JP2000002520A - Three-dimensional input apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire high-accuracy three-dimensional data, without receiving a plurality of operating instructions even if a body has different reflectivities at its portions by continuously scanning multiply with a detecting light projecting at a different intensity every scan in response to an operation start instruction. SOLUTION: The cameral position and orientation are determined to set the picture angle with seeing the indication of an LCD 21, while the focusing is made by a zoom unit 51. In a preliminary measurement, a system controller 61 calculates the output (slit light intensity) of a semiconductor laser 41, deflecting condition, etc., to set the projection angle so as to receive a reflected light on the center of a sensor 53, provided that a plane body exists at an object distance obtd. by the focusing, a slight light is continuously projected three times at three steps of intensity, and the output of the sensor 53 is sampled to obtain an optimum slit. This measuring method performs scanning three times at a different slit light intensity every scan in the same deflecting condition in all times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional input device for projecting detection light onto an object, scanning the object, and outputting data for specifying the shape of the object.

[0002]

2. Description of the Related Art A non-contact type three-dimensional input device called a range finder can perform higher-speed measurement than a contact type, and therefore can input data to a CG system or a CAD system, measure a body, and use a robot. It is used for visual recognition.

[0003] As a measurement method suitable for a range finder, a slit light projection method (also called a light cutting method) is known. In this method, an object is optically scanned and a distance image (3
(A two-dimensional image), and is a type of active measurement method for capturing an object by irradiating specific detection light. The distance image is a set of pixels indicating three-dimensional positions of a plurality of parts on the object. In the slit light projection method, a slit light in which a cross section of a projection beam is a straight band is used as detection light. At a certain point during the scanning, a part of the object is irradiated, and the position of the part can be calculated by a triangulation method from the projection direction and the high luminance position (that is, the light receiving direction) on the light receiving surface. Therefore, a group of data specifying the shape of the object can be obtained by sampling the brightness of each pixel on the light receiving surface.

Some rangefinders perform preliminary measurement and adjust the projection intensity of the detection light in the main measurement. That is, an operation setting for projecting the detection light on a part of the imaging range and optimizing the projection intensity according to the amount of the detection light incident on the light receiving surface is performed.

[0005]

Conventionally, however, the dynamic range of an imaging device or a signal processing system is limited when the reflectance of an object to be measured is not uniform and the difference in reflectance is large. Therefore, there has been a problem that the received light information of the detection light corresponding to a part of the object is saturated or becomes a black level (insensitive), and a part where the shape cannot be measured occurs. In such a case, it is necessary to perform another measurement to obtain the entire shape data of the object.

The present invention provides a three-dimensional input method for acquiring three-dimensional data with the same accuracy as in the case where the reflectivity is uniform without receiving a plurality of operation instructions even when the reflectivity of the object greatly differs depending on the part. It is intended to provide equipment.

[0007]

According to the present invention, a plurality of scans are performed by automatically changing the projection intensity. As a result, even for a part on an object for which appropriate light receiving information cannot be obtained at a certain projection intensity, appropriate light receiving information can be obtained at another projection intensity. That is, in at least one of the scans, the amount of incident light that depends on the reflectance of the target portion matches the dynamic range of imaging and signal processing. Therefore, by selecting and using appropriate light receiving information for each part from the light receiving information for a plurality of times, it is possible to measure the shape of the entire measurement range of the object. The object of the present invention is achieved when a plurality of light reception information is obtained, and it does not matter whether the selection of appropriate light reception information is performed inside the three-dimensional input device or by an external device.

[0008] Alternatively, in the present invention, photoelectric conversion signals obtained by one scan are amplified at different amplification factors. As a result, light reception information equivalent to the case of performing a plurality of scans with different projection intensities is obtained, and appropriate light reception information can be selected for each part.

The apparatus according to the first aspect of the present invention includes a light projecting means for projecting the detection light, and an image pickup means for receiving the detection light reflected by the object and converting the detection light into an electric signal. A three-dimensional input device that performs scanning for changing the direction and periodically imaging the object, and projects a plurality of scans of the detection light having different intensities each time in response to an operation start instruction. It is performed continuously. The instruction to start the operation is given by operating a switch or button or by a control signal from the outside.

According to a second aspect of the present invention, there is provided an apparatus comprising: a light projecting means for projecting a detection light; and an imaging means for receiving the detection light reflected by an object and converting the detection light into an electric signal. What is claimed is: 1. A three-dimensional input device for performing a scan for periodically imaging an object by changing a direction, amplifying the electric signal with different amplification factors, and generating a plurality of light reception data corresponding to each pixel of the image. It has signal processing means.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a configuration diagram of a measurement system 1 according to the present invention.

The measurement system 1 is a three-dimensional camera (range finder) for performing three-dimensional measurement by a slit light projection method.
2 and a host 3 for processing output data of the three-dimensional camera 2
It is composed of

The three-dimensional camera 2 outputs a two-dimensional image indicating color information of the object Q and data necessary for calibration together with measurement data for specifying three-dimensional positions of a plurality of sampling points on the object Q. The calculation processing for obtaining the coordinates of the sampling points using the triangulation method is performed by the host 3.
Is responsible.

The host 3 comprises a CPU 3a, a display 3
b, a keyboard 3c, a mouse 3d, and the like. Software for processing measurement data is incorporated in the CPU 3a. Between the host 3 and the three-dimensional camera 2, both online and offline data transfer by the portable recording medium 4 is possible. As the recording medium 4,
There are a magneto-optical disk (MO), a mini disk (MD), and a memory card.

FIG. 2 is a view showing the appearance of the three-dimensional camera 2. A light emitting window 20a and a light receiving window 2
0b is provided. The light projecting window 20a is located above the light receiving window 20b. Slit light (band-like laser beam with a predetermined width w) U emitted from the internal optical unit OU
Goes to the object (subject) to be measured through the light emitting window 20a. The radiation angle φ in the length direction M1 of the slit light U is fixed. A part of the slit light U reflected on the surface of the object enters the optical unit OU through the light receiving window 20b. Note that the optical unit OU includes a two-axis adjustment mechanism for optimizing the relative relationship between the light projecting axis and the light receiving axis.

On the upper surface of the housing 20, zooming buttons 25a and 25b, a manual focusing button 26
a, 26b and a shutter button 27 are provided. As shown in FIG. 2B, on the back of the housing 20,
A liquid crystal display 21, a cursor button 22, a select button 23, a cancel button 24, an analog output terminal 32, a digital output terminal 33, and an opening 30a for the recording medium 4 are provided.

A liquid crystal display (LCD) 21 is used as display means for an operation screen and as an electronic finder.
The photographer can set the photographing mode by using the buttons 21 to 24 on the back. From the analog output terminal 32, a two-dimensional image signal is output, for example, in the NTSC format. The digital output terminal 33 is, for example, a SCSI terminal.

FIG. 3 is a block diagram showing a functional configuration of the three-dimensional camera 2. In the figure, solid arrows indicate the flow of electric signals, and broken arrows indicate the flow of light. 3D camera 2
Has two optical systems 40 and 50 on the light projecting side and the light receiving side that constitute the optical unit OU described above. Optical system 40
, The wavelength 6 emitted by the semiconductor laser (LD) 41
The 70 nm laser beam becomes slit light U by passing through the light projecting lens system 42 and is deflected by the galvanomirror (scanning means) 43. Semiconductor laser 4
The driver 44, the driving system 45 of the light projecting lens system 42, and the driving system 46 of the galvanomirror 43 are controlled by a system controller 61.

In the optical system 50, a zoom unit 51
The light condensed by the beam splitter 52 is split by the beam splitter 52. The light in the oscillation wavelength band of the semiconductor laser 41 is
The light enters the sensor 53 for measurement. Light in the visible band enters the monitor color sensor 54. The sensor 53 and the color sensor 54 are both CCD area sensors. The zoom unit 51 is of an in-focus type, and a part of the incident light is used for auto focusing (AF). The AF function is realized by an AF sensor 57, a lens controller 58, and a focusing drive system 59. The zooming drive system 60 is provided for electric zooming.

The information captured by the sensor 53 is transmitted to the driver 5
5 is input to an output processing circuit 62, which is a component unique to the present invention, in synchronization with the clock signal from the clock 5. Output processing circuit 62
Is the data (hereinafter referred to as “centroid i” to be described later) for calculating the three-dimensional position of the target object based on the input imaging information.
p ″) is generated and output to the SCSI controller 66 as a measurement result. The data generated by the output processing circuit 62 is output to the display memory 74 as monitor information, and the distance image by the liquid crystal display (LCD) 21 is displayed. The output processing circuit 62 will be described later in detail.

On the other hand, imaging information from the color sensor 54 is sent to the color processing circuit 67 in synchronization with a clock from the driver 56. Imaging information that has undergone color processing
The data is output online via the NTSC conversion circuit 70 and the analog output terminal 32, or is quantized by the digital image generation unit 68 and stored in the color image memory 69. Thereafter, the color image data is transferred from the color image memory 69 to the SC.
The data is transferred to the SI controller 66.

The SCSI controller 66 outputs the data from the output processing circuit 62 and the color image on-line from the digital output terminal 33 or stores the data on the recording medium 4. Note that the color image is an image having the same angle of view as the distance image based on the output of the sensor 53, and is used as reference information at the time of application processing on the host 3 side. The processing using color information includes, for example, processing of generating a three-dimensional shape model by combining a plurality of sets of measurement data having different camera viewpoints, and processing of thinning out unnecessary vertices of the three-dimensional shape model. The system controller 61 sends a character generator (not shown)
An instruction for displaying appropriate characters and symbols on the screen of the LCD 21 is given.

FIG. 4 is a block diagram of the output processing circuit 62. The photoelectric conversion signal S53 input from the sensor 53 is
After being sampled and held by the S / H circuit 621, amplified by the amplifier circuit 622 at a predetermined amplification rate, and converted by the A / D converter 623 into 8-bit received light data Xi. The received light data Xi is temporarily stored in the memory 624, and is transferred to the maximum value discriminating circuit 626 and the center-of-gravity calculating circuit 627 at a predetermined timing. By storing the light receiving data Xi, the center of gravity can be calculated using a plurality of light receiving data Xi (32 in this example) whose imaging timing is shifted by the sensor driving cycle for each pixel. The address of the memory 624 is specified by the memory controller 625. It should be noted that the system controller 61 takes in the light reception data of a predetermined pixel via a data bus (not shown) in the preliminary measurement. The center-of-gravity calculation circuit 627 calculates the center of gravity ip, which is the basis of the calculation of the three-dimensional position in the host 3, and sends it to the output memory 628. The maximum value determination circuit 626 outputs a control signal CS1 indicating whether the center of gravity ip is appropriate for each pixel. This control signal CS1
The writing of the center of gravity ip to the output memory 629 is controlled by the output memory controller 629 according to the following. However, when the masking of the control signal CS1 is instructed by the control signal CS2 from the system controller 61, the writing of the center of gravity ip is performed regardless of the control signal CS1. The output memory controller 629 has a counter for address designation.

FIG. 5 is a block diagram of the maximum value judging circuit 626. The maximum value determination circuit 626 includes a maximum value detection unit 626.
1, a threshold storage unit 6262, and a comparison unit 6263. The maximum value detection unit 6261 has the light reception data Xi read from the memory 624 in units of 32 pixels per pixel.
Is entered. The maximum value detection unit 6261 calculates 3 for each pixel.
The maximum value Xmax of the two light reception data Xi is detected and output. The maximum value Xmax is compared with two threshold values XL and XH by the comparator 6263, and the comparison result is output as the control signal CS1. The thresholds XL and XH are fixed values and are stored in the threshold storage unit 6262.

FIG. 6 is a principle diagram for calculating a three-dimensional position in the measurement system 1. In FIG. 6, only five samplings of the amount of received light are shown for easy understanding, but the number of samplings per pixel in the three-dimensional camera 2 is 32.

As shown in FIG. 6, a relatively wide slit light U whose slit width on the imaging surface S2 of the sensor 53 is equal to a plurality of pixels g arranged at a pitch pv is projected onto the object Q. Specifically, the width of the slit light U is set to about 5 pixels. The slit light U is deflected from the top to the bottom of the figure at a constant angular velocity about the starting point A. The slit light U reflected by the object Q passes through the principal point O of image formation (the principal point H ′ on the rear side of zooming) and enters the imaging surface S2. By periodically sampling the amount of light received by the sensor 53 during the projection of the slit light U, the object Q (strictly, an object image) is scanned. The photoelectric conversion signal for one frame is output from the sensor 53 every sampling period (sensor driving period).

In the present embodiment, one frame is composed of 32 lines corresponding to a part of the imaging surface S2 of the sensor 53. Therefore, when focusing on one pixel g of the imaging surface S2,
32 samples will be taken during the scan,
32 light reception data are obtained. The center of gravity (time center of gravity) corresponding to the timing Npeak at which the optical axis of the slit light U passes through the object surface ag in the range where the pixel of interest gazes is calculated by the center of gravity calculation of the light reception data for these 32 frames.
Calculate ip.

When the surface of the object Q is flat and there is no noise due to the characteristics of the optical system, the amount of light received by the target pixel g is
As shown in FIG. 6B, the number increases at the timing when the slit light U passes, and its temporal distribution is close to a normal distribution. As shown in the figure, the nth time and the (n−
1) Timing Npeak between sampling times
If the received light amount is the maximum at the timing Np
eak almost coincides with the center of gravity ip.

The calculated timing Npeak (center of gravity ip)
Then, the position (coordinate) of the object Q is calculated based on the relationship between the irradiation direction of the slit light U and the incident direction of the slit light U to the pixel of interest g. This enables measurement with a higher resolution than the resolution specified by the pitch pv of the pixel array on the imaging surface S2.

Hereinafter, the operation of the three-dimensional camera 2 and the host 3 will be described together with the measurement procedure. The number of sampling points for measurement by the three-dimensional camera 2 is set to 200 × 262. That is, the number of pixels in the width direction of the slit U on the imaging surface S2 is 262, and the substantial number N of frames is 231.

The user (photographer) determines the camera position and direction while viewing the color monitor image displayed on the LCD 21, and sets the angle of view. At that time, a zooming operation is performed as needed. At this time, manual or automatic focusing is performed by moving a focusing unit in the zoom unit 51, and an approximate inter-object distance (do) is measured during the focusing process.

When the user turns on the shutter button 27, preliminary measurement is performed prior to the main measurement. In the preliminary measurement, the system controller 61 calculates the output (slit light intensity) of the semiconductor laser 41 and the deflection conditions of the slit light U (scan start angle, scan end angle, deflection angular velocity) in the main measurement.

FIG. 7 shows the slit light intensity L in the preliminary measurement.
It is a figure for explaining the calculation point of s. The procedure for calculating the slit light intensity is as follows. The projection angle is set so that the reflected light is received at the center of the sensor 53 on the assumption that a plane object exists at the approximate object distance (do) obtained by focusing. At the set projection angle,
The slit light U is continuously projected at three levels of intensities La, Lb, and Lc three times in total, and the output of the sensor 53 is sampled to obtain the relationship between the intensities La, Lb, and Lc and the output of the sensor 53. Then, the slit light intensity Ls at which the output of the sensor 53 becomes the optimum value Ss is obtained from the obtained relation. Note that the output of the sensor 53 is sampled by the imaging surface S
2, but not for the whole.

In calculating the deflection condition, the intensities La, L
The distance (d) between the objects is calculated by triangulation from the projection angle of the slit light U of b and Lc and the light receiving position of the slit light U. Then, based on the inter-object distance (d), the optical condition of light reception, and the operating condition of the sensor 53, the scan start angle, the scan end angle, and the deflection angular velocity are calculated so as to obtain a measurement result with a predetermined resolution.

Following the preliminary measurement, the main measurement is performed by applying the result of the preliminary measurement. FIG. 8 is a flowchart of the main measurement operation. In the main measurement of the present embodiment, the object is scanned three times in total. The deflection condition of the slit light U is the same for all scans, but the slit light intensity is different for each scan.

The slit light intensity L1 of the first scan (first scan) is the previously obtained slit light intensity Ls. The slit light intensity L1 is set as the operating condition of the semiconductor laser 41 (# 11), and the slit light U is projected in a range from the scan start angle to the scan end angle (# 12, # 13). Similarly, the second scan (second scan) is performed by setting the slit light intensity L2 (# 14 to # 16), and the third scan (third scan) is performed by setting the slit light intensity L3 (#) 17 ~ #
19).

By performing scanning with the slit light intensity Ls, it is possible to prevent data loss due to processing by the output processing circuit 62 as described later. Missing data includes
The reflectance distribution of the target object, the set number of slit light intensities (the number of scans), and the maximum value of the received light data of each pixel are related.

FIG. 9 is a flowchart for calculating the slit light intensity applied to the main measurement, and FIG. 10 is a schematic diagram for setting the slit light intensity. First, as described above, the slit light intensity Ls is calculated based on the result of the preliminary measurement (# 21), and the slit light intensity L2 is calculated according to the magnitude relationship between the obtained value and the predetermined thresholds LL and LH. , L3. Threshold L
L denotes two boundaries that partition the variable range of the slit light intensity (the minimum value Lmin to the maximum value Lmax) into three intensity ranges zL, zM, and zH of low (L), medium (M), and high (H). Is the value of the lower boundary. The threshold value LH is a high-side boundary value.

When Ls ≦ LL, L2 is set in the intensity range z.
The average value LMa of M and L3 is the average value L of the intensity range zH.
Ha (# 22, # 23). When Ls> LL,
Let L2 be the average value LLa of the intensity range zL (# 24),
3 is determined as follows. If Ls ≦ LH, L3 is LH
a (# 25, # 26), and if Ls> LH, L3 is set to LMa (# 27). That is, three intensity ranges z
One slit light intensity is selected from each of L, zM, and zH. Each value LL, LH, LLa, LM
a and LHa are represented by the following equations.

LL = (Lmax−Lmin) / 3 + Lmin (1a) LH = 2 (Lmax−Lmin) / 3 + Lmin (1b) LLa = (LL−Lmin) / 2 + Lmin (1c) LMa = (LH−LL) / 2 + LL (1d) LHa = (Lmax−LH) / 2 + LH (1e) In each of the three scans at the slit intensity set in this way, the output processing circuit 62 The center of gravity ip is calculated by performing a predetermined operation on the output, and the center of gravity ip corresponding to any one of the scans for each pixel is made valid as a measurement result according to the maximum value Xmax.

FIG. 11 is a diagram showing a reading range of the sensor 53. The reading of one frame by the sensor 53 is not performed on the entire imaging surface S2, but is performed on the imaging surface S2 for speeding up.
2 is performed only for the effective light receiving area (band-shaped image) Ae which is a part of the area 2. The effective light receiving area Ae is an area on the imaging surface S2 corresponding to the measurable distance range at a certain irradiation timing, and shifts by one pixel for each frame with the deflection of the slit light U. In the present embodiment, the number of pixels of the effective light receiving area Ae in the shift direction is fixed to 32.
A method of reading out only a part of the captured image of the CCD area sensor is disclosed in Japanese Patent Application Laid-Open No. 7-174536.

FIG. 12 is a diagram showing a relationship between a line and a frame on the imaging surface S2 of the sensor 53, and FIG. 13 is a diagram showing a storage state of received light data of each frame. As shown in FIG. 12, the frame 1 which is the first frame of the imaging surface S2 includes 32 (lines) × 2 from line 1 to line 32.
The received light data for 00 pixels is included. Frame 2 is shifted by one line per frame, such as from line 2 to line 33, frame 3 from line 3 to line 34, and so on. Frame 32 is from line 32 to line 63. In addition, as described above, one line is
0 pixels.

The light receiving information from frame 1 to frame 32 is sequentially A / D converted and stored in the memory 624 (see FIG. 4). As shown in FIG. 13, light reception data is stored in the memory 624 in the order of frames 1, 2, 3 and so on. The data of the line 32 included in each frame is the 32nd line of the frame 1 and the 31st line of the frame 2 Thus, the image is shifted upward by one line for each frame. The received light data from frame 1 to frame 32 is stored in the memory 624, so that the line 3
Sampling for each of the pixels 2 ends. The light receiving data of each pixel for which sampling has been completed is sequentially read from the memory 624 in order to perform the center of gravity calculation.

FIG. 14 is a diagram showing the concept of the center of gravity ip.
The center of gravity ip is 3 obtained by 32 samplings.
This is the center of gravity of the distribution of the two received light data on the time axis. Sampling numbers 1 to 32 are assigned to 32 pieces of received light data for each pixel. The i-th light reception data is represented by Xi. i is an integer of 1 to 32. At this time, i indicates the number of frames for one pixel after the pixel enters the effective light receiving area Ae.

The center of gravity ip of the 1st to 32nd light receiving data X1 to X32 is calculated by calculating the value of i ·
It is obtained by dividing the sum Σi · Xi of Xi by the sum ΣXi of Xi. That is,

[0046]

(Equation 1)

Is as follows. The center-of-gravity calculation circuit 627 calculates (2)
Performs a formula operation. In the center-of-gravity calculation processing, if the sampling data near the center of gravity ip is at the saturation level or the black level, the calculation processing is inaccurate or impossible, and the accuracy of calculating the position of the target object decreases. Therefore, the three-dimensional camera 2 of this example performs multiple scans with different slit light intensities in order to accurately calculate the center of gravity of all pixels, and the sampling data is saturated in each scan for each pixel. The scanning data which does not reach the level or the black level is selected.

FIG. 15 is a diagram showing a typical example of the relationship between the maximum value Xmax of the received light data and the threshold values XL and XH. Threshold X
L and XH are set to values equal to or lower than the saturation level Xt and equal to or higher than the black level Xu in the operation characteristics of the sensor 53.

FIG. 15A shows a case where the maximum value Xmax of the light receiving data sampled for each pixel satisfies the following expression (3). In this case, the writing of the center of gravity ip into the output memory 628 is performed. Is allowed.

FIG. 15B shows that the maximum value Xmax is equal to the threshold value XH.
(Allowable upper limit), and the received light data is saturated. In this case, since the calculation of the center of gravity may not be accurate, writing of the center of gravity ip to the output memory 628 is prohibited.

FIG. 15C shows that the maximum value Xmax is equal to the threshold value XL.
In this case, the light reception data approaches the black level, the influence of background light and noise in the circuit is large, and the distribution of the light reception data is narrow.
Also in this case, the calculation of the center of gravity may not be accurate.
Writing of the center of gravity ip to the output memory 628 is prohibited.

The comparing section 6263 described with reference to FIG. 5 performs a comparison operation to determine whether or not the input maximum value Xmax satisfies the condition of equation (3), and outputs a control signal CS1. XL <Xmax <XH (3) When the maximum value Xmax for each pixel satisfies the expression (3), the control signal CS1 indicates the center of gravity i to the output memory 628.
The writing of p is permitted, and if not satisfied, the writing is prohibited. Note that the output memory 628 has a capacity to hold the center of gravity of all the pixels of the sensor 53.

FIG. 16 is a flowchart of the output memory control. When the first scan of the main measurement is started (# 30),
In the output memory controller 629, the control signal CS1
Is masked by the control signal CS2 (# 31), and writing of the center of gravity ip of all pixels into the output memory 628 is permitted (# 32). When the first scan for writing the centroid ip of all the pixels into the output memory 628 is completed (# 33, # 34), the writing of the output memory 628 is prohibited (# 35), and the masking of the control signal CS1 is released (# 36). ). In the second scan, the maximum value Xmax is compared with the threshold values XL and XH, and writing to the output memory 628 is permitted or prohibited according to the comparison result (# 37 to # 40). If writing is permitted, the output memory 628 overwrites the center of gravity ip obtained in the second scan. The second in the third scan
As in the case of scanning, overwriting of the center of gravity ip is controlled in accordance with the maximum value Xmax.

As described above, the barycenter ip of each pixel calculated by the output processing circuit 62 for each of a plurality of scans is the maximum value X
If max satisfies the condition of the expression (3), it is updated every scanning. Here, if there is a pixel that does not satisfy the conditions in all scans, data loss occurs. Therefore, in the present embodiment, the result of the center-of-gravity calculation for all pixels is written to the output memory 628 in the first scan in order to prevent data loss. As described above, the slit light intensity Ls in the first scan is the slit light intensity Ls optimized for the reflectance at almost the center of the object in the preliminary measurement. By performing the first scan with the slit light intensity Ls, loss of data of another part near the center reflectance of the object is prevented.

In the illustrated three-dimensional camera 2, three scans are performed by switching the slit light intensity in the main measurement. However, by increasing the number of steps and the number of scans of the slit light intensity, each part of the target object can be further scanned. By adapting the slit light intensity to the reflectance, the accuracy of the center of gravity calculation can be improved. [Second Embodiment] FIG. 17 is a block diagram showing a functional configuration of a second three-dimensional camera 2b according to the present invention. 3, the elements corresponding to those in FIG. 3 are denoted by the reference numerals in FIG. 3 with "b" added.

The three-dimensional camera 2b has the same external appearance, basic internal structure and usage as the three-dimensional camera 2 described above (see FIGS. 1 to 3). Therefore, the description of FIG. 17 is simplified. The optical system 40b has a semiconductor laser 41b as a light source, and emits slit light U so as to scan an object to be measured. The optical system 50b has a sensor 53b for measurement and a color sensor 54b for monitoring, and forms an object image and converts it into an electric signal. A drive system 140 for operating the optical system 40b and a drive system 150 for operating the optical system 50b
Is controlled by the system controller 61b.

The photoelectric conversion signal S5 obtained by the sensor 53b
3b is sent to the output processing circuit 62b. Output processing circuit 6
2b outputs the distance image to the display memory 74b,
The data that is the basis for calculating the three-dimensional position is output to the SI controller 66b. The distance image is the liquid crystal display 21b
Displayed by The photoelectric conversion signal obtained by the color sensor 54b is input to the color data processing system 160.
The color data processing system 160 outputs an analog image signal to the terminal 32b, and sends digital image data to the SCSI controller 66b. SCSI controller 66b
Is responsible for controlling data communication with an external device via the terminal 33b and for accessing the recording medium 4b.

The feature of the three-dimensional camera 2b lies in the configuration and operation of the output processing circuit 62b as described below. FIG. 18 shows FIG.
9 is a flowchart of the main measurement performed by the three-dimensional camera 2b.

The three-dimensional camera 2b also performs the preliminary measurement in the same procedure as the three-dimensional camera 2, and performs the main measurement reflecting the result of the preliminary measurement. When shifting from the preliminary measurement to the main measurement, the system controller 61b gives a deflection condition to the drive system 140 and also gives a slit light intensity Ls as an output condition of the semiconductor laser 41b (# 51). Scanning is started so as to satisfy the scanning start angle of the deflection condition (# 52), and scanning is performed until the scanning end angle is satisfied (# 53). The signal processing by the output processing circuit 62b is performed on the photoelectric conversion signal sequentially output from the sensor 53b during scanning.

FIG. 19 is a block diagram of the output processing circuit 62b of FIG. The photoelectric conversion signal S53b of each pixel input from the sensor 53 is sampled and held by the S / H circuit 630, and the three amplifying units 631, 632, 6
At 33, the signals are amplified at different amplification factors A1, A2, A3. The relationship between the amplification factors A1, A2, and A3 is represented by the following equation.

A1 × b1 = A2 (b1> 1.0) A1 × b2 = A3 (b2 <1.0) A3 <A1 <A2 The output of the amplifier 631 is quantized by the A / D converter 634 and received. The data Xi1 is transferred to the memory 638. The use form of the memory 638 is the same as that of FIG. Similarly, the output of the amplification unit 632 is written to the memory 639 as light reception data Xi2 via the A / D converter 635, and the output of the amplification unit 633 is A / D
Through the converter 636, the memory 64 is provided as the received light data Xi3.
Written to 0. Light reception data Xi1, Xi2, Xi3
Are each 8 bits.

For the pixels for which writing for 32 frames has been completed, the received light data Xi is read from each of the memories 638 to 640.
1, Xi2 and Xi3 are read. Any of the light reception data Xi1, Xi2, and Xi3 is used as the selector 641,
642, and is sent to the center-of-gravity calculation circuit 644. Selectors 641 and 642 include a maximum value determination circuit 643
Receive select signals SL1 and SL2.

FIG. 20 is a block diagram of the maximum value judging circuit 643 of FIG. 19, and FIG. 21 is a diagram showing an example of the relationship between the maximum value Xmax2 of 32 pieces of received light data corresponding to one pixel and the threshold values XLb and XHb. It is.

The maximum value judging circuit 643 includes a maximum value detecting section 6
431, a threshold storage unit 6432, and two comparison units 643
3,6434. Maximum value detector 643
1, the light receiving data Xi1 is input from the memory 638. The maximum value detection unit 6431 detects the light reception data Xi of each pixel.
The maximum value Xmax2 of 1 (32 in this embodiment) is detected. The threshold value storage unit 6432 provides the threshold values XLb and XHb to the comparison unit 6433, and supplies the threshold value XLb to the comparison unit 6434. The comparing unit 6433 calculates the maximum value Xmax2 and the threshold XL
b, XHb, and outputs a select signal SL1 corresponding to the magnitude relationship. The comparing unit 6434 outputs the select signal SL2 according to the magnitude relation between the maximum value Xmax2 and the threshold value XLb.

As shown in FIG. 20, the threshold values XLb and XHb are set to be equal to or less than the saturation level Xtb determined by the characteristics of the sensor 53b and equal to or more than the black level Xub. Maximum value Xmax
When 2 satisfies the condition of (XLb <Xmax2 <XHb), the select signal SL1 becomes active, and the selector 641 selects the light receiving data Xi1 from the memory 638. That is, the light reception data Xi1 of the amplification factor A1 is used for the gravity center calculation (see FIG. 18). When the condition is not satisfied, the selector 641 selects the light receiving data (Xi2 or Xi3) from the selector 642. Also, the maximum value Xma
When x2 satisfies the condition of (XLb ≧ Xmax2), the select signal SL2 becomes active and the selector 642
Selects the light reception data Xi2 from the memory 639 and sends it to the selector 641. When the condition is not satisfied, the selector 642 selects the light receiving data Xi3 from the memory 640. Note that when focusing on one pixel, Xi3 <Xi1 <X
The relationship of i2 holds.

By such processing, for each pixel,
Accurate center-of-gravity calculations can be performed using light reception data that is neither the saturation level nor the black level obtained by appropriate amplification of the sensor output.

In the first and second embodiments described above, the three-dimensional cameras 2 and 2b calculate the center of gravity and
Is sent to the host 3, but the data ３i × X and ΣXi for each pixel are sent to the host 3 as measurement results by the three-dimensional cameras 2 and 2b, and the host performs the center of gravity calculation. Good. For each pixel (sampling point), it is not always necessary to select the optimal slit light intensity or the light receiving data of the amplification factor for each pixel.
The center of gravity may be calculated by selecting the optimal light receiving data in units of a plurality of pixels. In addition, the scan may be performed several times with different slit light intensities, and the photoelectric conversion signals obtained in each scan may be processed with different amplification factors, thereby expanding the substantial dynamic range of light reception.

[0068]

According to the first or second aspect of the present invention,
Even when the reflectivity of the object greatly differs depending on the part, it is possible to input three-dimensional data with the same accuracy as in the case where the reflectivity is uniform, without performing a plurality of operation instructions.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a measurement system according to the present invention.

FIG. 2 is a diagram illustrating an appearance of a three-dimensional camera.

FIG. 3 is a block diagram illustrating a functional configuration of a three-dimensional camera.

FIG. 4 is a block diagram of an output processing circuit.

FIG. 5 is a block diagram of a maximum value determination circuit.

FIG. 6 is a principle diagram of calculation of a three-dimensional position in the measurement system.

FIG. 7 is a diagram for explaining a calculation procedure of slit light intensity in preliminary measurement.

FIG. 8 is a flowchart of a main measurement operation.

FIG. 9 is a flowchart of calculation of the slit light intensity applied to the main measurement.

FIG. 10 is a schematic diagram of setting a slit light intensity.

FIG. 11 is a diagram showing a reading range of a sensor.

FIG. 12 is a diagram illustrating a relationship between a line and a frame on an imaging surface of a sensor.

FIG. 13 is a diagram showing a storage state of received light data of each frame.

FIG. 14 is a diagram illustrating a concept of a center of gravity.

FIG. 15 is a diagram illustrating a representative example of a relationship between a maximum value of light reception data and a threshold.

FIG. 16 is a flowchart of output memory control.

FIG. 17 is a block diagram showing a functional configuration of a second three-dimensional camera according to the present invention.

18 is a flowchart of the main measurement performed by the three-dimensional camera in FIG.

FIG. 19 is a block diagram of the output processing circuit of FIG. 17;

20 is a block diagram of the maximum value determination circuit of FIG.

FIG. 21 is a diagram illustrating an example of a relationship between a maximum value of 32 pieces of light reception data corresponding to one pixel and a threshold.

[Explanation of symbols]

 2, 2b Three-dimensional camera (three-dimensional input device) 40, 40b Optical system (light projecting means) Q Object U Slit light (detection light) 50, 50b Optical system (imaging means) 27 Shutter button L1-3 Slit light intensity A1 -3 Gain Xi1-3 Light reception data 62b Output processing circuit (signal processing means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Miyazaki 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Toshio Kaida Azuchi, Chuo-ku, Osaka-shi, Osaka 2-3-1, Machi, Osaka International Building Minolta Co., Ltd. F-term (reference) 2F065 AA03 AA04 AA17 AA45 DD09 FF02 FF04 FF09 GG06 HH05 JJ03 JJ16 JJ26 LL06 LL13 LL28 LL37 QQ03 QQ08 QQ24 QQ25 QQ29 SS02 SS

Claims (2)

[Claims] A light source for projecting the detection light; and an imaging means for receiving the detection light reflected by an object and converting the light into an electric signal. A three-dimensional input device for performing a scan for imaging the object, wherein in response to an operation start instruction, a plurality of scans are continuously performed by projecting the detection light of different intensity each time. Characteristic three-dimensional input device. 2. An image forming apparatus comprising: a light projecting means for projecting a detection light; and an image pickup means for receiving the detection light reflected by an object and converting the light into an electric signal. A three-dimensional input device for performing a scan for imaging the object, comprising signal processing means for amplifying the electric signal with different amplification factors and generating a plurality of light reception data corresponding to each pixel of the imaging. A three-dimensional input device characterized by the above-mentioned.