shift that a person would get if they actually viewed the image.

H=f (do, CG) The output means 83 visualizes this value H.

In this way, when inspecting the color shift table of a color image, find the seedlings with the maximum shift of the colors that are the most distant from each other and the color with the largest color shift m, and find the color that has the largest shift amount and color shift amount. Since a color image is evaluated based on large colors, it is possible to evaluate color shift in accordance with actual human vision.

In order to confirm the effects of the present invention, the present inventors conducted an experiment in which a pattern was actually copied onto copy paper 4 and the amount of color shift of this pattern was examined.

FIG. 26 shows the results of this experiment.

The vertical axis of this figure is a value indicating the correlation between the color shift evaluation "H" and the color shift that humans actually perceive visually. The closer this value is to 1, the more accurately the color shift evaluation ff1H corresponds to the color shift that humans actually perceive visually.

As is clear from this figure, as in the conventional case, the maximum deviation ff
If the color shift was evaluated only by 1do, the correlation value would be about 0.9Q, which is quite close to the color shift that humans actually feel visually, but it is insufficient. In the case of inventions, the value is high at about 0.94, which is almost equal to the color shift that humans actually perceive visually.
It was very satisfying.

By the way, in the color image inspection method of this embodiment, the area in which the object to be inspected is scanned is set to an extremely small rectangular size of 10 .mu.m.times.500 .mu.m. Therefore, unlike similar conventional image inspection devices, it is possible to perform an inspection that approximates human visual perception. This will be explained in detail next.

First, FIG. 20 is an enlarged view of a part of the chart for resolution inspection. In this way, in this chart, black lines 201 with different intervals and line widths are drawn in parallel, and the resolution of the copied image is determined by the line width that can be distinguished from the white background part 202. It is designed to be inspected.

FIG. 21 shows a further enlarged part of this chart, and FIG. 22 shows a sample of images copied by a copying machine in correspondence with this.

Here, FIG. 22 shows an example in which relatively large unevenness occurs in the boundary area between the ground color portion 202 and the black line 202, and FIG. 8 shows an example in which toner is scattered at these boundary areas. Further, C in the same figure is an example in which a blank area 203 to which no toner is attached is generated inside the black line 201. In addition, various other situations may occur, such as the density of the black line 021 not changing all at once at the boundary but changing stepwise, and the density occurring inside the black line 201. The delicate state of such images is
This is a relatively large factor in image quality evaluation.

By the way, FIG. 23 shows the signal level of an image signal read by a conventional device when the outline of the black line is uneven, as shown in FIG. 22A, for example. This image signal 205 is a signal obtained by horizontally scanning the chart shown in FIG.
This corresponds to FIG. 4 of Publication No. 03465. A signal portion 205- indicated by a broken line in this figure is an image signal obtained by scanning the protruding portion of the black line 201 in FIG. 22A, and has a thicker waveform than other portions indicated by a solid line.

However, when the image signals 205 and 205' are binarized at the threshold level shown by the dashed-dotted line 207 in the figure and the images are inspected, the resolution evaluations for both signals are completely the same. This is because in conventional devices, the resolution is determined based on the location where a signal change occurs due to binarization and the number of signal changes at that location.

FIG. 24 shows an image signal obtained by the conventional device for the image state shown in FIG. 22B, and FIG. 25 shows an image signal obtained by the conventional device for the image state shown in FIG. 22C. This represents an example.

In the example shown in FIG. 24, the level of the image signal 205 becomes high in a portion 208 where the scattered toner is scanned. However, since the scattered area is relatively small,
The signal level does not rise sufficiently in this part, and it is ignored in the binarization process.

FIG. 25 shows the opposite case, where the signal level in the area indicated by the arrow 209 is lowered due to the blank area 203 existing in the black area 1201. However, even in this case,
Since the signal change in the minute portion is not sufficient, this change is ignored in the binarization process. As described above, conventional devices have a problem in that images are judged at a level different from the quality of images perceived by the human eye.

However, in the color image inspection apparatus of this embodiment, as shown in FIG. 4, the optical density of the object to be inspected is inspected using an aperture of 10 .mu.m.times.500 .mu.m. The diameter of toner particles after fixing is approximately 10 to 20μ
m, it can be seen that this makes it possible to inspect the image of the object to be inspected at a level that is approximately the same as human sensitivity.

Furthermore, since the color image inspection apparatus of this embodiment measures the object to be inspected using a rectangular area as the minimum measurement range,
The object to be inspected can be efficiently scanned without gaps. Of course, the rectangular area is not limited to a rectangle of 10 μm×500 μm.

For example, it may be a rectangle larger than this, or it may be a square with sides the same length as the aforementioned short sides, or a square larger than this.

In the case of a square, when scanning a pattern consisting of diagonally inclined line segments, the aperture is also tilted accordingly (
(rotation) is not necessary.

Of course, the shape of the aperture used for measurement does not have to be a strict rectangle (for example, it may be a rectangle close to a circle or an oval. However, in these cases, In order to scan, images are read with some overlap, so processing to deal with these overlaps is required.

In the embodiment, a photomultiplier tube was used as the light receiving means, but the same optical density measurement operation can be performed using a photomultiplier using a semiconductor or a one-dimensional sensor such as a COD. Further, in the embodiment, the optical density was detected using reflected light, but it may be detected using transmitted light, for example, when inspecting the development state of photographic film.

Further, in the embodiments, toner particles were exemplified as a unit constituting an image to be inspected. For other non-impact type devices or impact type devices, the size and rotation angle of the opening may be considered in consideration of the size and shape of the in-line used in these devices.

[Effects of the Invention] As explained above, according to the color image inspection method according to the present invention, in addition to the maximum amount of deviation between colors that are farthest apart, color deviation flaws 1 that greatly affect human vision can be detected. Since the color with the largest amount of color shift is determined and the color image is evaluated based on the maximum amount of shift and the color with the largest amount of color shift, it is possible to inspect the amount of color shift that more accurately corresponds to human vision.

Moreover, according to the color image inspection apparatus according to the present invention, it is possible to provide an apparatus that can automatically inspect color shift peaks that more accurately correspond to human vision as described above.

[Brief Description of the Drawings] Fig. 1 is a perspective view of the automatic color image inspection device, Fig. 2 is a schematic configuration diagram showing the main parts of the inspection section, and Fig. 3 is a layout explanation showing the arrangement of optical components of the optical head. Figure 4 is an explanatory diagram showing the size of the area that is the measurement unit on copy paper, Figure 5
6 is a block diagram showing the outline of the circuit configuration of the automatic color image inspection device, FIG. 6 is a block diagram showing the configuration of external signal input means, FIG. 7 is a block diagram showing the configuration of pattern information storage means, and FIG. 9 is a block diagram showing the structure of the processing procedure storage means, FIG. 10 is an explanatory drawing showing the structure of the processing code storage means, and FIG. 11 is an explanatory diagram showing the structure of the processing procedure storage means. An explanatory diagram showing the structure of the means, FIG. 12 is a block diagram showing the structure of the measuring means, FIG. 13 is a block diagram showing the structure of the FA processing means, and FIG. 14 shows the arrangement of the position detection pattern. A plan view of the chart, FIG. 15 is a plan view 1 showing an example of a pattern for density measurement, FIG. 16 is an explanatory diagram showing an example of scanning in the X-axis direction, and FIGS. 17A and B are FIG. Fig. 18 is a plan view and an enlarged plan view showing the state of color misregistration in the pattern portion shown in the circle;
Figure 9 is an explanatory diagram showing the processing process of the image signal obtained by reading the image portion shown in Figure 17, and Figure a shows the profiles of each coloring material for red separation density, green separation density, blue separation density, and luminous density. 20 is an enlarged plan view of a part of the chart for resolution inspection, and FIG. 21 is an illustration of the chart shown in FIG. 20. Further, a partially enlarged plan view, FIGS. 22A to 22C are partially enlarged plan views showing various states of the sample of the copy image,
FIG. 23 is a waveform diagram showing the signal level of the image signal obtained by reading the image portion shown in FIG. 22A, and FIG. 24 is a waveform diagram showing the signal level of the image signal obtained by reading the image portion shown in FIG. 22B. Figure 25 is a waveform diagram showing the signal level of the image signal read from the image portion shown in Figure 22C, Figure 26 is a graph showing the experimental results of this example, and Figure 27 is color xerography. A principle diagram showing the copying principle of a copying machine, FIG. 28 is an explanatory diagram showing the state of detection of color shift amount in a conventional device, and FIG. 29A
, B, and C are explanatory diagrams showing different amounts of color shift, respectively. [Explanation of symbols] 1... Inspection section 2... Computer section 4... Copy paper 5... Supply tray 8... Chart holding section 41... Density detection section 58... Photoelectron multiplication Pipe 66... Filter unit 68... Color filter 76... Measuring means 78... Arithmetic processing means 221... Pattern 231... Red separation concentration 232... Green separation concentration 233... Blue Decomposition density 234... Cyan color material shop 235... Magenta color material record 236... Yellow color material interval CSM, Y... Center position d of each color material stone...
Color shift amount patent Applicant Fuji Xerox Co., Ltd. Representative Patent attorney Tomohiro Nakamura (one other person) Figure 3 Figure 5 Figure 5 (External signal input means 72) Figure 8 Figure 12 ■4 Figure 15 Figure 16 (A) Figure 17 (B) Figure 18 Figure 20 Figure 21 Figure 22 (A) (B) (C) Figure 19 Figure 23 Figure 24 Figure 25 Figure 26 Figure 27 Figure 0b Figure 28 Figure 29

Claims (2)

[Claims] (1) Read a specific inspection pattern on the object to be inspected,
After detecting the optical density of this test pattern as the density of an achromatic color and a predetermined chromatic color, the achromatic color and a predetermined chromatic color are detected based on the peak position of the achromatic color optical density and the peak position of the predetermined chromatic color optical density. Among them, the maximum amount of deviation between the colors that are the most distant from each other and the color with the largest amount of color deviation are determined, and the color image is evaluated based on the maximum amount of deviation and the color with the largest amount of color deviation. Color image inspection method. (2) Read a specific inspection pattern on the object to be inspected,
an optical density detection means for detecting the optical density of the read inspection pattern as the density of an achromatic color and a predetermined chromatic color; A color shift amount detection means for determining a peak position of a chromatic optical density and detecting a maximum shift amount between colors that are farthest apart from each other among an achromatic color and a predetermined chromatic color, and a color with a maximum color shift amount. 1. A color image inspection device, comprising: a color image inspection device that evaluates a color image based on the maximum amount of misregistration detected by the color misregistration amount detection means and the color with the largest amount of color misregistration.