JP3695169B2 - 3D input method and 3D input device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional input method and a three-dimensional input device for obtaining data for specifying an object shape by projecting reference light onto an object and scanning the object.
[0002]
[Prior art]
A non-contact type 3D input device called a range finder is capable of high-speed measurement compared to the contact type, so it can be used for data input to CG and CAD systems, body measurement, visual recognition of robots, etc. It's being used.
[0003]
A slit light projection method (also called a light cutting method) is known as a measurement method suitable for a range finder. This method is a method for obtaining a distance image (three-dimensional image) by optically scanning an object, and is a kind of active measurement method for photographing an object by projecting specific reference light. The distance image is a set of pixels indicating the three-dimensional positions of a plurality of parts on the object. In the slit light projection method, slit light in which the cross section of the projection beam is a straight belt is used as reference light. At a certain point during scanning, a part of the object is irradiated, and a bright line bent according to the undulation of the irradiated part appears on the imaging surface. Therefore, a group of data (three-dimensional input data) specifying the object shape can be obtained by sampling the luminance of each pixel on the imaging surface periodically during scanning.
[0004]
Conventionally, the incident angle of the slit light reflected on the object and incident on the imaging surface based on the position of the bright line in the imaging surface is obtained, and the incident angle, the projection angle of the slit light, and the base line length (projection origin and The position of the object was calculated by the triangulation method from the distance to the light receiving reference point. That is, position calculation based on the projection direction and the light receiving direction of the reference light has been performed.
[0005]
In the range finder, zooming for adjusting the angle of view of imaging is realized. In addition, in the luminance sampling of the imaging surface, there is a known method in which the sampling target is limited to a part of the region where the reference light is expected to enter instead of the entire imaging surface, and the region is shifted for each sampling. ing. According to this, the time required for one sampling can be shortened to increase the scanning speed, and the amount of data can be reduced to reduce the load on the signal processing system.
[0006]
[Problems to be solved by the invention]
Conventionally, the accuracy of the three-dimensional input data depends on the accuracy of the incident angle of the reference light specified based on the imaging information. For this reason, sufficiently high-precision three-dimensional input data cannot be obtained, There has been a problem that a complicated calculation is required to secure it. For example, when an object is imaged indirectly using a mirror, the accuracy of the incident angle is reduced as compared with the case of imaging directly because it is affected by the mirror surface accuracy and mounting orientation. In addition, when a zooming function or a focusing function is provided, a slightly different lens distortion correction must be performed for each stop position of the movable lens. In order to set the correction contents, it may be necessary to perform processing by switching the zoom stage and estimating the correction contents of other zoom stages from the measurement result.
[0007]
The present invention realizes a three-dimensional input that does not depend on the incident angle information of the reference light, eliminates the need for a calculation for obtaining the incident angle information, and performs 3 in the case where the accuracy of the incident angle information is lower than the projection angle information. The purpose is to improve the accuracy of the dimension input data.
[0008]
[Means for Solving the Problems]
In the present invention, reference light is projected onto an object starting from two points separated from each other, and triangulation is calculated from the distance between the starting points and the angle of projection from each starting point (the inclination with respect to a straight line connecting the starting points). The position of the object is calculated by the method. At that time, the imaging information of the object is used for confirming the coincidence of the irradiation position on the object projected from each starting point. However, information on the line-of-sight direction (incident angle of reference light) in imaging is not used. Projection from each starting point may be performed sequentially or simultaneously. When performing in order, the reference light of the same wavelength may be projected from each starting point. When performing at the same time, two kinds of distinguishable reference lights having different wavelengths and blinking periods are used.
[0009]
  The method of the invention according to claim 1 is the method of:MeasurementPartTo pass throughThe first reference light is projected and the second starting point separated from the first starting pointMeasurementPartTo pass throughProject a second reference beam,When the reflected light from the measurement part of the first and second reference lights is received at a position different from the first and second starting points, the first reference light passes through the measurement part. The projection angle of the first reference light and the second reference light when the second reference light passes through the measurement siteBased on the projection angle of the second reference light and the distance between the first and second starting points,MeasurementThis is a three-dimensional input method for calculating the position of a part.
  According to the method of the invention of claim 2, the reflected light from the measurement part of the first and second reference lights is received at a common position, and the first reference light passes through the measurement part. Based on the projection angle of the first reference light, the projection angle of the second reference light when the second reference light passes through the measurement site, and the distance between the first and second starting points. This is a three-dimensional input method for calculating the position of the measurement site.
[0010]
  Claim3The method of the present invention projects the first reference light so as to scan the virtual surface from the first starting point toward the virtual surface, and moves from the second starting point away from the first starting point toward the virtual surface. Projecting the second reference light so as to scan it, and detecting the time when each of the first and second reference light reflected by the object passes through each sampling section subdividing the virtual plane, The position of the object is calculated for each sampling section based on the respective projection angles of the first and second reference lights at each detected time point and the distance between the first and second starting points. This is a three-dimensional input method.
[0011]
  Claim4The apparatus according to the invention projects the first reference light so as to scan the virtual surface from the first starting point toward the virtual surface, and moves from the second starting point away from the first starting point toward the virtual surface. A light projecting system for projecting the second reference light so as to scan it, an imaging system for receiving the first and second reference lights reflected by the object and converting them into an electric signal, and the electric signal Based on signal processing means for detecting when each of the first and second reference light reflected by the object passes through each sampling section obtained by subdividing the virtual plane, and detected by the signal processing means It is a three-dimensional input device that outputs data corresponding to the projection angles of the first and second reference beams at each time point as position information of a plurality of parts in the object.
[0012]
  Claim5In the three-dimensional input device according to the invention, the light projecting system includes a first optical mechanism that projects the first reference light and a second optical mechanism that projects the second reference light.
[0013]
  Claim6In the three-dimensional input device of the invention, the light projecting system changes the projection start point by moving an optical mechanism for sequentially projecting the first and second reference lights and at least a part of the optical mechanism. Moving mechanism.
[0014]
  Claim7In the three-dimensional input device according to the invention, the first and second reference beams are slit beams, and the light projecting system scans the first and second reference beams in the first direction on the virtual plane. And the first reference light is projected so as to scan the virtual plane in a second direction orthogonal to the first direction.
[0015]
  Claim8In the three-dimensional input device according to the invention, the main point of image formation of the imaging system is a position between the first start point and the second start point.
  Claim9In the three-dimensional input device according to the invention, the principal point of image formation of the imaging system is a position equidistant with respect to both the first and second starting points.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a functional block diagram of a three-dimensional input device 1 according to the first embodiment.
The three-dimensional input device 1 includes a light projecting system 10 including two light projecting mechanisms 11 and 16 and an imaging system 20 capable of zooming and focusing, and is controlled by a CPU 31.
[0017]
The light projecting mechanism 11 includes a semiconductor laser 12 as a light source, a lens group 13 for projecting slit light, and a galvanometer mirror 14 as beam deflecting means for changing the projection angle. The lens group 13 includes a collimator lens and a cylindrical lens. Similarly, the light projecting mechanism 16 includes a semiconductor laser 17, a lens group 18, and a galvano mirror 19. The galvanometer mirrors 14 and 19 are supplied with deflection control signals from the light projection control circuit 32 via the D / A converters 33 and 34.
[0018]
The imaging system 20 includes a light receiving lens 21, a beam splitter 22, an image sensor 24 for obtaining a distance image representing the shape of the object Q, a monitor color image sensor 25, and a lens driving mechanism 26. The beam splitter 22 separates light in the emission wavelength range (for example, center wavelength 670 nm) of the semiconductor lasers 12 and 17 from visible light. The image sensor 24 and the color image sensor 25 are CCD area sensors. However, a CMOS area sensor may be used as the color image sensor 25. The output of the image sensor 24 is converted into received light data D35 by the A / D converter 35 and sequentially transferred to the memory circuit 37. The memory circuit 37 stores data (TA, TB) for specifying projection angles θA, θB, which will be described later, according to the value of the light reception data D35. The output of the color image sensor 25 is converted into received light data by the A / D converter 36 and is sequentially stored by the color image memory 38. The memory control circuit 39 is responsible for addressing the memory circuit 37 and the color image memory 38.
[0019]
The CPU 31 gives an instruction to the control target in a timely manner, and performs calculation to read out data from the memory circuit 37 and obtain distance image data. The distance image data is output to an external device (not shown) as three-dimensional input data in a timely manner. At this time, a two-dimensional color image stored in the color image memory 38 is also output. Examples of the external device include a computer, a display, and a storage device.
[0020]
FIG. 2 is a schematic diagram of projection, and FIG. 3 is a diagram for explaining how to generate distance image data.
The three-dimensional input device 1 projects the slit light U1 so as to scan the virtual surface VS with the point on the reflection surface of the galvanomirror 14 as the starting point A, and the virtual point with the point on the reflection surface of the galvanomirror 19 as the starting point B. The slit light U2 is projected so as to scan the surface VS. The virtual plane VS corresponds to a cross section orthogonal to the depth direction of a space (range within the angle of view) that can be imaged by the image sensor 24. A range corresponding to each pixel g in the image sensor 24 in the virtual plane VS is a sampling section for three-dimensional input. In FIG. 2, the starting point A, the starting point B, and the light receiving principal point C are arranged on a straight line. Here, the starting points A and B are aligned along the vertical direction, and the slit length direction of the slit light beams U1 and U2 is the horizontal direction.
[0021]
The outline of the three-dimensional input of the object Q is as follows.
The deflection angle of the galvanometer mirror 14 is controlled in synchronization with the imaging of the frame period by the image sensor 24. Then, it is detected at which point in time the projection of the slit light U1 that is being deflected by each pixel of the image sensor 24 is illuminated. The object projected with the slit light U1 is imaged by the image sensor 24, and the pixel g in the i column and the j row among the I × J pixels g._ijNote the output of pixel g_ijWhen the slit light U1 passes through the point P corresponding to, the output becomes the maximum value. That is, pixel g_ijThe point P exists on the plane specified by the projection angle θA (see FIG. 3) of the slit light U1 at the time TA at which the output of shows a peak and the spatial coordinates of the starting point A. Similarly, when the projection from the starting point B is performed, the pixel g_ijSince the point P exists on the plane specified by the projection angle θB of the slit light U2 and the spatial coordinates of the starting point B at the time TB at which the output becomes the maximum, the point P is on the intersection of these two planes. The existence of Therefore, based on the projection angles θA and θB and the base length L, the distance D in the depth direction between the base line passing through the starting points A and B and the point P can be calculated by applying the principle of triangulation. , B and the point P in the vertical direction and the relative position in the depth direction can be specified.
[0022]
If the above processing is performed for each pixel g, the position information of the sampling points for the number of pixels for the object Q can be obtained. In the configuration of the present embodiment, the position in the horizontal direction is undetermined, but depending on the application of the three-dimensional input data, the depth information is important and the position in the horizontal direction may not be so important. If the approximate position in the horizontal direction is sufficient, it can be simply calculated from the pixel position. Further, if the slit light U1 is deflected in the horizontal direction as will be described later, the position in the horizontal direction can be accurately measured. Note that the starting points A and B have a one-to-one correspondence with the projection angle at an arbitrary point in time, although the position and the time change of the position differ depending on the configuration of the light projecting system 10. Therefore, it is sufficient for the calculation of the three-dimensional position that only the projection angle of the projection angle and the starting position can be detected.
[0023]
Next, pixel g_ijA specific configuration of a circuit for detecting the times TA and TB at which the output of the output becomes maximum will be described.
FIG. 4 is a block diagram of a first example of the memory circuit.
[0024]
The illustrated memory circuit 37 includes two memories 371 and 376, a comparator 377, and an index generator 378. The memory 371 has a memory bank 371A used for the first scan by the light projecting mechanism 11 and a memory bank 371B used for the second scan by the light projecting mechanism 16. Similarly, the memory 376 has two memory banks 376A and 376B.
[0025]
The light reception data D35 is input from the A / D converter 35 to the memory 371, and the frame number T is input from the index generator 378 to the memory 376. . The comparator 377 compares the received light data D35 of the t-th frame which is the latest input data for each pixel of the image sensor 24 with the received light data D35 previously written in the memory 371, and the latest received light data D35 is the previous data. If the received light data is larger than the received light data D35, writing to the memories 371 and 376 is permitted. In response to this, each of the memories 371 and 376 overwrites with the latest input data. When the comparison result is opposite, the previous stored contents are held in the memories 371 and 376. Therefore, at the time when each scan is completed, the memory 371 stores each pixel g._ijEach time the maximum value of the received light data D35 is stored, the memory 376 stores each pixel g_ijEvery time, the frame number T in which the light reception data D35 is maximum is stored. Since the imaging of each frame is performed at a constant cycle, the frame number T represents the time during the scanning period (elapsed time from the start of scanning). That is, the frame number T stored in the memory 376 corresponds to the above-described times TA and TB, and is information for specifying the projection angles θA and θB.
[0026]
According to this example, the projection angles θA and θB can be detected with a relatively simple circuit configuration. However, the resolution for detecting the projection angle depends on the pixel pitch of the image sensor 24. The following second example is intended to improve the resolution.
[0027]
FIG. 5 is a block diagram of a second example of the memory circuit, and FIG. 6 is a diagram showing the relationship between the luminance distribution on the imaging surface and the received light data. 5, elements corresponding to those in FIG. 4 are denoted by the same reference numerals as those in FIG.
[0028]
The memory circuit 37b of the second example is provided with four memories 372, 373, 374, and 375 of the same size in addition to the memory 371, with a total of four 1-frame delay memories 379a to 379d interposed therebetween. Data input to each of the memories 372 to 375 is configured to be delayed by one frame from the memory 371 in order. That is, in the memory circuit 37b, each pixel g_ijConsecutive five frames of received light data D35 are simultaneously stored. The comparator 377 compares the input and output of the third memory 373 whose input is delayed by 2 frames. When the input data value of the memory 373 is larger than the output data value (the previously written data value), writing to the memories 371 to 375 and the memory 376 is permitted.
[0029]
At the end of each scan, the memory 373 stores each pixel g_ijEvery time, the maximum value of the received light data D35 is stored. The memories 371, 372, 374, and 375 store the light reception data D35 of a total of four frames, two frames before, one before, one after, and two after the frame in which the light reception data D35 is maximum. become. The memory 376 stores each pixel g_ijEvery time, the frame number T in which the light reception data D35 is maximum is stored.
[0030]
Here, as shown in FIG. 6A, the width of the slit light image formed on the imaging surface is 5 pixels, and the luminance distribution is a single peak. At this time, one pixel g_ijWhen attention is paid to this, the received light data of the change corresponding to the luminance distribution is obtained as shown in FIG. Therefore, by calculating the center of gravity based on the received light data D35 for five frames stored in the memories 371 to 375, the times TA and TB can be calculated in finer steps than the frame period (that is, the pixel pitch). it can. In the example of FIG. 6B, the time TA (TB) is between the t-th sampling time and the (t + 1) -th sampling time.
[0031]
According to the second example, the resolution is improved, but there is a problem that a desired accuracy cannot be obtained depending on the luminance distribution. That is, in actual imaging, some noise is added to the imaging due to the characteristics of the optical system. For this reason, a plurality of peaks occur in the luminance distribution, or the luminance distribution is flat and unclear. If the luminance distribution deviates greatly from the ideal shape, the reliability of the centroid calculation decreases.
[0032]
The effect of such noise is that the calculation of the center of gravity is performed based on the luminance distribution over a sufficiently long period rather than the short period of time when the frame where the maximum luminance value is obtained and the several frames before and after it are combined. Can be reduced. This is achieved by the third example below.
[0033]
FIG. 7 is a block diagram of a third example of the memory circuit, and FIG. 8 is a conceptual diagram of the center of gravity according to FIG.
The memory circuit 37c of the third example includes a memory 3710, a stationary light data storage unit 3720, a subtraction unit 3730, a first addition unit 3740, a second addition unit 3750, and a division unit 3760, and each pixel g_ijThe center of gravity (temporal center of gravity) is calculated based on the received light data D35 for the number of frames every time.
[0034]
The memory 3710 has two banks, and stores light reception data D35 of a predetermined number k of frames obtained by the first and second scans performed in order. Each pixel g_ijX is the received light data value of the Tth (T = 1 to k) frame._TIt expresses. The steady light data storage unit 3720 stores steady light data representing unnecessary incident light amounts other than the slit lights U1 and U2. The steady light data is calculated based on the received light data D35 when the slit lights U1 and U2 are not incident. The value s may be a predetermined fixed value or may be obtained in real time using the received light data D35. In the case of a fixed value, when the received light data D35 is 8 bits (256 gradations), for example, “5” “6” or “10” is set. The subtracting unit 3730 receives the value x of the received light data D35 read from the memory 3710._TThe value s of the stationary light data is subtracted from Here, the value of the output data from the subtracting unit 3730 is changed to X_TAnd The first addition unit 3740 includes a pixel g_ijFor each of the k received light data D35, each value X_TIs multiplied by the corresponding frame number T, and the total value of the obtained products is output. The second addition unit 3750 is connected to the pixel g_ijK values of received light data D35 for each value X_TOutput the sum of. Division unit 3760 divides the output value of first addition unit 3740 by the output value of second addition unit 3750, and outputs the obtained center of gravity as time TA (or TB).
[0035]
FIG. 9 is a diagram illustrating a setting example of the positional relationship between the light projection start point and the light receiving main point.
In the arrangement of the light projecting system 10 and the imaging system 20, it is not always necessary to have a configuration as shown in FIG. 9A or 9B in which the light projection starting points A and B and the light receiving principal point C are aligned. . For example, the configuration shown in FIG. 9C in which three points are arranged in an L shape when viewed from the object side, or the configuration in FIG. 9D arranged in a T shape may be adopted. In particular, if the main point C is arranged between the starting point A and the starting point B as shown in FIG. 9B or 9D, the occlusion that occurs due to the different positions of the starting points A and B can be reduced. . In this case, it is preferable to make the distance d between the main point C and the starting points A and B equal.
[0036]
FIG. 10 is a functional block diagram of the three-dimensional input device 2 according to the second embodiment. In FIG. 10 and each of the following drawings, the functions of the constituent elements denoted by the same reference numerals as those in FIG.
[0037]
The configuration of the three-dimensional input device 2 is the same as that of the three-dimensional input device 1 of FIG. 1 except for the light projecting system 10b and the part related to the control thereof. In the three-dimensional input device 2, the light projecting system 10 b includes a light projecting mechanism 11 and a moving mechanism 110 that translates the light projecting mechanism 11. By moving the light projecting mechanism 11 while maintaining the positional relationship of the semiconductor laser 12, the lens group 13, and the galvanometer mirror 14, the slit light starts from two points separated from each other, as in the case of providing two light projecting mechanisms. U1 and U2 can be projected. Instead of moving the light projecting mechanism 11, it is also possible to provide a mirror so as to be retractable in the optical path and change the starting point.
[0038]
FIG. 11 is a functional block diagram of the three-dimensional input device 3 according to the third embodiment.
In the third embodiment, spot light V1 and V2 having a beam cross section are projected instead of slit light, and imaging is performed using a one-dimensional image sensor (line sensor) 27.
[0039]
The three-dimensional input device 3 includes a light projecting system 10c composed of two light projecting mechanisms 11c and 16c, and an imaging system 20c capable of zooming and focusing. The light projecting mechanism 11 includes a semiconductor laser 12, a collimator lens 13c, and a galvanometer mirror 14c. Similarly, the light projecting mechanism 16c includes a semiconductor laser 17, a collimator lens 18c, and a galvanometer mirror 19c.
[0040]
The imaging system 20c includes a light receiving lens 21, a lens driving mechanism 26, an infrared cut filter F1, a band pass filter F2, a filter switching mechanism 28, and an image sensor 27 that is used for both three-dimensional input and monitor photographing. The image sensor 27 is a 3-line CCD sensor having pixel columns corresponding to RGB colors. An infrared cut filter F1 is used for monitor photographing. In the case of three-dimensional input, a band pass filter F2 that transmits light in the laser wavelength region is used, and only the output of the R pixel column of the image sensor 27 is used as light reception information.
[0041]
Also in the case of using the spot lights V1 and V2, the position of the point P on the object Q can be calculated by detecting the times TA and TB. Since the principle is the same as that in the case of using the slit lights U1 and U2, the description thereof is omitted here.
[0042]
FIG. 12 is a functional block diagram of the three-dimensional input device 4 according to the fourth embodiment, and FIG. 13 is a schematic diagram of projection according to FIG.
In the fourth embodiment, scanning in the horizontal direction by the slit light U1 is enabled, and the horizontal position of the point P on the object Q can be accurately specified.
[0043]
The configuration of the three-dimensional input device 4 is the same as that of the three-dimensional input device 1 of FIG. The light projecting system 10d of the three-dimensional input device 4 includes two light projecting mechanisms 11 and 16 and a rotating mechanism 120 for switching the deflection direction of the light projecting mechanism 11 between a vertical direction and a horizontal direction. . By rotating the light projecting mechanism 11 by 90 ° while maintaining the positional relationship among the semiconductor laser 12, the lens group 13, and the galvanometer mirror 14, scanning in the horizontal direction becomes possible.
[0044]
In the three-dimensional input device 4, the light projecting mechanism 11 is rotated about the starting point A by 90 ° following the scanning for detecting the time (center of time) TA and TB by deflecting the slit light beams U 1 and U 2 in the vertical direction. Thus, horizontal scanning with the slit light U3 is performed. In horizontal scanning, each pixel g is processed in the same manner as in the vertical direction._ijIs obtained as a time centroid (time) TC at which the output is maximized. The horizontal position of the point P is calculated by applying the triangulation method from the horizontal projection angle uniquely determined by the time center of gravity TC and the distance D obtained from the vertical projection angles θA and θB as described above. can do.
[0045]
FIG. 14 is a diagram showing a device configuration example that realizes omnidirectional input [FIG. 14A] and omnidirectional input [FIG. 14B] by rotation, and FIGS. 15 and 16 show omnidirectional input by a mirror (FIG. 15). FIG. 17 is a diagram illustrating a device configuration example that realizes all-around input (FIG. 16).
[0046]
The three-dimensional input device 5 of FIG. 14A includes an optical system 10e that performs light projection and imaging, and a turntable 45 that rotates with an object Q mounted thereon. The optical system 10e has a light receiving main point arranged between the light projection starting points, and is configured to switch a filter to perform three-dimensional input and color photographing with a single image sensor. When the turntable 45 scans the object Q from a certain direction to obtain the center of gravity, the turntable 45 rotates by a predetermined angle. By repeating the scanning by the optical system 10e and the rotation of the turntable 45 N times, three-dimensional input over an angular range of 360 ° at the maximum on the outer peripheral surface of the object Q is possible. The optical system 10e is provided with a memory capable of storing data for N times. Since it is the number of times of scanning data, the direction component can be obtained in the form of n × θ, so that three-dimensional position data in the space of the measurement object can be obtained. The object Q may be stationary and the optical system 10e may be rotated around the object Q.
[0047]
In the three-dimensional input device 6 of FIG. 14B, the optical system 10 e is attached on the turntable 46. If the three-dimensional input device 6 is used, omnidirectional three-dimensional input of the inner wall surface of an object having a cavity can be performed.
[0048]
FIG. 15 shows a configuration example of an omnidirectional three-dimensional measuring apparatus using a convex curved mirror 210. On the axis of the curved mirror 210, the imaging device (for example, video camera) 20f is arranged so that its optical axis coincides with the mirror axis. The curved mirror 210 has a shape that is axisymmetrical and has a curved surface that monotonously increases its inclination, such as a hyperboloid, for example. As a result, an image of the entire circumference around the axis in the range E in the drawing is taken into the imaging device 20f, except for a range in which the imaging system 20f and the optical system including the light projecting system are reflected.
[0049]
Further, a light projecting system 10 f including a light source 12, a lens 13 f, a scanning mirror 15, and a mirror rotating mechanism 130 is disposed on the axis of the curved mirror 210. The light emitted from the light source 12 is adjusted into a beam having an appropriate diameter by the lens 13f, reflected by the scanning mirror 15, and projected. The scanning mirror 15 can control the angle around the axis perpendicular to the axis of the curved mirror 210 (B in the figure), and deflects the projected beam as indicated by B 'in the figure. This is sub-scanning. For example, if a scanning mirror 15 with an angle control mechanism such as a galvano scanner is used, this sub-scanning can be realized.
[0050]
The mirror rotating mechanism 130 rotates the scanning mirror 15 during sub-scanning around the curved mirror axis alone or together with at least one of the lens 13f and the light source 12 (A in the figure). As a result, the beam scans the entire circumference around the curved mirror axis, that is, around the optical axis of the imaging device. This is referred to as main scanning.
[0051]
For one period of main scanning (one rotation in direction A), the angle of the scanning mirror 15 is changed by the resolution in the sub-scanning direction B. If this is repeated during one-way one sub-scan in the range B 'in the figure, the entire range around the curved mirror axis can be scanned with the beam in the range B'.
[0052]
One period of main scanning is set to be equal to or shorter than the exposure time of the imaging device 20f. The trajectory of the reflected light of the beam projected in all directions at the beam projection angle, that is, the deflection angle φ (direction B in the figure) of the scanning mirror 15 can be imaged. Each time an image is taken, the angle of the scanning mirror 15 is changed by the resolution in the sub-scanning direction B. While repeating this operation, the above-described center-of-gravity image A (a set of pixels indicating the time TA) is created.
[0053]
Thereafter, the moving mechanism 117 moves the position of the light projecting system 10f by a predetermined distance in the curved mirror axis direction (C in the figure), and creates the center-of-gravity image B (a set of pixels indicating the time TB) by the above-described operation. .
[0054]
Based on the principle of triangulation using the angular position of the scanning mirror 15 at each position of the light projection system with respect to each pixel and the distance moved by the light projection system 10f from the two gravity center images A and B, the vertical direction And the position in the depth direction. Further, the azimuth angle can be obtained from each pixel and the image center position (position corresponding to the curved mirror axis). Therefore, a three-dimensional position in space can be calculated for each pixel in the image.
[0055]
FIG. 16 shows a configuration example of an omnidirectional three-dimensional measuring apparatus using an inverted frustoconical curved mirror 220. A curved mirror 220 whose inner surface is a reflecting surface is arranged with its axis oriented in the vertical direction. The mirror shape can be expressed by the following equation, where the coordinate axis h is vertically upward, the mirror cross-sectional radius with respect to a certain height h is r, and the angle of the mirror surface with respect to the h axis is θm.
[0056]
r = h · tan θm + R
Here, R is the value of r for h = 0. It is assumed that an input target object Q (human body in the illustrated example) Q is placed therein. The imaging device 20g and the light projecting system 11g are arranged above the curved mirror 220 so that their optical axes coincide with the mirror axes. By appropriately setting the apex angle of the inverted truncated cone in the curved mirror 220, the distance from the imaging device 20g, and the angle of view of imaging, the imaging device 20g passes through the curved mirror 220 and the entire object Q except for the vicinity of the vertex. The image of the lap can be captured in one image. The light projecting system 11g can rotate the projection direction (M1 direction in the drawing) of the light beam with the axis of the mirror as the rotation axis. This is referred to as main scanning. At the same time, it is assumed that the projection angle θy of the light beam can be scanned in the vertical plane (M2 direction in the figure). This is sub-scanning. The scanning in the M1 direction can be realized by rotating part or all of the light projecting system 11g using a power source such as a motor. The change in the M2 direction can be easily performed by using a scanning device such as a galvano scanner. The light projecting system 11g has a size and a shape so that it falls within a circular area near the center where there is no reflecting surface of the mirror and is not involved in the input of three-dimensional information in the field of view of the imaging device 20g. And determine the installation position in the vertical direction.
[0057]
Assume that an image of a point P on the object Q is observed as a point Pi in the captured image. Since this three-dimensional input apparatus 8 is axially symmetric, for the sake of simplicity, the following description will be given focusing on a certain vertical section including the mirror axis with the azimuth angle fixed.
[0058]
Assume that the height of the projection start point of the light beam is h = hx, and the light beam reaches the point P from the path x through x ′ at a certain timing. With respect to the projection angle θx, the light beam follows the path x ′ expressed by the following expression after reflection through the path x.
[0059]
r = h · tan (θx + 2θm)
+ [Tan θx (hxtan θm + R)
−tan (θx + 2θm) (hxtanθx−R)] / (tanθm + tanθx)
A point P exists on this path x '.
[0060]
Further, it is assumed that the height of the projection start point of the light beam is h = hy and the light beam reaches the point P from the path y via y ′ at a certain timing. With respect to the projection angle θy, the light beam follows the path y ′ expressed by the following equation after reflection through the path y.
[0061]
r = h · tan (θy + 2θm)
+ [Tan θy (hytan θm + R)
−tan (θy + 2θm) (hytanθx−R)] / (tanθm + tanθy)
The point P exists on this path y ′.
[0062]
From the above, the position of point P (point Pi in the image) (depth position: r, vertical position: h) is determined as the intersection of path x 'and path y'. Therefore, the position of the point P can be calculated from the projection angles θx and θy of the light beam. Further, the azimuth angle can be obtained from the point Pi and the image center position (position corresponding to the curved mirror axis) in the image.
[0063]
Therefore, it is possible to calculate a three-dimensional position in space for each pixel in the image.
The process of three-dimensional input will be described although it is partly repeated. One period of the main scanning described above is set to be equal to or shorter than the exposure time of the imaging device 20f. The trajectory of the reflected light of the beam projected from all directions at the beam projection angle, that is, the deflection angle θ of the scanning mirror (direction M2 in the figure) can be imaged. Each time an image is taken, the angle of the scanning mirror is changed by the resolution in the sub-scanning direction. The center-of-gravity image A is created while repeating this operation. Thereafter, the position of the light projecting system 11g is moved by a predetermined distance in the curved mirror axis direction (M3 in the figure) by the moving mechanism 118, and the center of gravity image B is created by the above-described operation.
[0064]
The deviation angle of the scanning mirror at each position of the light projection system 11g with respect to each pixel is obtained from the two gravity center images A and B. Using these values and the distance moved by the projection system 11g, the positions in the vertical direction and the depth direction are obtained by the principle of triangulation. Further, the azimuth angle can be obtained from each element and the image center position (position corresponding to the curved mirror axis). Therefore, it is possible to calculate a three-dimensional position in space for each pixel in the image.
[0065]
【The invention's effect】
  Claims 1 to9According to the invention, when the three-dimensional input that does not depend on the incident angle information of the reference light is realized, the calculation for obtaining the incident angle information is unnecessary, and the accuracy of the incident angle information is lower than the projection angle information. The accuracy of the three-dimensional input data can be improved.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a three-dimensional input device according to a first embodiment.
FIG. 2 is a schematic diagram of projection.
FIG. 3 is a diagram for explaining how to generate distance image data;
FIG. 4 is a block diagram of a first example of a memory circuit.
FIG. 5 is a block diagram of a second example of the memory circuit.
FIG. 6 is a diagram illustrating a relationship between luminance distribution on the imaging surface and light reception data.
FIG. 7 is a block diagram of a third example of the memory circuit.
FIG. 8 is a conceptual diagram of the center of gravity according to FIG. 7;
FIG. 9 is a diagram illustrating a setting example of a positional relationship between a light projection start point and a light receiving main point.
FIG. 10 is a functional block diagram of a three-dimensional input device 2 according to the second embodiment.
FIG. 11 is a functional block diagram of a three-dimensional input device 3 according to a third embodiment.
FIG. 12 is a functional block diagram of a three-dimensional input device 4 according to a fourth embodiment.
13 is a schematic diagram of projection according to FIG. 12. FIG.
FIG. 14 is a diagram illustrating an example of a device configuration that realizes omnidirectional input or omnidirectional input by rotation.
FIG. 15 is a diagram illustrating a configuration example of an apparatus for realizing omnidirectional input by a mirror.
FIG. 16 is a diagram illustrating a configuration example of an apparatus that realizes all-around input using a mirror.
[Explanation of symbols]
1-8 3D input device
A, B starting point
P point (specific part on the object)
U1, U2 Reference light
L Baseline length (distance between starting points)
VS virtual plane
TA, TB time (when passing through the sampling section)
θA, θB Projection angle
10 Flood light system
20 Imaging system
37 Memory circuit (signal processing means)
11 Projection mechanism (first optical mechanism)
16 Light projection mechanism (second optical mechanism)
110 Movement mechanism

Claims (9)

The first reference light is projected from the first starting point so as to pass through the measurement site on the object, and the second reference is provided so as to pass through the measurement site from the second starting point that is separated from the first starting point. Project light,
The reflected light from the measurement site of the first and second reference light is received at a position different from the first and second starting points,
The projection angle of the first reference light when the first reference light passes through the measurement site and the projection angle of the second reference light when the second reference light passes through the measurement site The three-dimensional input method, wherein the position of the measurement site is calculated based on the distance between the first and second starting points. The first reference light is projected from the first starting point so as to pass through the measurement site on the object, and the second reference is provided so as to pass through the measurement site from the second starting point that is separated from the first starting point. Project light,
The reflected light from the measurement site of the first and second reference light is received at a common position,
The projection angle of the first reference light when the first reference light passes through the measurement site and the projection angle of the second reference light when the second reference light passes through the measurement site The three-dimensional input method, wherein the position of the measurement site is calculated based on the distance between the first and second starting points. The first reference light is projected so as to scan the virtual surface from the first starting point, and is scanned from the second starting point away from the first starting point toward the virtual surface. Project a second reference beam to
Detecting when each of the first and second reference beams reflected by the object passes through each sampling section obtained by subdividing the virtual plane;
The position of the object is calculated for each sampling section based on the respective projection angles of the first and second reference lights at each detected time point and the distance between the first and second starting points. A three-dimensional input method characterized by the above. The first reference light is projected so as to scan the virtual surface from the first starting point, and is scanned from the second starting point away from the first starting point toward the virtual surface. A light projecting system for projecting the second reference light to
An imaging system that receives the first and second reference lights reflected by the object and converts them into electrical signals;
Signal processing means for detecting when each of the first and second reference beams reflected by an object passes through each sampling section obtained by subdividing the virtual plane based on the electrical signal;
Data corresponding to the projection angles of the first and second reference lights at each time point detected by the signal processing means is output as position information of a plurality of parts in the object. apparatus. The three-dimensional input device according to claim 4 , wherein the light projecting system includes a first optical mechanism that projects the first reference light and a second optical mechanism that projects the second reference light. The light projection system, according to claim 4 and a moving mechanism for changing the optical mechanism for projecting the first and second reference light in order, the starting point of the projection by moving at least a portion of said optical mechanism The three-dimensional input device described. The first and second reference lights are slit lights,
The light projecting system projects the first and second reference lights so as to scan the virtual surface in a first direction, and the first reference light is orthogonal to the first direction. 3D input device according to any one of claims 4 to 6 projects so as to scan in the second direction. Principal point of the imaging of the imaging system, three-dimensional input device according to any one of claims 4 to 7 which is located between said second starting point and said first starting point. The three-dimensional input device according to claim 8 , wherein a principal point of image formation of the imaging system is a position equidistant with respect to both the first and second starting points.

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