JP2004117235A - 3-dimensional form measuring method and 3-dimensional form measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring method and apparatus which can measure a correct distance when an outdoor day light exists, and can measure the whole part independently of monochrome contrast of an object to be measures and distance from illumination, and improves instrumentation resolution. <P>SOLUTION: An object to be measured is irradiated with an airlight from a certain distance and photographed, thereby obtaining an image 1. The object is irradiated with an airlight from a different distance, thereby obtaining an image 2. Illumination is not used or light intensity is changed, thereby obtaining an image 3. Intensity values recorded on pixels of same position of the image 1, image 2 and image 3 are calculated. This process is applied to all pixels, and a 3-dimensional form of the object is obtained. About regions where the intensity value is larger or smaller than a prescribed value, measurement is again performed by changing the amount of airlight. Three or more portions of the object are irradiated with mutually changed airlight. An image is photographed for every irradiation, and photographing is performed from image 1 to image N. An image N+1 is obtained without illumination. Intensity values recorded on pixels of same coordinate value of the image 1 to the image N+1 are calculated. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a method and an apparatus for measuring a three-dimensional shape or a three-dimensional shape and color of an object to be measured, and is mainly used in the fields of the measurement industry, the communication industry, and the video industry.
[0002]
[Prior art]
Various measurement methods for acquiring a three-dimensional shape of an object to be measured using a camera have been proposed. These methods can be classified into a passive measurement method, which does not irradiate a special illumination to the object to be measured, represented by a stereo method, and an active measurement method, which irradiates a special illumination to the object to be measured.
[0003]
The passive measurement method is very low cost and versatile because it can be performed with two cameras, and has been studied vigorously for a long time. However, the measurement reliability is still low and it has reached the practical stage as a versatile method. Not in.
[0004]
On the other hand, the measurement accuracy, resolution, and measurement reliability of the active measurement method have reached practical levels, and moving image measurement has become possible in recent years. However, there is a problem that the apparatus is generally large and expensive, and it is difficult to reduce the apparatus to a size that can be portable.
[0005]
In some cases, the measurement accuracy and resolution may be low depending on the application. However, the conventional active measurement method cannot efficiently reduce the price and size of the apparatus even if these specifications are reduced.
[0006]
On the other hand, there is a device that obtains a distance by irradiating an object to be measured with diffused light from different distances and photographing the object, and calculating a ratio of luminance values of the images (Patent Document 1).
FIG. 1 shows the configuration of this device. 11 is a distant light source, 12 is a near light source, 13 is an object to be measured, and 14 is a camera. Although this device is not very high in measurement accuracy and resolution, it can basically be constructed simply by preparing two light sources and a camera. Can be used.
[0007]
The operation principle of this device will be described by using mathematical expressions.
The distance between the distant light source 11 and the object 13 to be measured is x, and the light amounts of the distant light source 11 and the near light source 12 are L. If the relative intensity ratio between 11 and 12 is known, the light amounts may be different.) And the luminance V1 of a certain point on the measured object 13 illuminated by the distant light source 11 is the distant light source 11 And k is the reflectivity of reflecting the irradiation light from the light source 12 in the vicinity toward the camera.
(Equation 1) V1 = kL / 4πx²
The image is shot at a brightness of. Assuming that the near light source 12 is closer to the measured object 13 by a distance x0 than the far light source 11, the brightness V2 of the point illuminated by the near light source 12 is:
(Equation 2) V2 = kL / 4π (x−x0)²
The image is shot at a brightness of. By taking the ratio of Equation 1 and Equation 2, the distance x becomes
(Equation 3) x = x0 / {1-{(V1 / V2)}}
Is obtained as
[0008]
Although Patent Document 1 does not specify whether the measurement is a distance measurement of one point or the measurement of the entire three-dimensional shape, an invention explicitly showing the three-dimensional shape measurement with the same measurement principle is described in the claim of Patent Document 2. Has been described. Further, the same invention as in Patent Document 2 changes the expression of the mathematical expression, and claims 1 and 2 of Patent Document 3, Claim 1 of Patent Document 4, Claim 1 of Patent Document 5, and Claim 1 of Patent Document 6. It is described in.
[0009]
[Patent Document 1]
JP-A-61-155909
[Patent Document 2]
Japanese Patent Publication No. 6-0768888
[Patent Document 3]
JP-A-2002-077944
[Patent Document 4]
JP-A-2002-065581
[Patent Document 5]
JP-A-2002-095625
[Patent Document 6]
JP 2002-065585 A
[0010]
[Problems to be solved by the invention]
However, this conventional measuring method has the following problems.
1. If external light is present, the correct distance cannot be obtained.
In the case where external light exists, assuming that the external light amount is La and the reflectance for reflecting the external light in the direction of the photographing camera is k ′, Expressions 1 and 2 are replaced by Expressions 4 and 5 below.
(Equation 4) V1 = k'La + kL / 4πx²
(Equation 5) V2 = k′La + kL / 4π (x−x0)²
Even if the ratios of these equations are taken, the distances x 'cannot be obtained because the unknown quantities k' and La remain. Therefore, the conventional measuring method can operate only in an environment without external light such as a dark room or an endoscope. It is a first object of the present invention to provide a measuring method and an apparatus capable of measuring a correct distance even when external light is present.
[0011]
2. It is difficult to simultaneously measure a black region or a region far from the illumination and a white region or a region near the illumination of the measured object.
When the light amount is increased so that the black (low reflectance) area of the measured object or the area far from the illumination can be measured, the brightness of the white (high reflectance) area of the measured object or the area near the illumination overflows and the image is captured. become unable. On the other hand, if the amount of light is reduced to avoid overflow, the luminance of a black area of the measured object or an area far from the illumination becomes extremely small. In this measurement method, the distance is calculated using a slight difference between the luminance values V1 and V2. Therefore, if the value of V1 or V2 itself is small, the difference becomes less than the luminance gradation that can be photographed by the TV camera, and the measurement becomes impossible. Problems occur. This unmeasurable state is called an underflow here. It is a second object of the present invention to provide a measuring method and apparatus capable of measuring the whole of an object to be measured irrespective of black and white shading of the object to be measured and distance from illumination.
[0012]
3. Poor measurement resolution.
The captured image has a wide range of luminance distribution due to the difference in reflectance on the measured object and the distance from illumination. In comparison, the difference between V1 and V2 is only a small value. For example, if the difference between V1 and V2 is only a few gradations, the measurement resolution is also only a few gradations. In this case, only rough distance information enough to know the position of the object can be obtained. It is a third object of the present invention to provide a measurement method and an apparatus with improved measurement resolution.
[0013]
[Means for Solving the Problems]
In order to solve the problem 1, the method according to the first aspect of the present invention performs processing in steps shown in FIG. In a first step 21, the object to be measured is irradiated with diffused light from a certain distance, and an image 1 is obtained by photographing and recording the object to be measured. In a second step 22, a distance closer by x0 than the first step is obtained. The object 2 is irradiated with diffused light from the object, and the image 2 is obtained by photographing and recording the object to be measured. In the third step 23, no illumination or the first step 21 or the second step 22 is performed. The object 3 is irradiated by changing the amount of diffused light from the distance, and the object 3 is photographed and recorded to obtain the image 3. In the fourth step 24, the same position of the image 1, the image 2, and the image 3 is obtained. By calculating the luminance value recorded in the pixel of, the distance to the object to be measured reflected in the pixel is calculated, and in the fifth step 25, the processing of the fourth step is performed on all the pixels. Obtaining the three-dimensional shape of the measurement subject by Ukoto.
[0014]
The operation performed for each step will be described. In a first step 21, an image 1 is obtained by irradiating diffuse light to a measured object from a certain distance, and photographing and recording the measured object. At this time, the luminance V1 at a certain point on the measured object is L, the intensity of the diffused light is L, the distance between the point and the illuminating means is x, the reflectance for reflecting the illuminating light in the direction of the photographing means is k, Assuming that the light amount is La and the reflectivity for reflecting external light in the direction of the photographing means is k ′,
(Equation 4) V1 = k'La + kL / 4πx²
An image is taken at a luminance value of
[0015]
Next, in a second step 22, diffused light is irradiated on the measured object from a distance closer to the distance x0 than in the first step 21, and the measured object is photographed and recorded to obtain the image 2. At this time, the brightness V2 of the point on the measured object is
(Equation 5) V2 = k′La + kL / 4π (x−x0)²
An image is taken at a luminance value of
[0016]
Next, in a third step 23, the object to be measured is illuminated without illumination, or the amount of diffused light is changed from the distance in the first step 21 or the second step 22, and the object to be measured is photographed and recorded. Thus, an image 3 is obtained. If there is no illumination here, the luminance V3 at the same position in the measured object illuminated by the light source is
(Equation 6) V3 = k′La
And irradiating the amount of diffused light at 1 / n times from the position of the first step 21,
(Equation 61) V3 = k′La + kL / 4nπx²
And irradiating the amount of diffused light at 1 / n times from the position of the second step 22,
(Equation 62) V3 = k′La + kL / 4nπ (x−x0)²
Becomes
[0017]
Next, in a fourth step 24, the distance of the measured object shown in the pixel is calculated by calculating the luminance value recorded in the pixel at the same position in the image 1, the image 2 and the image 3. For example, in the case where the image 3 is an image taken without lighting, by simultaneously combining Expressions 4, 5, and 6,
(Equation 7) x = x0 / [1-{(V1-V3) / (V2-V3)}]
Calculates the distance x.
[0018]
It should be noted that x can be calculated as long as n is known, even if Equations 61 and 62 are used instead of Equation 6. When there is external light but the amount of light is smaller than that of the illumination light, the method of Expressions 61 and 62 for auxiliary illumination is advantageous in increasing the measurement accuracy.
[0019]
Finally, in a fifth step 25, the three-dimensional shape of the measured object shown in the image is calculated by applying the pixel calculation processing of the fourth step 24 to the entire image.
[0020]
According to a second aspect of the present invention, there is provided an apparatus having illumination means for irradiating diffused light from different distances, means for photographing an object to be measured, image data recording means, and image data calculation means. Work according to the method.
[0021]
First, the first step 21, the second step 22, and the third step 23 are executed using illumination means for irradiating diffused light from different distances and means for photographing an object to be measured, and the captured image data Is recorded using recording means. Next, the fourth step 24 and the fifth step 25 are executed using the image data calculation means.
[0022]
By using the method according to claim 1 and the device according to claim 2, shape measurement can be performed even under conditions where external light is present, and thus problem 1 can be solved.
[0023]
In order to solve the problem 2, the method according to claim 3 of the present invention performs the following steps. In the sixth step, a sufficiently strong (weak) amount of diffused light is irradiated, and the three-dimensional shape of the measured object is measured by the method of claim 1. In the seventh step, the amount of light is reduced (increased) in an area where the luminance value overflowed (underflow) and could not be measured in the image acquired in the sixth step, and the sixth step is executed again. Re-measure the area that could not be measured. In the eighth step, the seventh step is repeated until there is no unmeasurable region or a predetermined number of repetitions is reached.
[0024]
The operation performed in each step will be described with an example in which measurement is started from a sufficiently strong light amount and the light amount is gradually decreased. First, in the sixth step, a sufficiently strong amount of diffused light is irradiated, and the three-dimensional shape of the measured object is measured by the method of claim 1. Then, as shown in FIG. 3A, an area 35 in which the luminance of a white area or an area close to the illumination of the measured object overflows in photographing and cannot be measured has occurred.
[0025]
Next, in a seventh step, the light amount is reduced, and the sixth step is repeated. Then, as shown in FIG. 3B, a part of the area which could not be measured due to the previous overflow can be measured again. On the other hand, an area 36 that cannot be measured due to underflow occurs in a black area of the measured object or an area far from the illumination, but this area has already been measured in the previous measurement. In the eighth step, the seventh step is repeated until there is no unmeasurable region or a predetermined number of repetitions is reached. Then, as shown in FIG. 3 (C), all the areas where the overflow has occurred can be re-measured, and all the measured areas from FIGS. 3 (A) to 3 (C) can be measured together. become.
When starting from a sufficiently weak light amount, the measurement starts from FIG. 3 (C) and ends the measurement in FIG. 3 (A).
[0026]
The apparatus according to claim 4 of the present invention includes an illuminating unit that irradiates diffused light from different distances with variable light amounts, a unit that captures an object to be measured, a recording unit for image data, and a computing unit for image data. It operates according to the method of claim 3.
[0027]
First, the sixth step is executed by using an illuminating unit that changes the amount of light and irradiates diffused light from different distances and a unit that captures an image of an object to be measured, and records a measurement result only in a region where measurement was possible. Next, the seventh step is executed to additionally record the measurement result for the newly measurable area. Then, the three-dimensional shape of the object to be measured is obtained by repeating the seventh step until there is no unmeasurable region or a predetermined number of repetitions is reached.
[0028]
By using the method of the third aspect or the apparatus of the fourth aspect, the entire three-dimensional shape of the object to be measured can be measured irrespective of the black and white shading of the object or the distance from the illumination, so that the problem 2 can be solved.
[0029]
In order to solve the problem 3, the method according to claim 5 of the present invention performs the following steps. In the first step, the object to be measured is irradiated with diffused light from a distance obtained by gradually changing the distance to the object to be measured N times, and an image of the object to be measured is photographed and recorded for each irradiation, whereby N sheets are obtained. Images 1 to N are acquired. In the second step, an image N + 1 is obtained by photographing and recording an object to be measured without illumination. In the third step, the distance of the measured object shown in the pixel from the image 1 to the image N + 1 is calculated by calculating the luminance value recorded in the pixel at the same position.
[0030]
As an example, a method of calculating a distance by combining the method of claim 1 will be described. In order to calculate the distance by using the method of claim 1, two images and an image N + 1 photographed by diffused lights having different distances are required, so that, for example, photographing of N = 4 (image 1 to image 4) is performed. If performed, a set of image 1 and image 2, image 2 and image 3, image 3 and image 4, image 1 and image 3, image 2 and image 4, image 1 and image 4, and image 5 (N + 1) By calculating with, six distances can be calculated. The average of these values is used as the final distance. In the fourth step, the three-dimensional shape of the measured object is calculated by performing the third step on all pixels.
[0031]
The operation of claim 5 will be described. FIG. 4 is a diagram showing a graph representing a relationship between an actual distance and a distance obtained as a result of measurement for each combination of images. When images 4 are obtained from four images 1 by irradiating diffused light from four distances x1, x2, x3, x4 (where x1> x2> x3> x4), a graph obtained by combining these images is obtained. 45 to 410. Originally, graphs should ideally be diagonal lines, but all graphs have stepwise broken lines due to poor resolution. However, when the average value of these graphs is calculated, 411 is obtained, and it can be seen that the stairs become finer, that is, the measurement resolution is improved and approaches the oblique line.
[0032]
The apparatus according to claim 6 of the present invention has illumination means for irradiating diffused light from at least three or more different distances, means for photographing an object to be measured, means for recording image data, and means for calculating image data. , According to the method of claim 5.
[0033]
The operation of the device according to claim 6 will be described. The first step and the second step are executed by using illumination means for irradiating diffused light from at least three or more different distances, means for photographing an object to be measured, and means for recording image data. Next, the third step and the fourth step are executed by using image data calculation means.
[0034]
By using the method of claim 5 or the device of claim 6, a measuring method and device with improved measurement resolution can be realized, and the problem 3 can be solved.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
One embodiment of the method of the present invention and the apparatus of the present invention will be described with reference to FIGS. FIG. 5 is a block diagram of the device of the second embodiment, and FIG. 6 is a flowchart of the method of the first embodiment performed by using the device of FIG. In FIG. 5, reference numeral 51 denotes a light for irradiating diffused light from a distance, 52 denotes a light for irradiating diffused light from this side, 53 denotes an object to be measured, and 54 denotes a photographing camera. In this embodiment, image data is output as digital data. Use a camera to Reference numeral 55 denotes a storage memory for image data, 56 denotes an arithmetic unit for an image, 57 denotes a storage memory for shape data, and 58 denotes an overall control device. Incidentally, 55 to 58 may be constituted by personal computers or workstations, CPUs may be used for 56 and 58, and 55 and 57 may be used by dividing a storage area such as a memory or a magnetic recording medium.
[0036]
The operation of executing the method of claim 1 using the device of claim 2 will be described with reference to the flowchart of FIG. In step 61, the control device 58 turns on the distant light 51, stores the image data 1 obtained by causing the photographing camera 54 to photograph the measured object 53 in the image memory 55, and then turns off the distant light 51. In step 62, the control device 58 turns on the front light 52, stores the image data 2 obtained by causing the photographing camera 54 to photograph the measured object 53 in the image memory 55, and then turns off the front light 52. In step 63, the image data 3 obtained by causing the photographing camera 54 to photograph the measured object 53 is stored in the image memory 55. In step 64, the control device 58 gives the coordinate value (i, j) to the image calculator 56, and instructs calculation of distance data from the luminance value of the pixel having the coordinate value. In step 65, the image calculator 56 extracts the luminance value of the pixel having the coordinate value (i, j) from the image 1, the image 2, and the image 3. These luminance values are denoted by V1, V2, and V3, respectively. In step 66, the image calculator 56 calculates the distance data x (i, j) at the coordinate value (i, j) by performing the calculation represented by the following equation, and stores the distance data x (i, j) in the shape data memory 57.
(Equation 8) x (i, j) = x0 / [1-{(V1-V3) / (V2-V3)}]
[0037]
It is assumed that the distance x0 between the far light 51 and the near light 52 is known and given to the image calculator 56 in advance. In step 67, the control device 58 determines whether the calculation processing has been completed for all the coordinates of the image, and ends if the calculation processing has been performed. Otherwise, the uncalculated coordinate value (i, j) is determined in step 68, and the process returns to step 64. The image is sequentially scanned from the upper left to determine the coordinate value (i, j), and the arrival at the lower right coordinate value is used as a determination condition of the end. It goes without saying that the determination can be realized.
[0038]
One embodiment of the method of the present invention and the apparatus of the present invention will be described with reference to FIGS. FIG. 7 is a block diagram of the apparatus according to claim 4, and FIG. 8 is a flowchart of a method according to claim 3 performed using the apparatus of FIG. 7, reference numeral 71 denotes a distant light for irradiating a specified amount of diffused light, 72 denotes a light in front of irradiating a specified amount of diffused light, 73 denotes an object to be measured, and 74 denotes a photographing camera. In the embodiment, a camera that outputs image data as digital data is used. 75 is an image data storage memory, 76 is an image arithmetic unit, 77 is shape data storage memory, 78 is an overall control device, and 79 is measured flag data storage memory. Incidentally, 75 to 79 may be constituted by a personal computer or a workstation, CPUs may be used for 76 and 78, and 75, 77 and 79 may be used by dividing a storage area such as a memory or a magnetic recording medium.
[0039]
Further, instead of controlling the light amounts of the distant light 71 and the near light 72, the same operation as controlling the light amount may be performed by controlling the shutter release time of the photographing camera 74.
[0040]
The operation of executing the method of claim 3 using the device of claim 4 will be described with reference to the flowchart of FIG. In step 81, an initial illumination intensity L is set. L is set to a sufficiently large value when the measurement is performed while gradually decreasing the illumination intensity, and L is set to a sufficiently small value when the measurement is performed while the illumination intensity is gradually increased. Next, all the measured flags F provided for all the pixels of the image stored in the shape data memory 77 are reset to zero. In step 82, the control device 78 turns on the distant light 71 after turning on the distant light 71 at the intensity L and storing the image data 1 obtained by causing the photographing camera 74 to photograph the object 73 to be measured in the image memory 75. Turn off the light. In step 83, the control device 78 turns on the front light 72 at the intensity L, stores the image data 2 obtained by causing the photographing camera 74 to photograph the object 73 to be measured in the image memory 75, and then turns on the front light 72. Turn off the light. In step 84, the image data 3 obtained by causing the photographing camera 74 to photograph the measured object 73 is stored in the image memory 75. In step 85, the control device 78 sequentially reads out all the flags stored in the measured flag storage memory 79 for each pixel, and if F = 0 of the coordinate value (i, j), the coordinate value (i, j) is displayed in the image. It is given to the arithmetic unit 76 to instruct the calculation of the distance data of the pixel having the coordinate value. Since the initial state is all flags F = 0, step 85 to be executed first instructs all pixels. In step 86, the image calculator 76 extracts the luminance value of the pixel having the coordinate value (i, j) from the image 1, the image 2, and the image 3. These luminance values are denoted by V1, V2, and V3, respectively. In step 87, it is checked whether an overflow or underflow condition exists. When V1> Vmax or V2> Vmax with respect to a preset maximum luminance value Vmax, it is regarded as an overflow, and when Vmin> | V1-V2 | with respect to a preset Vmin, it is regarded as an underflow. In either state, the image calculator 76 does not perform the process of step 88. If neither state exists, it is considered that measurement is possible, and the routine proceeds to step 88. In step 88, the image calculator 76 calculates the distance data x (i, j) at the coordinate value (i, j) by performing the calculation represented by the following equation, stores the distance data x (i, j) in 77, and stores the coordinate value (i, j) Is set to 1.
(Equation 8) x (i, j) = x0 / [1-{(V1-V3) / (V2-V3)}]
[0041]
It is assumed that the distance x0 between the far light 71 and the near light 72 is known and given to the image calculator 76 in advance. In step 89, the control device 78 checks all the flags in the measured flag storage memory 79, and ends if all the flags F = 1. Otherwise, steps 810 to 82 to 88 are repeated and repeated, but also ends when the number of repetitions has exceeded a certain value. In step 810, L is decreased when the measurement is performed while the illumination intensity is gradually reduced, and L is increased when the measurement is performed while the illumination intensity is gradually increased, and the process returns to step 82.
[0042]
In the present embodiment, the distance of any pixel is obtained by one measurement, but actually, it may be measured several times. Therefore, when the measurement can be performed, the distance may be calculated and written in the shape data memory 77, and an average or a weighted average of the distances measured a plurality of times after the measurement is completed may be used as a final distance. In this case, although the calculation cost increases, there is an advantage that the SN ratio of the measurement data can be improved. In the present embodiment, an example has been described in which measurement is performed while the illumination intensity is monotonously reduced or increased. However, in the method of the present invention, the illumination intensity need only be set to be different from each other in each photographing, and does not necessarily need to be changed monotonically.
[0043]
One embodiment of the method according to claim 5 and the apparatus according to claim 6 will be described with reference to FIGS. 9 and 10. FIG. 9 is a block diagram of the apparatus of claim 6, and FIG. 10 is a flowchart of a method of claim 5 performed using the apparatus of FIG. 9, reference numeral 91 denotes a light for irradiating diffused light; 92, a moving device for changing the distance of the light; 93, an object to be measured; and 94, a photographing camera. In this embodiment, a camera for outputting image data as digital data is used. use. Reference numeral 95 denotes a memory for storing image data corresponding to the number of times of image capturing, 96 denotes an image calculator, 97 denotes a memory for storing shape data for a plurality of images, 98 denotes an overall control device, and 99 denotes a memory for storing final shape data. Note that 95 to 99 may be constituted by personal computers or workstations, CPUs may be used for 96 and 98, and 95, 97 and 99 may be used by dividing storage areas such as memories or magnetic recording media. Instead of combining 91 and 92, a plurality of lights may be prepared at different distances and used by switching.
[0044]
The operation of executing the method of claim 5 using the apparatus of FIG. 9 will be described with reference to the flowchart of FIG. In step 101, the control device 98 instructs the moving device 92 to move the light 91 to a predetermined position, turns on the light 91 in step 102, and causes the photographing camera 94 to photograph the object 93 to be measured. After the stored image data is stored in the image memory 95, the light 91 is turned off. In step 103, steps 101 and 102 are repeated a predetermined number of times N. It should be noted that the light 91 is moved so that the distance from the measured object 93 becomes smaller at each repetition. In step 104, image data obtained by causing the photographing camera 94 to photograph the measured object 93 is stored in the image memory 95. In step 105, the control device 98 gives the image data i and the image data j (i ≠ j) to be used for calculating the shape data to the image calculator 96 to instruct the calculation of the shape data. In step 106, the image calculator 96 extracts the image data i, the image data j, and the image data N + 1 from the image memory 95, calculates three-dimensional shape data based on the method of claim 1, and stores it in the shape data memory 97. Note that a region that cannot be measured due to overflow or underflow is marked as unmeasurable. This can be easily realized in the area by writing 0 or a negative number in the distance. In step 107, control device 98 repeats steps 105 and 106 M times. It should be noted that i and j given to the image computing unit 96 are changed each time it is repeated. For example, when N images captured under illumination are obtained, the combinations of i and j are N (N-1) / 2 at the maximum, so if all the combinations are executed, M = (N-1) ) / 2. However, it is not always necessary to calculate all combinations. In step 108, the average value of the shape data M is obtained from the shape data 1, and the final shape data is written in the final shape data memory 99. When calculating the average of the distance for each pixel, if a pixel that cannot be measured is included, the average is calculated excluding the pixel.
[0045]
In this embodiment, the method according to claim 1 is used, but the method according to claim 3 can be used to remove an unmeasurable region.
In particular, since underflow is easily generated when the difference in illumination distance is small, shape data may be obtained by excluding all combinations of photographing data having small distance differences. In addition, since the shape data calculated using an image having a large distance difference has less influence of noise, a weighted average weighted according to the distance difference may be used in step 108 instead of a simple average.
[0046]
As described above, the invention made by the inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and can be variously modified without departing from the gist of the invention. Of course.
[0047]
【The invention's effect】
By using the method according to claim 1 and the device according to claim 2, shape measurement can be performed even under conditions where external light exists.
By using the method according to the third aspect or the apparatus according to the fourth aspect, it is possible to measure the entire three-dimensional shape of the object to be measured irrespective of the density of black and white or the distance from illumination.
By using the method of claim 5 or the device of claim 6, a measurement method and device with improved measurement resolution can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a conventional device.
FIG. 2 shows a method according to claim 1 of the present invention.
FIG. 3 is a diagram showing occurrence of an overflow area and an underflow area.
FIG. 4 is a graph showing a correspondence between an actual distance and a measured distance.
FIG. 5 is a block diagram of an embodiment of the apparatus according to claim 2 of the present invention.
FIG. 6 is a flow chart of an embodiment of the method of claim 1 of the present invention.
FIG. 7 is a block diagram of an embodiment of the apparatus according to claim 4 of the present invention.
FIG. 8 is a flowchart of an embodiment of the method according to claim 3 of the present invention.
FIG. 9 is a block diagram of an embodiment of the apparatus according to claim 6 of the present invention.
FIG. 10 is a flowchart of an embodiment of the method according to claim 5 of the present invention.
[Explanation of symbols]
11: distant light source, 12: near light source, 13: measured object, 14: camera, 35: area that could not be measured due to overflow, 36: area that could not be measured due to underflow, 45 to 411: actual A graph showing the relationship between the distance and the distance obtained as a result of the measurement, 51, 71: far lights, 52, 72: front lights, 53, 73, 93: measured object, 54, 74, 94: photographing camera ..., 55, 75, 95 ... image memory, 56, 76, 96 ... image calculator, 57, 77, 97 ... shape data memory, 58, 78, 98 ... controller, 79 ... measured flag storage memory, 91 ... write , 92: moving device, 99: final shape data memory

Claims (6)

A first step of irradiating the object to be measured with diffused light from a certain distance, photographing and recording the object to be measured, and acquiring an image 1;
A second step of irradiating the object to be measured with diffused light from a distance different from that of the first step, and capturing and recording the object to be measured to obtain an image 2;
Irradiating the object to be measured with no light or changing the amount of diffused light from the distance of the first step or the second step, and photographing and recording the object to obtain the third image 3 Steps and
A fourth step of calculating a distance to an object to be measured in the pixel by calculating a luminance value recorded at a pixel at the same position in the image 1, the image 2, and the image 3; A method for measuring a three-dimensional shape, comprising: a fifth step of obtaining a three-dimensional shape of an object to be measured by performing the process on all pixels. An illumination unit for irradiating diffused light from different distances, a unit for photographing an object to be measured, a unit for recording image data, and a unit for calculating image data, and are operated by the method according to claim 1. 3D shape measuring device. A sixth step of measuring the three-dimensional shape of the object to be measured by the method according to claim 1 using a certain amount of diffused light; For a region that is larger than the value or the absolute value of the difference in luminance value between pixels at the same position in the image 1 and the image 2 is smaller than a predetermined value, the sixth step is executed again by changing the amount of diffused light. A seventh step of re-measurement by
The method of measuring a three-dimensional shape according to claim 8, further comprising an eighth step of repeating the seventh step until the region disappears or a predetermined number of repetitions is reached. An illumination unit that changes the amount of light and emits diffused light from different distances, a unit that captures an image of the object to be measured illuminated by the illumination unit, an image data recording unit, and an image data calculation unit. 3. A three-dimensional shape measuring apparatus which operates by the method according to 3. By irradiating the object to be measured with diffused light whose distance to the object to be measured is changed at least three places or more, and taking images of the object to be measured for each irradiation, N images 1 to N are taken, A first step of recording;
A second step of acquiring an image N + 1 by photographing and recording an object to be measured without illumination;
A third step of calculating a distance of an object to be measured reflected on the pixel by calculating a luminance value recorded on a pixel having the same coordinate value of the image 1 from the image 1;
A method for measuring a three-dimensional shape, comprising: a fourth step of obtaining a three-dimensional shape of an object to be measured by performing a third step on all pixels. 6. An apparatus according to claim 5, comprising: irradiating means for irradiating diffused light from at least three or more different distances, means for photographing an object to be measured, means for recording image data, and means for calculating image data. A three-dimensional shape measuring apparatus.

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