JPH05340727A - Three-dimensional shape measuring instrument - Google Patents

Abstract

PURPOSE:To remarkably reduce data omission so as to extremely improve the three-dimensional shape measuring accuracy of the title instrument by ena bling the device to always obtain a stable input even when the luminance of reflected light from an object to be measured fluctuates due to its color or surface condition. CONSTITUTION:The title instrument is provided with a CCD camera 2A which has variable shutter speeds and picks up the image of the same part of an object 3 to be measured at different shutter speeds and a light spot detecting section 24 which selects the highest-luminance point among the highest-luminance points on the same scanning line in the plurality of images picked up by the camera 2A as a light spot and finds the coordinates of the light spot. In addition, the instrument is also provided with a transforming section 16 which transforms the found coordinates of the light spot into positional coordinates on the object 3. Therefore, the section 16 can always obtain a stable input even when the luminance of ref1.ected light from the object 3 fluctuates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention projects a spot light such as a laser beam or a slit light onto an object to be measured, and an optical image thereof is picked up by an image pickup section such as a CCD camera to obtain an object to be measured. The present invention relates to a three-dimensional shape measuring apparatus that obtains the position of and measures its shape in a non-contact manner.

[0002]

2. Description of the Related Art As a non-contact type three-dimensional shape measuring apparatus, a line sensor is used to project spot light such as a laser beam onto an object to be measured. Based on the principle of triangulation, by capturing the reflected light, or by the so-called light-section method, laser slit light is projected onto the measurement target and the slit light image is captured by a surface sensor such as a CCD camera. It is common to adopt a method of calculating the position and shape of the measurement object.

Among the conventional three-dimensional shape measuring devices as described above, a measuring device for projecting spot light sequentially measures a plurality of measuring points of an object to be measured one by one, whereas a measuring device for projecting slit light is used. Since it is possible to input and process multiple measurement points located on one slit light at once,
The accuracy is generally inferior to the spot light measurement, but the measurement speed is excellent.

By the way, in a measuring device using such reflected light, a threshold value (threshold level) with respect to an upper limit value or a lower limit value of an input signal is used for the purpose of accurately and smoothly removing noise and processing after input. ),
A method of inputting a signal level within that range as effective is generally adopted, but in this case, for example, because the brightness of the reflected light varies depending on the color and surface properties of the measurement target, such as glossiness, In some cases, only signal levels above the upper threshold value or below the lower threshold value can be obtained, and as a result, the input becomes unstable, and there is a drawback that the predetermined measurement accuracy deteriorates due to missing data.

As described above, in the conventional three-dimensional shape measuring apparatus utilizing reflected light, when the color of the object to be measured has a low brightness of reflected light from the surface, such as black, When the input signal is below the threshold value and the brightness of the reflected light from the surface of the measurement object is high, CC of the imaging unit
A phenomenon such as blooming occurs in the D camera, and in any case, a stable input cannot be obtained due to the color of the measurement object, the surface properties, or the like. Therefore, in order to obtain a predetermined shape measurement accuracy, it is necessary to perform a preliminary work such as coloring the surface of the object to be measured so that the brightness of the reflected light from the surface becomes constant.

The present invention has been made in view of the above circumstances, and a stable input can always be obtained and a predetermined measurement accuracy can be obtained irrespective of variations in the brightness of reflected light due to the color of the object to be measured or the surface properties. It is an object of the present invention to provide a three-dimensional shape measuring device capable of significantly improving

[0007]

In order to achieve the above object, a three-dimensional shape measuring apparatus according to claim 1 of the present invention comprises:
A light projecting unit that projects light onto the measurement target, an image capturing unit that captures the projected measurement target, and a light input amount control unit that controls the amount of light input to this image capturing unit. Is scanned to find the maximum luminance point for each scanning line, and one of the maximum luminance points within the predetermined luminance range obtained on the same scanning line of the plurality of camera screens is determined. As a light spot, it has a light spot detection unit that obtains the coordinates thereof and a conversion unit that transforms the obtained light spot coordinates into position coordinates on the measurement target.

A three-dimensional shape measuring apparatus according to a second aspect of the present invention includes a light projecting section for projecting light onto a measurement object, an imaging section for imaging the projected measurement object, and this imaging section. Light amount control unit for controlling the amount of light incident on the light, and light for determining the coordinates of the light spot on the light image on the n (where n is an integer of 2 or more) camera images in which the same portion is imaged with different light amounts. It has a point detection unit and a conversion unit that converts the obtained light point coordinates into position coordinates on the measurement object, and the light point detection unit is
Peak value detecting means for scanning the (n-1) th camera screen imaged with the (n-1) th subsequent light quantity to obtain the highest luminance point for each scanning line, and the obtained luminance of the highest luminance point within a predetermined range. When outside, the highest brightness point is obtained by scanning the nth order camera screen in which the same portion is imaged with an nth order light input amount different from the (n-1) th order light input amount, and a predetermined brightness in the (n-1) th order camera screen is obtained. Rewriting means for rewriting the highest luminance point having a luminance outside the range by the highest luminance point obtained on the n-th camera screen.

[0009]

According to the first aspect of the present invention, the same portion of the measuring object projected by the light projecting unit is imaged a plurality of times with different light incident amounts, and the plurality of imaged camera screens are scanned to perform each scanning. The maximum brightness point is calculated for each line, and the coordinates are calculated using any one of the maximum brightness points within the predetermined brightness range obtained on the same scanning line of a plurality of camera screens as the light point, and the calculated coordinates are further calculated. By converting the measured light spot coordinates into position coordinates on the measurement target, a stable input signal can be obtained even if the brightness of the reflected light varies due to the color or surface texture of the measurement target. As a result, it is possible to improve the predetermined shape measurement accuracy.

According to the second aspect of the present invention, a portion of the object to be measured is imaged with the (n-1) th order incident light quantity, and
-1) The maximum luminance point is obtained for each scanning line by scanning the next camera screen, and only when the luminance of the obtained maximum luminance point is outside the predetermined range, the n-th order that is different from the (n-1) th order incident light amount is obtained. The same portion of the measurement object is imaged with the amount of light incident, the maximum luminance point is obtained by scanning the nth order camera screen, and the maximum luminance point obtained on the (n-1) th order camera screen is written by the maximum luminance point. Change. Therefore, when the highest luminance point obtained by the imaging with the (n-1) th incident light amount is within the predetermined range, re-imaging with the nth incident light amount is not performed and the light spot coordinates are directly input to the conversion unit. Therefore, a stable input signal can be obtained as soon as possible, and the measurement speed can be improved.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a system configuration diagram of a three-dimensional shape measuring apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is a laser light source that constitutes a light projecting unit and rotates a polygon mirror (not shown). As a result, the slit light is projected onto the measuring object 3. Reference numeral 2 is an image pickup unit having a CCD camera 2A with a variable shutter speed for picking up a slit light image. Two units are installed to reduce a blind spot.
It may be a stand. Reference numeral 4 denotes a table on which the measuring object 3 is fixed and movable in the X direction.

Reference numeral 5 denotes a light source control unit which turns the laser light source 1 on.
N, OFF control. Reference numeral 6 is a light incident amount control unit for controlling the light incident amount on the image pickup unit 2 by switching the shutter speed of the CCD camera 2A, and 7 is a video input to which the video signal of the slit light image picked up by the CCD camera 2A is inputted. Reference numeral 8 denotes a drive system control unit that moves the table 4 by a unit movement amount in order to scan the measuring object 3 with slit light.

Reference numeral 9 denotes an A / D conversion unit, which is the video input unit 7 described above.
The video signal output from is binarized. Reference numeral 10 denotes a peak value detection unit, which uses each of the scanning lines of a plurality of camera screens with the highest luminance point within the predetermined luminance range of the video signal binarized by the A / D conversion unit 9 as a coordinate point on the camera coordinates. In order to improve the measurement accuracy, the true maximum luminance point is obtained using the camera pixel position (address) actually sampled as a peak value and the sampling values at both positions adjacent to it. .. This brightest point corresponds to the contour line (slit light image) of the measuring object 3. Reference numeral 11 denotes a sync signal generator, which comprises a sync separator 11A for separating a horizontal sync signal and a vertical sync signal from the video signal, and an image clock generator 11B for generating a sampling clock on each scanning line.

Reference numeral 12 denotes a first storage unit, which is an address of the first peak value obtained by the peak value detecting unit 10 and imaged with the primary incident light amount, that is, the incident light amount at the primary shutter speed and the brightness. Stores synthetic data. Reference numeral 13 denotes a second storage unit which combines the address and the luminance of the second peak value obtained by the peak detection unit 10 when the same portion of the measuring object 3 is imaged at a shutter speed different from the primary shutter speed. Store the data. Reference numeral 14 is a data selection unit, which is the first
Also, one of the two pieces of measurement data of the same portion stored in the second storage unit, the data for which the highest brightness point is obtained, is selected and transferred to the data generation unit 16 described later.

The peak value detecting section 10, the first and second storing sections 12 and 13, and the data selecting section 14 respectively pick up the same portion at different shutter speeds on the same scanning line of two camera screens. The light spot detection unit 24 is configured to find the coordinates of any one of the brightest spots within the obtained predetermined brightness range as a light spot.

An address generator 15 generates a Y-direction address based on the horizontal sync signal separated by the sync separator 11A of the sync signal generator 11 and uses the Y-direction address as the data generator 16. Output to. The data generation unit 16 includes a data selection unit 1 that constitutes the light spot detection unit.
The height (Z coordinate) on the object coordinates, which is the space in which the measuring object 3 is placed, is obtained from the luminance address transferred from 4, and the three-dimensional position coordinates (X, Y,
Z), which exists in the form of software, which functions on the personal computer 23 in this system.

FIG. 2 is a block diagram showing a detailed configuration of the peak value detecting section 10. In FIG. 2, reference numeral 17 is a threshold level setting section for setting a threshold level for obtaining a stable input value. In the present embodiment, as the upper threshold level, Vref1 =
150, Vref2 = 8 as the lower threshold level
1 is set.

Reference numerals 18 and 19 are digital converters, and one digital converter 18 is an A / D converter 9.
The binarized video signal obtained in step 1 is compared with the upper limit threshold level Vref1 and is output when the binarized video signal is smaller than the upper limit threshold level Vref1, and the other digital converter 19 outputs the binarized video signal. 2 is compared with the lower limit threshold level Vref2 described above and 2
Output when the binarized video signal is higher than the lower threshold level Vref2.

Reference numeral 20 denotes an AND circuit section, which outputs to the subsequent stage only when both the digital converters 18 and 19 output. Reference numeral 21 is a peak value calculation unit, which is the logical product circuit unit 2
When 0 is output, the binarized video signal obtained by the A / D converter 9 and the address on the horizontal scanning line obtained by the clock counter 22 are input to perform the calculation of the maximum brightness and the address. .. Reference numeral 11B is an image clock generator in the synchronizing signal generator 11, and the clock counter 22 counts the sampling clock from the image clock generator 11B to generate an address on a horizontal scanning line, It is input to the peak value calculation unit 21.

Therefore, in the peak value detecting section 10, the highest luminance point is obtained as a point showing the highest luminance within the predetermined luminance range Vref2 to Vref1.

FIG. 3 shows a processing flow of the peak value calculator 21. In the present embodiment, the shutter speed of the CCD camera 2A is switched between two stages, the shutter speed is increased at the time of the first input, for example, 1/1000 second (referred to as shutter speed 1), and the shutter speed is changed at the time of the second input. For example, the shutter speed is set to be as small as 1/60 seconds (referred to as shutter speed 2), whereby the amount of light incident on the image pickup unit 2 is changed in two steps.

Only when the AND circuit section 20 outputs, that is, the level of the binarized video signal is within a predetermined range Vref2 to Vre.
The binarized video signal is determined to be valid data only when it is within f1, and its output is output to the image clock generator 11
It is input to the peak value calculation unit 21 in synchronization with the sampling clock from B (steps S30 and 31). at the same time,
The address on the horizontal scanning line at that time is the clock counter 2
Enter from 2. Then, the input data is temporarily stored until the third consecutive input is made, and when the third consecutive input is made, the address of the true peak value is calculated by using the three input data (step S32- Three
4).

Next, the obtained address data and the maximum brightness data are combined, and the combined data is stored in the storage units 12, 1.
Stored in 3. One piece of this combined data is obtained for each horizontal scanning line, and is stored in the first storage unit 12 at the time of the first input and in the second storage unit 13 at the time of the second input (step S35).
~ 38). Further, for the horizontal scanning line for which the output of the AND circuit section 20 is not continuously output for 3 clocks, the three input signals are not input, so that the synthetic data is not created. Each of the storage units 12 and 13 is initialized to -1 in advance, and -1 remains set in the storage area for the scanning line for which the composite data is not created.

When the peak value calculation by the first input is completed, the shutter speed is switched to 2 and the same processing as above is performed again on the same portion of the measuring object 3 (steps S39 to 42). When the peak value calculation by the second input is completed, the shutter speed is returned to 1, and the table 4 is moved one step in the X direction of FIG. The same processing as above is repeated (step S43).

By the way, in the above processing, the combined data stored in the first and second storage units 12 and 13 is
As shown in (a) and (b) of FIG. 4, it has a two-word configuration in which the luminance data is stored in the upper one word and the peak value address is stored in the lower one word. The data -1 for the fourth scanning line in FIG. 4A is too high in brightness as shown in FIG. 5B in the video signal (> 150).
It indicates that the synthesized data was not obtained, and -1 of the data for the first scanning line of FIG. 4C indicates that the brightness of the video signal is too low as shown in FIG. 5C. (<81) indicates that synthetic data could not be obtained.

The data selection unit 14 is provided with the address data of the same portion of the measurement object 3 stored in the first storage unit 12 and the second storage unit 13, that is, the address of the brightest point on the same scanning line. One of the data is selected, or one address data is generated by averaging. In this embodiment, the peak value address having the higher luminance data is selected. Therefore, the peak value address transferred to the data generation unit 16 has the value shown in (c) of FIG.

That is, regarding the first scanning line in FIG.
The brightness of the second storage unit 13 in (b) is within a predetermined brightness range Vref2.
Since it is not within Vref1, it is not the highest brightness point, and therefore the data of the highest brightness point stored in the first storage section 12 of (a) is selected as it is and data is generated as the address data of (c). It is transferred to the section 16.

Regarding the second scanning line in FIG. 4, (a),
Both (b) are the highest luminance points in the predetermined luminance range Vref2 to Vref1, and in this case, since the luminance is higher in (a), the address data is transferred as data (c). Since both (a) and (b) are the highest brightness points within the predetermined brightness range Vref2 to Vref1 for this second scanning line, any of them may be selected originally, and therefore, unlike the present embodiment, the brightness is different. You can select the address of (b)
Further, the average value of the addresses of (a) and (b) may be obtained. When the average value of the addresses is obtained, it becomes 121.5, so this is replaced with 121 or 122 and transferred.

In this way, the predetermined brightness range Vref2 to Vref is always maintained.
The brightest point in ref1 is selected and the data generator 16 of FIG.
Therefore, even if the brightness of the video signal is too high or too low in relation to the shutter speed, data loss is compensated for and a stable input can be obtained.

FIG. 6 is a block diagram showing the structure of a main part of a three-dimensional shape measuring apparatus according to another embodiment of the present invention, that is, a light spot detecting section 24. In the figure, the combined data of the peak value address and the brightness detected by the peak value detection unit 10 is first stored in the first storage unit 12, and this data is rewritten by the rewriting means 26 to be stored in the second storage unit. Part 1
3 is stored.

The rewriting means 26 is an n-th camera screen in which the same portion of the measuring object 3 is imaged at an n-th shutter speed higher than the (n-1) -th order (where n is an integer of 2 or more) shutter speed. Scanning, the brightest point for each scan line,
That is, the combined data of the peak value address and the maximum brightness is obtained, and the maximum brightness point on the (n-1) th camera screen exceeds the upper limit threshold level Vref1 = 150 set by the threshold level setting unit 17 described above. If it is, the value is rewritten by the brightest point obtained on the n-th camera screen. In this embodiment, the configuration other than the light spot detection unit 24 having the configuration shown in FIG. 6 is the same as the configuration shown in FIGS.

Next, the operation of the above configuration will be described with reference to the flowchart shown in FIG. In the following description, N is the shutter speed, L is the number of scanning lines,
F indicates a flag, and in this embodiment, the shutter speed N is N = 1 ... 1/60 seconds, N = 3 ... 1 /
250 seconds, N = 5 ... 1/1000 seconds are set in 3 stages.

First, a shutter speed N = 1 (primary shutter speed) is set, a line image of one cross section of the measuring object 3 is taken, and the taken primary camera screen A is indicated by an arrow X in FIG.
Scan in the direction (matching the X direction in FIG. 1)
The data of the maximum brightness and the address on the scanning line is stored in the first storage unit 12. At this time, L = 0 and F = 0 (steps S50 to 53). Then, this first storage unit 1
The maximum brightness on the first scanning line stored in 2 is compared with the upper limit threshold level Vref1, and the flag F is set to 1 only when the maximum brightness exceeds the upper limit threshold level Vref1 (steps S54, 55).

The data of the maximum brightness and the address on the first scanning line are the maximum brightness and the upper limit threshold level Vref1.
All are moved to the second storage unit 13 regardless of the comparison result with (S56, 57). Subsequently, the number of scanning lines L is L + 1
(Step S58), the flow returns to step S54 through step S59 to compare the maximum brightness on the second scanning line with the upper limit threshold level Vref1, and to determine the maximum brightness on the second scanning line and the address data. 2 is transferred to the storage unit 13 (S54-5).
After 7), the same operation is repeated until the number of scanning lines L reaches 256.

In the above operation, the number of scanning lines L is 256.
, The shutter speed N is set to 3 and the flow goes through step S63 to step S64.
If the flag F is not set to 1, that is, if the maximum brightness on each scanning line is less than or equal to the upper limit threshold level Vref1, the process proceeds to step S60, and the drive system controller 8
The table 4 is step-moved in the X direction of FIG. 1 via the, and the cross-section of the next line of the measuring object 3 is imaged.
Further, in step S61, the maximum brightness and address data on each scanning line stored in the second storage unit 13 is converted into position coordinate data on the measurement object 3.

On the other hand, in the above operation, when the flag F is 1 when the number of scanning lines L reaches 256, that is, even if one of the maximum luminances on the scanning lines from L = 1 to 256, the upper limit is reached. If it exceeds the threshold level Vref1, the process returns from step S64 to step S51 to image the cross section of the same line of the measurement object 3 at the shutter speed N = 3, and the imaged secondary camera screen A is shown in FIG. Arrow X
Scan in the direction (matching the X direction in FIG. 1)
The data of the maximum brightness and the address on the scanning line is stored in the first storage unit 12 (S52). Then, the maximum brightness on the first scanning line at N = 3 stored in the first storage unit 12 is compared with the upper limit threshold level Vref1 and only when the maximum brightness exceeds the upper limit threshold level Vref1. The flag F is set to 1 in the same manner as (S53-5).
5).

When it is determined in step S56 that the image pickup is performed at the shutter speed N = 3, step S56
At 65, the maximum brightness of the primary camera screen stored in the second storage unit 13 is compared with the upper limit threshold level Vref1, and if the maximum brightness is higher, step S57.
Then, the maximum brightness and the address data of the second storage unit 13 are rewritten by the current data stored in the first storage unit 12. The operations of steps S54 to 57 and 65 are performed by the rewriting means 26 of FIG.

Subsequently, in step S58 of FIG. 7, the number L of scanning lines is incremented to L + 1, and the flow returns to step S54 through step S59 to display the secondary camera screen imaged at the shutter speed N = 3 (secondary shutter speed). A comparison between the maximum brightness on the second scan line of A and the upper limit threshold level Vref1 and the second storage section 13 of the maximum brightness on the second scan line
Is rewritten, and thereafter, the same operation is repeated until the number of scanning lines L reaches 256.

In the above-described operation for the secondary camera screen A, when the number of scanning lines L reaches 256, the process proceeds to step S62, the shutter speed N is set to 5, and step S
After 63, the process proceeds to step S64. If the flag F = 0 in step 64, as in the case of the primary camera screen A, the process proceeds to step S60 and the table 4 is step-moved in the X direction of FIG. An image of the cross section of the next line of the object 3 is captured, and further, in step S61, the maximum brightness and address data on each scanning line stored in the second storage unit 13 are measured.
Convert to upper position coordinate data

If the flag F = 1 in step S64, the process returns from step S64 to step S51, and the cross section of the same line of the measuring object 3 is imaged at the shutter speed N = 5 (third shutter speed). The same operation as described above is performed on the tertiary camera screen A up to the final line, and the measurement is completed (step S66).

As described above, according to the embodiments shown in FIGS. 6 and 7, the highest luminance point obtained by the image pickup at the primary shutter speed (N = 1) is the set threshold level Vref1.
In the following cases, re-imaging at an n-th order (n> 1) shutter speed is not performed, and the data generation unit 16 uses the light spot coordinates as they are.
Therefore, a stable input signal can be obtained as soon as possible, and the measurement speed can be improved.

Regarding the secondary and subsequent camera screens,
Instead of obtaining the maximum luminance point for all the scanning lines, the maximum luminance point may be obtained only for the scanning line in which the maximum luminance point exceeds the threshold level Vref1 in the preceding low-order camera screen. Further, in the above-described embodiment, the case where the shutter speed N is changed from the smaller one (1/60) to the larger one has been described, but the shutter speed N may be sequentially changed from the larger one to the smaller one. .. In this case, the data that does not reach the minimum brightness Vref2 is rewritten.

By the way, in each of the above-described embodiments, the shutter speed of the image pickup unit 2 is controlled to control the amount of light incident on the image pickup unit 2 in FIG. 1. However, unlike this, the amount of light emitted from the light projecting unit 1 is controlled. (Luminous intensity) may be controlled. Of course, both the shutter speed and the emitted light amount may be controlled.

[0044]

As described above, according to the first aspect of the present invention, the same portion of the object to be measured is imaged a plurality of times with different light incident amounts, and the plurality of imaged camera screens are scanned to scan each scanning line. The maximum luminance point is obtained for each of the plurality of camera screens, and one of the maximum luminance points within the predetermined luminance range obtained on the same scanning line of the plurality of camera screens is used as the light point to obtain its coordinates, and the obtained light is obtained. By converting the point coordinates to the position coordinates on the measurement target, a stable input signal can be obtained even if the brightness of the reflected light varies due to differences in the color and surface properties of the measurement target. It is possible to significantly reduce the loss of the input signal due to the variation in the brightness of the reflected light. Therefore, it is possible to remarkably improve the accuracy of the predetermined shape measurement without performing a preliminary work such as coloring in order to make the brightness of the reflected light constant before the image pickup.

According to the second aspect of the present invention, a portion of the measuring object is imaged with the (n-1) th order light input amount to obtain the maximum luminance point, and the luminance of the maximum luminance point is out of the predetermined range. Only when
The same portion of the measurement target is imaged with an n-th order light quantity different from the (n-1) th-order light quantity to obtain the highest brightness point, and the highest brightness point is obtained on the (n-1) th order camera screen. Since the highest brightness point is rewritten, if the highest brightness point obtained by the imaging with the (n-1) th order light quantity is within the predetermined range, re-imaging with the nth order light quantity is not performed, and the light point is left as it is. The coordinates can be input to the conversion unit, so that a stable input signal can be obtained as soon as possible and the measurement speed can be improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a three-dimensional shape measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a main part of FIG.

FIG. 3 is a diagram illustrating a processing flow of a main part of FIG.

FIG. 4 is a diagram showing an example of combined data stored in first and second storage units.

FIG. 5 is a signal waveform diagram showing the luminance of a video signal.

FIG. 6 is a block diagram showing a configuration of a main part of a three-dimensional shape measuring apparatus according to another embodiment of the present invention.

FIG. 7 is a diagram illustrating a processing flow of the embodiment shown in FIG.

FIG. 8 is an explanatory diagram of a scanning state on the camera screen.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laser light source (projection unit), 2 ... Imaging unit, 2A ... CCD
Camera, 3 ... Object to be measured, 6 ... Incident light quantity control unit, 10 ... Peak value detection unit, 12, 13 ... First and second storage units, 14 ...
Data selection unit, 16 ... Data generation unit (conversion unit), 24 ...
Light spot detector, 26 ... Rewriting means.

Claims (2)

[Claims] 1. A light projecting unit for projecting light onto an object to be measured, an imaging unit for imaging the projected object to be measured, and a light amount control unit for controlling the amount of light entering the image unit are different from each other. Scan the multiple camera screens where the same portion was imaged with the amount of light input to find the maximum brightness point for each scanning line, and find the maximum brightness point within the predetermined brightness range found on the same scanning line of the multiple camera screens. A three-dimensional shape measuring apparatus having a light spot detection unit that obtains coordinates of any one of the light spots and a conversion unit that converts the obtained light spot coordinates into position coordinates on a measurement target. 2. A light projecting unit for projecting light onto a measurement target object, an image capturing unit for capturing an image of the projected measurement target object, and a light incident amount control unit controlling the light incident amount on the image capturing unit, which are different from each other. A light spot detection unit that finds the coordinates of the light spot on the light image on the n (n is an integer of 2 or more) camera screens where the same portion is imaged by the amount of incident light, and the obtained light spot coordinates are the object to be measured. The light spot detection unit scans the (n-1) th camera screen imaged with the (n-1) th incident light amount and scans each scanning line. The peak value detecting means for obtaining the highest luminance point and the nth-order camera in which the same portion is imaged with the nth-order incident light amount different from the (n-1) th-order incident light amount when the obtained luminance of the highest luminance point is out of a predetermined range The screen is scanned to obtain the maximum brightness point, and the maximum brightness point having a brightness outside the predetermined range on the (n-1) th camera screen is set to n. Three-dimensional shape measuring apparatus comprising a rewriting means for rewriting the highest brightness point obtained by the camera screen.