JPH09325019A - Three-dimensional measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand the application range of measurement by providing a function which allows a range finder to perform measurement cyclicly. SOLUTION: When a power is tuned on, control parameters including bits of a CTRL registor are set intially, and a mode is set according to the command from a host. When an instruction to start operation is received, the measurement starts. In the first scanning sequence, a passive AF starts and the position of a focusing lens is adjusted corresponding to the relative movement of an object to a three-dimensional camera. Scanning processing is executed to obtain a distance picture, and the passive AF starts again after the scanning is completed. After the command input and its operation starts, its completion is checked for appropriateness by confirming whether the input count value of frame synchronization signal reaches the set value. In the case of one-shot mode or when the completion instruction is received in continuous mode, the operation returns to main routine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional measuring device that irradiates an object with detection light typified by slit light to measure the shape of the object in a non-contact manner.

[0002]

2. Description of the Related Art A non-contact type three-dimensional measuring device (three-dimensional camera) called a range finder is capable of high-speed measurement as compared with a contact type, and therefore a CG system or a CA.
It is used for data input to the D system, body measurement, and visual recognition of robots.

[0003] As a measurement method suitable for a range finder, a slit light projection method (also called a light cutting method) is known. This method is a method of optically scanning an object to obtain a distance image (three-dimensional image) based on the principle of triangulation, and is a kind of active measurement method of irradiating detection light to photograph an object. . The range image is a set of pixels indicating the three-dimensional positions of a plurality of parts on the object. In slit light projection,
Slit light having a linear cross section is used as the detection light.
A light projection method is also known in which spot light, step light, density pattern light, or the like is emitted instead of slit light.

[0004]

By providing the range finder with a function of periodically measuring, the range of application of three-dimensional measurement is expanded. For example, it is possible to enhance the practicality of the shape inspection of articles in the production line of a factory, the visual recognition of a mobile robot, the surveillance system of security, and the like. By comparing a plurality of time-series distance images obtained by the periodic three-dimensional measurement, it is possible to easily distinguish the front-back movement and the shape change of the object.

It is an object of the present invention to provide a three-dimensional measuring device that performs periodic measurement and performs a condition setting operation suitable for the purpose.

[0006]

[Means for Solving the Problems] When periodically measuring, it is preferable to keep the measurement conditions constant, and it is preferable to set the measurement conditions suitable for the measurement environment at each time of measurement. There are cases. For example, the former involves product inspection in factories and the latter involves visual recognition of mobile robots. If the measurement conditions are fixed, time-series measurement data can be easily handled, and if the measurement conditions are variable, appropriate measurement data can be obtained regardless of changes in the measurement environment. The measurement environment is the state of the measurement area such as the distance from the object, the material (reflectance) of the object, and the ambient light. Examples of the measurement conditions include the projection light angle range of the detection light, the intensity of the detection light, and the focusing state.

If the user can select a mode in which the measurement condition is fixed and a mode in which the measurement condition is variable, the versatility of the apparatus is enhanced. On the other hand, limiting the mode is advantageous in terms of cost.

The apparatus according to the invention of claim 1 has a light projecting means for irradiating the detection light to optically scan the object, and an imaging means for receiving the detection light reflected by the object. A three-dimensional measuring device for measuring an object shape by a light projection method, comprising: preliminary measuring means for measuring a measuring environment, and control means for setting a measuring condition according to the measuring environment measured by the preliminary measuring means. However, a continuous measurement mode for periodically measuring is provided, and as a choice of the operation mode of the control means in the continuous measurement mode, a first mode in which the measurement condition of each time is fixed to the measurement condition set at the time of the first measurement. , A second mode in which the measurement condition for each time is set in accordance with the measurement environment newly measured for each measurement.

According to a second aspect of the present invention, there is provided a device for projecting light for irradiating detection light to optically scan an object, and imaging means for receiving the detection light reflected by the object. A three-dimensional measuring device for measuring an object shape by a light projection method, comprising: preliminary measuring means for measuring a measuring environment, and control means for setting a measuring condition according to the measuring environment measured by the preliminary measuring means. Then, a continuous measurement mode for periodically measuring is provided, and in the continuous measurement mode, the control means is configured to fix the measurement condition of each time to the measurement condition set at the time of the first measurement.

According to a third aspect of the present invention, there is provided a device for projecting light for irradiating the detection light to optically scan the object, and imaging means for receiving the detection light reflected by the object. A three-dimensional measuring device for measuring an object shape by a light projection method, comprising: preliminary measuring means for measuring a measuring environment, and control means for setting a measuring condition according to the measuring environment measured by the preliminary measuring means. Then, a continuous measurement mode for periodically measuring is provided, and in the continuous measurement mode, the control means is configured to set the measurement condition for each time according to the measurement environment newly measured for each measurement. .

[0011]

FIG. 1 is a configuration diagram of a measurement system 1 according to the present invention. The measurement system 1 includes a three-dimensional camera (range finder) 2 that performs three-dimensional measurement by the slit light projection method, and a host 3 that processes output data of the three-dimensional camera 2.

The three-dimensional camera 2 collects measurement data (distance image) for specifying three-dimensional positions of a plurality of sampling points on the object Q, a two-dimensional image showing color information of the object Q and data necessary for calibration. Output. The host 3 is responsible for the arithmetic processing for obtaining the coordinates of the sampling points using the triangulation method.

The host 3 includes a CPU 3a and a display 3
This is a computer system including a keyboard b, a keyboard 3c, a mouse 3d, and the like. Software for processing measurement data is incorporated in the CPU 3a. Online data transfer is performed between the host 3 and the three-dimensional camera 2.

FIG. 2 is a view showing the outer appearance of the three-dimensional camera 2. A light projecting window 20a and a light receiving window 2 are provided on the front surface of the housing 20.
0b is provided. The light projecting window 20a is located above the light receiving window 20b. Slit light (band-shaped 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 projecting window 20a. The emission angle φ of the slit light U in the length direction M1 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. The optical unit OU includes a biaxial adjustment mechanism for optimizing the relative relationship between the light projecting axis and the light receiving axis.

On the top surface of the housing 20, there are zooming buttons 25a, 25b and a manual focusing button 26.
a, 26b, and a start / stop button 27 are provided. As shown in FIG. 2B, on the rear surface of the housing 20, a liquid crystal display 21, cursor buttons 22,
A select button 23, a cancel button 24, analog output terminals 31, 32, and a digital output terminal 33 are provided. A distance image DG is output as measurement data from the analog output terminal 31, and a two-dimensional image DM is output from the analog output terminal 32. The output format of the analog signal is, for example, the NTSC format. Digital output terminal 3
Reference numeral 3 is, for example, an RS232-C terminal, which is used to output the shooting condition data DS.

A liquid crystal display (LCD) 21 is used as a display means for an operation screen and an electronic finder.
The photographer can set the photographing mode by using the buttons 22 to 24 on the rear surface.

FIG. 3 is a block diagram showing the functional arrangement 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 above-mentioned optical unit OU. Optical system 40
At 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 No. 1 driver 44, the drive system 45 of the projection lens system 42, and the drive system 46 of the galvanometer mirror 43 are controlled by the system controller 61.

In the optical system 50, the 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. Both the sensor 53 and the color sensor 54 are 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 mechanism is a passive system adopted in a single-lens reflex camera, and is composed of 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 passive distance measurement using the AF sensor 57 has an advantage over the active distance measurement described later in that the measurable distance range is wide and the measurement can be repeated in a short cycle. However, the passive range measurement accuracy (resolution) is not sufficient.

Information on the image picked up by the sensor 53 is stored in the driver
The data is transferred to the output processing circuit 62 in synchronization with the clock from 5. The output processing circuit 62 generates slit data corresponding to each pixel of the sensor 53 and stores the slit data in the memory 63. After that, the slit data is read from the memory 63 and sent to the gravity center calculation circuit 64. The center-of-gravity calculation circuit 64 generates a high-resolution range image based on the slit data. The distance image is output online as measurement data in the form of a frame-synchronized video signal via the NTSC conversion circuit 65. The center-of-gravity calculation circuit 64 is provided with a CTRL register R1 that stores bit data (GCALC) for control by the system controller 61.

On the other hand, the image pickup information from the color sensor 54 is transferred to the color processing circuit 67 in synchronization with the clock from the driver 56. The imaging information (two-dimensional image DM) that has undergone color processing is output online via the NTSC conversion circuit 70 and the analog output terminal 32. The two-dimensional image DM is a color image having the same angle of view as the distance image obtained by the sensor 53, and is used as reference information for application processing on the host 3 side.

The system controller 61 gives an instruction to the character generator 71 to display appropriate characters / symbols on the screen of the LCD 21 according to the operation state at that time.

FIG. 4 is a principle diagram of the calculation of the three-dimensional position in the measuring system 1. The slit light U having a relatively wide width corresponding to a plurality of pixels on the image pickup surface S2 of the sensor 53 is transmitted to the object Q.
Irradiation. Specifically, the width of the slit light U is set to 5 pixels. The slit light U has an image pickup surface S for each sampling cycle.
It is deflected from top to bottom so that it moves by one pixel pitch pv on 2, thereby scanning the object Q.
The photoelectric conversion information for one field is output from the sensor 53 every sampling period.

Focusing on one pixel g on the image pickup surface S2,
Effective light reception data can be obtained in 5 out of N samplings performed during scanning. The pixel of interest g
The timing at which the optical axis of the slit light U passes through the object surface ag in the glare range (time barycenter Npeak: the time at which the amount of light received by the target pixel g becomes maximum) is determined. In the example of FIG. 4B, the amount of received light is maximum between the n-th time and the (n-1) -th time before the n-th time. Obtained time center of gravity Npeak
The position (coordinates) of the object Q is calculated based on the relationship between the irradiation direction of the slit light and the incident direction of the slit light with respect to the target pixel. As a result, it is possible to measure with a resolution higher than the resolution defined by the pixel pitch pv on the imaging surface. The irradiation direction of the slit light is uniquely specified by the time centroid Npeak if the irradiation start direction and the deflection angular velocity are known. Also, the incident direction is the sensor
And the light receiving lens.

The amount of light received by the pixel of interest g depends on the reflectance of the object Q. However, the relative ratio of each received light amount of the five samplings is constant regardless of the absolute amount of received light. That is, the shading of the object color does not affect the measurement accuracy.

In the measurement system 1 of the present embodiment, the center of gravity calculation circuit 64 of the three-dimensional camera 2 calculates the time center of gravity Npeak for each pixel g of the sensor 53, and the time center of gravity Npeak of the number of effective pixels is in NTSC format as a range image. It is transmitted to the host 3. As a result, the received light data for 5 fields is sent to the host 3 and the time center Np is
Compared with the case where eak is calculated, the amount of transmission data is significantly reduced, and the time required for serial transmission using an analog signal can be shortened. Note that the imaging condition and the device condition necessary for obtaining the coordinates of the object from the time center of gravity Npeak are the digital output terminal 33 in parallel with the transmission of the range image.
Is transmitted to the host 3 via.

FIG. 5 is a block diagram of the output processing circuit 62 and the memory 63, and FIG. 6 is a diagram showing a read range of the sensor 53. The output processing circuit 62 includes an AD conversion unit 620 that converts the photoelectric conversion signal output from the sensor 53 into 8-bit received light data, and four delay memories 621 to 621 connected in series.
624, a comparator 626, and a generator 62 indicating the field number (sampling number) FN.
7. The memory 63 includes five memory banks 63A to 63E for storing effective received light data (slit data) for five fields, a memory bank 63F for storing a field number FN having the maximum received light data, and a memory bank. It is composed of a memory control means (not shown) for addressing 63A to 63F. Each of the memory banks 63A to 63E has a capacity capable of storing the same number of received light data as the number of sampling points for measurement (that is, the number of effective pixels of the sensor 53).

By performing data delay in the four delay memories 621 to 624, the received light data for 5 fields for each pixel g is simultaneously stored in the memory banks 63A to 63A.
It can be stored in E. The sensor 5
In order to speed up reading of one field in S3, not the entire image pickup surface S2, as shown in FIG.
Is performed only on a part of the effective light receiving area (belt-shaped image) Ae. The effective light receiving area Ae is shifted by one pixel for each field as the slit light U is deflected. 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.

The AD conversion unit 620 uses 3 fields for each field.
The received light data D620 for two lines are serially output in the order of arrangement of the pixels g. Each delay memory 621 to 624
Is a FIFO having a capacity of 31 (= 32-1) lines
It is.

The light reception data D620 of the pixel of interest g output from the AD conversion unit 620 is delayed by two fields, and the past light reception data D620 of the pixel of interest g stored in the memory bank 63C is stored by the comparator 626. Is compared to the maximum value of. When the delayed received light data D620 (output of the delay memory 622) is larger than the past maximum value, the AD conversion unit 620 at that time point
And the outputs of the delay memories 621 to 624 are
Memory banks 63E, 63D, 63C, 63B, 63A
And the stored contents of the memory banks 63A to 63E are rewritten. At the same time, the received light data D620 stored in the memory bank 63C is stored in the memory bank 63F.
The field number FN corresponding to is stored.

That is, when the amount of light received by the target pixel g is maximized in the nth (n <N) field, the data of the (n-2) th field is stored in the memory bank 63A, The data of the (n-1) th field is stored in 63B and the data of the nth field is stored in the memory bank 63C.
The data of the (n + 1) th field is stored in D,
The data of the (n + 2) th field is stored in the memory bank 63E, and n is stored in the memory bank 63F.

FIG. 7 is a block diagram of the gravity center calculation circuit 64. The center of gravity calculation circuit 64 includes five multipliers 641 to 64.
5, a total of three adders 646 to 648, a divider 649, and a delay circuit 640 are included. (N-2) to (n +
The weights of -2, -1, 0, 1, and 2 are assigned to the five field numbers of 2) (that is, sampling time),
A weighted average calculation is performed on the received light data from each of the memory banks 63A to 63E. The weighted average value output from the divider 649 is the n-th sampling time and the time centroid Npeak.
It is the amount of time difference with respect to [see FIG. 4 (b)]. The time center of gravity Npeak can be obtained by adding this time shift amount and the field number FN from the memory bank 63F. The delay circuit 640 is provided to input the field number FN to the adder 648 at the same time as the time shift amount,
The field number FN is delayed by the time required for the weighted average calculation.

By sequentially reading the data corresponding to each pixel from the memory banks 63A to 63F and inputting it to the center of gravity computing circuit 64, the distance image DG which is the measurement information for one time is generated. The distance image DG is repeatedly output, for example, at a cycle of 30 times per second.

Next, the basic procedure of measurement by the three-dimensional camera 2 will be described. In the measurement system 1, the positional relationship between the three-dimensional camera 2 and the measurement target is variable. That is, the user can appropriately change the shooting distance and the angle according to the application. Therefore, prior to the measurement, the pre-processing of checking the layout relationship with the measurement target and setting the shooting conditions (shooting preparation)
Is done automatically.

FIG. 8 is a diagram showing the relationship between each point of the optical system and the object Q. When a zooming instruction is given to the three-dimensional camera 2 by a direct operation or a remote operation by the host 3, the variator part of the zoom unit 51 moves and the focusing part moves to perform focusing. An approximate object distance d ₀ is measured during the focusing process. In response to the driving of the lens of the light receiving system, the movement amount of the variator lens on the light projecting side is calculated, and the lens movement control is performed based on the calculation result. However, during shooting, zooming and focusing are prohibited to avoid changing shooting conditions due to lens movement.

The system controller 61 reads the encoder output of the focusing drive system 59 (extending amount Ed) and the encoder output of the zooming drive system 60 (zoom increment value fp) via the lens controller 58. Inside the system controller 61, the distortion aberration table, the principal point position table, and the image distance table are referred to, and shooting condition data corresponding to the extension amount Ed and the zoom step value fp are output to the host 2. The shooting condition data here includes a front principal point position, an image distance, and the like.

The system controller 61 also calculates the output (laser intensity) of the semiconductor laser 41 and the deflection conditions (projection start angle, projection end angle, deflection angular velocity) of the slit light U.

First, assuming that a plane object exists at an approximate object distance d ₀ , the projection angle is set so that the reflected light is received at the center of the sensor 53. Next, the laser intensity is calculated. In consideration of safety for the human body, the semiconductor laser 41 is pulse-lighted with the minimum intensity, and the output of the sensor 53 is captured. The projection angle at this time is the angle previously set based on the object distance d ₀ . The ratio between the captured signal and the proper level is calculated, and the temporary laser intensity is set. The pulse is turned on again with the set temporary laser intensity, and the output of the sensor 53 is captured. The temporary setting of the laser intensity and the confirmation of suitability are repeated until the output of the sensor 53 becomes a value within the allowable range. If the amount of received light is insufficient even if the light is emitted at the maximum intensity, exposure control is performed to extend the charge accumulation time of the sensor 53.

Subsequently, the distance d between the objectives is determined by the triangulation method from the projection angle of the slit light U and the light receiving position. Then, finally, the deflection condition is calculated based on the determined inter-object distance d. When the deflection condition is calculated, the offset doff between the rear principal point H ′ of the light receiving system, which is the distance measurement reference point of the inter-object distance d, and the light emission starting point A is considered. In addition, in order to secure the same measurable distance range d ′ at the ends in the scanning direction as well, a predetermined amount (for example, 8 pixels) of overscan is performed. The projection start angle th1, the projection end angle th2, and the deflection angular velocity ω are represented by the following equations.

Th1 = tan ^-1 [β × pv (np / 2 +
8) + L) / (d + doff)] × 180 / π th2 = tan ⁻¹ [−β × pv (np / 2 + 8) + L)
/ (D + doff)] × 180 / π ω = (th1-th2) / np β: Imaging magnification (= d / effective focal length freal) pv: Pixel pitch np: Number of effective pixels in the horizontal direction of the imaging surface S2 L: Base line Length Actual measurement is performed under the conditions calculated in this way, and device information including the specifications of the sensor 53 and shooting conditions are transmitted from the three-dimensional camera 2 to the host 3 together with the distance image DG. However, in the continuous mode described later, the device information is transmitted only at the first measurement. Table 1
Is a collection of main data that the three-dimensional camera 2 sends to the host 3.

[0040]

[Table 1]

The operation of the measuring system 1 will be described in more detail below. The operation of the three-dimensional camera 2 is a one-shot mode in which measurement is performed only once in response to a start instruction, and a continuous mode (continuous shooting in which continuous measurement is performed until a stop instruction is issued after receiving a start instruction). Mode)).

AF modes in the continuous mode include a variable mode and a fixed mode. The variable mode is a mode in which focusing is performed according to the output of the AF sensor 57 during a period other than during measurement. The fixed mode is a mode in which focusing is performed only at the first measurement. In either mode, the measurement of the object-to-object distance by the AF sensor 57 is constantly performed, including during measurement. When the photographing magnification is large (telephoto state), focus shift easily occurs, so the variable mode is suitable for obtaining a clear distance image. Further, according to the variable mode, the position of the object can be grasped even when the object moves largely. On the other hand, according to the fixed mode, the drive control of the lens can be omitted.

9 and 10 are time charts showing the operation of the three-dimensional camera 2 in the continuous mode. Table 2 shows the contents of control signals.

[0044]

[Table 2]

Here, the operation of the system controller 61 will be described focusing on the system controller 61. [1] In response to turning on of the start / stop button 27 or input of a start command from the host 3, preparation for photographing (preprocessing) is started. To prepare for shooting, as described above, the inter-object distance d is obtained by the light projection method, and the active AF (A
-AF) / projection angle setting / laser intensity setting.

[2] When the preparation for photographing is completed, the RUN bit of the CTRL register R1 is set to 1. And SSt
Wait for the art bit to become 1. [3] First VSync after the RUN bit becomes 1
In response to, the SStart bit is set to 1 and the frame counter is reset. The SStart bit is set back to 0 at the next VSync.

[4] [5] When the SStart bit becomes 1, the lens movement is prohibited in order to fix the photographing condition, and the scanning (photographing) of the object by the slit light U is started. During a period of about 0.8 seconds thereafter, the system controller 61 concentrates on scanning control, and the lens controller 58 executes distance measurement by the AF sensor 57. In this distance measurement, it is possible to predict the object distance at the start of the next scanning from the transition of the object distance.

[6] [7] When scanning is completed,
The GCALC bit of the CTRL register R1 is set to 1.
In response to this, the center-of-gravity calculation circuit 64 receives the time center of gravity Npeak
The calculation of is started. GCALC bit is a range image DG
When the generation of is completed, it is reset to 0 by the gravity center calculation circuit 64.

The lens controller 58 is permitted to restart lens movement. In response to this, the lens controller 58 starts passive AF (P-AF) in which the AF sensor 57 measures the distance between the objectives and moves the lens.

[8] [9] The NextI bit is set to 1 in response to the first VSync after the GCALC bit becomes 0.
At the same time, the frame memory is switched and the output of the latest distance image DG is started. After that, until the next scanning is performed and a new range image DG is generated,
The distance image DG having the same content is repeatedly output. Next
The I bit is reset to 0 at the first VSync after setting it to 1.

[10] Imaging conditions and device information are output to the host 3 from a port (digital output terminal 33) different from the distance image DG. Host 3 receives this signal
It is recognized that the latest distance image DG is output.
After the output of the predetermined data, the calculation for obtaining the distance condition and the exposure condition for the next shooting is executed based on the shooting information of this time, and waits until the SStart bit becomes 1. In addition,
At this stage, in the variable mode described above, the change in the object distance is detected based on the output of the passive AF.
Then, when there is a change in the distance between the objectives that exceeds the allowable value, high-precision distance measurement is performed again by the optical projection method, and focusing and shooting conditions are calculated.

[11] When the count value of the frame counter reaches one less than the specified value (OPR), the next V
The count value is reset with Sync and SSt
Set the art bit to 1. SS at the next VSync
Reset the start bit to 0. The OPR is manually set on the host side. That is, the user can set a desired measurement cycle.

[12] [13] If the SStart bit becomes 1, the lens movement is prohibited and scanning (imaging) is started, as in [4] [5]. After that, [6] to [1
1] is performed, and the measurement operations of [3] to [11] are repeated each time the SStart bit becomes 1. However,
In the second and subsequent measurements, counting from the start instruction,
The output of device information is omitted.

[14] [15] As shown in FIG. 10, the RUN bit is set to 0 in response to turning on the start / stop button 27 again or inputting a stop command from the host 3.
Return to When the stop instruction is given during the calculation of the center of gravity, the GCALC bit is reset to 0 at that point. No matter at what point in time the stop instruction is given, the output of the last obtained distance image DG is continued.

FIG. 11 is a time chart showing the operation of the three-dimensional camera 2 in the one-shot mode. [21] to [29] Perform the same operations as [1] to [9] in the continuous mode described above.

[30] If the NextI bit becomes 1,
Set the RUN bit back to 0. [31] The shooting condition and device information are output to the host 3 from the digital output terminal 33. After that, a start instruction is given, and the output of the last obtained distance image DG is continued until a new distance image DG is obtained.

FIG. 12 is a main flowchart of the operation of the system controller 61 of the three-dimensional camera 2. When the power is turned on, the control parameters including the bits of the CTRL register R1 are initialized (# 1). The mode is set according to a button operation or a command from the host 3 (# 2). At this time, the user can set the measurement cycle in the continuous mode in frame units.

When the start instruction is received, the measurement operation starts (# 3). If the AF mode is the variable mode, the first scan sequence is executed (# 4, 5), and if it is the fixed mode, the second scan sequence is executed (# 6).

FIG. 13 shows the first scan sequence and the second scan sequence.
It is a flowchart of a scan sequence. FIG.
As in (A), in the first scan sequence, passive AF is first started, and the focusing lens position is adjusted according to the relative movement of the object with respect to the three-dimensional camera 2 (# 51). When the start instruction is received, the passive AF is stopped and zooming is prohibited in order to prevent the lens movement during scanning (# 52, 5).
3).

The scanning process for obtaining the range image DG is executed, and when the scanning is completed, the passive AF is performed.
And resume zooming and remove the prohibition of zooming (#
54-56). After accepting command input and operation,
Waiting for the count value of the frame synchronization signal VSync to reach the set value, it is checked whether or not the end is appropriate (# 57-5).
9). In the one-shot mode, or when the end instruction is received in the continuous mode, the process returns to the main routine. If there is no end instruction in the continuous mode, the process returns to step # 52 to repeat the measurement.

On the other hand, in the second scan sequence as shown in FIG. 13B, first, the passive AF is started, and when the start instruction is received, the passive AF is stopped and zooming is prohibited (# 61 to 63). After performing the scanning process, the prohibition of zooming is released (# 64,
65). Passive AF does not restart. The command input and operation are accepted, and the suitability of the end is checked after waiting for the count value of the frame synchronization signal VSync to reach the set value (# 66 to 68). In the one-shot mode, or when the end instruction is received in the continuous mode, the process returns to the main routine. If there is no end instruction in the continuous mode, step # 63.
Return to and repeat the measurement.

FIG. 14 shows the scanning process (#
54 and # 64). As described above, the distance to the subject (object to be measured) is constantly measured by the distance measuring sensor 57. The amount of change in this distance (distance between objectives) is checked, and if the amount of change exceeds an allowable value, setting processing is performed to determine the distance between objectives by the slit light projection method and determine the imaging conditions (# 100, 10).
1). Even if the change amount does not exceed the allowable value, the setting process is executed in the first measurement in response to the start instruction (# 102). That is, as a general rule, the setting process (# 100) is omitted in the second and subsequent measurements, and the setting process is executed only when there is a large change in the object distance. This ensures the accuracy of the three-dimensional measurement and reduces the control load.

When the distance calculation mode is designated as the shooting condition setting mode in the continuous mode, the scanning control is executed to obtain the distance image DG under the shooting condition at that time, and then the immediately preceding shooting information is set. As a process for calculating the imaging condition for the next measurement based on this, the projection angle and the slit light amount are calculated (#
103-106). When the brightness calculation mode is designated, the slit light amount is calculated after executing the scanning control (# 107 to 109). When neither the distance calculation mode nor the brightness calculation mode is designated, that is, in the one-shot mode, the scanning control is executed and the process returns to the main routine (# 103, 107, 110).

By calculating the shooting condition for the next measurement based on the immediately preceding shooting information, the measurement cycle is set to the time required for the preliminary measurement, as compared with the case where the preliminary measurement is performed for each measurement and the shooting condition is calculated. It can be shortened. In addition, since detailed information on the space of the scanning range can be obtained in the measurement, when the measurement information of each time is used as the preliminary measurement information of the next measurement, for example, the case of the preliminary measurement in which the slit light U is projected in one direction is used. Compared with this, it is possible to calculate the shooting conditions more accurately.

FIG. 15 is a flowchart for calculating the projection angle. First, the distance image is analyzed to determine the representative value of the distance between the objectives (# 1051). The decision method is as follows.
There are various methods including.

Pixels are uniformly sampled from the entire image, and the shortest distance is used as a representative value. According to this, it is possible to avoid an error in which the distance of the background portion in the image is used as the representative value.

A plurality of pixels arranged vertically and horizontally near the center of the image are sampled, and the average value or the intermediate value of the distances is used as the representative value. This method has the advantage that the influence of noise is small. This is a method in which and are combined, and a plurality of pixels arranged vertically and horizontally from each area obtained by equally dividing the image are sampled.

Next, the principle of triangulation is applied to find the actual distance based on the device conditions such as the representative value and the pixel pitch, and the photographing conditions such as the focal length (# 1052).
Then, the start angle and the end angle of the projection in the scanning are set so that the predetermined range before and after the position of the obtained distance becomes the measurement target.

FIG. 16 is a flow chart for calculating the slit light amount. The received light data (reflected light amount) of the nth field stored in the memory bank 63C of the memory 63 is uniformly sampled, and the largest sampled value is used as the representative value. At this time, if the largest sampling value is the upper limit value, that is, if the amount of light received by the measurement sensor 53 is saturated, interpolation calculation is performed based on the light reception data of the pixel of interest in the (n ± 1) th field. The maximum amount of light is obtained by and the result is used as a representative value (# 1061).

Next, according to the representative value, the measuring sensor 53
The set value of the slit light amount is increased or decreased so that the received light amount of is the optimum value (# 1062). At this time, the amount of received light is optimized by adjusting the exposure time of the measurement sensor 53 together with the adjustment of the slit light amount as needed.

FIG. 17 is a flow chart of the setting process of FIG. If the shooting distance is not specified by operation or command input, the slit light U is emitted to obtain the distance between the objects based on the shooting information, and the scan is performed so that a predetermined range before and after the position of the obtained distance becomes the measurement target. Set the start angle and the end angle of the projection in the training (# 1011 to 1).
015). If the slit light intensity is not specified,
Based on the photographing information, the set value of the slit light amount is increased or decreased so that the received light amount of the measurement sensor 53 becomes the optimum value (# 1
015, 1019).

When the photographing distance is designated but the slit light amount is not designated, the slit light U is emitted and the set value of the slit light amount is increased or decreased based on the photographing information (# 1016).
-1019).

FIG. 18 is a flowchart of the measuring process of the host 3. A start command is sent to the three-dimensional camera 2 and the input of the shooting condition data DS is waited (# 31,
32).

In response to the input of the photographing condition data DS, the distance image DG is fetched as one measurement information (# 3).
3). Then, information processing is performed on the distance image DG (# 34). This information processing includes coordinate calculation based on the distance image DG and shooting conditions, writing the distance image DG to a recording medium, and the like. Predetermined end conditions (time,
Until the capture number end operation) is established, the capture of the latest range image DG in response to the input of the shooting condition data DS is repeated.

When the end condition is satisfied, a stop command is sent to the three-dimensional camera 2 to end the measurement process (# 35). The user can monitor the measurement situation by displaying the distance image DG on the display 3b of the host 3. It is also possible to display the distance image DG and the two-dimensional color photographed image.

According to the above-mentioned embodiment, since the photographing condition data DS is used as the capture control signal for the distance image DG, it is not necessary to separately provide the capture control signal.
The user can change the measurement cycle in the continuous mode in frame units according to the application.

[0077]

According to the first to third aspects of the present invention,
The measurement can be performed periodically and the setting of the measurement condition for each time can be adapted to the application.

[Brief description of drawings]

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

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

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

FIG. 4 is a principle diagram of calculation of a three-dimensional position in the measurement system.

FIG. 5 is a block diagram of an output processing circuit and a memory.

FIG. 6 is a diagram showing a reading range of a sensor.

FIG. 7 is a block diagram of a centroid calculation circuit.

FIG. 8 is a diagram showing a relationship between each point of the optical system and an object.

FIG. 9 is a time chart showing the operation of the three-dimensional camera in the continuous mode.

FIG. 10 is a time chart showing the operation of the three-dimensional camera in the continuous mode.

FIG. 11 is a time chart showing the operation of the three-dimensional camera in the one-shot mode.

FIG. 12 is a main flowchart of the operation of the system controller of the three-dimensional camera.

FIG. 13 is a flowchart of a first scan sequence and a second scan sequence.

14 is a flowchart of the scanning process of FIG.

FIG. 15 is a flowchart of calculation of a projection angle.

FIG. 16 is a flowchart of a calculation of a slit light amount.

17 is a flowchart of the setting process of FIG.

FIG. 18 is a flowchart of a host measurement process.

[Explanation of symbols]

2 three-dimensional camera (three-dimensional measuring device) 40 light projecting system (light projecting means) 53 measurement sensor (imaging means) 61 system controller (preliminary measuring means, control means) Q object U slit light (detection light)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takuto Ueko 2-33 Azuchi-cho, Chuo-ku, Osaka-shi, Osaka, Osaka International Building Minolta Co., Ltd. (72) Eiichi Ide Chuo-ku, Osaka-shi, Osaka 2-3-3 Azuchicho Osaka International Building Minolta Co., Ltd.

Claims (3)

[Claims] 1. An object shape is formed by a light projection method, comprising: a light projecting means for irradiating a detection light to optically scan an object, and an imaging means for receiving the detection light reflected by the object. A three-dimensional measuring device for measuring, comprising a preliminary measuring means for measuring a measuring environment, and a control means for setting a measuring condition according to the measuring environment measured by the preliminary measuring means, and measuring periodically. A continuous measurement mode is provided, and as a choice of the operation mode of the control means in the continuous measurement mode, a first mode in which the measurement condition of each time is fixed to the measurement condition set at the time of the first measurement, and a measurement condition of each time is measured. And a second mode for setting each measurement environment according to the newly measured measurement environment. 2. An object shape is formed by a light projection method, comprising: a light projecting means for irradiating the detection light to optically scan the object, and an imaging means for receiving the detection light reflected by the object. A three-dimensional measuring device for measuring, comprising a preliminary measuring means for measuring a measuring environment, and a control means for setting a measuring condition according to the measuring environment measured by the preliminary measuring means, and measuring periodically. A continuous measurement mode is provided, and in the continuous measurement mode, the control means fixes the measurement condition of each time to the measurement condition set at the time of the first measurement. 3. An object shape is formed by a light projection method, comprising a light projecting means for irradiating the detection light to optically scan the object, and an imaging means for receiving the detection light reflected by the object. A three-dimensional measuring device for measuring, comprising a preliminary measuring means for measuring a measuring environment, and a control means for setting a measuring condition according to the measuring environment measured by the preliminary measuring means, and measuring periodically. A continuous measurement mode is provided, and in the continuous measurement mode, the control means sets a measurement condition for each measurement in accordance with a newly measured measurement environment for each measurement.