JP2007003543A - Light irradiator for image processing and light irradiation method for image processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light irradiator for image processing, as it were, to be called as an intelligent light irradiator, structured so as to provide an image optimum for image processing by dynamically and automatically producing an illumination environment. <P>SOLUTION: This light irradiator A4 for image processing irradiates a prescribed area with light L1 in such a manner that at least one of light irradiation conditions can be changed which are irradiation direction, irradiation solid angle, irradiation intensity, irradiation range and spectrum distribution, while detecting the state of light irradiation in whole or in part of the prescribed area. While referring to the state of light irradiation, at least any one of the irradiation conditions is adjusted prior to image processing by an image processor each time the prescribed area is changed, thereby setting light irradiation conditions corresponding to the purpose of image processing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing light irradiation apparatus and the like that are suitably used for surface inspection of products, mark detection, and the like.

  Conventionally, when a product or the like (work) is automatically inspected for scratches, mark detection, symbol reading, etc., the work is imaged with an imaging device such as a CCD camera to obtain image data. Image processing such as digitization (monochrome) is added to automatically discriminate the scratches and symbols. At that time, the work is irradiated with light according to the purpose of the image processing.

  As one example, there is known one that is capable of detecting defects such as scratches by irradiating light with low directivity from the surroundings (hereinafter referred to as low angle light) (Patent Document 1, FIG. 3 and the like). According to such illumination, when the surface is mirror-like, when observed from the direction perpendicular to the surface (imaging direction), light is scattered only at the defective part, and only that part appears to shine. Therefore, the defect can be detected.

In addition, for example, it is possible to irradiate parallel light or light that is almost parallel (hereinafter referred to as coaxial parallel light) from substantially directly above the workpiece, that is, from substantially the same direction as the imaging direction, so that mark detection and symbol reading can be performed smoothly. In addition, there are known ones that change the color of the irradiated light and allow only a specific color printed on the surface of the workpiece to be lifted and read.
Japanese Patent Laid-Open No. 10-21729

  Conventionally, in this type of light irradiation, settings related to light irradiation conditions such as work brightness and light irradiation angle are set only at the initial stage of installation, at the time of maintenance, when the work model is changed, or when a problem occurs, for example, image processing. Actually, it is done manually by trial and error using the results. And it is no exaggeration to say that the dynamic and automatic light irradiation condition control during running is not actually performed to the extent that FB control is performed to keep the light amount of the light source constant. .

  However, when inspecting a workpiece having fine streak-like eyes uniformly on the surface, such as a metal forging shown in FIG. 14, depending on the irradiation direction of low angle light, the light is scattered by the eyes. It may happen that the surface inspection or the mark reading cannot be performed due to the shadow or shadow.

  Of course, for a single workpiece, the operator can perform surface inspection and mark reading by appropriately setting the workpiece installation position and light irradiation direction by trial and error while referring to the image processing results. It is. In addition, for example, in a character reader, there is also known a device that re-trys by appropriately changing the irradiation angle when a character cannot be cut out or read as a result of image processing. However, there is no guarantee that such trial and error settings are optimal.

  Furthermore, for example, when such a workpiece is conveyed on the line and it is necessary to sequentially inspect it, the method described above takes too much time and cannot be dealt with at all. Even if it is configured to automatically determine the result of image processing and automatically adjust the light irradiation conditions, image processing including the automatic adjustment processing still takes a considerable amount of time (several tens of milliseconds). Because of this, quick inspection is not possible.

  Therefore, the present invention does not perform various corrections for image processing on the image processing apparatus side, but the light irradiation state on the workpiece, that is, the light irradiation apparatus side can obtain an optimal image for image processing, that is, Provided is an image processing light irradiation device that can be said to be an intelligent light irradiation device that dynamically and automatically generates a light irradiation mode while referring to a mode of reflected light from a workpiece, and is described above. This is to solve the problem.

  That is, the image processing light irradiation apparatus according to the present invention, together with an image processing apparatus that processes image information obtained by imaging a predetermined area on a workpiece for a predetermined purpose such as surface inspection or mark detection in the predetermined area. A light irradiating unit that irradiates the predetermined region with light so that at least one of light irradiation conditions including an irradiation direction, an irradiation solid angle, an irradiation intensity, an irradiation range, and a spectrum distribution can be changed; A light irradiation condition control unit capable of controlling at least one of the light irradiation conditions by controlling the light irradiation unit, wherein the light irradiation condition control unit is all or part of the predetermined region. The light irradiation condition according to the purpose of the image processing can be set prior to the image processing each time the image processing is performed while referring to the light irradiation state in FIG.

  If it is such, since it is possible on the light irradiation apparatus side to create the optimal light irradiation conditions for the purpose of image processing, the load such as correction on the image processing apparatus side is greatly reduced. Moreover, since the light irradiation conditions can be set each time prior to image processing, for example, even when inspecting workpieces flowing on the line one after another, an optimal image can be obtained after inspection for each workpiece. it can. Compared to image processing, the detection of light irradiation state and the setting of light irradiation conditions do not require so complicated processing, and the time required is 1 / 10th to 1 / 100th of the image processing time. Time is not a bottleneck, and there is no hindrance to quick inspections.

  Preferably, a light irradiation state detection unit that detects the light irradiation state is further provided, and the light irradiation condition control unit refers to the light irradiation state detected by the light irradiation state detection unit. . The light irradiation state detection unit may use, for example, the imaging device itself, or may use a CMOS camera, a photodiode, or the like separately from the imaging device or the like.

  Furthermore, the light irradiation condition control unit may be configured to be able to set a plurality of light irradiation conditions according to the purpose of image processing. Such a configuration is effective in the case where multiple inspections are performed to improve the inspection reliability, such as inspection under each light irradiation condition.

  As a specific embodiment, the present invention is applied to a work in which a large number of streak-like eyes extending in a certain direction are formed in the predetermined region, and the light irradiation unit is in an imaging direction with respect to the predetermined region. The irradiation direction viewed from the viewpoint is irradiated with low-angle light, the light irradiation state is the lightness of the predetermined area as viewed from the imaging direction, and the light irradiation condition control unit has the lightness is substantially highest. The light irradiation direction as seen from the imaging direction can be set so as to become or substantially the lowest.

  Here, the “constant direction” includes the circumferential direction and the like, for example, eyes generated concentrically.

  If it is such, when the light irradiation direction is set to the direction where the lightness is substantially maximum by the irradiation direction changing unit, the irradiation direction is the direction in which the scattered light from the eyes is generated most strongly, that is, The direction is substantially perpendicular to the eyes. Then, since the scattered light is weakened at the defect portion, the defect can be detected as a dark portion compared to the surroundings when observed from the imaging direction. On the other hand, when the direction of light irradiation is set to a direction where the lightness is substantially the lowest, the irradiation direction is a direction in which scattered light is hardly generated by the eyes, that is, a direction substantially along the eyes. Since scattered light is generated at the defect site, the defect can be detected as a brighter part compared to the surroundings when observed from the imaging direction. Also, depending on the defect, there are some that shine brightly due to the difference in scattering rate, and some that do not shine. Therefore, if the defect is detected in both the direction in which the brightness is substantially the highest and the direction in which the brightness is the lowest, the detection accuracy can be further improved.

  As a specific embodiment for enabling quick switching of the light irradiation direction and shortening the inspection time, the light irradiation unit includes a plurality of LEDs arranged in a ring around the predetermined region. The light irradiation condition control unit can selectively turn on some of the LEDs and set the light irradiation direction.

  An example of light irradiation suitable for automatic detection by defect image processing is one in which the light irradiation unit irradiates light from a facing direction along a predetermined irradiation direction.

  As a light irradiation mode suitable for visual inspection or inspection by an operator of a captured image, the light irradiation unit irradiates light from a single direction along a predetermined irradiation direction. Can be listed.

  On the other hand, even if the workpiece is slightly inclined, the light irradiation unit changes the imaging angle with respect to the predetermined region in order to change the irradiation angle of light correspondingly and perform defect detection or mark detection suitably. And the light irradiation state detector detects the lightness of the predetermined area as seen from the imaging direction, and controls the light irradiation condition control. It is desirable that the portion sets the solid angle of light irradiation so that the lightness is substantially highest or substantially lowest.

  In order to reduce the mechanical operation mechanism as much as possible and change the irradiation solid angle with a simple configuration, the light irradiation unit includes a plurality of LEDs laid on a plane, and the light It is preferable that the irradiation condition control unit selectively turns on a part of the LEDs and sets the light irradiation solid angle.

  In the case of a work in which a transparent thin film is formed on the surface of the predetermined area, marks, scratches, etc. formed on the work can be effectively detected by changing the color of light. Specifically, the light irradiation unit irradiates the predetermined region with light so that a spectrum distribution can be changed, and the light irradiation state detection unit detects the lightness of the predetermined region viewed from the imaging direction. The light irradiation condition control unit can set the light irradiation direction as viewed from the imaging direction so that the lightness is substantially highest or substantially lowest.

  The surface of the workpiece, such as metal, in which streak-like eyes remain is not finished and is often uneven due to dullness, dirt, minute roughness, and the like. Such unevenness may cause contrast when light having a high directivity as described above is applied at a low angle, which may lead to erroneous detection. In order to cancel such a phenomenon and improve the detection accuracy, it is desirable to further include an auxiliary light irradiation unit that irradiates the predetermined region with diffused light.

  To make it possible to flexibly change the irradiation direction and solid angle of the auxiliary light depending on the type and state of the workpiece, and to suitably detect defects and marks, the auxiliary light emitting surface includes a plurality of light emitting surface elements. It is preferable to separate the light emitting surface elements and to selectively emit some of the light emitting surface elements.

  As a specific aspect of the auxiliary light irradiating unit, an auxiliary light emitting surface provided so as to cover the predetermined area from substantially the whole sky except the imaging direction can be exemplified.

  In order to achieve uniform surface light emission in the auxiliary light irradiating unit using LEDs having excellent lifetime, luminous stability, operability, switching characteristics, response speed, etc., the auxiliary light irradiating unit has the bottom surface of the auxiliary light. It is desirable to include a light diffuser serving as a light emitting surface and a plurality of second LEDs that introduce light into the light diffuser.

  The light diffuser is separated into a plurality of diffuser elements in order to flexibly change the irradiation direction and solid angle of the auxiliary light depending on the type and state of the work and to suitably detect the defect. What is comprised so that light can be selectively introduce | transduced into a diffuser element is preferable.

  In order to reduce the luminous intensity loss in the light diffuser as much as possible, the light diffuser preferably includes a transparent member and a minute light reflecting member mixed in the transparent member.

  As described above, according to the present invention, it is possible to create a light irradiation condition optimal for the purpose of image processing on the light irradiation device side, so that a load such as correction on the image processing device side is greatly reduced. Moreover, since the light irradiation conditions are set every time prior to image processing, for example, even when inspecting works flowing on the line one after another, an optimal image can be obtained after inspection for each work. . Compared to image processing, the detection of light irradiation state and the setting of light irradiation conditions do not require so complicated processing, and the time required is 1 / 10th to 1 / 100th of the image processing time. Time is not a bottleneck, and there is no hindrance to quick inspections.

Embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>

  As shown in FIG. 1, the image processing light irradiation apparatus A4 according to the present embodiment images a predetermined holding area on the surface of the workpiece holding unit A1 that holds the workpiece W from the opposite direction, and outputs the image as image data. Surface inspection using CCD camera A2 as an image pickup device and image processing device A3 that takes in the image data and binarizes the image data and automatically detects defects generated on the surface of the workpiece W It constitutes the system.

  First, the basic operation of this system will be described. When the surface of the workpiece W is irradiated with the low-angle light L1 and observed from the direction facing the workpiece surface, if there is no defect on the surface, the low-angle light L1 passes through to the side, so that it cannot be observed at all. If there is a defect, the light L1 is scattered there, so that the scattered light can be detected as light from the defect.

  Therefore, the image processing light irradiation apparatus A4 of the present embodiment is applied to the workpiece W in which a large number of streak-shaped eyes extending in a certain direction are formed, and has a great effect on defect detection. A device main body 1 and a control power supply device 2 are provided. Each part will be described in detail with reference to FIGS.

  The apparatus main body 1 is a block-shaped device including a casing 3 and a light irradiation unit 4 and an auxiliary light irradiation unit 5 held in the casing 3, and a peephole H is vertically penetrated in the center. . A predetermined area of the workpiece W arranged on the bottom surface side can be observed from, for example, the CCD camera A2 from the direction facing directly through the viewing hole H.

  The casing 3 includes a cylindrical first casing element 31 having a bottom surface having a peripheral wall 31a and a top wall 31b, and a cylindrical second casing element 32 mounted on the first casing element 31. Become. The second casing element 32 is provided with a half mirror M therein, and is configured to be able to irradiate the predetermined region through the viewing hole H with the coaxial diffused light incident from the side.

  The light irradiating unit 4 irradiates the predetermined area with the low-angle light L1 having strong directivity, and a plurality of LEDs 41 arranged in an annular shape on the inner periphery of the bottom of the peripheral wall 31a with the light emitting direction directed toward the casing axis. It is equipped with. The LEDs 41 are attached by, for example, arranging them in a row on a flat flexible wiring board (not shown) in a flat state, and then bending the flexible wiring board along the inner circumference of the peripheral wall 31a. It is. On the other hand, in terms of electricity, the plurality of LEDs 41 are equally divided, for example, in the circumferential direction into a plurality of (eight) groups, and a power supply line is provided for each group of LEDs 41 belonging to each group. Independently, it is configured so that the lighting, extinction, and emission intensity of each LED 41 group can be controlled. Of course, each LED 41 may be controlled.

  The auxiliary light irradiating unit 5 has auxiliary light (diffusion light) having a large number of random incident angles from the auxiliary light emitting surface 5a provided so as to cover almost the whole sky except the peephole H in the imaging direction of the predetermined area. Light) L2 is uniformly applied to the predetermined region, and includes a light diffuser 51 and a plurality of second LEDs 52 that introduce light into the light diffuser 51.

  The light diffuser 51 has a ring shape in which a large number of minute light reflecting members are mixed in a transparent member, and the bottom surface of the light diffuser 51 has a partially concave spherical shape as the auxiliary light emitting surface 5a. The light diffuser 51 has its outer peripheral surface closely attached to the inner surface of the peripheral wall 31a, and the central through hole becomes the peep hole H. Furthermore, in the present embodiment, as shown in FIG. 4 in particular, the light diffuser 51 is vertically separated into a plurality of diffuser elements 511... And adjacent diffusers at the boundary between the diffuser elements 511. A light reflecting layer 512 that shields light to the element 511 is provided. Therefore, the auxiliary light emitting surface 5 a is also composed of unit light emitting surfaces divided for each diffuser element 511.

  The second LED 52 is attached to the bottom surface of the casing top wall 31b via the wiring substrate 53 so that the light emission direction thereof faces the bottom surface side of the light diffuser 51, for example. The light emitted from the second LEDs 52 is introduced into the light diffuser 51 from above and is derived from the auxiliary light emitting surface 5a as auxiliary light L2 that is scattered light. In addition, the power supply line is made independent for each group of second LEDs 52 corresponding to each diffuser element 511, and the lighting, extinction, and emission intensity of each of the second LEDs 52 group can be controlled. Of course, each second LED 52 may be controlled.

  The control power supply device 2 has a function as a light irradiation condition control unit. As shown in FIG. 1, the control power supply device 2 refers to the lightness of the predetermined area, and each time the light irradiation is performed prior to image processing by the image processing device. The light irradiation direction as viewed from the imaging direction can be set so that the brightness is substantially the highest or substantially the lowest.

  In the present embodiment, the lightness is lightness when the predetermined area is viewed from the imaging direction, and is obtained by measuring the intensity of reflected light from the predetermined area with a light irradiation state detection unit. . The light irradiation state detection unit outputs a current or voltage corresponding to the intensity of received light. For example, a dedicated device such as a CMOS camera or a photodiode may be used. In this embodiment, a CCD is used. The camera A2 plays a role as a light irradiation state detection unit, and brightness is obtained from the value of the output signal. Specifically, the brightness is the average value (average value of the entire predetermined area) or the integrated value (total value of the entire predetermined area) of the output signal values of all the CCD elements constituting the CCD camera A2. Of course, the average value or integrated value of the output signal values of some CCD elements (the average value or the total value of a part of the predetermined area) may be used as the brightness.

  Therefore, the setting of the light irradiation direction by the control power supply device 2 is performed depending on which group of LEDs 41 among the LEDs 41 divided into eight groups is lit. In the present embodiment, the groups opposed to the center are turned on in pairs, and the irradiation direction of the light L1 can be switched to four directions.

  Next, an example of the operation of the system configured as described above will be described below with reference to FIGS.

  First, when the workpiece W is installed at a predetermined position, the control power supply device 2 turns on the LEDs 41 belonging to any group pair of the light irradiation unit 4 and irradiates the predetermined predetermined region of the workpiece W with the light L1 (step ST1). ).

  Next, the control power supply device 2 receives an output signal from each CCD element of the CCD camera A2 that images the predetermined area, calculates the sum or average of these output signal values as the brightness, and stores it in the predetermined storage area. (Step ST2).

  In the same procedure, the control power supply 2 sequentially turns on the LEDs 41 belonging to each group pair, changes the irradiation direction of the light L1, calculates the brightness each time, and stores it in a predetermined storage area (steps ST2 to ST4). .

  Then, an irradiation direction (bright direction) in which the brightness is substantially highest and an irradiation direction (dark direction) in which the brightness is substantially lowest are determined (step ST5).

  Next, the light L1 is irradiated along the bright direction determined in this way (step ST6). At this time, the control power supply device 2 selects unit light emitting surfaces along the bright direction, and emits auxiliary light from these unit light emitting surfaces (step ST6). On the other hand, an illumination mode identification signal indicating that the current illumination is performed in the bright direction is output to the image processing apparatus A3 (step ST7).

  Thereafter, the image processing apparatus A3 acquires image data from the CCD camera, and detects a portion having a lightness lower than a predetermined threshold as a defect based on the content of the illumination mode identification signal. The time required for the light irradiation state detection step and the light irradiation condition setting step in steps ST2 to ST5 is about 1/10 to 1/100 as compared with the image processing time.

  On the other hand, the irradiation direction is set in the dark direction and the light L1 is irradiated, and the auxiliary light is also irradiated along the direction (step ST8). Then, an illumination mode identification signal indicating that the light L1 is emitted in the dark direction is transmitted to the image processing apparatus A3 (step ST9).

  Based on the illumination mode identification signal, the image processing apparatus A3 detects a portion having a brightness higher than a predetermined threshold as a defect.

  Therefore, according to the present embodiment described above, it is possible to create a light irradiation condition optimal for the purpose of image processing on the light irradiation device A4 side, so that a load such as correction on the image processing device A3 side is greatly increased. To be reduced. Moreover, since the light irradiation conditions can be set each time prior to image processing, for example, even when inspecting workpieces flowing on the line one after another, an optimal image can be obtained after inspection for each workpiece. it can. Compared to image processing, the detection of light irradiation state and the setting of light irradiation conditions do not require so complicated processing, and the time required is 1 / 10th to 1 / 100th of the image processing time. Time is not a bottleneck, and there is no hindrance to quick inspections.

  Furthermore, in the present embodiment, it is possible to reliably detect a defect even when the eyes are present on the surface, and to switch the irradiation direction of the light L1 between the bright direction and the dark direction, and to detect the defect in both. Since the detection is performed, the detection accuracy can be greatly increased.

  In addition, the surface of workpieces such as metal with streak-like eyes is not finished and is often uneven due to dullness, dirt, minute roughness, etc. Since the unevenness can be canceled in the observation by the unit 5, it is possible to effectively detect only defects that are substantially problematic.

  Specific examples of the effects described above will be described below. As shown in FIG. 7, it is clear from the image shown in FIG. 9 by irradiating light L1 in the bright direction and simultaneously irradiating auxiliary light L2 (in this example, only the diffuser element along the bright direction is lit). In this way, defects are clearly extracted in such a manner that they can be automatically detected. FIG. 10 shows a defect detection image when the light L1 is irradiated in the dark direction and the auxiliary light L2 is simultaneously irradiated as shown in FIG. Even in this example, defects are clearly extracted in such a manner that they can be automatically detected. In FIGS. 7 and 8, the hatched portion is a portion that is unlit.

  On the other hand, FIG. 11 shows an image in the case where the low-angle light L1 is irradiated from almost the entire periphery of the same workpiece W as in FIG. Flaws can hardly be recognized. FIG. 12 shows an image when only the auxiliary light L2 is irradiated on the same workpiece W as in FIG. 9, but the defect can hardly be recognized.

Various modifications can be made to this embodiment. For example, if the LEDs 41 of only one group can be turned on and the light L1 can be irradiated from a single direction along the irradiation direction, a three-dimensional shadow image of a defect as shown in FIG. Although some problems may occur, the method is suitable for visual inspection or inspection by the operator of the captured image.
In addition, if the LED 41 is not controlled to blink for each group, but can be controlled to blink one by one, the light irradiation direction can be changed more precisely, and the light irradiation direction can be accurately set to the dark and bright directions. it can.

  Further, the following method may be used to determine the bright direction or the dark direction more accurately. That is, the workpiece W or the light irradiation device A4 is automatically rotated around the axis center in a state where the LEDs 41 belonging to the group pair from which the image with the highest brightness is obtained are turned on. Then, FB control or the like is performed so that the brightness is the highest, and the bright direction is determined. The dark direction is a direction orthogonal to the bright direction. Of course, conversely, the bright direction may be determined from the image brightness first, and the direction orthogonal thereto may be set as the dark direction. In addition, the rotation support mechanism which supports the light irradiation apparatus A4 or the workpiece | work holding | maintenance part A1 rotatably is utilized for rotation drive.

  Specifically, for example, when determining the bright direction, as shown in FIG. 15, first, the light L1 is irradiated in the initial direction, and the lightness of a predetermined region is acquired (step ST21). Next, the irradiation angle of the light L1 is changed in either direction by a controllable unit angle, and the brightness of the predetermined region is acquired (step ST22). At this time, it is determined whether or not the brightness has increased (step ST23). If the lightness is high, the process returns to step S22, and if the lightness is low or the same, the irradiation direction of the light L1 in the previous step is determined as the light direction (step ST24). The same applies to the dark direction determination process.

Further, not only the unit irradiation surface that emits the auxiliary light L2 may emit light, but a part of the unit irradiation surface may emit light, or the emission intensity may be controlled.
Second Embodiment

  Hereinafter, a second embodiment will be described with reference to the drawings. In the following description, members corresponding to those in the first embodiment are denoted by the same reference numerals.

  As shown in FIG. 16, the image processing light irradiation apparatus A4 according to this embodiment has a workpiece holding portion A1 that holds a workpiece W having a mirror-like surface, and a predetermined predetermined area on the surface of the workpiece W from the facing direction. Used together with a CCD camera A2 as an image pickup device that picks up an image and outputs it as image data, and an image processing device A3 that takes in the image data, performs binarization processing on the image data, and automatically detects a mark or the like engraved on the surface of the workpiece W Thus, the surface inspection system is configured, and a large effect can be obtained when the work W is slightly inclined due to an installation error or the like in the work holding unit A1.

  First, the basic operation of this system will be described. When a substantially parallel light L3 is applied to the mirror-like workpiece surface at an angle that is approximately directly opposite, and when the reflected light L4 is observed, a mark or the like is carved on the surface. Then, in the portion where the surface accuracy is rough, the light L3 is scattered and the reflected light intensity becomes small and is recognized as dark, so that the dark portion can be detected as a mark by contrast with the surroundings.

  Accordingly, the image processing light irradiation device A4 in the present embodiment includes the apparatus main body 1, the control power supply device 2, and the light irradiation state detection unit 6.

  The apparatus main body 1 includes a light irradiation unit 4. The light irradiation unit 4 includes a light source 45 composed of a number of LEDs (not shown) and a base end portion connected to each of the LEDs one by one. And a lens 47 (for example, Fresnel) that refracts light L5 emitted from the tip of the optical fiber 46 in a direction orthogonal or substantially orthogonal to the imaging direction in a direction that is parallel or slightly converged. Lens) and a half mirror 48 that directs the light L3 emitted from the lens 47 to the workpiece from the same or substantially the same direction as the imaging direction. As shown in FIG. 17, the tip portion of each optical fiber 46 forms a light emitting surface 49 bundled in a matrix, for example, and the light emitting position on the light emitting surface 49 can be changed by changing the LED to be lit. It is made to be able to. Then, by changing the light emission position in this way, the irradiation solid angle of the light L3 with respect to the predetermined region can be slightly changed.

  The control power supply device 2 functions as a light irradiation condition control unit. As shown in FIG. 16, each time the predetermined area is changed, the image processing apparatus A3 refers to the brightness of the predetermined area. Prior to image processing by the above, the light irradiating unit is controlled, that is, the LED to be lit is set, and the solid solid angle of the light L3 with respect to a predetermined region is set so that the lightness is substantially the highest or the lowest It is.

  The brightness is the brightness when the predetermined area is viewed from the imaging direction, as in the first embodiment, and the intensity of the reflected light L4 from the predetermined area is measured by the light irradiation state detection unit 6 described at the beginning. To get by.

  Unlike the first embodiment, the light irradiation state detection unit 6 uses a dedicated device such as a CMOS camera or a photodiode, and is used as a component of the image processing light irradiation device A4. Accordingly, the lightness may be an average value or a total value of the entire predetermined area as in the first embodiment, or may be an average value or a total value of a part of the predetermined area. Note that a second half mirror 7 is provided on the optical path of the reflected light L4 in order to guide the reflected light L4 from a predetermined region to the light irradiation state detector 6.

  Next, an example of the operation of the system configured as described above will be described below with reference to FIGS.

  When the workpiece W is installed at a predetermined position, the control power supply device 2 sequentially turns on the optical fibers 46 on the light emitting surface 49 in the X direction one by one vertically as shown in FIG. At this time, an output signal from the light irradiation state detection unit 6 is received each time, and the position (X position) of the optical fiber 46 when the brightness is the highest from the output signal value is stored. Next, the optical fibers 46 are sequentially turned on side by side in the Y direction, and similarly, the position (Y position) of the optical fiber 46 when the brightness is highest is stored. In the figure, the graph exemplifies the transition of lightness (reflected light intensity) obtained by sequentially lighting the optical fiber 46 in the X direction and the Y direction.

  Then, the optical fiber 46 (ON) at the position having the X position and the Y position as coordinates is turned on, and the other optical fibers 46 (OFF) are turned off.

  By turning on the optical fiber 46 (ON), the irradiation solid angle of the light L3 at which the lightness is substantially maximum is set. That is, as shown in FIG. 18, even if the work W has a slight inclination θ, the solid angle of irradiation of the light L3 is set according to the inclination angle θ, and the reflected light from the work W is always applied to the imaging device A2. L4 is incident as much as possible. Of course, various other methods are conceivable, such as setting the optical fiber 46 in which the lightness is substantially maximized by sequentially lighting the optical fibers 46 one by one.

  Therefore, for example, when inspecting the workpiece W flowing on the line, even if a part or all of the workpiece W is inclined at the time of installation, for example, the image processing light irradiation device A4 automatically and automatically responds thereto. The irradiation solid angle of the light L3 is changed, and the reflected light L4 from the work W is allowed to enter the imaging device A2 as much as possible without shifting. For this reason, even if the workpiece W is slightly inclined, it is possible to quickly detect a mark or the like formed in the predetermined area as a sufficient contrast difference without imposing a burden on the image processing apparatus A3.

  As shown in FIG. 19, one optical fiber 46 (OFF) may be turned off and all remaining optical fibers 46 (ON) may be turned on. In this case, contrary to the above, the mark or the like can be detected with the contrast because the part with the mark or the like becomes bright and the other part becomes dark. Of course, as in the first embodiment, an illumination mode identification signal indicating which illumination mode is being used is transmitted to the image processing apparatus A3, and the image processing apparatus A3 receives a predetermined threshold value from the content of the illumination mode identification signal. It is necessary to determine whether a portion with higher brightness is detected as a mark or a lower portion is detected as a mark.

In addition, when only one optical fiber 46 is turned on or off, the degree of scattering of the light L3 after passing through the lens 47 near the point light source is reduced, so that even the scattered reflection due to slight roughness of the workpiece surface. Can be detected as contrast. However, depending on the purpose, there is a case where it is not desired to detect slight roughness as noise. In such a case, as shown in FIG. 20 and FIG. 21, the light L3 after passing through the lens 47 is made by turning on or off a plurality of optical fibers 46 to obtain a light source having a certain area. The detection accuracy may be lowered by slightly increasing the degree of scattering.
<Third Embodiment>

  The image processing light irradiation device (not shown) in this embodiment detects a recess 8 such as a mark formed on the transparent thin film 7 of the workpiece W having the transparent thin film 7 on the surface, as shown in FIG. It is used for this purpose. The transparent thin film 7 is a resin film called an ITO (Indium Tin Oxide) film, for example, and is a very thin film having a thickness of 0.02 μm to 0.4 μm.

  Therefore, the light irradiation unit (not shown) in this embodiment irradiates the predetermined region of the workpiece W with the parallel light or the substantially parallel light L7 so that the spectrum distribution can be changed from the imaging direction. In order to change the spectral distribution, the light irradiation unit has, for example, a plurality of LEDs having different peak wavelengths, and can selectively light any of those LEDs. Of course, it is also possible to make the spectral distribution variable using a prism or the like.

  As in the first and second embodiments, the light irradiation state detection unit (not shown) detects the lightness of the predetermined region as viewed from the imaging direction, and the light irradiation condition control unit (not shown) determines that the lightness is substantially the highest. The light irradiating unit is controlled so as to become or approximately the lowest, and the spectral distribution of the light is set.

  In this way, for example, when the light spectrum distribution is set so that the lightness is substantially the highest or substantially the lowest, the concave portions 8 such as marks can be recognized as dark or bright portions. This is due to the following reason.

  That is, when the brightness is substantially highest, as shown in FIG. 23, the phases of the reflected light L5 on the front surface 71 of the transparent thin film 7 and the reflected light L6 on the back surface 72 match and strengthen each other. . This is determined from the relationship between the wavelength (spectral distribution) of the irradiated light L7 and the thickness of the transparent thin film 7. On the other hand, since the thickness of the concave portion 8 is thin, the reflected lights L5 'and L6' from the front surface 81 and the back surface 82 are out of phase with each other, and some or all cancel each other and weaken as a whole. FIG. 24 shows a case where phases are shifted by half a wavelength and almost completely cancel each other. As a result, the intensity difference can be detected as contrast.

  On the other hand, when the brightness is substantially the lowest, the phase of the reflected light L5 on the front surface 71 of the transparent thin film 7 and the reflected light L6 on the back surface 72 is shifted by half a wavelength and cancels each other almost completely. At this time, at least the reflected lights L5 'and L6' do not cancel each other out in the concave portion 8, but a certain intensity is maintained, so that the intensity difference can be detected as contrast.

Therefore, for example, when inspecting a workpiece W flowing on a line, even if the thickness of a part or all of the transparent thin film 7 is slightly different or the thickness of the concave portion 8 with a mark or the like is slightly different, Accordingly, by dynamically changing the wavelength (spectral distribution) of the light L7, it is possible to always maintain the contrast between the concave portion 8 and other portions, and to form the image processing device A3 in the predetermined region without imposing a burden. The recessed portion 8 thus made can be detected quickly.
<Other embodiments>

  The present invention is not limited to the above embodiments. For example, although the LED is used in the embodiment, for example, a semiconductor laser may be used, or another light emitter may be used.

  It is also possible to optimize the light irradiation conditions by changing the light irradiation intensity, irradiation range, and the like.

  Furthermore, although the light irradiation condition control unit is incorporated in the control power supply device in the above embodiment, it may be incorporated in another device, and in the future, the light irradiation condition detection unit and the light irradiation condition control unit have one. An embodiment in which the chip is integrated into the chip is also conceivable. For example, a logic circuit may be mounted on a hardware sensor (for example, a plurality of optical sensors) or the image sensor chip itself, and this may have a function as a light irradiation condition control unit.

  Of course, the present invention is not limited to the above illustrated example, and various modifications can be made without departing from the spirit of the present invention.

The typical block diagram which shows the whole system in 1st Embodiment of this invention. FIG. 2 is a schematic vertical end view of the image processing light irradiation apparatus according to the embodiment. The schematic bottom view of the light irradiation apparatus for image processing in the embodiment. The schematic exploded perspective view of the light diffusing body in the embodiment. The flowchart which shows the system operation example in the embodiment. The flowchart which shows the system operation example in the embodiment. Explanatory drawing of lighting of the image processing light irradiation apparatus in the case of irradiating light and auxiliary light in the bright direction in the embodiment. Explanatory drawing of lighting of the image processing light irradiation apparatus in the case of irradiating light and auxiliary light in the dark direction in the embodiment. The example figure which shows the defect image obtained when light and auxiliary light are irradiated in the bright direction in the embodiment. The example figure which shows the defect image obtained when light and auxiliary light are irradiated in the dark direction in the embodiment. The example figure which shows the defect image shown in FIG. 9 obtained by the conventional irradiation method. The example figure which shows the defect image shown in FIG. 9 obtained by the conventional irradiation method. The example figure which shows the defect image obtained in the modification of the said 1st Embodiment. The image figure which shows the workpiece | work which has a streak-like eye. The flowchart which shows the optical direction control method in the further another modification of the said 1st Embodiment. The typical block diagram which shows the whole system in 2nd Embodiment of this invention. The light irradiation end figure of the optical fiber for demonstrating the method to change the irradiation solid angle in the embodiment. The typical block diagram which shows the whole system for demonstrating the method to change the irradiation solid angle in the same embodiment. The light irradiation end figure which shows an example of the light emission mode of the optical fiber in the embodiment. The light irradiation end view which shows the other example of the light emission mode of the optical fiber in the embodiment. The light irradiation end view which shows the further another example of the light emission mode of the optical fiber in the embodiment. The schematic diagram which shows the light with which the workpiece | work in 3rd Embodiment of this invention is irradiated, and the reflected light. The optical waveform diagram for demonstrating interference with the light irradiated to the workpiece | work in the same embodiment, and the reflected light. The optical waveform diagram for demonstrating interference with the light irradiated to the workpiece | work in the same embodiment, and the reflected light.

Explanation of symbols

A2 ... Imaging device (CCD camera)
A3 ... Image processing device A4 ... Light irradiation device for image processing 2 ... Light irradiation condition control unit (control power supply)
4 ... Light irradiation part 41 ... LED
5 ... Auxiliary light irradiation part 51 ... Light diffuser 511 ... Diffuser element 52 ... Second LED
5a ... auxiliary light emitting surface 6 ... light irradiation state detection units L1, L3, L7 ... light L2 ... auxiliary light W ... work

Claims (6)

It is used with an image processing apparatus that processes image information obtained by imaging a predetermined area on a workpiece,
A light irradiation unit that emits light so that the irradiation solid angle can be slightly changed from a direction substantially the same as the imaging direction with respect to the predetermined region;
A light irradiation condition control unit configured to control the light irradiation unit and set the light irradiation solid angle so that the brightness of all or a part of the predetermined region as viewed from the imaging direction is substantially highest or substantially lowest. A light irradiation device for image processing,   The light irradiation apparatus for image processing of Claim 1 further provided with the light irradiation state detection part which detects the said brightness. The light irradiation unit is provided with a number of light emitting elements laid on the surface,
The light irradiation apparatus for image processing according to claim 1 or 2, wherein the light irradiation condition control unit selectively turns on a part of the light emitting elements to set a light irradiation solid angle.   The light emitting device for image processing according to claim 3, wherein the light emitting element is an LED or a tip portion of an optical fiber having a base end connected to the LED. It is used in an image processing system that uses an imaging device that captures a predetermined area on a workpiece and an image processing device that processes image information obtained by the imaging device,
For the predetermined area, using a light irradiation unit that emits light so that the irradiation solid angle can be slightly changed from the same direction as the imaging direction,
A light irradiation state detection step of detecting brightness in all or a part of the predetermined region as seen from the imaging direction;
A light irradiation condition control step of controlling the light irradiation unit prior to the image processing and setting a light irradiation solid angle so that the lightness is substantially highest or substantially lowest. A light irradiation method for image processing as a feature.   6. The light irradiation method for image processing according to claim 5, wherein in the light irradiation condition setting step, the solid angle of light irradiation is set so that the lightness is substantially highest or substantially lowest every time image processing is performed. .