JP2005257655A - Auxiliary system and method for the same at recognizing of low contrast image with naked eyes - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an auxiliary system for utilizing the relation between the contrast sensitivity and the spatial frequency of naked eyes and the intensity and/or the color of a light source, and easily recognizing the state and defects of images and/or graphics by naked eyes, when a low contrast image is recognized by naked eyes, and to provide a method for the auxiliary system. <P>SOLUTION: The naked eye of a measuring person is positioned at a fixed distance from the image and/or the graphic of a measured object. The auxiliary system optimizes the size of the image and/or the graphic of the measured object viewed by the naked eye. A recognition ability of the naked eye of the measuring person to the low contrast image of the measured object is enhanced by utilizing the relation of the spatial frequency of naked eye to the low contrast image, and adjusting the contrast sensitivity of naked eye to an optimal state. At the same time, the recognition accuracy of the measuring person to the low contrast image is enhanced, by adjusting an intensity and/or a color tone of a backlight of the image and/or the graphic. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a low-contrast image with the naked eye that makes it easy to recognize the state and defects of images and / or figures with the naked eye, particularly utilizing the relationship between the contrast sensitivity and spatial frequency of the naked eye and the brightness and / or color of the light source. The present invention relates to an auxiliary system and method for recognition.

In recent years, flat displays such as liquid crystal displays and plasma displays have been widely used in place of CRT displays due to market development, yield, and improvement in production volume.
However, in general, the manufacturing cost of a flat display is high, and high quality control is required before shipping. In a flat display, for example, black spots, white spots, spot / mura defects, line defects, and non-uniform phenomena on the screen. Are all defective products.
Further, such unevenness is difficult to detect automatically because the contrast in the surface image becomes too low or has a directionality, so it is difficult to detect it automatically. There is a need.

  However, when detection is performed with the human naked eye, for example, if the contrast in the image of the object to be measured is too low, it is not easy to detect wrinkles in the image with the naked eye. Moreover, since there is no objective standard for detection with the naked eye, there is a problem that the reliability of the detection result is lacking. In short, the limit of recognition by the naked eye for low-contrast images is open to the image sensing method of the optic nerve cell, so the sensitivity with which the naked eye recognizes the spatial frequency of the object is different (the spatial frequency is The reciprocal of the size of the target, the larger the object, the smaller the corresponding spatial frequency, and the smaller the object, the larger the corresponding spatial frequency).

FIG. 5 is a diagram often used in visual psychology. The horizontal coordinate is a spatial frequency and the cycle per degree is regarded as one unit, and the vertical coordinate is contrast sensitivity. In FIG. 5, a specific range at a specific spatial frequency (usually 5-10 cycles per degree) shows the highest contrast sensitivity of the naked eye, which is the target frequency, eg a display Is related to the brightness and color wavelength.
That is, for example, if the image formed by the object with the naked eye is adjusted to the above-mentioned size, the recognition degree for the low-contrast image is the highest, so that a display having a wrinkle in the image can be easily confirmed.

  6A and 6B are diagrams showing the strength of an image sensed by the optic nerve cell. In FIG. 6A, the center is the reinforcement region 70 and the periphery thereof is the suppression region 71. The sensitivity corresponds to the curve in FIG. 6B.

  In addition, when a single line is seen with the naked eye, what the optic nerve cell senses is a sensing area arranged in a line as shown in FIG. 7, and the center is a linear reinforcement area 70 ′, on both sides of the sensing area. Is a linear suppression region 71 ′, and the widths of the enhancement region 70 and the suppression region 71 are related to the range sensed by the optic nerve cell, and thus have a certain width. In this situation, when the luminance contrast of an image is recognized by the naked eye, whether or not it can be recognized effectively has a great relationship with the spatial frequency.

  FIG. 8 shows the correspondence relationship between the optic nerve cell sensing areas when the images have different spatial frequencies (different sizes). In FIG. 8A, the image spatial frequency and the optic nerve cell sensing frequency are shown. And the enhancement region 70 'in the sensing region is located on the bright stripe pattern of the image, and the suppression region 71' is also located on the dark stripe pattern of the image. This is the case when the sensitivity of the optic nerve cell to the image is the highest.

  8B and 8C show the relationship when the spatial frequency of the image is larger or smaller than the highest sensing frequency of the optic nerve cell, in which case the enhancement region and the suppression region of the sensing region are the bright stripe pattern and Since it deviates from or overlaps with the dark stripe pattern, the contrast sensitivity of the naked eye is lowered.

  As described above, since the contrast sensitivity of the naked eye and the spatial frequency of the image are closely related, the spatial frequency of the image is important in order to improve the recognition ability of the naked eye to the image in a low contrast state. It was necessary to consider as an important point.

  The present invention adjusts the distance between the optical element 30 located between the naked eye of the measurer and the image of the object to be measured 100 and the distance between the optical hand 30 and the image of the object to be measured 100. And a driving mechanism 60 for adjusting an enlargement / reduction ratio with respect to the device under test 100, and adjusting the spatial frequency of the image of the device under test 100 to measure the object 100 with a low contrast with the naked eye of the measurer. An auxiliary system for low-contrast image recognition by the naked eye, characterized by enhancing the recognition ability of the image of the human eye, and a step of positioning the naked eye of the measurer at a predetermined distance from the image of the measurement object 100; Measuring the spatial frequency of the image of the measurement object 100 by the measurer at the distance, and when the measured spatial frequency is not optimal, the image of the measurement object 100 by the measurer. The step of adjusting the spatial frequency with respect to the image to optimize the contrast sensitivity of the naked eye sequentially causes irregularities or other quality problems to occur in the image of the measurement object 100 with the naked eye of the measurer. There is provided an auxiliary method for low-contrast image recognition by the naked eye, characterized by determining whether or not there is.

  The present invention uses the relationship between the contrast sensitivity of the naked eye and the spatial frequency of the image to adjust the spatial frequency when viewing the image and / or figure to be measured with the naked eye, thereby reducing the low contrast image and / or Alternatively, it is easy to recognize the state of the graphic and the defect.

  In order to achieve the above object, the present invention adjusts the distance between the optical element positioned between the naked eye of the measurer and the image of the object to be measured, and the distance between the optical element and the image of the object to be measured. And a drive mechanism for adjusting the magnification / reduction magnification of the optical element with respect to the object to be measured, and by adjusting the spatial frequency of the image of the object to be measured, the object to be measured having a low contrast with the naked eye of the measurer The recognition ability for images is improved.

  The low-contrast image auxiliary assistance system may further include a control unit connected to the drive mechanism, and the low-contrast image recognition auxiliary system is preset in images of different objects to be measured. The system may further include a database connected to the control unit and serving as a basis for controlling the driving mechanism, and the low-contrast image recognition assisting system may further include an object to be measured. And a half mirror provided at a position a certain distance away from the image sensor, and an image capturing device whose image capturing angle faces the object to be measured via the half mirror and is connected to the control unit.

  As described above, the present invention captures an object to be measured through a half mirror and an optical element by an image capturing device, transmits it to a control unit, and compares it with a predetermined spatial frequency value stored in advance in a database. The control unit controls the drive mechanism to raise and lower the optical element, thereby adjusting to a predetermined spatial frequency.

  At this time, since there is a certain distance between the measurer and the half mirror, the object to be measured that has already been subjected to spatial frequency adjustment is observed through the mirror. Image recognition can be performed with contrast sensitivity. Therefore, the accuracy of image recognition can be further improved.

  The image capturing device also has a function of measuring the luminance of the image of the object to be measured, and the control unit is further connected to a luminance adjusting device for measuring the luminance of the image of the object to be measured. In addition, the brightness adjusting device is built in a display that displays an image of the object to be measured, and the brightness adjusting device is built in a backlight unit that is used when projecting an image of the object to be measured. The adjusting device may be provided in the external light source, and the external light source may be projected on the screen of the reflective display.

  Further, in the present invention, in order to provide an auxiliary method at the time of low-contrast image recognition by the naked eye, a step of positioning the naked eye of the measurer at a predetermined distance from the image of the object to be measured; Measuring the spatial frequency of the measured object with respect to the image of the measured object, and adjusting the spatial frequency of the measured object with respect to the image of the measured object when the measured spatial frequency is not optimal, and contrast sensitivity of the naked eye In order to determine whether or not there is any unevenness or other quality problem in the image of the object to be measured with the naked eye of the measurer.

  According to the above steps, the measurer can perform the recognition operation on the image of the object under measurement with the optimum contrast sensitivity of the naked eye, so that the accuracy of the recognition operation can be further improved.

  Further, in the step, after measuring the spatial frequency, the measured spatial frequency is compared with the data of the spatial frequency stored in advance, and if the spatial frequency is different from the predetermined spatial frequency, the measurer By adjusting the spatial frequency of the image of the object to be measured, the contrast sensitivity of the naked eye can be brought into an optimum state.

  Further, in the above step, after adjusting the spatial frequency of the image of the object to be measured with respect to the naked eye of the measurer, the relationship between the contrast sensitivity of the naked eye, the light source of a specific wavelength, and the light source intensity is used. The contrast sensitivity of the naked eye may be further improved by changing the color of the image and the intensity of the backlight (or reflected light) for the image.

  Further, in the step, when measuring the spatial frequency in the image of the object to be measured, at the same time, by measuring the luminance in the image of the object to be measured, whether or not to adjust the intensity of the backlight or reflected light for the image. You may judge.

  In addition, the light source color and background color in the image of the object to be measured are generally preferably green, but a preferable color may be obtained by experiment for a specific object to be measured.

  Further, the image of the object to be measured may be an image projected on a screen of a flat display, an X-ray film, or a wiring pattern on a circuit board.

  Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  1 is a use state diagram according to the present invention, FIG. 2 is another use state diagram according to the present invention, FIG. 3 is a block diagram of a system according to the present invention, and FIG. 5 is a curve diagram showing the relationship with contrast sensitivity, FIG. 5 is a curve diagram showing characteristics of contrast sensitivity of the naked eye with respect to spatial frequency, and FIGS. 6A and 6B show the intensity and suppression of images sensed by optic nerve cells. FIG. 7 is a diagram showing a region sensed by an optic nerve cell when a single line is viewed with the naked eye, and FIGS. 8A to 8C each show inter-space wave numbers (different sizes). It is the figure which showed the sensing effect of the optic nerve cell with respect to a different image.

  As shown in the embodiment of FIG. 1, the auxiliary system for recognizing a low-contrast image by the naked eye according to the present invention is a lens (for example, a concave mirror or a convex mirror) positioned between the naked eye of the measurer and the image of the object 100 to be measured. ), An optical element 30 such as a lens system, an optical lens or a zoom lens, and a distance or focal length female (for example, a zoom lens) between the optical element 30 and an image of the object 100 to be measured. By adjusting the magnification / reduction magnification of the optical element 30 with respect to the object 100 to be measured, and the system is configured such that the measurer passes the optical element 30 with the naked eye. The measurement is performed by observing the image of the object to be measured. However, in more detail, in this measurement method, the optical element 30 is first visible to the naked eye when it is in the initial position. It is determined whether the image size of the measurement object is easy to recognize. If it is difficult to recognize, the optical element 30 is moved by the drive mechanism to adjust the spatial frequency of the image of the measurement object, Set the image size appropriately. As a result, the ability to recognize the image of the low-contrast measurement object with the naked eye of the measurer is enhanced.

  As shown in FIG. 2, in the said structure of this invention, it can further expand to an automation assistance system. The configuration will be described below.

  Provided at a position away from the object to be measured 100 by a certain distance, performs semi-reflection for measurement by a measurer and semi-transmission for an image capturing device (for example, a digital camera) to perform automation processing. The half mirror 10 that can be rotated and can be measured by a measurer when the angle with respect to the object to be measured 100 is 45 degrees and that can be imaged by an image capturing device when the angle is 90 degrees, and the half mirror 10 And an image capturing device 20 that captures an image of the device under test 100 via the half mirror 10 and a drive mechanism (not shown) that is positioned between the half mirror 10 and the device under test 100. The distance between the half mirror 10 and the device under test 100 is adjusted by adjusting the enlargement / reduction magnification of the image of the device under test 100 projected onto the half mirror 10. A lens system (for example, a concave mirror, a convex mirror, etc.), a lens system, an optical lens, or an optical element 30 of a zoom lens. In the measurement method of the system, the distance from the half mirror 10 to the measurer and the image from the half mirror 10 The distance to the capturing device 20 is related, that is, the measurement subject's naked eye and the image capturing device 20 have the same spatial frequency of images captured from the half mirror 10. Thus, the image capturing device 20 captures an image of the device under test 100 (for example, a screen of a flat display through the half mirror 10 and the optical element 30, but when the measured spatial frequency is not an optimal value, The distance (that is, the enlargement or reduction ratio) of the optical element 30 with respect to the device under test 100 is adjusted by the drive mechanism, and the spatial frequency of the image projected on the half mirror 10 is changed and adjusted to the optimum spatial frequency accordingly. Therefore, the measurer can always perform the measurement with the optimum contrast sensitivity.

  The change of the enlargement / reduction ratio of the optical element 30 is achieved by a control unit and a database. As shown in FIG. 3, the configuration of the system is preset and optimized for images and / or figures of different objects to be measured. A data base 40 in which various spatial frequency values are stored, and a control unit 50 which is a control center connected to the image capturing device 20, the driving mechanism 60 of the optical element 30 and the database 40.

Thereby, after the image capturing device 20 captures the image of the object to be measured and calculates the spatial frequency, it is sent to the control unit 50 and the measured spatial frequency is compared with the spatial frequency data stored in the database 40 in advance. Then, the control mechanism 50 controls the drive mechanism 60 to raise and lower the optical element 30 to adjust the enlargement / reduction ratio for the image and achieve a predetermined spatial frequency.
Therefore, the naked eye of the measurer can measure the image of the object to be measured with the optimum contrast sensitivity by the half mirror 10, so that the accuracy of image recognition can be further improved.

  In the system, in addition to adjusting the spatial frequency in the image of the object to be measured, the image of the object to be measured is further combined by combining the contrast sensitivity of the naked eye with the luminance and color of the image of the object to be measured. The brightness and color may be adjusted to improve the accuracy of the measurer with the naked eye.

  FIG. 4 is a continuation diagram showing the relationship between the light source wavelength and the contrast sensitivity of the naked eye. As can be seen from the figure, the naked eye has an optimum contrast sensitivity for light having a wavelength force axis of 500 nm. The light of this wavelength is green. Therefore, if it is desired to increase the contrast sensitivity of a low-contrast image measured with the naked eye, the light source relating to the object to be measured may be adjusted to green. In the above method, when the object to be measured is a flat display, a green background image may be generated.

  When measuring the image of the reflective display according to the present invention, the external light source projected on the reflective display may be green, and when the X-ray film is analyzed according to the present invention. The background light source of the X-ray film may be green.

  On the other hand, in the method of increasing the contrast sensitivity of the naked eye by adjusting the brightness, the image capturing device 20 has a function of measuring the brightness of the image of the device under test 100, and the database 40 stores in advance the optimum brightness of various devices under test. A brightness adjustment device 51 is connected to store the value, compare the brightness value with the measured value by the control unit 50, and measure the brightness of the image of the play object 100 based on the comparison result. The image brightness of the object to be measured is adjusted by the control unit 50.

  As described above, by using the present invention, various low-contrast images (for example, flat display, X-ray film, chip pattern, printed circuit board (PCB), etc.) can be measured. The embodiment of the device 51 varies depending on the object to be measured as described below.

When the object to be measured is a liquid crystal display, the brightness adjusting device 51 is built in the liquid crystal display.
When the object to be measured is a reflective display, the brightness adjusting device 51 is provided in an external light source.
When the object to be measured is an X-ray film, the brightness adjusting device 51 is provided in the backlight unit of the X-ray film.

  The above description merely shows one embodiment of the brightness adjusting device 51, and any form may be used as long as it is within the scope of the claims shown in this specification. Needless to say, even within the conceivable range, it is within the scope of the claims of the present invention.

  Further, in the present invention, the spatial frequency values of the images of various objects to be measured are stored in the database in advance, but the measurement person does not always have the same contrast sensitivity for the same spatial frequency, in other words, the database. The spatial frequency of the image of the object to be measured adjusted by the above does not always match the contrast sensitivity of each measurer. Therefore, according to the present invention, the optimum contrast sensitivity can be obtained by the operator himself / herself adjusting the drive mechanism of the optical element.

  The data base data may be obtained from literature or may be obtained by conducting an experiment under specific conditions.

Moreover, as a method for obtaining the spatial frequency in advance, the method shown in Table 1 below may be adopted.

  As described above, the present invention uses the relationship of the spatial frequency to the contrast sensitivity of the naked eye, and adjusts the spatial frequency of the naked eye to the object to be measured, so that the measurer can perform the measurement with the optimal contrast sensitivity of the naked eye. Since the recognition operation for the image of the measurement object can be performed, the accuracy in the measurement for the low-contrast image is improved. Furthermore, this technique can measure various low-contrast images. For example, it can be used for flat panel display wrinkle detection, circuit board pattern confirmation, and X-ray film analysis. It is also used for measurement. Therefore, the present invention can clearly solve the conventional problems.

It is a use condition figure concerning the present invention. It is another use condition figure concerning the present invention. It is a system block diagram concerning the present invention. It is a curve figure which shows the relationship between a light source wavelength and the contrast sensitivity of the naked eye. It is a curve diagram showing characteristics of contrast sensitivity of the naked eye with respect to spatial frequency. A and B are diagrams showing intensity and suppression of an image sensed by an optic nerve cell. It is a figure which shows the area | region which the optic nerve cell sensed when seeing one line | wire with the naked eye. FIGS. 8A to 8C are diagrams showing the sensing effect of optic nerve cells on different images of spatial frequencies (different sizes).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Half mirror 100 Measured object 20 Image acquisition apparatus 30 Optical element 40 Database 50 Control unit 51 Brightness adjustment apparatus 60 Drive mechanism 70,70 'Strengthening area | region 71,71' Suppression area | region

Claims (23)

An optical element 30 positioned between the naked eye of the measurer and the image of the object 100 to be measured;
A drive mechanism 60 for adjusting the magnification / reduction magnification of the optical element 30 with respect to the measurement object 100 by adjusting the distance between the optical element 30 and the image of the measurement object 100;
At the time of low-contrast image recognition by the naked eye, which is characterized by enhancing the ability of the naked eye of the measurer to recognize the image of the low-contrast object 100 by adjusting the spatial frequency of the image of the object 100 to be measured. Auxiliary system.   The auxiliary system at the time of low-contrast image recognition by the naked eye according to claim 1, further comprising a control unit 50 connected to the drive mechanism 60.   The apparatus further includes a database 40 that stores values of preset spatial frequencies of images of different objects to be measured 100 and is connected to the control unit 50 and serves as a basis for controlling the drive mechanism 60. Item 3. An auxiliary system for low-contrast image recognition by the naked eye according to Item 2. A mirror provided at a certain distance from the DUT 100;
4. The low contrast by the naked eye according to claim 3, further comprising: an image capturing device having an image capturing angle directed toward the object to be measured 100 through the mirror and connected to the control unit 50. Auxiliary system for image recognition.   5. The auxiliary system for low-contrast image recognition with the naked eye according to claim 4, wherein the mirror is a total reflection mirror.   The auxiliary system at the time of low-contrast image recognition by the naked eye according to claim 4, wherein the mirror is a half mirror 10.   The auxiliary system at the time of low-contrast image recognition by the naked eye according to any one of claims 1, 4, 5 and 6, wherein the drive mechanism 60 of the optical element 30 can be finely adjusted manually.   The auxiliary system for low-contrast image recognition by the naked eye according to claim 7, wherein the optical element 30 is a convex race.   The auxiliary system for low-contrast image recognition by the naked eye according to claim 7, wherein the optical element 30 is a concave mirror.   The auxiliary system for low-contrast image recognition by the naked eye according to claim 7, wherein the optical element (30) is a zoom lens. The auxiliary system for low-contrast image recognition by the naked eye according to claim 7, wherein the optical element 30 is an optical lens.   The image capturing device 20 also has a function of measuring the luminance of the image of the device under test 100, and a brightness adjusting device 51 for measuring the luminance of the image of the device under test 100 is further connected to the control unit 50. The auxiliary system at the time of low contrast image recognition by the naked eye according to claim 4.   The auxiliary system for low-contrast image recognition by the naked eye according to claim 12, wherein the brightness adjusting device 51 is built in a display that displays an image of the device under test 100.   The auxiliary system for low-contrast image recognition by the naked eye according to claim 12, wherein the brightness adjusting device 51 is built in a backlight unit used when projecting an image of the device under test 100.   The auxiliary system for low-contrast image recognition by the naked eye according to claim 12, wherein the brightness adjusting device 51 is provided in an external light source, and the external light source is projected on a screen of a reflective display. Positioning the measurer's naked eye at a predetermined distance from the image of the object to be measured 100;
Measuring a spatial frequency of an image of the object 100 to be measured by a measurer at the distance;
When the measured spatial frequency is not optimal, the step of adjusting the spatial frequency with respect to the image of the object 100 to be measured to optimize the contrast sensitivity of the naked eye is sequentially performed. An assisting method at the time of low-contrast image recognition by the naked eye, characterized by determining whether the image of the object to be measured 100 is uneven or other quality problems with the naked eye.   After the spatial frequency is measured, the measured spatial frequency is compared with the spatial frequency data stored in advance in the database 40. If the spatial frequency is different from the predetermined spatial frequency, the measurer quickly measures the measured frequency. The assisting method for low-contrast image recognition by the naked eye according to claim 16, wherein the spatial frequency of the object 100 is adjusted to optimize the contrast sensitivity of the naked eye.   The assisting method at the time of low-contrast image recognition by the naked eye according to claim 16, wherein the image of the device under test 100 is an image projected on a screen of a flat display.   The assisting method at the time of low-contrast image recognition by the naked eye according to claim 16, wherein the image of the device under test 100 is an X-ray film. The auxiliary method for recognizing a low-contrast image by the naked eye according to claim 16, wherein the image of the device under test 100 is a wiring pattern on a circuit board.   21. The assist method for recognizing a low-contrast image by the naked eye according to any one of claims 16 to 20, wherein the light source color and the background color in the image of the object to be measured 100 are preferably green.   When measuring the spatial frequency in the image of the object to be measured 100, it is determined whether to adjust the light source intensity for the image by measuring the luminance in the image of the object to be measured 100 at the same time. 21. A method for assisting low-contrast image recognition with the naked eye according to any one of claims 16 to 20. When measuring the spatial frequency in the image of the object to be measured 100, it is determined whether to adjust the light source intensity of the image by measuring the luminance in the image of the object to be measured 100 at the same time. The assisting method at the time of low contrast image recognition by the naked eye according to claim 21.