JPH01501114A - Image analysis device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Image analysis device This invention applies to images such as those shown by private circuit television (CCTV). The present invention relates to a device for analyzing images. According to a preferred embodiment of the invention, the invention provides C. Static indentation hardness tester that analyzes indentations using a CTV camera and processor become applicable.

To accurately analyze images using such equipment, the object must be ideally illuminated. It is well known that this is necessary. For many semi-class objects, this is a special Metal objects with varying surface finishes and reflectances that can be achieved without difficulty It is extremely difficult to illuminate the image in such a way that it can be analyzed accurately. . As a result, it is generally necessary to keep the illumination to a reasonable level, and it is necessary to The result is that the accuracy of image analysis becomes insufficient.

This invention provides ideal illumination by varying the intensity of illumination on the object. The aim is to overcome the above-mentioned difficulties.

In many applications, for example when used in indentation hardness testers, CCTV cameras are An image is used to judge the size of an object (such as an indentation in a sample) that can be captured by the camera. - Requires a processor. In such applications, traditional methods require Calibrate the processor by showing the reference object that forms the correct image on CCTV. However, this reference object forms the calibration image and, in some cases, the calibrated Scale shape, substitute of the same type as the test object, or identical to the test object It may be any type of actual sample. However, substitutes or actual The samples shall be of known size. Check data on the size of the reference object. Dimensions of image size in units such as cells or chordlength into a processor capable of representing The size of the object to be displayed can be determined automatically. These dimensions are in pixels or chord length The size of the object expressed in units such as and the calibration image expressed in similar units. It is determined by comparing the known size of

However, such a method has a major drawback in practice. Generally, the calibration image is This is replaced by hand, and positioning is extremely important for accurate subsequent measurements. While it has to be accurate, the data regarding the size of the calibration image cannot be processed by hand. There is a risk of operator error as the Ru. Moreover, recalibrating the processor requires interrupting the measuring operation of the machine. Must be. As a result, there is a tendency to perform recalibration only rarely. Ma Images captured by CCTV cameras may shift over time or due to temperature fluctuations. It may become distorted or distorted. Due to these changes, the precision of the II This can have serious consequences. This is rarely done because recalibration takes time. The fact that it is not possible is something that cannot be overlooked.

The present invention overcomes the drawbacks of known calibration devices by eliminating the need for an operator and making the measurement process easier. Image analysis equipment that accurately and automatically positions calibration images without interrupting the process. The aim is to resolve this by providing As a result, recalibration is short This reduces the possibility of operator error. performance, and the shift in camera images due to time and temperature has been largely eliminated. Ru.

According to the first invention of the present application, an image provided with a means for forming an image of an object and an illumination device An analysis device is provided. The lighting device is a lighting device for object illumination: and Compare the brightness of the image with one or several preset brightness levels and A process that allows the light output of a lighting device to be increased or decreased based on the results of this comparison. consisting of sing means.

According to a preferred embodiment of the first invention of the present application, the size of the indentation formed in the sample A static indentation hardness tester that determines the hardness of the sample based on the A testing machine with an image analysis device is provided.

The forming means for forming an image of the object is constituted by a dedicated line television system. Advantageously, an image array may alternatively be used. this image When using the analyzer in combination with a static indentation tester, the pressure on the sample surface A lighting device is arranged to illuminate the area around the mark. In this case, the image analysis device Determine the gray level at one or several locations, and calculate the average gray level based on the results. Advantageously, the processing means comprises processing means for calculating the -level. Also preferable In some embodiments, the calculated average gray level identifies the extremes of a given range. In order to do this, it is compared with two preset gray Φ levels. and the average If the calculated light level is outside the specified range, the light output of the lighting device will be It will be increased or decreased appropriately.

According to the second invention of the present application, a measuring device for comparing the size of an object with that of a reference object An image analysis device is provided. The measuring device a means for forming an image of the object to be determined for size; and It is attached to the measuring device and is used instead of or in addition to the object whose size is to be measured. a reference object that is projected onto a means for forming an image.

In a preferred embodiment of the second invention of the present application, the object whose size is to be measured and the reference pair The processed object is projected through a beam splitting mirror, and one image is split into a beam splitting mirror. The image is obtained by light passing through a split mirror, and the other image is reflected by the mirror. Obtained by light. Preferably the object to be sized is captured using a CCTV camera camera. while the reference object is also positioned in the field of view in the focal plane of the camera lens. Since the object to be measured is positioned within the focal plane of the lens, the object to be measured must be within the field of view. It is a good idea to have the camera capture the reference object only when necessary.

Next, the present invention and its effects will be further explained with reference to the following attached drawings relating to embodiments. will be explained in detail.

FIG. 1 shows an image illumination device that constitutes a part of the image analysis device based on the first invention of the present application. This is a schematic block diagram.

FIG. 2 is a cross section of a measuring device that constitutes a part of an image analysis device based on the second invention of the present application. It is a diagram.

FIG. 3 is a view of the measuring device of FIG. 2 from below.

FIG. 1 shows an outline of an image illumination device based on an embodiment of the first invention of the present application. . Sample 1 is captured by television camera 2. In a preferred embodiment of this invention If so, this sample corresponds to the sample of the hardness tester and its size is measured. It has an impression. The image from that camera is transmitted to the frame◆store 4, and From there, the image is further sent to the processor 3, where it is analyzed. The processor is a lamp that can freely access the contents of the storage device 20 and illuminates the object 1; Control the voltage supplied to 5.

A pocket of fixed butter surrounding the image of the hardness test impression stored in the storage device. The average gray level of the int falls within a specific range of gray levels. If so, accurate analysis of the image, i.e. the correct size of the indentation in the sample. It has been found that accurate measurements can always be made.

During the indentation hardness test, as the material moves, material is deposited in the area adjacent to the indentation. This fixed pattern has an important meaning because it increases excitement. Control the lighting level Otherwise, the same point will be affected by the reflection of the indented sample. The average gray level at the target will vary over a wide range. This reflectance is It is related to the characteristics of the metal itself and the degree of finish on the sample surface.

The image captured by camera 2 is divided into pixels in frame store 4, and Each is assigned a gray level from 0 to 63. Processor dedicated professional According to Gramm, the likely maximum indentation size is based on known data from hardness tests. and identify it. A processor then constructs a pattern that approximately surrounds the theoretical indentation. select the number of pixels that make up the . The pixels sampled here form part of the image of the actual indentation itself. It is certain that it is not something that surrounds it, but only forms part of the substance that surrounds it. It's true. However, the results of a number of secondary and secondary tests show that such an average - Determining the level range - makes it possible to accurately analyze images. It was. Therefore, in any case, the calculation result of the average gray level is It is compared with both ends of the range stored in the storage 20. and the average gray level The illuminance of the bell meter must be increased, but the calculation result exceeds the predetermined level. If there is a problem, the illuminance of the light must be reduced.

According to another embodiment, as long as the processor 3 has a sufficiently large storage capacity. For example, it becomes possible to analyze images in real time. And in this case, separate There is no need for a frame store as a storage device.

The lamp is of the conventional type, in which the output voltage is variable in 16 steps. controlled by a lamp controller. Therefore, reduce the lighting level. If it is necessary to increase the lamp voltage, the lamp voltage will be increased by one step, while the lighting If a level reduction is required, the lamp voltage is reduced by one step. Ru. You can also repeat the above steps to keep the average gray level within the specified range. It is sufficient to repeat this process by changing the lamp supply voltage several times.

Figures 2 and 3 show the equipment for attaching the object to be measured and the reference object. The location is depicted. With this device, the reference object can be measured without interrupting the measurement process. measurement errors caused by camera image misalignment are greatly reduced. It will be resolved.

On the front side of camera 2 in FIG. - The extension tube 6 is horizontally protruded. The extensilla There is a beam splitting mirror 8 at one end of the main tube 6, and a front silver-plated mirror behind it. -9 are placed respectively. In the holder 11 above this silver-plated mirror A reference object 10 is placed which is illuminated from behind by an attached light source. light The bundle splitting mirror is attached to optical blocks 12 and 13 and The optical block is also connected to further optical blocks 14.15. block 14.15 is equipped with a polarizer 16.17, and an optical lens is installed near the beam splitting mirror. A mirror window 18 is provided, and a diffuser 19 is provided on the opposite side of the mirror. I'm being kicked.

This equipment is an indentation hardness tester, especially static for performing Brinell hardness test. It is intended for use in combination with an indentation hardness tester. This Germany In a particular test, the impression formed on the sample after a known load is measured. The hardness of the material is determined by measuring the hardness of the material. A circular ball with a given load The average diameter of the indentation formed when pressed is opposite to the Brinell hardness value of the material f4. Proportional. The indented sample is passed through an optical window 18 along axis B. put it under. The image of the indentation is reflected along axis A by a beam splitting mirror, Reaches the camera via an extension tube, but is attached to the tube. The image is enlarged to a size appropriate for the purpose of measurement.

As the beam splitting mirror 8, it transmits approximately 50% of the incident light and One that reflects 0% is selected. Therefore, the indentation can be irradiated from above the mirror. However, this means that the light guided from the lamp 5 by the optical fiber cable etc. This is done by positioning the light source so that the

Thanks to the characteristics of the beam splitting mirror mentioned above, the second image can also be captured by the camera. becomes possible. In this embodiment of the invention, a backlit base The image of the quasi-object 10 is reflected by the front silver-plated mirror 9, and a part of it is reflected by the beam splitting mirror. The light passes through the mirror 8 and reaches the camera 2 along the extension tube 6.

The reference object was manufactured to accurately represent the indentation made by the indentation hardness tester. It is opalescent glass with a polished and etched surface. This reference object is the focus of the camera. It is attached to a point surface, and this is illuminated along the axis by a light source attached to the holder 11. It can only be captured on camera when illuminated from behind.

Although this reference object is fixed in position, the instrument may need to be recalibrated. irradiated only when Therefore, the reference object is only occasionally backlit. While it is not used, the lamp 5 that illuminates the sample is left unlit. It is more convenient. However, in any case, only one image can be shown. is required, so the scattered light from the light source passes through mirror 8.9 along axis C. It is necessary to prevent the reference object from being illuminated. This thing is cross-arranged This is achieved by polarizing filters 16 and 17.

When used for the first time, the device must first be calibrated. Illuminating the reference object from behind A sample with no indentations made by the indentation hardness tester was taken along axis B. and place it. The only image displayed is a reference object of known size. It is that of. Therefore, the image analysis device uses the processor device to detect the vibrations of the calibration image. Measure the number of cells, and the size in millimeters of the object and the measured pixels is itself calibrated by determining the correlation between the number of After that, D Turn off the light on the axis, and place the metal sample with the indentation made by the indentation hardness tester on the B axis. Move the camera to the focal point along the At this point, the camera passes through the indentation hardness tester. After recording an image of the indentation and making any necessary adjustments to the illumination of the sample. and the correlation between pixels and millimeters obtained during the calibration process. The size of the indentation by the indentation hardness tester by applying it to the size of the image measurements are achieved. Calibration time is extremely short when using this system. Moreover, the calibration involves moving one indentation from the device to guide the next indentation. This allows the device to be recalibrated periodically.

Errors that can be caused by camera image misalignment or operator error. This image analysis device can perform quick and accurate calibrations to eliminate errors. It is provided as follows. Moreover, according to this invention, it is possible to properly illuminate the object. This provides a device that can accurately analyze images.

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Claims (10)

[Claims] 1. An image analysis device comprising means for forming an image of an object and an illumination device. So, the lighting device is An illumination means for illuminating the object, and one with preset brightness of the surface image or compare several brightness levels and adjust the lighting means based on the result of this comparison. An image analysis device equipped with processing means for increasing or decreasing light output. 2. the means for forming an image of the object comprises a dedicated line television; 2. The apparatus of claim 1. 3. The means for forming an image of the object consists of an image array A system according to claim 1. 4. The hardness of the sample is determined based on the size of the indentation formed on the sample. A static indentation hardness tester comprising: an image solution according to any one of claims 1 to 3; Testing machine equipped with analysis equipment. 5. The processing means determines the brightness of the image from the brightness of the sample surface surrounding the indentation. The static indentation hardness tester according to claim 4, which is applied to determine hardness. 6. The processing means determines the gray level of the image at several locations within the image; Calculation of average gray level based on measured gray levels Static indentation hardness tester according to claim 4 or 5. 7. The average gray level calculation value identifies the extremes of a preset range. The gray level is compared with two preset gray levels, and the average gray level is If the calculated value is outside the preset range, the light output of the illumination means will be reduced. The static indentation hardness tester according to claim 6, wherein the static indentation hardness tester is adjusted appropriately. 8. Image with a measuring device for comparing the size of the object with that of a reference object an analysis device, wherein the measurement device determines the size of an object when it is in its field of view; means for forming an image of an object; and attached to the device instead of, or in addition to, the object whose size is to be measured; a reference object that can be projected using means to form a A device made up of. 9. The object whose size is to be measured and the reference object are reflected through a beam splitting mirror. and the image of one of the objects passes through the beam splitting mirror. and the other image is obtained using the light reflected by the beam splitting mirror. 9. The device of claim 8, wherein the device is 10. The object whose size is to be determined is in the field of view located in the focal plane of the camera lens. The reference object is also the focal point of the camera lens, whereas the reference object is also positioned and illuminated. When the object is positioned within the plane and illuminated, but there is no object within the field of view. 10. The device according to claim 8 or 9, wherein the device is imaged by a camera only in the following.