WO2011052693A1 - Three-dimensional measurement device and three-dimensional measurement method - Google Patents

Abstract

In order to obtain a three-dimensional measurement device capable of measuring the distance to and position of a subject with high accuracy, disclosed is a three-dimensional measurement device provided with: an image capturing system (10) which captures an image of a subject (5) by an image capturing element (14); a bright point extraction unit (32) which detects the subject (5) by luminances that are detected from respective images captured at different distances between the subject (5) and the image capturing system (10) and have a predetermined threshold value or more; a luminance centroid calculation unit (36) which detects luminances in each given region including a plurality of pixels around a bright point of the image, finds the luminance distribution within the given region, and finds the luminance centroid value on the basis of the luminance distribution; a luminance correction unit (38) which obtains the luminance corrected value as a result of correcting the luminance possessed by a pixel (14a) in which the luminance centroid value is detected and the luminances detected by surrounding pixels (14a) to the luminance of the luminance centroid value; and a three-dimensional detection unit (43) which finds the value of the distance to the subject (5) on the basis of the luminance corrected value and detects the position of the subject (5) on the basis of the luminance centroid value.

Description

Three-dimensional measuring apparatus and three-dimensional measuring method

The present invention relates to a three-dimensional measuring apparatus and a three-dimensional measuring method.

A three-dimensional measuring apparatus using the depth-of-focus method evaluates the amount of out-of-focus and determines the in-focus position. Evaluation of the out-of-focus amount includes a method in which a photographed image is passed through a differential filter and evaluated from its dispersion value or from the sum of luminance.
A three-dimensional measurement apparatus using a depth of focus method is a three-dimensional shape detection apparatus that optically detects a three-dimensional shape of an object as shown in Patent Document 1 below, and is obtained for the same object. In addition, a focal point is obtained for each point on the object from a plurality of images with different focal positions in correspondence with the image, and the maximum value of the focusing measure between the plurality of images obtained for the point correspondence is obtained. The focal position at the moment is obtained as the height of the point.
Then, the contrast of the image is obtained in consideration of the luminance blur, and the contrast is second-order differentiated to obtain the focal point.

According to such a three-dimensional measuring apparatus, a plurality of images having different focal positions are obtained for each point on the object, and the focal position of the image having the maximum in-focus measure is obtained as the height for that point. The three-dimensional shape of the object can be measured from the height of each point thus obtained.

Japanese Unexamined Patent Publication No. 3-63507

However, as a result of repeated researches by the inventor, according to the above three-dimensional measurement apparatus, since the blur of the brightness is noticeably generated in the captured image as it is out of focus, the object to be detected based on the brightness The first problem is that the position on the XY plane is difficult to specify, and the position detection accuracy on the XY plane is lowered.
Furthermore, the detection in the height direction (distance) is performed based on the luminance detected by the pixels (pixels) in the image sensor, but by raising or lowering the imaging system, the object to be detected in the XY plane is detected. The detection position is also slightly shifted. Along with this, since the object is moved from the vicinity of the center of the pixel to the peripheral portion, the detection position of the pixel of the image sensor is shifted.
Therefore, since the luminance based on the object of the pixel cannot be detected accurately, the distance of the object cannot be accurately detected, and the position of the object corresponding to the distance on the XY plane is also accurately detected. We found a second problem that things that can't be done.

The present invention has been made to solve the above-described two problems, and with a simple configuration, the detection accuracy of an object on the XY plane can be improved even when luminance blur occurs in an image obtained by imaging the object. It is an object of the present invention to obtain a three-dimensional measurement apparatus and a three-dimensional measurement method capable of measuring the distance and the position of the object with high accuracy even when the detection position of the object in the pixel of the image pickup device is shifted. .

The three-dimensional measurement apparatus according to the present invention includes an imaging unit that images an object using an imaging element having pixels,
The target object is extracted in units of pixels when the brightness detected by each image captured by the image capturing means at a different distance between the target object and the image capturing means is a predetermined brightness or more. Bright spot extraction means;
Including the pixel having the bright point, the brightness of each constant area formed by the pixels around the pixel is detected, and the brightness distribution for each of the X axis and Y axis in the constant area is obtained, and based on the brightness distribution Means for calculating a luminance centroid to obtain a first luminance centroid value;
A luminance correction means for obtaining a luminance correction value obtained by correcting the luminance of the pixel in which the luminance centroid value is detected and the luminance detected by pixels surrounding the pixel to the luminance of the luminance centroid value;
3D detection means for obtaining a distance value with respect to the object based on the brightness correction value and detecting a position on the X and Y of the object based on the brightness centroid value. It is characterized by.

According to such a three-dimensional measuring apparatus, the brightness detected by each image picked up by the image pickup means at a different distance between the object and the image pickup means is determined in advance by the bright spot detection means being equal to or higher than a threshold value. The pixel is detected, and the luminance center of gravity calculation means detects the luminance for each fixed region centered on the bright point of the image, obtains the luminance distribution for each X axis and Y axis in the fixed region, and based on the luminance distribution Therefore, the position of the bright point on the XY plane can be accurately detected according to the luminance distribution. Therefore, even if luminance blur occurs in the image, the detection accuracy of the object on the XY plane can be improved, and the position can be detected without being affected by sampling in which the luminance is regarded as a constant value in pixel units.
Here, the fixed region may form a circle with pixels centered on the bright point. This is because the luminance blur often becomes substantially circular.
Further, the fixed area may be, for example, a substantially square having a fixed area of 3 × 3 pixels, 5 × 5 pixels, and 7 × 7 pixels centered on the bright point. Therefore, even if a bright spot exists around the pixel of the image sensor, the brightness is detected from a plurality of pixels, so that the position of the bright spot can be accurately detected.

Further, the luminance correction unit obtains a luminance correction value obtained by correcting the luminance detected from the pixel in which the luminance centroid value is detected and the pixels around the pixel based on the luminance centroid value. As a result, the three-dimensional detection means measures the distance by the luminance correction value obtained by correcting the luminance for measuring the distance of the object to the luminance of the luminance centroid value, and based on the luminance centroid value, A position on X and Y is detected.
Thereby, for example, when the imaging system is raised or lowered, the detection position of the object in the XY plane is slightly shifted. Thereby, even if the detection position of the pixel of the image sensor is shifted, a luminance correction value is obtained by correcting the luminance detected by the pixels having the luminance centroid value and the pixels around the pixel to the luminance of the luminance centroid value. . Since the distance to the object is measured by this brightness correction value, the distance can be accurately detected. Therefore, the distance can be accurately detected even if the bright point (vertex) due to the reflection of light based on the object is smaller than one pixel of the image sensor.
The three-dimensional detection means may also detect the position of the object on the X and Y coordinates from the luminance centroid value corresponding to the luminance correction value obtained from the distance of the object. Furthermore, it has a large number of luminance centroid values obtained for the imaging system, the object, and the distances Z1, Z2,... Zn, and interpolates a large number of luminance centroid values by a quadratic function, for example. Obtain the interpolation value of the center of gravity, detect the distance value to the object based on the brightness correction value, and the object on the X and Y coordinates based on the brightness center value corresponding to the brightness correction value obtained the distance value The position of the object may be detected.

For the correction of the luminance of the luminance centroid value in the luminance correction means, for example, the luminance that the luminance of each pixel contributes to the luminance centroid value is obtained based on the distance from each pixel to the luminance centroid value. Here, in order to determine the degree of contribution, for example, the luminance of each pixel may be obtained as the luminance of the luminance centroid value by a Gaussian distribution of the distance to the luminance centroid value.

The three-dimensional measurement apparatus of the present invention comprises a luminance offset detection means for detecting a luminance offset from the certain region of the image,
Preferably, the luminance centroid calculating means obtains a new luminance distribution obtained by removing the luminance offset from the luminance distribution, and obtains a second luminance centroid value based on the new luminance distribution.
Here, the luminance offset is a constant luminance generated in all regions from the luminance of the certain region, and is preferably a minimum luminance value. This is because it is easy to detect only the luminance change of the object.
In this three-dimensional measuring apparatus, the luminance offset detecting means detects the luminance offset from the luminance of the image, and the luminance centroid calculating means obtains a new luminance distribution from which the luminance offset is removed from the luminance distribution. Find the luminance centroid value. Therefore, the luminance centroid value is obtained based only on the luminance change near the bright point from which the luminance offset is removed from the luminance distribution, that is, the luminance change caused by the object, and the XY of the object is determined based on the luminance centroid value. Detect the position in the plane.
Therefore, the luminance centroid value is obtained from the luminance detected by the pixels in the vicinity of the bright point by removing the influence of the pixel detecting the irregular reflection from the object as the luminance and the luminance centroid value detection accuracy is improved. This improves the position detection accuracy of the object in the XY plane.
Furthermore, since the brightness correction means detects the distance of the object based on the brightness correction value corrected based on the brightness centroid value with improved detection accuracy by removing the brightness offset, the distance detection accuracy is further improved. improves.

The three-dimensional measurement apparatus according to the present invention includes a luminance offset detection unit that detects a luminance offset from the certain region of the image, obtains a new luminance distribution obtained by removing the luminance offset from the luminance distribution, and It is preferable to include a second luminance centroid calculating means for obtaining a second luminance centroid value based on the luminance distribution.
As a result, the luminance correction means corrects the luminance detected by the pixel having the first luminance centroid value and the luminance detected by pixels around the pixel to the luminance of the first luminance centroid value. A brightness correction value is obtained.
The three-dimensional detection means obtains a distance value to the object based on the first luminance correction value and detects the position on the X and Y of the object based on the second luminance gravity center value. good. Thus, the luminance offset is taken into account for detecting the position of the object without considering the luminance offset to obtain the distance value with the object. Therefore, the detection accuracy of the position of the object is further improved.
In addition, the luminance correction unit corrects the luminance detected by the pixel having the second luminance centroid value and the luminance detected by the pixels around the pixel to the luminance of the second luminance centroid value. Get the correction value.
The three-dimensional detection means obtains a distance value to the object based on the second luminance correction value and detects the position on the X and Y of the object based on the first luminance centroid value. good. As a result, the luminance offset is taken into account for obtaining the distance value from the object, and the luminance offset is not taken into account for detecting the position of the object. Therefore, the detection accuracy of the distance of the object is further improved.

The three-dimensional measurement apparatus of the present invention includes a luminance interpolation unit that interpolates the luminance correction value with a predetermined function to obtain a luminance interpolation value,
The three-dimensional detection means preferably obtains a distance value with respect to the object based on the luminance interpolation value.
In this three-dimensional measurement apparatus, the luminance interpolation means interpolates the luminance correction value with a predetermined function to obtain the luminance interpolation value, and the three-dimensional detection means detects the object based on the luminance interpolation value. Find the distance value.
Thereby, the brightness | luminance calculated | required for every distance is interpolated, a brightness | luminance interpolation value is obtained, and the distance value with a target object is calculated | required based on a brightness | luminance interpolation value. Therefore, since the continuity of the brightness between the images detected for each height of the imaging system is maintained, the distance of the object can be obtained with high accuracy.

In the three-dimensional measurement method of the present invention, after executing a bright point extraction step of detecting a bright point of each image captured by the imaging unit at different distances between the object and the imaging unit,
Luminance centroid calculation step of detecting the luminance for each constant region including the bright point of the image, obtaining the luminance distribution for each X-axis and Y-axis in the fixed region, and obtaining the luminance centroid value based on the luminance distribution After running
After setting a certain region having a plurality of pixels based on the luminance centroid value, and obtaining a luminance correction value obtained by correcting the luminance detected from the pixel based on the luminance centroid value,
A distance value with respect to the object is obtained based on the correction value of the luminance, and a position on the X and Y of the object is detected based on the luminance centroid value.
According to the three-dimensional measurement method of the present invention, since the position of the bright spot as the object can be detected based on the luminance centroid value, it is not easily affected by the luminance blur around the bright spot. Further, the detected luminance is corrected based on the luminance centroid value to obtain a luminance correction value, and the distance to the object is detected based on the luminance correction value. Therefore, the distance is detected regardless of the detection position of the pixel in the image sensor. Detection accuracy is improved.

In the three-dimensional measurement method of the present invention, after executing the bright spot extraction step, after executing a luminance offset detection step of detecting a luminance offset from the image,
In the luminance centroid calculation step, a new luminance distribution is obtained for each of the X axis and Y axis in the fixed region obtained by removing the luminance offset from the luminance distribution, and a luminance centroid value is obtained based on the new luminance distribution. Is preferable.
According to the three-dimensional measurement method of the present invention, a new luminance distribution is obtained for each of the X axis and the Y axis in the certain region from which the luminance offset is removed from the luminance distribution, and the luminance centroid value is calculated based on the new luminance distribution. Ask. As a result, the luminance center of gravity is obtained from the amount of change in luminance based on the object, so that the luminance center of gravity can be accurately detected. Therefore, the detection accuracy of the distance and position of the object is improved.

According to the present invention, even when luminance blur occurs in an image obtained by capturing an object with a simple configuration, the detection accuracy of the object on the XY plane is improved and the object in the pixel of the image sensor is improved. Even if the detection position is shifted, it is possible to obtain a three-dimensional measuring apparatus or a three-dimensional measuring method capable of measuring the distance and position with the object with high accuracy.

1 is an overall view of a three-dimensional measuring apparatus showing an embodiment of the present invention. FIG. 4 is an actual image (a) according to an embodiment of the present invention, an image (b) showing a bright spot and a fixed area, and a schematic diagram (c) showing a fixed area and a bright spot in the image. FIG. 3 is a characteristic diagram showing a luminance center of gravity while showing a sampled luminance value and an X coordinate in the three-dimensional measuring apparatus according to FIG. 1. FIG. 2 is a schematic diagram (a) illustrating a ratio of luminance depending on positions of pixels and metal particles of the image sensor of the three-dimensional measurement apparatus in FIG. 1, and a partial cross-sectional view (b) of the image sensor. FIG. 2A is a diagram illustrating a pixel value of an image sensor of the three-dimensional measurement apparatus in FIG. 1, and FIG. 2B is a plan view illustrating a relationship between a luminance centroid value and a center position of each pixel. It is a characteristic curve figure which shows the relationship between the distance with the brightness | luminance value detected by the three-dimensional measuring apparatus of FIG. 1, a brightness | luminance correction value, and a target object. It is a flowchart which shows the whole operation | movement of the three-dimensional measuring apparatus of FIG. It is a flowchart which shows the bright spot extraction process by the three-dimensional measuring apparatus of FIG. It is a flowchart which shows the calculation process of the 1st brightness | luminance gravity center by the three-dimensional measuring apparatus of FIG. It is a flowchart which shows the correction process of the brightness | luminance by the three-dimensional measuring apparatus of FIG. It is a whole figure of the three-dimensional measuring device which shows other embodiment of this invention. FIG. 12 is a characteristic curve diagram illustrating a relationship between a detected luminance value, a luminance change value obtained by removing a luminance offset from the detected luminance value, and an X coordinate in the three-dimensional measurement apparatus according to FIG. 11. It is a characteristic curve figure which shows the relationship between the luminance value of a metal particle by the presence or absence of a brightness | luminance offset, and X coordinate. FIG. 12 is a characteristic curve diagram illustrating a relationship between a brightness value, a brightness correction value, a continuous interpolation value of brightness, and a distance from an object by the three-dimensional measurement apparatus of FIG. 11. It is a flowchart which shows the whole operation | movement of the three-dimensional measuring apparatus of FIG. It is a flowchart which shows the operation | movement of the detection process of the brightness | luminance offset by the three-dimensional measuring apparatus of FIG. It is a flowchart which shows operation | movement of the calculation process of the 2nd brightness | luminance gravity center by the three-dimensional measuring apparatus of FIG. It is a flowchart which shows the operation | movement of the brightness | luminance interpolation process by the three-dimensional measuring apparatus of FIG.

Embodiment 1 FIG.
An overall configuration of a three-dimensional measuring apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is an overall view of a three-dimensional measuring apparatus showing an embodiment of the present invention.
In FIG. 1, a three-dimensional measuring apparatus 1 detects a distance Z to the surface of an object 5 that is easily reflected and a position on an XY plane.
The first three-dimensional measurement apparatus 1 captures an image of the object 5, and includes an imaging system 10 including an imaging device 14 having a large number of pixels 14a, and an L shape for moving the imaging system 10 up and down in the Z-axis direction. A ball screw 62 erected on the base 7, a drive mechanism 60 having a motor or the like to which the imaging system 10 is fixed, and a position command signal for operating the drive mechanism 60. A control unit 55 is included.
One pixel 14a is referred to as a pixel unit U1.

Furthermore, the first three-dimensional measuring apparatus 1 has an imaging system driving unit 65 that drives the driving mechanism 60 in response to a position command signal from the control unit 55, takes in an image captured by the imaging element 14, and And a first three-dimensional detector 30 that detects the position of the object 5 on the XY plane, as well as the distance from the imaging system 10 to the surface of the object 5.
Here, the object 5 is not particularly limited, but is preferably provided on the surface of the resin plate 5 and is preferably a plurality of metal particles 5h such as six spheres that easily reflect light. It may be larger or smaller than one pixel 14a.

The first three-dimensional detector 30 is composed of a microcomputer, and has a known interface, CPU, RAM, and ROM, and extracts a bright point at which a luminance of a predetermined value or more from the metal particle 5h is generated in a pixel unit U1. In addition, it has a bright spot extraction unit 32 for detecting luminance.
Here, the reason why the metal particles 5h are detected with a luminance equal to or higher than a predetermined value is that if the metal particles 5h are present, the luminance is higher than the surroundings due to the reflection.
Furthermore, the first three-dimensional detector 30 corrects the brightness of the bright point using the first brightness centroid value calculating unit 36 for obtaining the first brightness centroid value from the brightness having the bright point, and the first brightness centroid value. The distance between the first luminance correction unit 38 and the metal particle 5h is obtained from the first luminance correction value, and the position of the XY plane of the metal particle 5h is determined from the first luminance centroid value corresponding to the distance. And a first three-dimensional detection unit 43 for detection.

The configuration of each part of the three-dimensional measuring apparatus 1 will be described with reference to FIGS. FIG. 2 is an actual image (a) according to an embodiment, an image (b) showing a bright spot and a fixed area, and a schematic diagram (c) showing a fixed area and a bright spot in the image.
As shown in FIG. 2 (a), the bright spot extraction unit 32, from each of the image files G1, G2,... Gn captured at the distances Z1, Z2,. A pixel 14a having a luminance equal to or higher than a threshold value is detected, and this pixel 14a is extracted as a luminance cell B1... B6, and as shown in FIGS. The center, that is, the vertex directly reflected from the plurality of metal particles 5h is detected in the pixel unit U1 as the first bright point P1 to the sixth bright point P6.
Even if the metal particle 5h is spherical, a vertex is generated by direct reflection from the metal particle 5h, and this vertex is less than one pixel 14a.

Then, the light spot extraction unit 32 calculates the difference in luminance in the fixed area A1... A6 formed by the central pixel 14a including each bright spot P1... P6 and the pixels 14a around the central pixel 14a. It is configured to obtain a contrast value and detect that the contrast value is greater than or equal to a predetermined threshold value. Here, in order to extract the bright point by the vertex 5h of the metal particle, it is determined that the contrast value is equal to or greater than the threshold value by preventing the influence of the fluctuation of the brightness, and the bright points P1, P2,. This is to prevent erroneous detection.
For example, the predetermined area A1... A6 formed by the plurality of pixels 14a is 5 × 5 pixels.

<Necessity of First Luminance Center of Gravity Calculation Unit 36>
By specifying the metal particle 5h, that is, the imaging element 14 showing a high luminance value by the pixel unit U1 by the bright spot extraction unit 32, the position of the metal particle 5h on the XY plane can be detected from the pixel 14a.
However, not only the detection accuracy having a resolution higher than that of the pixel unit U1 can be obtained, but also the detected luminance is blurred, and therefore the specification of the pixel 14a having a bright point may be inaccurate.
Therefore, a fixed region formed by a plurality of pixels 14a including the pixel 14a from which the bright point is extracted is determined, and the first luminance barycentric value is obtained from the luminance distribution of the fixed region, and the position of the bright point, that is, the metal particle 5h. The position of is detected.
Here, the fixed regions A1... A6 are regions formed by 5 × 5 pixels 14a. In addition, since the luminance blur centered on each of the dotted bright points P1,... P6 is generally circular, the central pixel 14a including each bright point and the pixels around the central pixel 14a. 14 may be formed in a substantially circular shape. Furthermore, the fixed area may be determined by the plurality of pixels 14a depending on the blurred shape of the received luminance.

<Configuration of First Luminance Center of Gravity Calculation Unit 36>
The first luminance centroid operation unit 36 calculates the first luminance distribution in the fixed region A1, that is, the first luminance centroid value (Xg, Yg) in the X and Y coordinates from the detected luminance L by the following equation (1). ) And (2) respectively. Then, the first luminance centroid value (Xg, Yg) is the position of the metal particle 5h in the X, Y coordinates.
Xg = ΣxL / ΣL (1)
Yg = ΣyL / ΣL (2)
Here, L: Detected luminance Further, the first luminance center-of-gravity calculation unit 36 obtains a first luminance center-of-gravity value for each of the distances Z1, Z2,... Zn between the imaging element 14 and the metal particles 5h. Remember.
For other fixed areas A2... A6 corresponding to other bright points P2.

The reason for obtaining the luminance center of gravity is to detect the positions of the bright points P1,... P6 more accurately than the pixel unit U1. That is, by obtaining the first luminance barycentric value from the first luminance distribution at the positions of the bright points P1,... P6, the bright points P1,. The position of P6 can be detected. Therefore, as shown in FIG. 3, even if the brightness of the bright spot is sampled so as to be a constant value in the unit of the pixel 14a by obtaining the first brightness centroid value, each coordinate of the metal particle 5h is obtained. An accurate position in the XY direction can be detected.
3 shows only the X coordinate, the relationship between the Y coordinate and the luminance value is the same as that of the X coordinate.

<Necessity of Luminance Correction Unit 38>
As shown in FIG. 4A, the imaging element 14 has square pixels 14a formed in a lattice shape, and each pixel 14a has a circular three-dimensional detection unit 14s. For this reason, when there is a bright point Pc as the first bright point P1 due to the metal particles 5h narrower than the area of the pixel 14a at the center of the pixel 14a, the luminance detection ratio of one pixel 14a is 1, and It is sufficient to detect the point Pc with one pixel 14a that has detected the point Pc.
Even if the size of the metal particle 5h itself is larger than one pixel 14a, the bright point P1 based on the direct reflection from the metal particle 5h may be one pixel 14a.

However, as shown in FIG. 4A, the first luminance center of gravity is a cross formed between the thresholds of the pixels 14a and 14a, that is, the threshold, as a bright point Pa as the first bright point P1. , The luminance detection ratio of the surrounding four pixels 14a is 0.25, respectively. When the bright spot Pb as the first bright spot P1 is located at the upper and lower borders of the pixel 14a with the first brightness center of gravity, the surrounding four pixels 14a have a detected brightness detection ratio of 0.6, respectively. 0.2, 0.0, 0.2.
Therefore, if the luminance at the first luminance centroid value is determined by the luminance detected by only one pixel 14a from which the bright point is extracted, the luminance at the first luminance centroid value may not be detected accurately.

As described above, the detection characteristics of the pixel 14a of the image sensor 14 are different between the central portion and the peripheral portion. As shown in FIG. 4B, the pixel 14a passes through the microlens 14s as a circular three-dimensional detection portion. The received light is received by the photodiode 14p provided in the wiring layer 14c through the filter 14f. Therefore, as described above, the detection characteristics deteriorate in the peripheral portion of the pixel 14a.

Since the imaging element 14 has the detection characteristics as described above, as shown in FIG. 6, the distance between the imaging system 10 and the metal particles 5h is changed, and one pixel 14a having a bright point P1 at each distance is changed. When the brightness detected by the pixel 14a is plotted, a characteristic curve indicated by a cross in FIG. 6 is obtained. When observing this characteristic curve, the detected brightness increases as the focal point of the imaging system 10 is approached, and the luminance decreases as the distance from the focal point increases. What is shown may show a substantially V characteristic indicated by a one-dot chain line in which the luminance suddenly decreases and increases as the luminance increases.

Such a phenomenon occurs when the first luminance center-of-gravity value is shifted from the vicinity of the center of the pixel 14a to the vicinity thereof as the imaging system 10 moves. This is because the center of the image sensor 14 is not at the same position on the XY plane and slightly shifts with the movement of the image pickup system 10 in the height direction.
Therefore, if the detected luminance is not corrected, an area having the highest luminance is regarded as a focal point, and an error occurs in distance detection of the metal particles 5h.
For this reason, it is necessary to correct the luminance value for detecting the distance of the metal particles 5h with the movement of the first luminance centroid value in the XY plane. Therefore, the luminance is corrected by using the luminance detected by the pixel 14a including the first luminance centroid value and the pixels 14a around the pixel 14a as the luminance of the first luminance centroid value. By correcting the luminance, the distance of the metal particles 5h is obtained, so that the distance detection accuracy is improved.
Note that the luminance is corrected for each extracted bright point P1... P6 for each distance between the imaging system 10 and the metal particle 5h.

<Configuration of Luminance Correction Unit 38>
The first luminance correction unit 38 detects the luminance detected by each of the pixels 14 a having the first luminance centroid and the pixels 14 a around the pixel 14 a, the first luminance centroid value, and each of the pixels in the image sensor 14. The brightness inherent in the first brightness centroid is estimated by correcting the distance from the center position of the pixel 14a.
That is, the luminance correction unit 38 obtains the luminance correction value Lm from the following equation (3), using the luminance detected by the surrounding pixels 14a as the luminance of the luminance centroid value.
Further, the first luminance correction unit 36 obtains each based on the first luminance centroid value obtained for each of the distances Z1, Z2,... Zn between the imaging element 14 and the metal particles 5h.

The identification number for specifying each pixel 14a in the image sensor 14 is specified by determining the pixel values in the X direction and the Y direction in the order of alignment of the pixels 14a in the X direction and the Y direction. As shown in FIG. 5A, the pixel value (xn, yn) is the sum of the pixel 14a that detects the bright point Pa, which is the first luminance centroid value, and the pixels 14a around the pixel 14a. The four are pixel (1, 2), pixel (2, 2), pixel (1, 3), and pixel (2, 3), respectively.
The correction luminance is Lm, the luminance value at which each pixel 14a is detected is ΣL (<x>, <y>), and the difference between the detected center position of the pixel 14a and the first luminance centroid value (Xg, Yg). Is set to Δx and Δy in the X and Y directions, respectively, the following equation (3) is established.

Lm (Xg, Yg) = ΣL (<x>, <y>) (Δx, Δy) (3)
Here, <x>: Pixel value in the X direction, <y>: Pixel value in the Y direction Further, Δx and Δy are expressed by the following equations (4) and (5).
Δx = Xg− <x> (4)
Δy = Yg− <y> (5)

The luminance detected by the pixel 14a having the first luminance centroid value and the pixels 14a around the pixel 14a affects the first luminance centroid, so that the luminance of the first luminance centroid is It is assumed that the model function of the distances Δx and Δy between the center value of each pixel 14a and the first luminance centroid value is affected by a Gaussian distribution. Then, f (Δx, Δy) becomes the following equation (6).

.... (6)

Therefore, the first luminance correction value Lm (x, y) is the detected luminance value ΣL (<x>, <y>) and the distance from the first luminance centroid value to the center value of each pixel 14a. And the luminance of the first luminance centroid value can be obtained by correcting the luminance detected by each pixel 14a by the Gaussian distribution of the distance.
Here, the model function is not limited to the Gaussian distribution, and may be inversely proportional to the distances Δx and Δy with respect to the first luminance center of gravity, for example.
In the above description, the four pixels 14a including the first luminance centroid value are used. However, 3 × 3 pixels 14a or 5 × 5 pixels 14a including the first luminance centroid value may be used. That is, the number of pixels 14a for obtaining the first luminance correction value is determined from the resolution of the pixels 14a, the nature of the object 5 and the like.

<Specific example of brightness correction>
Now, as shown in FIG. 5B, assuming that the first luminance centroid Pa (1.5, 2.7), the luminance at the first luminance centroid Pa is the pixel 14a having the first luminance centroid Pa. Correction is performed as follows from the luminance detected by the four pixels 14a included.
ΣL (<x>, <y>) = L (1,2) f (0.5,07) + L (2,2) f (0.5,07)
+ L (1,3) f (0.5,03) + L (3,2) f (0.5,03)
If the luminance detected by the pixel (1, 2), the pixel (2, 2), the pixel (1, 3), and the pixel (3, 2) is 100, 90, 90, 100, respectively, f (Δx, Δy) is It becomes.
Lm = ΣL (<x>, <y>) f (Δx, Δy)
= 100e- ^{0.74 / 2σ2} + 90e- ^{0.74 / 2σ2} + 90e- ^{0.74 / 2σ2} + 100e- ^{0.74 / 2σ2}
Here, assuming that σ = 0.5, the luminance correction value Lm is as follows.
Lm = 100e- ^{0.74 / 0.5} + 90e- ^{0.74 / 0.5} + 90e- ^{0.74 / 0.5} + 100e- ^{0.74 / 0.5}
Lm = 2 × 100 × 0.228 + 2 × 90 × 0.228 = 86.6
In this way, by obtaining the first brightness correction value possessed by each of the first brightness centroid values, the characteristic curve plotted with a circle shown in FIG. 6 is obtained. According to this characteristic curve, the V-shaped characteristic curve becomes a substantially mountain-shaped characteristic curve, and the luminance characteristic is improved.

The first three-dimensional detection unit 43 calculates the luminance from the luminance near each bright point from each of the image files G1, G2,... Gn captured at the distances Z1, Z2,. Find the correction value. Then, as shown in FIG. 6, the brightness correction value is stored in relation to the distance of the metal particle 5h, the distance value with the metal particle 5h is detected based on the brightness correction value, and the highest brightness is obtained. The position of the metal particle 5h on the X and Y coordinates is detected from the luminance centroid value obtained from the first luminance correction value.

The first detection unit 43 also detects the position of the metal particle 5h on the X and Y coordinates from the luminance centroid value corresponding to the first luminance correction value having the highest luminance. Also good. That is, by interpolating, for example, a quadratic function, the luminance centroid values obtained by the imaging system 10, the metal particles 5h, and the distances Z1, Z2,. In this case, the distance value to the metal particle 5h is detected based on the brightness correction value, and the position of the metal particle 5h on the X and Y coordinates is detected based on the brightness centroid value corresponding to the distance value. good.
Thus, the luminance correction value affects not only the distance detection of the metal particles 5h but also the selection of the luminance centroid value for detecting the position of the metal particles 5h. Thereby, the luminance centroid value based on the luminance correction value obtained from the distance of the metal particle 5h is selected, and the position detection accuracy of the metal particle 5h is also improved based on the luminance centroid value.

The overall operation of the three-dimensional measuring apparatus configured as described above will be described with reference to FIGS. 1 to 7 for the three-dimensional measurement of the six metal particles 5h provided on the resin plate 5 as the object.
First, in response to a position command signal from the imaging system driving unit 65, the drive mechanism 60 is operated, the imaging system 10 is lowered in the Z-axis direction, and an image file for each of the heights Z1, Z2,. As shown in FIG. 2A, G1, G2,... Gn store the luminance for each read pixel unit U1 (step S100), and the bright spot extracting unit 32 stores the image files G1, G2,. The vertices of the six metal particles 5h are extracted from Gn as bright points P1, P2,... P6, and the position and luminance are detected in pixel unit U1 (step S200).

The first luminance centroid operation unit 36 calculates the luminance centroids (Xg1, Yg1), (Xg2, Yg2),... From the luminance distribution of the fixed area A1 for each of the heights Z1, Z2,. .. (Xgn, Ygn) is obtained (step S400). The brightness correction unit 38 obtains the brightness correction value of the first brightness centroid value for each height Z1, Z2,... Zn of the imaging system 10 using, for example, a Gaussian distribution as described above (step S500). ). The first three-dimensional detection unit 43 measures the distance of the metal particles 5h based on the luminance correction value, and detects the XY planar position of the metal particles 5h based on the first luminance centroid value (step) S700).
The other bright points P2... P6 also correspond to the fixed areas A2,... A6 and detect the distance and position of the metal particles 5h in the same manner as the bright point P1 as described above.

The operation of each step of the three-dimensional measuring apparatus configured as described above will be described with reference to FIGS.
In the bright spot extraction step S200 of the metal particles 5h, the bright spot extraction unit 32 uses the image files G1, G2,... Gn captured for the heights Z1, Z2,. As shown in FIG. 8, the vertices of the six metal particles 5h are extracted as bright points P1, P2,... P6, and the brightness of the bright point P1 is compared with the brightness of the bright point P1 and a predetermined brightness threshold. It is determined whether or not the luminance is equal to or higher than the threshold value (step S201). If the luminance is equal to or higher than the threshold value, it is detected that the luminance of the bright point P1 is equal to or higher than the peripheral luminance in the fixed area A1 with the bright point P1 as the center. ), The maximum value and the minimum value of the luminance in the fixed area A1 are acquired, and the contrast is obtained from the difference between the maximum value and the minimum value of the luminance (step S205).
The bright spot extraction unit 32 determines that the contrast is equal to or higher than a predetermined threshold (step S207), and determines the X and Y coordinate metal particles 5h of the metal particles 5h in the image files G1, G2,. Detected by the pixel unit U1, the position of the metal particle 5h is stored in association with the heights Z1, Z2,... Zn (step S209).
Note that the other bright points P2 to P6 also detect the metal particles 5h in pixel units U1 in the same manner as the bright points P1.

In the luminance center-of-gravity calculation step S400, as shown in FIG. 9, the first luminance center-of-gravity calculation unit 36 determines the luminance value of each pixel 14a in each image file G1, G2,... Gn detected in step S100. (Step S401), the luminance barycentric value Xg at the X coordinate is obtained by the above equation (1) within the constant area A1 of the bright point P1, and corresponds to the heights Z1, Z2,. Then, the luminance centroid value Xg is stored (step S403), and the luminance centroid value Yg at the Y coordinate is obtained by the above equation (2) and stored in the constant area A1 of the bright point P1 (step S405).
Also, the other bright points P2,..., P6 obtain the luminance centroid values in the same manner as described above, and store the first luminance centroid values corresponding to the heights Z1, Z2,.

In the luminance correction step S500, as shown in FIG. 10, the luminance correction unit 38 reads the luminance value of each pixel 14a in the 5 × 5 pixel area A1 as a fixed area including the bright point P1 detected in step S100. (Step S501), the luminance distribution of a new constant region A1 ′ is obtained centering on the first luminance centroid value (Xg1, Yg1) obtained in Steps S403 and S405 (Step S503). Here, the reason why the new constant area A1 ′ is used is that there may be a constant area different from that in step S501 depending on the luminance centroid value.
Note that the constant area A1 ′ in step 503 may be the same constant area A1 as in step S501.
Using the luminance distribution obtained in step S503, a luminance correction value is obtained from the new luminance centroid values (Xg1, Yg1) by the above formulas (3) to (6), and the height Z1, Z2,. A brightness correction value is stored in association with Zn (step S505).
Further, the brightness correction values of other bright points P2... P6 are obtained in the same manner as described above, and the brightness correction values are stored in correspondence with the heights Z1, Z2,.

The first three-dimensional detection unit 43 measures the distance of the metal particle 5h from the highest luminance by the first luminance correction based on the first luminance correction value by the bright point P1, and the highest luminance. The position of one metal particle 5h on the XY plane is detected from the first luminance centroid value obtained from the first luminance correction value (step S700).
Further, the other bright points P2,... P6 also detect the distance and position of the metal particles 5h in the same manner as described above.
Thereby, the distance of the plurality of metal particles 5h and the position on the XY plane can be accurately detected. Moreover, even if the detected luminance is sampled in the pixel unit U1, it is possible to detect the exact bright spot position.

The three-dimensional measuring device 1 configured as described above includes an imaging system 10 that images the metal particles 5h using the imaging device 14 having the pixels 14a, and an imaging element for each different distance between the metal particles 5h and the imaging system 10. 14, the bright point extraction unit 32 that detects the bright point P 1 (P 2... P 6) of each of the images G 1, G 2,. Detecting the luminance distribution for each of the X axis and Y axis in the fixed region and calculating the luminance centroid value based on the luminance distribution, and the luminance centroid value detected. The brightness obtained from the brightness detected from the pixel 14a and the surrounding pixels 14a based on the distance between the center value of each pixel 14a and the brightness centroid value as a brightness correction value Correction unit 38 and the luminance correction value A first three-dimensional detection unit 43 that obtains the distance from the metal particle 5h and obtains the position of the metal particle 5h on the XY plane based on the brightness centroid value based on the brightness correction value obtained from the distance. It is.

According to the three-dimensional measuring apparatus 1, the bright point extraction unit 32 performs the bright point P1 of each of the images G1, G2,... G6 captured by the imaging system 10 at different distances between the object 5 and the imaging system 10. (P2... P6) is detected, and the first luminance centroid calculating unit 36 detects the luminance for each constant region A1 (A2... A6) centered on the bright point of the image, and X in the constant region is detected. The first luminance distribution for each of the axes and the Y-axis is obtained, and the luminance centroid value is obtained based on the first luminance distribution, so that the position of the bright spot in the fixed area is accurately detected according to the first luminance distribution. it can.
In addition, the luminance centroid calculating unit 36 obtains the luminance centroid value by limiting to the pixels 14a for each fixed region, so that the processing speed is increased.

Further, the three-dimensional measurement apparatus 1 sets a constant area A1 (A2... A6) based on the luminance centroid value, and determines the luminance of the luminance centroid value from the luminance detected by each pixel 14a in the predetermined area. A luminance correction unit 38 to be obtained as a correction value is provided, and the three-dimensional detection unit 43 obtains a distance value from the metal particle 5h based on the luminance correction value, and a luminance centroid value based on the luminance correction value obtained from the distance. To obtain the position of the metal particle 5h on the XY plane. Thereby, the luminance of the luminance centroid is obtained as a luminance correction value based on the luminance of the pixel 14a including the luminance centroid and the surrounding pixels 14a, and the distance from the metal particle 5h is detected based on the luminance correction value. Therefore, even if the detection position of the bright point (metal particle 5h) detected based on the reflection of the light of the metal particle 5h in the pixel 14a of the image sensor 14 is shifted in the one-dimensional image sensor 14a, the three-dimensional measuring device 1 is the distance of the metal particle 5h. Can be detected accurately.
Furthermore, since the position on the XY plane of the metal particle 5h is obtained from the luminance centroid value based on the luminance correction value for which the distance is obtained, the distance is determined while taking into account the luminance blur around the bright point P1 (P2... P6). The position on the XY plane of the metal particle 5h (at the focal point) at the detected point can be detected. Therefore, the position of the metal particle 5h at the point can be accurately detected, and the position of the metal particle 5h can be detected without being affected by sampling in which the luminance is regarded as a constant value in the pixel unit U1.

In the three-dimensional measurement method of the above embodiment, the bright points P1 (P2...) Of the images G1, G2,... Gn captured by the imaging system 10 at different distances between the object 5 and the imaging system 10. After detecting Pn), the brightness of each fixed area A1 (A2... An) centered on the bright point P1 (P2... Pn) of the images G1, G2. The luminance distribution for each of the X-axis and Y-axis is obtained, and the luminance centroid value is obtained based on the first luminance distribution. Then, after obtaining the luminance correction value obtained by correcting the luminance detected from the pixel 14a in which the luminance centroid value is detected and the pixels 14a around the pixel 14a to the luminance of the luminance centroid value, the correction of the luminance is performed. Based on the value, the distance value with respect to the metal particle 5h is obtained, and the position on the X and Y of the metal particle 5h is detected based on the luminance centroid value based on the luminance correction value obtained from the distance.
Thereby, the position of the metal particle 5h on the XY plane can be accurately measured based on the luminance centroid value, and the luminance centroid has the luminance detected from the pixel 14a having the luminance centroid and the pixels 14a around the pixel 14a. A brightness correction value as brightness is obtained, and the distance from the metal particle 5h is detected based on the brightness correction value. Therefore, in the three-dimensional measurement method, even if the detection position of the bright spot (metal particle 5h) detected based on the reflection of the light of the metal particle 5h is shifted in one pixel 14a of the image sensor 14, the distance of the metal particle 5h is changed. It can be detected with high accuracy.

Embodiment 2. FIG.
A three-dimensional measuring apparatus according to another embodiment of the present invention will be described with reference to FIG. FIG. 11 is an overall view of a three-dimensional measuring apparatus according to another embodiment. In FIG. 11, the same reference numerals as those in FIG. 1 denote the same parts, and the description thereof is omitted.
In FIG. 11, the second three-dimensional detector 130 in the second three-dimensional measuring apparatus 101 is composed of a microcomputer, has a well-known interface, CPU, RAM, and ROM, and from an image having a bright point P1. A luminance offset detector 34 for detecting a luminance offset, a second luminance distribution obtained by subtracting the luminance offset from the luminance distribution of a certain area having the bright point P1, and a second luminance centroid value from the luminance distribution. Brightness center of gravity calculation unit 136, second brightness correction unit 138 that obtains a second brightness correction value based on the second brightness center of gravity value, and heights Z1, Z2,... The luminance interpolator 41 that uses a number of second luminance correction values obtained in the above as continuous luminance interpolation values by a function and the distance between the metal particles 5h from the luminance interpolation values and corresponding to the distance And a second three-dimensional detection unit 143 for detecting the position of the XY plane of the metal particles 5h based on 2 luminance centroid value.

The configuration of each part of the three-dimensional measuring apparatus 1 will be described with reference to FIGS. Since the bright spot extraction unit 32 is the same as that in the first embodiment, the description thereof is omitted.
The luminance offset detection unit 34 detects a luminance offset that achieves a minimum luminance value in each of the images G1, G2,... Gn in a certain region including each of the dot-like bright points P1,.
Here, the luminance offset is generated because the pixel 14a of the image sensor 14 detects irregularly reflected light from other metal particles 5h and the like.

The second luminance center-of-gravity calculating unit 136 removes (subtracts) the luminance offset from the first luminance distribution value detected from the image in the fixed area A1 made up of 5 × 5 pixels 14a having a bright point. After obtaining the luminance distribution, the second luminance centroid value (Xgo, Ygo) in the constant area A1 having the bright point P1 is obtained by the following equations (7) and (8).
As shown in FIG. 12, the luminance offset is removed by obtaining the luminance change value (luminance distribution) Ld of only the luminance change due to the reflected light of the metal particles 5h, and obtaining the second luminance centroid value from this luminance change value. This is because the position of the metal particle 5h is accurately detected based on the second luminance centroid value. As shown in FIG. 13, the first luminance distribution (detected luminance) indicated by the dotted line is changed to the second luminance distribution (luminance change value) indicated by the solid line, and an accurate vertex position of the metal particle 5 h can be obtained.
The luminance offset is preferably set to the minimum luminance value, but may be a constant luminance value higher than the minimum luminance value in a certain region.

Xgo = ΣX (L−Lo) / Σ (L−Lo) (7)
Ygo = ΣY (L−Lo) / Σ (L−Lo) (8)
Where L: detected luminance Lo: luminance offset

The second luminance centroid value is obtained by calculating the position of the point-like bright point P1 (P2... P6) in relation to the ambient luminance from which the luminance offset is removed, thereby reducing the influence of luminance blur. This is because the position of the metal particle 5h is accurately detected without being affected by the influence of irregular reflection light from the other metal particle 5h.

The second luminance correction unit 38 includes the pixel 14a having the second luminance centroid value, the luminance detected by the pixel 14a, the luminance detected by the pixels 14a around the pixel 14a, and the center of each pixel 14a. Assuming that the luminance detected as a model function of the distances Δx and Δy between the value and the second luminance centroid value is affected by the Gaussian distribution, the second luminance centroid value has the following expression (3) to (6). It is formed so as to obtain luminance.
When the luminance of the second luminance centroid value obtained in this way is displayed as a luminance correction value, a characteristic curve indicated by a circle shown in FIG. 14 is obtained.

The luminance interpolation unit 41 obtains the maximum luminance value using the luminance correction value, obtains the luminance correction value within ± Z as the height of the imaging system around the maximum luminance value, and is indicated by a solid line in FIG. Thus, a continuous interpolation value of brightness obtained by interpolating the brightness correction value by a quadratic function is obtained.
By interpolating the luminance, matching with each luminance correction value obtained for each different distance between the imaging system 10 and the metal particle 5h is obtained. In addition, by continuously interpolating the luminance, the continuity of the interpolation value of the luminance can be obtained, and the detection accuracy of the distance from the metal particle 5h can be improved.

As shown in FIG. 14, the second distance detection unit 143 uses the characteristic curve of the luminance continuous interpolation value and the distance value between the metal particles 5h as the object and the distance between the metal particles 5h and the imaging system 10. And the positions of the X and Y coordinates of the metal particle 5h are also detected based on the second luminance centroid value corresponding to the detected distance value.

The overall operation of the three-dimensional measuring apparatus configured as described above will be described with reference to FIGS. First, in response to a position command signal from the imaging system driving unit 65, the drive mechanism 60 is operated, the imaging system 10 is lowered in the Z-axis direction, and an image file for each of the heights Z1, Z2,. As shown in FIG. 2A, the light spot extraction unit 32 detects the position and brightness of the light spot P1 as the vertex of the metal particle 5h from the image file in the pixel unit U1 (step S100) (step S100). S200). The luminance offset detector 34 detects the luminance offset from the constant area A1 centered on the bright point P1 (step S300).

The second luminance centroid operation unit 136 obtains the luminance centroid within the constant area A1 with the bright point P1 as the center (step S1400). The second luminance correction unit 138 uses the luminance centroid values (Xg1, Yg1), (Xg2, Yg2),... (Xgn, Ygn) for the heights Z1, Z2,. For example, the luminance of the second luminance centroid value is obtained as a luminance correction value using a Gaussian distribution (step S1500). The luminance interpolation unit 41 obtains a continuous interpolation value by using a plurality of luminance correction values using a function (step S600). The second three-dimensional detection unit 143 measures the distance of the metal particle 5h from the maximum luminance value in the fixed region A1, and also determines the position of the metal particle 5h in the XY plane from the second luminance centroid value corresponding to the maximum luminance value. Is detected (step S700).

The operation of each step of the three-dimensional measuring apparatus configured as described above will be described with reference to FIGS.
In the brightness offset detection step S300, the brightness offset detection unit 34 in each of the image files G1, G2,... Gn has respective bright points P1. In the fixed area A1... A6, the brightness of each X, Y coordinate is detected and stored (step S301), and the minimum brightness value in the fixed area A1 centered on the bright point P1 is set as the brightness offset Lo. Then, the luminance offset Lo is removed (subtracted) from the luminance of each of the X and Y coordinates, and the luminance change value Ld is obtained (step S307).
That is, a luminance change value obtained by removing the luminance offset Lo from the detected luminance is obtained after detecting the luminance offset Lo in the constant area A1 centered on the bright point P1.
The other bright points P2... P6 also correspond to the fixed areas A2,... A6, and obtain luminance change values from which the luminance offset Lo has been removed in the same manner as the bright points P1 as described above.

In the luminance centroid calculation step S1400, as shown in FIG. 17, the second luminance centroid calculation unit 136 reads the luminance value of the pixel 14a detected in step S100 (step S1401), and includes a constant including the bright point P1. Within the area A1, the second luminance centroid value Xgo at the X coordinate is obtained by the above equation (7) and stored (step S1403), and the second luminance centroid at the Y coordinate is obtained within the certain area A1 including the bright point P1. The value Ygo is obtained and stored (step S1405).
The luminance center-of-gravity calculation unit 136 executes steps S1401 to S1405 with the image files G1, G2,... Gn.
Accordingly, the second luminance centroid is obtained from the luminance change value shown in FIG. 13 obtained by subtracting the luminance offset from the luminance distribution, so that the luminance centroid value in a certain region can be accurately detected.

In the luminance correction step S1500, as shown in FIG. 10, the luminance correction unit 38 reads the luminance value of each pixel 14a detected in step S100 (step S501), and uses the X and Y coordinates obtained in step S400. A new fixed area of 5 × 5 pixels is set using the second luminance centroid (step S503), and a second luminance correction value is obtained by correcting the luminance by the above equations (3) to (6). (Step S505).

In the luminance interpolation step S600, as shown in FIG. 18, when the metal particle 5h is detected (step S601), the maximum luminance value at the heights Z1, Z2... Zn of the imaging system 10 is acquired (step S603). The maximum luminance value is determined and acquired (step S605), and n luminance data values are acquired centering on the maximum luminance value (step S607).
Here, the limitation to n luminance data values is that high-speed processing is possible by omitting continuous interpolation of unnecessary data away from the focal point. Then, the n luminance data values are subjected to quadratic interpolation to obtain a continuous interpolation curve as shown by the solid line in FIG. 14 (step S609). The second three-dimensional detection unit 143 detects the distance of the metal particle 5h based on the maximum luminance value in the luminance interpolation value, and based on the luminance centroid value corresponding to the luminance interpolation value that has detected the distance, The position of the metal particle 5h on the X and Y coordinates of 5h is detected (step S700).

The three-dimensional measuring apparatus 101 configured as described above is picked up by the image pickup system 10 at different distances between the image pickup system 10 that picks up the metal particles 5h using the image pickup device 14 and the metal particles 5h and the image pickup system 10. A bright point three-dimensional detector 32 that detects the bright points P1, P2,... Pn of each image G1, G2,... Gn, a luminance offset detector 34 that detects a luminance offset from a certain area of the image, The brightness of each fixed area centered on the bright point of the image is detected, a second brightness distribution obtained by removing the brightness offset from the brightness distribution of each X axis and Y axis in the fixed area is obtained, and the second brightness The luminance center of gravity is calculated from the luminance detected by the second luminance center-of-gravity calculating unit 136 for obtaining the second luminance center-of-gravity value based on the distribution, the pixel 14a in which the luminance center-of-gravity value is detected, and the pixels 14a around the pixel 14a. The brightness of the value The distance between the brightness correction unit 38 obtained as the brightness correction value and the metal particle 5h based on the brightness correction value and the metal particle based on the second brightness center of gravity corresponding to the brightness correction value for which the distance has been determined. And a second three-dimensional detection unit 143 for obtaining a position on X, Y of 5h.

According to the three-dimensional measuring apparatus 101, the function / effect of the first embodiment is provided, and the luminance offset detecting unit 34 that detects the luminance offset from a certain region of the image is provided, and the constant is centered on the bright point of the image. The luminance of each region is detected, a second luminance distribution obtained by removing the luminance offset from the luminance distribution for each X-axis and Y-axis in the fixed region is obtained, and the second luminance centroid is calculated based on the second luminance distribution. Since the pixel 14a is not easily affected by the luminance detected by the reflection from the metal particle 5h, the second luminance center of gravity calculation unit 136 for obtaining the value is provided. Therefore, the second luminance based on the luminance correction value obtained for the distance is used. The barycentric value of the brightness of is exactly overlapped with the position of the metal particle 5h on the XY plane.
Accordingly, the three-dimensional measurement apparatus 101 obtains the second luminance centroid value based only on the luminance change value obtained by removing the luminance offset from the luminance near the bright point, and determines the position of the bright point by the second luminance centroid value. Since the detection is performed, the position of the bright point on the XY plane can be accurately detected without being affected by the reflection of the metal particles 5h. Therefore, the detection accuracy of the position of the metal particle 5h is improved.
Further, the second luminance correction value corrected based on the second luminance centroid value is obtained, and the distance of the metal particles 5h is detected based on the second luminance correction value. Detection accuracy is further improved.

In the three-dimensional measurement method of the above embodiment, the bright points P1, P2,... Of the images G1, G2,... Gn captured by the imaging system 10 at different distances between the object 5 and the imaging system 10. After detecting Pn, after performing a luminance offset detection process for detecting a luminance offset from a certain region centered on the bright point from the images G1, G2,... Gn, the bright point of the images G1, G2,. P1, P2,..., Pn are detected for each constant region, and the first luminance distribution for each X-axis and Y-axis in the fixed region is obtained, and the luminance offset is calculated from the first luminance distribution. A second luminance centroid value is obtained based on the subtracted second luminance distribution. Thereafter, the distance value with the metal particle 5h is obtained based on the brightness correction value, and the positions of the metal particles 5h on X and Y are determined based on the second brightness centroid value based on the brightness correction value obtained from the distance. Detect.
Thereby, in the three-dimensional measurement apparatus 101, since the position of the bright point is detected based only on the luminance change value obtained by removing the luminance offset from the luminance near the bright point, it is not affected by the reflection of the metal particles 5h, etc. It can be detected accurately. Therefore, the detection accuracy of the distance and position of the metal particles 5h is improved.

Embodiment 3 FIG.
In the first and second embodiments, the first (second) three-dimensional detector 30 (130) obtains the distance value from the metal particle 5h based on the first (second) luminance correction value, and Although the position on the X and Y of the metal particle 5h is detected based on the first (second) luminance center-of-gravity value, it may be as follows.
The three-dimensional measurement apparatus according to the present embodiment includes a bright point extraction unit 32, a first luminance centroid calculation unit 36, a luminance offset detection unit 34, a second luminance centroid calculation unit 136, and a first luminance. A correction unit 43 and a third three-dimensional detector are provided.
The third three-dimensional detector obtains a distance value with respect to the metal particle 5h based on the first brightness correction value, and based on the second brightness centroid value corresponding to the distance value, X, A position on Y may be detected. As a result, the luminance offset is taken into account for detecting the position of the metal particle 5h without taking the luminance offset into consideration when obtaining the distance value with the metal particle 5h. Therefore, the detection accuracy of the position of the metal particle 5h is further improved.

The three-dimensional measurement apparatus according to another embodiment includes a bright point extraction unit 32, a first luminance centroid calculation unit 36, a luminance offset three-dimensional detection unit 34, and a second luminance centroid calculation unit 136. , A first luminance correction unit 43 and a fourth three-dimensional detector.
In place of the third three-dimensional detector, a fourth three-dimensional detector is provided, and the fourth three-dimensional detector obtains a distance value from the metal particle 5h based on the second luminance correction value, The positions on the X and Y of the metal particles 5h may be detected based on the first luminance centroid value corresponding to the distance value. As a result, the luminance offset is taken into account for obtaining the distance value with respect to the metal particle 5h, and the luminance offset is not taken into account for detecting the position of the object 5. Therefore, the detection accuracy of the distance of the metal particles 5h is further improved.

The present invention can be applied to a three-dimensional measuring apparatus.

The present invention is not limited to the description of the embodiment of the above invention. Various modifications are also included in the present invention as long as those skilled in the art can easily conceive without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1,101 Three-dimensional measuring apparatus, 5 Resin plate, 5h Metal particle (object), 10 Imaging system, 32 Bright point extraction part, 34 Luminance offset detection part, 36 1st luminance gravity center calculation part, 38 1st 1 luminance correction unit, 41 luminance interpolation unit, 43 first three-dimensional detection unit, 136 second luminance gravity center calculation unit, 138 second luminance correction unit, 143 second three-dimensional detection unit.

Claims (6)

1. Imaging means for imaging an object by an imaging device having pixels;
   The target object is extracted in units of pixels when the brightness detected by each image captured by the image capturing means at a different distance between the target object and the image capturing means is a predetermined brightness or more. Bright spot extraction means;
   Including the pixel having the bright point, the brightness of each constant area formed by the pixels around the pixel is detected, and the brightness distribution for each of the X axis and Y axis in the constant area is obtained, and based on the brightness distribution Means for calculating a luminance centroid to obtain a first luminance centroid value;
   A luminance correction means for obtaining a luminance correction value obtained by correcting the luminance of the pixel in which the luminance centroid value is detected and the luminance detected by pixels surrounding the pixel to the luminance of the luminance centroid value;
   A three-dimensional detection means for obtaining a distance value to the object based on the luminance correction value and detecting a position on the X, Y of the object based on the luminance centroid value;
   A three-dimensional measuring device comprising:
2. A luminance offset detecting means for detecting a luminance offset from the certain area of the image;
   The luminance centroid calculating means obtains a new luminance distribution obtained by removing the luminance offset from the luminance distribution, instead of obtaining the first luminance centroid value, and generates a second luminance based on the new luminance distribution. Find the center of gravity value,
   The three-dimensional measuring apparatus according to claim 1.
3. A luminance offset detecting means for detecting a luminance offset from the certain area of the image;
   A second luminance centroid calculating means for obtaining a new luminance distribution obtained by removing the luminance offset from the luminance distribution and obtaining a second luminance centroid value based on the new luminance distribution,
   The three-dimensional measuring apparatus according to claim 1, comprising:
4. A luminance interpolation means for interpolating a plurality of luminance correction values with a predetermined function to obtain a luminance interpolation value,
   The three-dimensional detection means obtains a distance value to the object based on the luminance interpolation value.
   The three-dimensional measuring apparatus according to any one of claims 1 to 3, wherein
5. After performing a bright spot extraction step of detecting a bright spot of each image captured by the imaging means at different distances between the object and the imaging means,
   Luminance centroid calculation step of detecting the luminance for each constant region including the bright point of the image, obtaining the luminance distribution for each X-axis and Y-axis in the fixed region, and obtaining the luminance centroid value based on the luminance distribution After running
   After obtaining the luminance correction value obtained by correcting the luminance of the pixel in which the luminance centroid value is detected and the luminance detected by the pixels around the pixel to the luminance of the luminance centroid value,
   Obtaining a distance value with respect to the object based on the correction value of the luminance, and detecting a position on the X and Y of the object based on the luminance gravity value;
   A three-dimensional measurement method characterized by this.
6. After performing the light spot extraction step, after performing a brightness offset detection step of detecting a brightness offset from a certain region including the light point of the image,
   In the luminance centroid calculation step, a new luminance distribution is obtained for each of the X axis and Y axis in the fixed region obtained by removing the luminance offset from the luminance distribution, and a luminance centroid value is obtained based on the new luminance distribution. ,
   The three-dimensional measurement method according to claim 5.

Images