JPH06162195A - Dot pattern inspection device - Google Patents

Abstract

PURPOSE:To provide the dot pattern inspection device which positions an image to be inspected by high-speed processing by using small-capacity memory. CONSTITUTION:A positioning mechanism which scans and selects an inspection object dot pattern position in a two-dimensional image obtained by picking up an image of an inspection object dot pattern display surface is equipped with an image projection data preparation part 1 which prepares image projection data by projecting density values of a two-dimensional image on a prescribed axis, a run-length data generation part 2 which prepares projection run-length data by replacing the image projection data for combined data of the magnitude with width of cumulative addition density value, and a projection run-length data matching pat 4 which scans the two-dimensional image on the dot pattern display surface to be inspected with reference projection run- length data and determines the position where the inspection object dot pattern is present.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection device for inspecting a visual recognition device, and more particularly to a dot pattern inspection device for inspecting a display function of a liquid crystal, a light emitting diode or the like of the visual recognition device on a dot pattern display surface. Is.

[0002]

2. Description of the Related Art A dot pattern inspection device takes an image of a dot pattern formed by the liquid crystal, the light emitting diode or the like in order to inspect the dot pattern display function of the liquid crystal, the light emitting diode or the like of a visual recognition device. Image processing is performed, and the two-dimensional image of the dot pattern to be inspected, in which the liquid crystal, light emitting diode, etc. are formed on the dot pattern display surface, is compared with a reference dot pattern, and the liquid crystal, light emitting diode, etc., produces an accurate dot pattern. It is to inspect whether or not it is formed.

A conventional example of a dot pattern inspection apparatus is shown in FIG.
It will be described based on.

In FIG. 9, what is shown on the right side is a two-dimensional image of the dot pattern display surface to be inspected, and the dot pattern inspection apparatus inspects various dot patterns to be inspected in this two-dimensional image by image processing. In order to do so, first, the dot pattern inspection device needs to position which inspection target dot pattern is at which position.

In the conventional example, FIG. 9 is used for this positioning.
By using the partial image template of the reference dot pattern shown on the left side of the figure, the two-dimensional image on the right side dot pattern display surface is scanned and compared, and the position where the degree of coincidence of the partial image template is highest on the two-dimensional image is obtained. , This position is positioned as an inspection area having an inspection target dot pattern.

[0006]

However, in the above-mentioned conventional example, there are a method by hardware and a method by software for checking the degree of coincidence and performing positioning, both of which are formed by the partial image template. Since the dot pattern itself is directly compared with the dot pattern itself formed by the inspection target dot pattern, each dot of the partial image template and each dot of the inspection target dot pattern are compared one by one and matched. There is a problem that it takes time to process because the degree is to be determined and positioned.

The hardware method has a problem that if the partial image template is made large in order to improve the inspection accuracy, the hardware scale becomes large and the cost becomes high. This is not practical, and there is a problem that the memory capacity of the template increases because the partial image data itself is used as the template.

Further, in the above-described conventional example, when the dot pattern of the two-dimensional image on the dot pattern display surface to be inspected has an angular deviation, a plurality of reference patterns having different inclinations are included in the various reference dot patterns. It is necessary to add one. Then, even if a plurality of reference patterns having different inclinations are added, it is difficult to detect the angle deviation accurately.

Further, in the above-mentioned conventional example, when a binary image is used for the partial image pattern matching, the binary image is
Accurate inspection is not possible when there is uneven lighting. As a measure against the uneven illumination, there is a method in which a background image having uneven illumination is created in advance and binarized by taking the difference from the background image. However, this method cannot deal with uneven illumination that changes with time. Further, in a grayscale image, there is a problem that matching takes a long processing time and is not practical.

The present invention solves the above-mentioned problems, enables high-speed processing, has a small memory capacity, is low in cost, can measure the angular deviation of the dot pattern to be inspected, and has uneven illumination. It is an object of the present invention to provide a dot pattern inspection device capable of performing high-speed and accurate inspection even if there is.

[0011]

In order to solve the above problems, the dot pattern inspection apparatus of the first invention of the present application inspects the dot pattern displayed on the dot pattern display surface for visual recognition by image processing. In the dot pattern inspection apparatus, a positioning mechanism for scanning and selecting a dot pattern position to be inspected on a two-dimensional image obtained by imaging the dot pattern display surface is a two-dimensional image of the dot pattern display surface captured by an imaging unit. An image projection data creation unit that creates image projection data in which the density values of each pixel are projected on a predetermined axis and cumulatively added to respective projection positions, and the image projection data is created by the cumulative addition density value. Run-length data that creates projection run-length data by replacing it with combination data of the size of the The projection run length data created by the creation unit and the run length data creation unit from the two-dimensional image of the dot pattern display surface to be inspected is used as an individual dot pattern of the inspection target included in the dot pattern display surface to be inspected. The reference projection run length data created in advance from the reference dot pattern is compared for scanning, and the projection run length data matching unit for positioning the position with the highest degree of coincidence as the position where the inspection target dot pattern exists is provided. It is characterized by having.

In the dot pattern inspection apparatus of the second invention of the present application, in order to solve the above problems, the positioning mechanism provides a line window in the two-dimensional image of the dot pattern to be inspected positioned by the projection run length data matching unit. A line window edge detection unit for obtaining the edge point sequence of the light-dark boundary of the inspection target dot pattern, and the obtained edge point sequence are linearly approximated, and the inspection target dot is obtained from the direction of the obtained approximate straight line. It is preferable to have an edge point sequence straight line approximation unit that measures the amount of angular deviation of the light-dark boundary line of the pattern.

In order to solve the above problems, the dot pattern inspecting apparatus of the third invention of the present application is a dot pattern inspecting apparatus for image-processing and inspecting a dot pattern displayed on a dot pattern display surface for visual recognition. A dot pattern inspecting unit that inspects an inspection target dot pattern positioned on the two-dimensional image on the dot pattern display surface divides the two-dimensional image into dot sizes of the dot pattern, and each of these divided dot portions. Is an image data compression unit that compresses information into a compressed image that is replaced with a representative pixel having a representative image density that represents the brightness of each dot portion, and a difference in brightness between adjacent representative pixels of the compressed image as a threshold value. By comparing, the compressed image data that determines whether the position between the representative pixels corresponds to the position of the light-dark boundary line of the inspection target dot pattern And having a neighbor density comparing means.

[0014]

According to the present invention, a two-dimensional image of an inspection target dot pattern displayed on a visual recognition dot pattern display surface is subjected to image processing to inspect the shape of the inspection target dot pattern. The invention relates to the positioning of the dot pattern to be inspected prior to the shape inspection, and the third invention is to perform a rapid shape inspection by compressing the information of the two-dimensional image of the dot pattern to be inspected after the positioning. It has the structure and function of.

In the first invention of the present application, first, the image pickup section picks up an image of a dot pattern to be inspected, for example, a visual recognition dot pattern display surface displaying the dot pattern to be inspected to obtain two-dimensional image data. .

Next, the positioning mechanism positions the dot pattern to be inspected.

First, the image projection data creation unit of the positioning mechanism converts the two-dimensional image of the dot pattern to be inspected, which requires the same troublesome positioning method as the conventional example, into image projection data that can be easily positioned. . The image projection data creation unit translates the density value at each position of the two-dimensional image data of the dot pattern display surface of the inspection target in parallel in a predetermined direction and projects it on a predetermined axis, and the density value at each projection position. Cumulative addition is performed, and image projection data in which these cumulatively added density values are arranged is created. To compare the dot patterns of two-dimensional images, it is necessary to compare all the dots one by one in order, whereas to compare the above-mentioned image projection data, the density values of all the pixels are compared. Is projected on a predetermined axis, it is only necessary to compare the shapes of the cumulative added density values of the image projection data.

Next, the run-length data creating unit determines the shape of the cumulative addition density value of the image projection data on the predetermined axis where the magnitude of the cumulative addition density value and the cumulative addition density value of the same size are successively arranged. The projection run length data is created by replacing the combination data with the number of pixels corresponding to the width with the arranged data. Since the projection run-length data is compared only by comparing the above-mentioned one-row combination data, the inspection target dot pattern can be positioned at high speed.

Next, the projection run-length data matching unit outputs the projection run-length data of the two-dimensional image of the dot pattern display surface of the inspection object created by the run-length data creation unit by the run-length data creation unit. Dot pattern to be inspected Scan comparison based on reference projection run length data created in advance from reference dot patterns of individual dot patterns to be inspected included in the display surface, and the position with the highest degree of coincidence is the inspected dot pattern. Is positioned as the position where exists.

The second invention of the present application is the two-dimensional image of the two-dimensional image of the dot pattern to be inspected on the dot pattern display surface of the inspected object, which is positioned by the projection run length data matching unit of the first invention of the present application. This is to measure the angular deviation. The positioning mechanism of the second invention of the present application for measuring the angular deviation of the two-dimensional image has an in-line-window edge detection unit and an edge point sequence straight line approximation unit.

First, the process until the projection run-length data matching unit positions the two-dimensional image of the dot pattern to be inspected is the same as in the first invention of the present application.

Next, the edge detector in the line window of the positioning mechanism according to the second aspect of the present invention is arranged on a portion of the two-dimensional image of the dot pattern to be inspected positioned on the display surface of the dot pattern to be inspected, where there is a light-dark boundary. A line window is provided along the line window to obtain the edge point sequence of the light-dark boundary line of the inspection target dot pattern. This edge point sequence indicates the direction of the bright / dark boundary line of the inspection target dot pattern.

Next, the edge point sequence straight line approximation unit of the positioning mechanism of the second invention of the present application linearly approximates the edge point sequence of the bright-dark boundary line of the inspection target dot pattern obtained by the in-line window edge detection unit, From the direction of the obtained approximate straight line, the amount of angular deviation of the bright / dark boundary line of the dot pattern to be inspected is measured.

The third invention of the present application is the first invention of the present application and the second invention of the present application.
With respect to the two-dimensional image of the dot pattern to be inspected on the dot pattern display surface to be inspected, which is positioned by the positioning mechanism of the invention, the dot pattern inspection unit compresses the information of the two-dimensional image of the dot pattern to be inspected and inspects the shape. It is a thing.

The dot pattern inspecting unit of the third invention of the present application for inspecting the shape has image data compression means and compressed image data adjacent density comparison means.

First, the image data compression means of the dot pattern inspecting unit divides the two-dimensional image into dot sizes of the dot pattern, and the brightness data of each of the divided dot parts is divided into data of each dot part. The average image data of the brightness of each pixel is replaced with the brightness data of one representative pixel, and information is compressed into a compressed image formed by these representative pixels.

Next, the compressed image data adjacent density comparison means of the dot pattern inspection unit compares the difference in brightness between the adjacent representative pixels of the information-compressed compressed image with a threshold value and inspects between the representative pixels. It is determined whether or not it is the light / dark boundary position of the compressed image of the target dot pattern, and the light / dark boundary position of the inspection target dot pattern before compression is selected according to the result.

With this arrangement, in the conventional example, in the shape inspection of the dot pattern to be inspected, it is necessary to compare a large number of pixels forming each dot for each dot of the dot pattern of the two-dimensional image. However, the amount of calculation is extremely large, whereas when the information-compressed pixel pattern is used, only one representative pixel needs to be compared for one dot portion, and therefore the amount of calculation is extremely small.

Further, even if there is illumination unevenness, it is possible to eliminate the influence of illumination unevenness by selecting a threshold value because it is the comparison judgment of the density difference.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment of the present invention is for positioning the dot pattern to be inspected in the XY directions, and its configuration and action will be described with reference to FIGS. 1, 4 and 5.

FIG. 1 is a block diagram showing the configuration of this embodiment, in which the image projection data creation unit 1 uses the image data of the dot pattern to be inspected which requires the same troublesome positioning method as the conventional example. As shown by the projection run length data in FIG. 4, it is converted into projection data that can be easily positioned. That is, the density value at each position of the two-dimensional image on the dot pattern display surface to be inspected is moved in parallel in a predetermined direction to move the predetermined axis 2
0 is projected, the density values are cumulatively added to the respective projection positions, and image projection data in which the cumulatively added density values are arranged is created. In order to compare the dot patterns of the two-dimensional image, it is necessary to compare all the dots one by one in order, whereas to compare this image projection data, the density values of all pixels are Since the image is projected on the predetermined axis 20, it is only necessary to compare the shapes of the cumulative added density values of the image projection data.

Next, the run-length data creating section 2 determines the shape of the cumulative addition density value of the image projection data on the predetermined axis in which the magnitude of the cumulative addition density value and the cumulative addition density value of the same size are arranged side by side. The projection run-length data is created by replacing the combination data with the number of pixels corresponding to the width of. In FIG. 4, the magnitude of the cumulative added density value is 3 and 2, and the number of pixels corresponding to the width is 4 and 1. Since the projection run-length data is compared only by comparing the above-mentioned one-row combination data, the positioning performed by scanning the dot pattern to be inspected can be processed at high speed.

Next, as shown in FIG. 5, the projection run-length data matching unit 4 projects the projection run-length data of the two-dimensional image of the dot pattern display surface of the inspection object created by the run-length data creating unit 2. Receiving the inspection image projection run-length data, the run-length data creating unit 2 creates it in advance from the reference dot patterns of the individual dot patterns to be inspected included in the dot pattern display surface to be inspected, Once, the template projection run length data, which is the reference projection run length data stored in the template run length data storage unit 3, is used as a reference for scanning comparison, and the position with the highest degree of coincidence is the position where the inspection target dot pattern exists. To position as.

As shown in FIG. 5, the inspection of the degree of coincidence is performed as follows.
This is performed by changing the start point Xr of the projection run-length data and calculating a simple residual difference of both projection run-length data and a correlation coefficient.

Next, the dot pattern inspecting unit 5 detects the dot pattern of the inspection target dot pattern 2 positioned as described above.
The shape inspection is performed by comparing the two-dimensional image with the two-dimensional image of the reference dot pattern. However, in this case, if the dot pattern has a simple shape, the shape can be inspected by comparing the shapes with the projection run-length data.

Next, the second embodiment of the present invention measures the angular displacement of the dot pattern to be inspected, and its configuration and action will be described with reference to FIGS. 2 and 6.

FIG. 2 is a block diagram showing the configuration of the present embodiment, which is characterized by an in-line-window edge detection unit 6 and an edge point sequence straight line approximation unit 7 of the positioning mechanism, and includes an image projection data creation unit 1 and a run. The length data creating unit 2, the template run length data storage unit 3, the projection run length data matching unit 4, and the dot pattern inspecting unit 5 are the same as those in the first embodiment, and therefore their explanations are omitted.

As shown in FIG. 6, the in-line-window edge detection unit 6 of the positioning mechanism uses a line window on the two-dimensional image of the dot pattern 21 to be inspected, which has been positioned by the projection run-length data matching unit 4 in the XY directions. 22 is provided, and the edge point sequence 23 of the bright / dark boundary line of the inspection target dot pattern 21 is obtained. The obtained edge point sequence 23 indicates the direction of the bright / dark boundary line of the inspection target dot pattern 21.

Next, the edge point sequence straight line approximation unit 7 of the positioning mechanism linearly approximates the edge point sequence 23 to obtain an approximate straight line 24. Since the direction of the approximate straight line 24 accurately indicates the direction of the light-dark boundary line of the inspection target dot pattern 21, the light-dark boundary line of the inspection target dot pattern 21 is calculated by calculating the direction of the approximate straight line 24. The direction of can be accurately inspected.

Such processing is performed in both the XY directions, and the intersection point of the obtained two approximate straight lines is set as the origin of the representative XY coordinates. From the angle formed by the two approximate straight lines with the representative XY coordinates, the dot to be inspected Calculate the amount of angular displacement of the pattern. As a calculation method, a method of using the approximation line with the larger number of sample points among the two approximation lines, and the approximation line with the smaller variation of the edge points among the two approximation lines is used. There is a method of using and calculating. In this method, the edge points are calculated in sub-pixels, so that if the pattern has a clear contrast, it is possible to perform precise measurement and improve the inspection accuracy.

Next, a third embodiment of the present invention is to perform a rapid shape inspection by compressing the information of the two-dimensional image of the dot pattern to be inspected after positioning, and its configuration and action are shown in FIG. 7 and FIG. 8 will be described.

FIG. 3 is a block diagram showing the configuration of this embodiment. The inspection area determining unit 8 of FIG. 3 includes an image projection data creating unit 1, a run length data creating unit 2 and a template run length of the second embodiment. The data storage unit 3, the projection run-length data matching unit 4, the in-line window edge detection unit 6, and the edge point sequence straight line approximation unit 7 are the same as those of the data storage unit 3, and a description thereof will be omitted. The dot pattern inspection unit 5 is characterized by
The dot pattern inspection unit 5 has a dot bright / dark boundary determination mechanism including the image data compression unit 10 and the compressed image data adjacent density comparison unit 11 shown in FIG. 3 in the dot pattern inspection unit 5 of the first and second embodiments. 9 is added.

A dot pattern for inspecting the dot pattern to be inspected by the inspection area determining unit 8 after the position measurement in the XY directions of the dot pattern to be inspected and the measurement of the angular deviation are completed and correction is performed based on these measurements. Inspection section 5
In FIG. 7, the image data compression means 11 of the dot light / dark boundary determination mechanism 9 divides the two-dimensional image of the dot pattern to be inspected into the dot portions 25 of the dot size of the dot pattern, and these are divided. The representative image density of the brightness of each pixel 26 of each dot portion 25 is replaced with the brightness data of one representative pixel 27, and the two-dimensional image is compressed into a compressed image formed by the representative pixel 27. To do. As shown in FIG. 7, these processes are performed by calculating the representative image density of each pixel 26 of the dot portion 25.

This calculation method includes a method of calculating the average of pixel density values and a method of sorting the pixel density to calculate the median value thereof. Even if the pixels are thinned out in order to increase the calculation speed, good.

Next, as shown in FIGS. 7 and 8, the compressed image data adjacent density comparison means 1 of the dot light / dark boundary determination mechanism 9 is used.
1 compares the brightness difference between adjacent representative pixels 27 of the compressed image with a threshold value to determine the position of the light-dark boundary line of the two-dimensional image dot pattern of the dot pattern to be inspected. In these processes, as shown in FIG. 8, a density difference between adjacent representative pixels 27 is calculated in a vertical or horizontal line, and the density difference is compared with a predetermined threshold value. In the embodiment, as compared with the threshold value 30, when the density difference is +30 or more, OFF → ON, and when the density difference is −30 or less, ON → OFF, and the density difference is −3.
If it exceeds 0 and is less than +30, there is no change.

In this way, in the conventional example, in the shape inspection of the inspection target dot pattern, it is necessary to compare all the pixels forming each dot for each dot of the dot pattern of the two-dimensional image. However, the amount of calculation is extremely large, whereas when the information-compressed pixel pattern is used, only one representative pixel needs to be compared for one dot portion, and therefore the amount of calculation is extremely small.

Moreover, as shown in FIG. 8, even if there is illumination unevenness, since the density difference is determined, the influence of illumination unevenness can be eliminated.

[0048]

According to the first invention of the present application, high-speed and low-cost projection calculation hardware can be used for the positioning calculation of the dot pattern to be inspected, and the image data is extremely reduced by the projection process, and the memory capacity is reduced. Since it is small, the dot pattern inspection device can be processed at high speed.
Moreover, it has an effect of reducing the cost.

The second invention of the present application has an effect of improving the measurement accuracy of the angular deviation and improving the reliability of the dot pattern inspecting apparatus because the angular deviation of the dot pattern to be inspected is calculated at the sub-pixel level.

According to the third invention of the present application, in the shape inspection of the inspection target dot pattern, for each dot of the dot pattern of the two-dimensional image, a large number of pixels forming each dot are all compared one by one. Although it is necessary and the amount of calculation is very large, when the information-compressed pixel pattern of the third invention of the present application is used, only one representative pixel needs to be compared for one dot portion, and therefore the amount of calculation is extremely large. Therefore, the dot pattern inspection device can be processed at high speed, and even if there is illumination unevenness, the density difference determination can determine the influence of illumination unevenness.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a third exemplary embodiment of the present invention.

4 is an operation diagram of the image projection of FIG.

5 is an operation diagram for positioning the dot pattern to be inspected in FIG.

FIG. 6 is an operation diagram of edge point sequence measurement and straight line approximation in FIG.

7 is an operation diagram of the image data compression of FIG.

8 is an operation diagram of adjacent density comparison of FIG.

FIG. 9 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 1 Image projection data creation unit 2 Run length data creation unit 3 Template run length data storage unit 4 Projection run length data matching unit 5 Dot pattern inspection unit 6 Line window edge detection unit 7 Edge point sequence approximation unit 8 Inspection area determination Part 9 Dot light / dark boundary judgment unit 10 Image data compression unit 11 Compressed image data Adjacent density comparison unit 20 Predetermined axis 21 Inspection target dot pattern 22 Line window 23 Edge point sequence 24 Approximate straight line 25 Dot portion 26 Pixel 27 Representative pixel

Claims (3)

[Claims] 1. A dot pattern inspection apparatus for image-processing and inspecting a dot pattern displayed on a dot pattern display surface for visual recognition, and an inspection on a two-dimensional image obtained by imaging the dot pattern display surface. The positioning mechanism that scans and selects the target dot pattern position projects the density value of each pixel of the two-dimensional image of the dot pattern display surface imaged by the imaging unit onto a predetermined axis and cumulatively adds the density value to each projection position. An image projection data creation unit that creates aligned image projection data and the image projection data are replaced with combination data of the size of the cumulative addition density value and the width in which the cumulative addition density values of the same size are consecutive. A run length data creating unit for creating projection run length data, and the run length data from a two-dimensional image of the dot pattern display surface of the inspection target. The projection run-length data created by the creation unit is scanned and compared with reference projection run-length data created in advance from the reference dot patterns of the individual dot patterns of the inspection target included in the dot pattern display surface of the inspection target. And a projection run-length data matching unit that positions a position with the highest degree of coincidence as a position where the dot pattern to be inspected exists. 2. A line for providing an edge point sequence of a light-dark boundary line of the dot pattern to be inspected by providing a line window in the two-dimensional image of the dot pattern to be inspected positioned by the projection run length data matching unit. An in-window edge detection unit and a linear approximation of the obtained edge point sequence, and from the direction of the obtained approximate straight line, an edge point sequence straight line approximation for measuring the amount of angular deviation of the light-dark boundary line of the inspection target dot pattern The dot pattern inspection apparatus according to claim 1, further comprising: 3. A dot pattern inspection apparatus for image-processing and inspecting a dot pattern displayed on a dot pattern display surface for visual recognition, wherein the dot pattern to be inspected is positioned on a two-dimensional image of the dot pattern display surface. A dot pattern inspecting unit that inspects the two-dimensional image into dot sizes of a dot pattern, and divides each of these divided dot portions into a representative pixel having a representative image density representative of the brightness of each dot portion. Image data compression means for compressing information in the compressed image replaced with, and comparing the difference in brightness between adjacent representative pixels of the compressed image with a threshold value,
A dot pattern inspection apparatus, comprising: compressed image data adjacent density comparison means for determining whether or not the position between the representative pixels corresponds to the position of the light-dark boundary line of the inspection target dot pattern.