JP5648255B2 - Luminance measuring device and luminance measuring method - Google Patents

Description

  The present invention relates to a luminance measuring apparatus and a luminance measuring method for measuring the luminance of a light emitting unit incorporated in a display surface of an operation panel of a car air conditioner, car navigation, or car audio.

  Lighting functions are incorporated in the switch surface and display surface of car air conditioners, car navigation systems, and car audio operation panels in order to improve nighttime visibility and operability.

  Then, in order to confirm that the illumination function of the switch surface and the display surface is made as designed, the light emitting unit is determined by measuring the luminance of the light emitting unit incorporated in the switch surface and the display surface. And the uniformity of the brightness of the switch surface and the display surface are evaluated.

  Conventionally, the luminance of a light emitting unit incorporated in a switch surface or a display surface of an operation panel is measured by installing a luminance meter on a slider that moves along two orthogonal directions so as to face the operation panel. The brightness was sequentially measured by aligning the measurement point of the luminance meter with the measurement point on the set operation panel.

  Recently, a luminance measuring apparatus that simultaneously measures the luminance of a two-dimensional plane using a camera has also been proposed (Patent Document 1).

JP 2002-62219 A

  However, in order to improve operability, recent car air conditioners, car navigation systems, and car audio operation panels are provided with steps on the switch surface and display surface so that the height of the switch surface and display surface is different. It is often arranged.

  As described above, when measuring the luminance of the light emitting part of the stepped switch surface or the display surface, if a luminance measuring device that measures the luminance of the planar light emitter from the direction facing the surface is applied, the stepped part Therefore, it is necessary to measure the luminance while focusing on the light emitting parts having different heights while focusing on the measurement area of the luminance meter each time.

  Furthermore, when measuring the luminance of illumination of different operation panels having the same form, it is necessary to repeat the measurement while focusing on the measurement area of the luminance meter.

  Therefore, there has been a problem that the luminance of the light emitting portion on the switch surface or display surface with a step cannot be easily measured. In addition, there is a problem that the luminance at the same position of different operation panels having the same form cannot be easily and repeatedly measured.

  The present invention has been made in view of the above circumstances, and even an operation panel having a step on the switch surface or the display surface can easily measure the luminance of a preset measurement point, and different operation panels having the same form. An object of the present invention is to provide a luminance measuring apparatus and a luminance measuring method capable of easily and repeatedly measuring the luminance at the same position when measuring the luminance of the luminance.

  In order to solve the above-mentioned problem, the invention described in claim 1 is directed to a work in which a plurality of switch surfaces and display surfaces having a light emitting part are arranged with a step, and the brightness of a specific point of the light emitting part is opposed to the work. A luminance measuring unit that measures from the direction to be taken, an imaging unit that is integrated with the luminance measuring unit and arranged so that the optical axes of each other form a coaxial system, and images a peripheral region including a specific point, and a work is fixed The workpiece measuring table for moving the fixed workpiece in two directions orthogonal to the luminance measuring unit and the plane orthogonal to the optical axis of the imaging unit, the luminance measuring unit, and the imaging unit are fixed and fixed. An imaging unit moving table for moving the luminance measuring unit and the imaging unit in the front-rear direction along the optical axis of the luminance measuring unit and the imaging unit, and at least two reference points spaced vertically and horizontally on the front surface of the light emitting unit Reference point setting section for setting A corresponding point search unit for searching for a point corresponding to the reference point from the layout image representing the edge position of the light emitting unit, and a luminance measurement point for setting a plurality of luminance measurement points in the layout image of the light emitting unit A luminance measurement point calculation unit that calculates coordinates of points on the front surface of the workpiece, each corresponding to a plurality of luminance measurement points set by the luminance measurement point setting unit, based on the search result of the setting unit and the corresponding point search unit; Workpiece movement instructing the movement direction and amount of movement of the workpiece movement table to the workpiece movement table so that the point on the front of the workpiece calculated by the luminance measurement point calculation unit matches the measurement point of the luminance measurement unit Based on the calculation results of the table control unit, the in-focus state calculation unit that detects the in-focus state of the image of the light emitting unit captured by the imaging unit, and the image focused on the front surface of the work Move the imaging unit so that you can shoot An area centered on each luminance measurement point in the layout image set by the imaging unit movement table control unit for instructing the moving direction and movement amount of the imaging unit movement table with respect to the table, and the luminance measurement point setting unit The template creation unit for setting the template as a template, each template set by the template creation unit, and template matching between the image captured by the imaging unit and including an image corresponding to each luminance measurement point, and each luminance measurement point A template matching calculation unit that calculates the coordinates of each point in the image including the point corresponding to the luminance measurement point corresponding to the point, and each luminance measurement point is calculated by the template matching calculation unit The work movement table is moved so as to match, and the brightness is measured by the brightness measuring unit.

  Further, in the invention described in claim 2, in the above, the luminance measurement point setting unit has a shape congruent or similar to the shape of the region of the light emitting unit included in the template set by the template creation unit. Luminance measurement points are set so that the area of the light-emitting portion that does not exist in the layout image.

  Furthermore, in the invention described in claim 3, in the above, the luminance measurement point setting unit sets the luminance measurement point so that the template set by the template creation unit includes a plurality of regions of the light emitting unit. It is characterized by setting.

  In the invention described in claim 4, in the above description, the templates set in the template creation unit are vertically long rectangular, horizontally long rectangular, and square, and the template matching operation is performed on the plurality of templates. In the section, template matching is performed, and a point to which a template giving the highest matching degree is applied is set as a point where matching is achieved.

Further, the invention described in claim 5, in the above, the template set in the template creation unit, with four templates set points were placed at the four corners of the rectangle, respectively luminance measurement point setting unit A template matching operation unit performs template matching on the four templates , and a point to which a template that gives the highest matching degree is applied is a matching point.

  And the invention described in claim 6 is a luminance measuring method using the luminance measuring apparatus according to any one of claims 1 to 5, wherein the luminance measuring unit measures the luminance. The work movement table is moved so that each luminance measurement point coincides with each point calculated by the template matching calculation unit.

  According to the invention of claim 1 configured as described above, even when there is a step in the light emitting part of the switch surface or the display surface installed on the front surface of the workpiece, the image is taken by the imaging unit by the focusing degree calculation unit. The in-focus state of the image is detected, and in accordance with the detected in-focus state, the imaging unit movement table control unit moves the imaging unit movement table in the front-rear direction with respect to the workpiece to focus on the front surface of the workpiece. Therefore, the luminance measurement unit can measure the luminance of the light emitting unit on the front surface of the workpiece having a step.

  Further, the corresponding point search unit associates the reference point on the front surface of the work with the layout image representing the edge position of the light emitting unit, and the work corresponding to the luminance measurement point set in the layout image of the light emitting unit. Since the coordinates of the point on the front side of the can be calculated, the luminance of the point corresponding to the preset luminance measurement point can be easily measured.

  Further, the template matching calculation unit uses the region including the luminance measurement point in the layout image of the light emitting unit as a template to perform template matching with the image of the work including the luminance measuring point of the luminance measuring unit. Even if there is a deviation in the installation position due to rattling or a deviation in the work installation position during luminance measurement, the brightness of the point to be measured can be reliably measured. The brightness of the light emitting portions of different operation panels having the same form can be easily and repeatedly measured.

  According to the second aspect of the present invention, the luminance measurement point setting unit does not set a point at which the shape of the light emitting unit included in the template is congruent or similar as the luminance measurement point. When template matching is performed, occurrence of erroneous matching can be avoided, thereby improving the accuracy of template matching and accurately measuring the luminance of a preset point.

  Furthermore, according to the invention of claim 3, by the operation of the luminance measurement point setting unit, in addition to the light emitting unit to which the central point of the template belongs, a luminance measuring point is set such that another light emitting unit is included in the vicinity thereof. Therefore, even if there is an area that is congruent or similar to the light emitting part including the set luminance measurement point, that point can be set as the luminance measurement point, thereby setting the luminance measurement point. The degree of freedom can be improved.

  According to the invention of claim 4, since the template creating unit creates a vertically long rectangular shape, a horizontally long rectangular shape, and a square template, it is close to the edge portion of the image of the workpiece to be subjected to template matching. Templates can be placed. For this reason, the area where template matching can be performed is widened, so that even if a deviation occurs in the installation position of the workpiece or a deviation in the installation position of the switch having the light emitting unit, the brightness of the preset point is set. Can be measured with high accuracy.

Further, according to the invention of claim 5, since the template matching is performed for each of the four templates in which the points set by the luminance measurement point setting unit are arranged at the four corners of the rectangle , the images were photographed. The area where template matching can be performed in the image is further widened, thereby further increasing the tolerance for displacement of the installation position of the workpiece and displacement of the installation position of the switch having the light emitting unit. it can.

  According to the invention of claim 6, even if there is a step in the light emitting part of the switch surface or the display surface installed on the front surface of the workpiece, the in-focus state of the photographed image is detected, and the detected in-focus state is detected. Depending on the state, the imaging unit can move in the front-rear direction and can be focused on the front surface of the workpiece, so that the luminance of the light emitting unit on the front surface of the workpiece with a step can be measured.

  Further, the coordinates of the front point of the work corresponding to the luminance measurement point set in the layout image of the light emitting unit can be calculated by associating the reference point on the front side of the work with the layout image of the light emitting unit. Therefore, it is possible to easily measure the brightness of a point corresponding to a preset brightness measurement point.

  Furthermore, because the template matching is performed with the workpiece image including the luminance measurement point using the region including the luminance measurement point in the layout image of the light emitting unit as a template, the light emitting unit installation position may be shifted due to rattling. Or, even if a deviation occurs in the position of the work when measuring the brightness, it is possible to reliably measure the brightness of the point to be measured, whereby the brightness of the light emitting parts of different operation panels having the same form Can be easily and repeatedly measured.

These are block diagrams which show the structure of the brightness | luminance measuring apparatus based on this invention. These are figures which show the example of a workpiece | work. These are the examples of the layout image of the light emission part mounted in the workpiece | work. These are the flowcharts which show the flow of embodiment of this invention. These are the figures explaining the setting method of a luminance measurement point. These are actual examples of an image I (x, y) photographed by the imaging unit. These are examples of the edge image E (x, y) extracted from the image photographed by the imaging unit. (1) is an example of a vertically long rectangular template, FIG. 8 (2) is an example of a horizontally long rectangular template, and FIG. 8 (3) is an example of a square template. (1) is an example in which luminance measurement points are arranged in the lower right corner of the template, FIG. 9 (2) is an example in which luminance measurement points are arranged in the lower left corner of the template, and FIG. 9 is an example in which luminance measurement points are arranged in the upper right corner of FIG. 9, and FIG. 9 (4) is an example in which luminance measurement points are arranged in the upper left corner of the template. These are diagrams explaining a template matching method.

Hereinafter, embodiments of a luminance measuring apparatus and a luminance measuring method according to the present invention will be described with reference to the drawings.
[Embodiment 1]

  In the first embodiment, the present invention is applied to the measurement of the luminance of a light emitting portion on a switch surface or a display surface of an operation panel for operating a car air conditioner, car navigation, or car audio. Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG.

  As shown in FIG. 1, this apparatus measures the brightness of a work 10 that is an operation panel for a car air conditioner, car navigation, and car audio, and the brightness of a light emitting unit on a switch surface or a display surface disposed on the front surface of the work 10. In addition, the work information table 20 that moves the image information acquisition unit 20 in two orthogonal directions on the surface orthogonal to the optical axis of the brightness and image information acquisition unit 20 with the work 10 fixed, and the brightness and image information. With the acquisition unit 20 fixed, the imaging unit moving table 40 that moves in the front-rear direction with respect to the workpiece 10 in the direction along the optical axis of the luminance and image information acquisition unit 20, and the luminance and image information acquisition unit 20 Based on the degree of focus calculation unit 50 that calculates the degree of focus on the workpiece 10 and the degree of focus calculated by the degree-of-focus calculation unit 50 for the photographed image of the work 10. In order to match the actual scale of the workpiece 10 and the scale of the image captured by the luminance and image information acquisition unit 20 with the imaging unit movement table control unit 60 that moves the imaging unit movement table 40 by a predetermined amount in the front-rear direction. A reference point setting unit 70 for setting at least two reference points spaced apart in the vertical and horizontal directions on the front surface of the workpiece 10, and light emission of the display surface of the workpiece 10 corresponding to the reference point set by the reference point setting unit 70 A corresponding point search unit 80 for searching for a point on the layout image L (x, y) of the light emitting unit of the work 10 in which the edge position of the part is expressed as a line image, and the layout image L (x, y) Based on the result calculated by the luminance measurement point setting unit 90 for setting a plurality of luminance measurement points on the upper side and the corresponding point search unit 80, the luminance measurement point setting unit 90 sets it on the layout image L (x, y). Brightness measurement The brightness measurement point calculation unit 100 that calculates the position of the point on the front surface of the workpiece 10 and the template creation unit that creates a template from the images around the brightness measurement point calculated by the brightness measurement point setting unit 90 110, a template matching calculation unit 120 that performs template matching on an image including a point on the front surface of the workpiece 10 calculated by the luminance measurement point calculation unit 100 using the template created by the template creation unit 110, and a template Based on the result of matching, the work movement table 30 is placed on the optical axis of the luminance and image information acquisition unit 20 so that the matching point matches the luminance measurement point by the luminance and image information acquisition unit 20. The workpiece movement table control unit 130 moves in two orthogonal directions on an orthogonal surface.

  Note that the luminance and image information acquisition unit 20 includes an optical system 22 including an optical lens, an optical path branching unit 25 including a half mirror 23 and a mirror 24 that splits a light beam that has passed through the optical system 22, and a luminance. A luminance measurement unit 26 that measures the luminance of the measurement point and an imaging unit 28 that captures an area including the luminance measurement point and obtains image information are included.

  Here, the luminance measuring unit 26 has the same configuration as a commonly used luminance meter, and the imaging unit 28 has the same configuration as a camera having an imaging element such as a commonly used CCD or C-MOS. Therefore, a more detailed description of the configuration is omitted.

  In addition, the workpiece | work 10 assumes the operation panel for vehicle mounting. An example of this is shown in FIG. This operation panel has many switches for operating in-vehicle devices such as car air conditioners, car navigation systems, car audios, etc. Characters and symbols representing the functions of the switches are displayed on the front of each switch. Has been. The characters and symbols are provided with a light emitting section that emits light in conjunction with an illumination switch in order to improve nighttime operability.

  Hereinafter, the brightness measuring apparatus according to the first embodiment will be described based on the flowcharts of FIGS.

  In measuring the luminance, first, the work 10 is set and fixed on the work movement table 30 (step S1 in FIG. 4).

  Next, in the reference point setting unit 70, at least two reference points are set on the front surface of the work 10 in order to clarify the correspondence between the work 10 and the layout image L (x, y) (FIG. 4). Step S2).

  The reference point is set by first moving the workpiece movement table so that the reference point visually determined by the operator on the front surface of the workpiece 10 is focused on the center of the image captured by the imaging unit 28. 30 is moved in two orthogonal directions on a plane orthogonal to the optical axis of the luminance and image information acquisition unit 20, and the imaging unit movement table 40 is moved along the optical axis of the luminance and image information acquisition unit 20. This is done by moving it back and forth.

  At that time, the image I (x, y) (for example, FIG. 6) photographed by the imaging unit 28 in a state where the switch surface of the work 10 and the light emitting unit of the display surface are lit, and the work movement table at that time The up / down direction 30 and the movement amount from the reference position in the left / right direction are sent to the corresponding point search unit 80 and stored therein.

  Then, the same operation is repeated to set at least two reference points on the front surface of the workpiece 10. At this time, in order to increase the accuracy of the correspondence relationship between the work 10 and the layout image L (x, y), at least two horizontal coordinates are separated from each other on the front surface of the work 10 and the vertical coordinates are separated from each other up and down. A reference point is selected. Since the two points set here are used for scale conversion between the layout image L (x, y) and the actual workpiece 10, the two points should be set as far apart as possible so as to increase the accuracy. desirable.

  Next, the corresponding point search unit 80 searches the layout image L (x, y) shown in FIG. 3 for points corresponding to at least two reference points set on the front surface of the workpiece 10 in step S2. (Step S3 in FIG. 4). Here, the layout image L (x, y) shown in FIG. 3 extracts only the light emitting part of the switch surface and the display surface arranged in FIG. 2 from the design drawing of the work 10, and the edge position of the light emitting part. Is a diagram. The layout image L (x, y) can be easily generated from the CAD drawing of the workpiece 10. The layout image L (x, y) is stored in the corresponding point search unit 80 in advance.

  In step S3, edge detection is performed on the image I (x, y) on the front surface of the workpiece 10 photographed in step S2, and this template and the image are displayed using the edge image E (x, y) in FIG. 7 as a template. Template matching is performed with the layout image L (x, y) shown in FIG. 3, and a corresponding point is searched. A specific method of template matching will be described later.

  Since the scale of the image I (x, y) on the front surface of the workpiece 10 is different from the scale of the layout image L (x, y), it is necessary to match both scales in order to perform template matching. . For this scale adjustment, for example, the observation range of one pixel of the imaging unit 28 is calculated based on the positional relationship between the workpiece 10 and the luminance and image information acquisition unit 20 and the specifications of the optical system of the imaging unit 28 in advance. Based on the calculated observation range, the image I (x, y) is enlarged or reduced so that the image I (x, y) matches the scale of the layout image L (x, y). Template matching may be performed between I (x, y) and the layout image L (x, y).

  Here, it is not necessary to perform template matching by moving the template over the entire layout image L (x, y) in FIG. 3, and the layout image L (x, y) roughly corresponding to the reference point set in step S <b> 2. Template matching may be performed only around the position.

  In this way, the coordinates of the point P1 (x1, y1) searched from the layout image L (x, y) and the reference point set in step S2 can be observed at the center of the image captured by the imaging unit 28. The vertical movement amount Dy1 from the reference position of the workpiece movement table 30 and the horizontal movement amount Dx1 from the reference position are associated with each other and stored in the corresponding point search unit 80.

  Then, the same corresponding point search is performed for all the reference points set in step S2, and based on the result calculated in this way, the layout is expressed as in (Expression 1) and (Expression 2) described later. A conversion formula from the coordinate system in the image L (x, y) to the coordinate system on the front surface of the actual workpiece 10 is calculated.

  Next, in the luminance measurement point setting unit 90, a plurality of points of the light emitting unit of the work 10 that actually measures the luminance are set from the layout image L (x, y) (step S4 in FIG. 4).

  In step S <b> 4, a plurality of points for luminance measurement are selected from the layout image L (x, y) stored in the corresponding point search unit 80. This is because the operator displays the layout image L (x, y) stored in the corresponding point search unit 80 on a display unit (not shown in FIG. 1), and necessary points while viewing the display unit. Should be selected.

  At this time, it is assumed that the point A1 in FIG. 5 is selected from the region R1 in FIG.

  Next, in the luminance measurement point calculation unit 100, a point corresponding to the point A1 is detected from an image obtained by photographing the workpiece 10 (step S5 in FIG. 4).

  The point corresponding to the point A1 is detected by searching for an area corresponding to the template T1 centered on the point A1 from the image I (x, y) obtained by photographing the workpiece 10 by the imaging unit 28 by template matching. Done. For this purpose, first, a point corresponding to the point A1 is observed approximately at the center of the image I (x, y), and is calculated in advance by a scale conversion formula of (Expression 1) and (Expression 2) described later. The work movement table 30 is moved by the amount.

  Here, the workpiece moving table 30 is moved in advance even if the workpiece moving table 30 is moved in accordance with the scale conversion formula due to manufacturing tolerance of the workpiece 10 or shakiness of the switch surface. This is because the corresponding point is not always observed at the center of the image I (x, y). That is, it is a measure for efficiently performing template matching processing.

  Then, when template matching is applied to the point A1 in FIG. 5, in addition to the actual corresponding point of the point A1, for example, the corresponding point of the point A2 is also selected as the point corresponding to the point A1, and the luminance measurement is performed. A point is not fixed.

  This is because the edge shape of the light emitting portion in the template T1 and the edge shape of the light emitting portion in the vicinity of the point A2 are substantially equal, and therefore the matching frequency M (described later) calculated when template matching is performed. ) Is almost equal.

  Therefore, in step S4, the luminance measurement point selected from FIG. 3 is the same as or similar to the edge shape of the light emitting unit included in the template set around the selected point. It is necessary to set the area where the shape is such that it does not exist in the layout image L (x, y).

  It should be noted that here, in order to avoid similar shapes other than congruent shapes, when measuring the luminance, when the luminance meter is focused on the light emitting portion of the work 10, the steps of the light emitting portion are not affected. This is because the focus position changes accordingly, and the magnification of the captured image changes, thereby changing the size of the observed light emitting section.

  The layout image L (x, y) is set in order not to have a region having a shape that is congruent with or similar to the edge shape of the light emitting part included in the template. Set a template centered on the luminance measurement point, apply the template, and perform template matching, which will be described later, in the layout image L (x, y) to confirm that there is no point with a high matching frequency M. That's fine.

  When a plurality of luminance measurement points are set in the layout image L (x, y) in this way, each set luminance measurement point is then set to the center of the image captured by the imaging unit 28. Therefore, the movement amounts of the work movement table 30 in the left-right direction and the up-down direction are calculated.

  For example, as shown in FIG. 3, in step S2, reference points P1 ′ (xw1, yw1) and P2 ′ (xw2, yw2) are set on the front surface of the workpiece 10, and in step S3, a layout image L (x, y) is set. Are searched for points P1 (x1, y1) and P2 (x2, y2) corresponding to these reference points.

  Then, the movement amount from the reference position of the work movement table 30 for causing the reference point P1 ′ to appear in the center of the image taken by the imaging unit 28 is Dx1 in the left-right direction and Dy1 in the up-down direction. To do. Further, the movement amount from the reference position of the work movement table 30 for causing the reference point P2 ′ to appear in the center of the image taken by the imaging unit 28 is Dx2 in the left-right direction and Dy2 in the up-down direction. To do.

  At this time, if the luminance measurement point Q1 (xa, ya) is set in the layout image L (x, y) in step S4, the point Q1 ′ (xwa) on the workpiece 10 corresponding to the luminance measurement point Q1. , Ywa) is displayed in the center of the image captured by the imaging unit 28. The horizontal movement amount Dxa and the vertical movement amount Dya from the reference position of the workpiece movement table 30 are respectively expressed by 1) and (Equation 2).

Dxa = Dx1 + (Dx2-Dx1) {(xa-x1) / (x2-x1)} (Formula 1)
Dya = Dy1 + (Dy2-Dy1) {(ya-y1) / (y2-y1)} (Formula 2)
Next, the template creation unit 110 creates a template centered on the luminance measurement point Q1 set in step S4 in the layout image L (x, y) (step S6 in FIG. 4).

  In step S <b> 6, templates are generated for all the luminance measurement points set in step S <b> 4 and stored in the template creation unit 110.

  Next, the work movement table 30 is moved so that each luminance measurement point set in step S4 is reflected in the center of the image I (x, y) photographed by the imaging unit 28. (Step S7 in FIG. 4). The amount of movement of the workpiece movement table 30 at this time may be calculated according to (Expression 1) and (Expression 2) described above.

  After the workpiece movement table 30 has moved by a predetermined amount, the image I is captured by the imaging unit 28 and the focusing degree calculation unit 50 is applied to the captured image I (x, y). In FIG. 4, the degree of focus of the image is calculated (step S8 in FIG. 4).

  The degree of focus is determined based on, for example, dividing the photographed image I (x, y) into small areas, calculating the contrast ratio of the gradation values in the divided small areas, and calculating the contrast ratio value. Is done. Many specific methods for calculating the contrast ratio have been introduced, and any of these methods may be used. When the subject is in focus, the contrast ratio becomes a large value.

  Here, when the degree of focus is less than a predetermined value (when step S10 in FIG. 4 is NO), it is determined that the imaging unit 28 is out of focus, and the imaging unit moving table 40 is moved back and forth. The image I (x, y) is captured again by the imaging unit 28. This operation is repeated until an in-focus image is obtained. In addition, since it cannot be determined whether the focus is in focus (front pin or rear pin), the imaging unit moving table 40 may be moved by a predetermined amount in a predetermined direction.

  For example, first, the imaging unit moving table 40 may be moved to a position where the imaging unit 28 is farthest from the workpiece 10, and from there, the imaging unit 28 may be moved in a direction toward the workpiece 10 by a predetermined amount.

  Then, every time the imaging unit moving table 40 moves by a predetermined amount, the imaging unit 28 captures an image I (x, y) of the workpiece 10 and calculates the focus degree from the captured image I (x, y). In the unit 50, the contrast ratio of the image is calculated, and it is determined that the image is in focus when the contrast ratio is equal to or higher than a predetermined value or when it is detected that the contrast ratio has a peak higher than the predetermined value. (When step S10 in FIG. 4 is YES), template matching is performed in template matching calculation unit 120 (step S11 in FIG. 4).

  Next, this template matching will be described with reference to FIG.

  FIG. 10 shows an example in which the horizontally long rectangular template shown in FIG. 8A is superimposed on the upper left corner of the edge image E (x, y) extracted from the image I (x, y) taken by the imaging unit 28. It is.

  Note that the process of extracting the edge image E (x, y) from the image I (x, y) is generally performed widely as a basic technique of image processing, and various edge extraction methods are available. Proposed. Here, the edge extraction may be performed by applying any of these methods.

  Here, the horizontally long rectangular template is represented by S1 (α, β). In the edge image E (x, y), it is assumed that 1 is stored in a pixel that appears black and 0 is stored in a pixel that appears white. In the template S1 (α, β), it is assumed that 1 is stored in pixels that appear black and 0 is stored in pixels that appear white.

The template matching calculation unit 120 performs the calculation shown in (Expression 3) to (Expression 5) on the overlapped pixels of the edge image E (x, y) and the template S1 (α, β) to obtain the evaluation function value. m (x, y) is calculated.
When E (xi, yj) = 1 and S1 (xi, yj) = 1, m (xi, yj) = 1 (Formula 3)
When E (xi, yj) = 0 and S1 (xi, yj) = 0, m (xi, yj) = 1 (Formula 4)
Otherwise, m (xi, yj) = 0 (Formula 5)
Here, xi and yj are values obtained by converting the coordinates of the template into the coordinates of the edge image in accordance with the position of the edge image to which the template is applied.

  Then, the evaluation function value m (xi, yj) calculated in this way is calculated for all the pixels in the area covered with the template S1 (α, β), and the sum is calculated. The total sum of the evaluation values will be referred to as matching frequency M (xi, yj).

From (Equation 3) to (Equation 5), the matching frequency M (xi, yj) increases as the black pixel overlaps with the black pixel and the white pixel overlaps with the white pixel. Then, the edge image E (x, y), the template S1 (alpha, beta) superimposed there with, but when fully matched, the matching degree becomes the maximum value n ^2.

  As shown in FIG. 10, the same calculation is performed while changing the position of the center point O of the template S1 (α, β) from left to right and from top to bottom on the edge image E (x, y). Repeatedly. As a result, the point that outputs the highest matching frequency is determined.

  Next, the same calculation is performed for the vertically long rectangular template S2 (α, β) in FIG. 8B and the square template S3 (α, β) in FIG.

  After the calculation is completed for the three types of templates, the type of the template that outputs the highest matching frequency and the position of the center point O to which the template is applied are specified (the center point in the edge image E (x, y)) When the coordinate value of O is (x0, y0) and the matching frequency calculated at that time is equal to or greater than a predetermined value determined in advance, it is determined that matching has been achieved at the point (x0, y0). .

  The reason why template matching is performed using three different templates is to ensure matching even when the point to be matched is at the corner of the edge image E (x, y).

  In other words, even if the point to be matched is at the corner of the edge image E (x, y), the template matching is performed using the vertically long rectangular template S2 (α, β), so that the square template In contrast to the case of performing template matching using S3 (α, β), it is possible to match to the left and right corners of the edge image E (x, y). Further, by performing template matching using the horizontally long rectangular template S1 (α, β), the edge image E (x) is compared with the case where template matching is performed using the square template S3 (α, β). , Y) can be matched up to the upper and lower corners. Since the three types of templates all have the same area, the matching frequencies calculated when each template is applied can be compared with each other without performing conversion or the like.

  Since the light emitting portion of the workpiece 10 has a step, the scale of the image I (x, y) observed by the imaging unit 28 is different every time the luminance measurement point is focused.

  Therefore, the template matching process described above needs to be performed for templates of several sizes by changing the scale of the template.

  In this process, the created template is enlarged or reduced at a predetermined magnification set in advance, and the template thus enlarged or reduced is applied to the edge image E (x, y) to perform template matching. Just do it. Then, the type of template and the coordinates of the point at which the matching is obtained, which have a value equal to or higher than a predetermined value and the maximum, are specified.

  In addition, since the template is enlarged or reduced, the template size is different, so that the maximum value of the matching frequency when perfect matching is obtained is also different.

  Therefore, the matching frequencies obtained when different size templates are applied cannot be compared with each other. Therefore, when comparing the matching frequencies obtained when different size templates are applied, for example, the calculated matching frequency is The normalized matching frequency may be compared by normalizing with the area of the template.

  Next, the work movement table 30 is set according to an instruction from the work movement table control unit 130 so that the matching position (x0, y0) calculated by template matching matches the measurement point of the luminance measurement unit 26. Move (step S12 in FIG. 4).

  At this time, the workpiece movement table control unit 130 instructs the workpiece movement table 30 to move in the horizontal direction Dxi and the vertical movement amount Dyi, and the workpiece movement table 30 is set so as to correspond to the instructed amount. Move.

  Here, Dxi and Dyi are values calculated from the deviation between the center coordinates of the image I (x, y) and the coordinates (x0, y0) for which the template matching has been taken, and the work movement table 30 is moved. The movement amount given to the work movement table 30 so that the center of the image I (x, y) becomes (x0, y0). Then, the relationship between the deviation of coordinates in the image I (x, y) and the movement amount of the work movement table 30 may be obtained in advance by calibration work.

  Next, the luminance measurement unit 26 measures the luminance (step S13 in FIG. 4). Specifically, the color filter mounted on the front surface of the luminance measuring unit 26 is rotated to measure the R (red) component, G (green) component, and B (blue) component of the luminance, respectively.

  This luminance measurement is performed for all the luminance measurement points set in step S4, and when the luminance measurement for all luminance measurement points is completed (when step S14 in FIG. 4 is YES), the measurement is terminated.

  Then, it is analyzed whether the absolute value or variation of the measured luminance information of each point is a value as designed.

  The reference point corresponding point search performed in step S3 in FIG. 4 may be performed by applying template matching as described above, or may be performed by the operator visually specifying the corresponding point. .

  Further, in the above description, template matching is performed using the template shown in FIG. 8, but this is because the four templates U1 (α, β), U2 (α, β), U3 (α, β) and U4 (α, β) may be used.

  Each of the four templates shown in FIG. 9 is a square template having n ′ pixels on one side in which points P corresponding to the point O in FIG. 8 are arranged at the four corners of the template. Note that there is no particular restriction on the size of the template, and it may be set as appropriate according to the size of the captured image. In the example of FIG. 9, the vertical size and horizontal size of the template are equal, but this may be different in vertical and horizontal sizes.

  In this way, the four corner points P of the templates U1 (α, β), U2 (α, β), U3 (α, β), U4 (α, β) are respectively represented by the edge image E ( The matching frequency M (xi, yj) is calculated while shifting the position of the template by applying to the point (xi, yj) of x, y). Then, the type of template that gives the maximum value of the matching frequency M (xi, yj) and the position to which the template is applied are obtained, and when the calculated matching frequency is equal to or greater than a predetermined value, matching is performed. Judge that it was taken.

  Then, the work movement table 30 is moved so that the matched position is observed at the center of the image I (x, y), and the brightness measurement unit 26 measures the brightness.

  In this manner, by performing template matching using the template of FIG. 9, even if the pixel to be matched is at the corner of the edge image E (x, y), matching can be reliably performed. Thus, the range in which matching can be achieved can be further expanded, and even if a deviation occurs in the installation position of the work or a deviation in the installation position of the switch having the light emitting unit, a predetermined luminance measurement is performed. The brightness of the point can be measured with high accuracy.

  According to the luminance measuring apparatus and the luminance measuring method according to the first embodiment configured as described above, the in-focus state of the image photographed by the imaging unit 28 is detected and detected by the in-focus degree calculating unit 50. Depending on the in-focus state, the imaging unit movement table control unit 60 causes the imaging unit movement table 40 to move in the front-rear direction along the optical axis of the luminance and image information acquisition unit 20 to focus on the front surface of the workpiece 10. Therefore, even if there is a step in the light emitting portion of the workpiece 10, the luminance measuring unit 26 can measure the luminance of the light emitting portion on the front surface of the workpiece 10. In addition, the corresponding point search unit 80 sets in the layout image L (x, y) based on the result of associating the reference point on the front surface of the workpiece 10 with the layout image L (x, y). Since the coordinates of the point on the front surface of the workpiece 10 corresponding to the brightness measurement point can be calculated, the brightness of the point corresponding to the preset brightness measurement point can be measured without much manpower and time. it can. Further, the template matching calculation unit 120 uses the region including the luminance measurement point as a template and performs template matching with the region including the point where the luminance measurement unit 26 actually measures the luminance. Even if a shift occurs due to rattling or a shift occurs in the installation position of the work 10 at the time of luminance measurement, the luminance of the point to be measured can be reliably measured. It is possible to measure the luminance of the display surface of different operation panels having high reproducibility.

  In addition, since the said Embodiment 1 is only an illustration of this invention, this invention is not limited only to the structure of Embodiment 1, the design change etc. of the range which does not deviate from the summary of this invention Of course, this is included in the present invention. For example, in the first embodiment, the reference point setting unit 70 sets two reference points on the front surface of the workpiece 10, but by setting more reference points, the workpiece 10 and the layout image L (x, y ) Can be improved more accurately.

  In the first embodiment, the work 10 is fixed to the work movement table 30 and moved in two directions orthogonal to each other on the surface orthogonal to the optical axis of the luminance and image information acquisition unit 20. The information acquisition unit 20 is fixed to the imaging unit moving table 40, and is configured to move in the front-rear direction along the optical axis of the luminance and image information acquisition unit 20. However, the configuration of the embodiment is not limited to this, and the workpiece Only one of the moving table 30 and the imaging unit moving table 40 may be moved in three directions, up, down, left, and right. This eliminates the need for the movement function of one of the work movement table 30 and the imaging unit movement table 40, and eliminates the need for a movement table control unit connected to the table. Can be simplified.

  Further, in the first embodiment, the imaging unit 28 captures only the periphery of the luminance measurement point. However, an imaging unit having a wider observation field of view than that of the imaging unit 28 by adding one camera is used as the luminance unit. The image information acquisition unit 20 may be added. In this way, by using an image captured by the imaging unit capable of observing a wide field of view, a wide range of the workpiece 10 can be imaged by one imaging, and thus, in step S3 of FIG. The process of searching for a point corresponding to the reference point set on the front surface of the work 10 from the layout image L (x, y) of the light emitting unit can be performed more quickly.

DESCRIPTION OF SYMBOLS 10 Work 20 Luminance and image information acquisition part 22 Optical system 23 Half mirror 24 Mirror 25 Optical path branching part 26 Luminance measurement part 28 Imaging part 30 Work movement table 40 Imaging part movement table 50 Focus degree calculation part 60 Imaging part movement table control part 70 Reference Point Setting Unit 80 Corresponding Point Searching Unit 90 Luminance Measurement Point Setting Unit 100 Luminance Measurement Point Calculation Unit 110 Template Creation Unit 120 Template Matching Operation Unit 130 Work Movement Table Control Unit

Claims (6)

A work in which a plurality of switch surfaces and display surfaces having light emitting portions are arranged with steps,
A luminance measuring unit for measuring the luminance at a specific point of the light emitting unit from a direction facing the workpiece;
An imaging unit that is integrated with the luminance measurement unit and arranged so that the optical axes of each other form a coaxial system, and images a peripheral region including the specific point;
A workpiece moving table that fixes the workpiece and moves the fixed workpiece in two orthogonal directions on a surface orthogonal to the optical axis of the luminance measuring unit and the imaging unit;
The luminance measuring unit and the imaging unit are fixed, and the fixed luminance measuring unit and the imaging unit are moved in the front-rear direction along the optical axis of the luminance measuring unit and the imaging unit. A moving table;
A reference point setting unit for setting at least two reference points spaced from each other in the vertical and horizontal directions on the front surface of the light emitting unit;
A corresponding point search unit for searching for a point corresponding to the reference point from the layout image representing the edge position of the light emitting unit;
A luminance measurement point setting unit for setting a plurality of luminance measurement points in the layout image of the light emitting unit;
Based on the search result of the corresponding point search unit, a luminance measurement point calculation unit that calculates the coordinates of the point on the front surface of the workpiece, each corresponding to a plurality of luminance measurement points set by the luminance measurement point setting unit;
The movement direction and amount of movement of the workpiece movement table with respect to the workpiece movement table so that the point on the front surface of the workpiece calculated by the luminance measurement point calculation unit coincides with the measurement point of the luminance measurement unit. A workpiece movement table control unit for instructing
An in-focus degree calculating unit for detecting an in-focus state of the image of the light-emitting unit captured by the imaging unit;
Based on the calculation result of the focusing degree calculation unit, the moving direction and the moving amount of the imaging unit moving table are set with respect to the imaging unit moving table so that an image focused on the front surface of the workpiece can be shot. An imaging unit moving table control unit for instructing;
A template creation unit for setting a region around each luminance measurement point in the layout image set by the luminance measurement point setting unit as a template;
Performing template matching between each template set by the template creation unit and an image taken by the imaging unit and including a point corresponding to each luminance measurement point, the luminance measurement point corresponding to each luminance measurement point A template matching calculation unit that calculates the coordinates of each point in the image including the point corresponding to the point, so that each luminance measurement point coincides with each point calculated by the template matching calculation unit The brightness measuring apparatus, wherein the work movement table is moved, and the brightness is measured by the brightness measuring unit.   The luminance measurement point setting unit includes a shape of the light emitting unit included in the template set by the template creating unit and a region of the light emitting unit having a shape that is congruent or similar to each other in the layout image. The brightness measurement device according to claim 1, wherein brightness measurement points are set so as not to exist in the brightness measurement point.   The brightness measurement point setting unit sets the brightness measurement point so that a plurality of regions of the light emitting unit are included in the template set by the template creation unit. The brightness measuring apparatus described.   The templates set in the template creation unit are a vertically long rectangular shape, a horizontally long rectangular shape, and a square shape. The template matching calculation unit performs template matching on each of the plurality of templates, and the highest matching degree is obtained. The brightness measuring apparatus according to claim 1, wherein a point on which a template that gives a value is applied is a point where matching is achieved. The templates set in the template creation unit are four templates in which the points set in the luminance measurement point setting unit are arranged at four corners of a rectangle, respectively. 4. The matching operation unit according to claim 1, wherein template matching is performed in each of the matching calculation units, and a point to which a template that gives the highest matching degree is applied is set as a point where matching is achieved. 5. The brightness measuring apparatus described.   The workpiece movement table is moved so that each luminance measurement point coincides with each point calculated by the template matching calculation unit when the luminance measurement unit measures the luminance. 5. A luminance measuring method using the luminance measuring apparatus according to claim 1.