JP2010048662A - Visual system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visual system which enables attainment of high resolution and high-speed processing. <P>SOLUTION: The visual system measures the distance to an object by receiving the reflection of light radiated to the object, and is equipped with a light source, an optical element and a light-receiving part. The optical element varies the direction of a reflecting surface which reflects the light emitted from the light source, and thereby shifts the direction of radiation of the light, for scanning, to the main scanning direction. When the light that the optical element emits is radiated on the object, the light-receiving part receives at least part of the scattered light reflected on the surface of the object. The light source includes a plurality of light-emitting elements and a light emission control part. The light-emitting parts are provided apart from each other and emit lights, respectively toward the reflecting surface that the optical element has. The light emission control part makes one of the light-emitting elements emit the light sequentially. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a visual device, and more particularly to a visual device used in a machine vision system, a manipulator, or the like.

  Conventionally, visual devices used for machine vision systems, manipulators, and the like have been actively developed. There are various methods by which a visual device recognizes an object. For example, a method using a stereo image (for example, see Patent Document 1), a laser radar method (for example, see Patent Document 2), and triangulation are used as detection principles. A method (for example, refer to Patent Document 3) is known.

  In the three-dimensional image display device using the method using the stereo image disclosed in Patent Document 1, object recognition is performed using stereo images respectively captured from two different positions. Specifically, the 3D image display apparatus obtains 3D measurement data using a stereo image, and visualizes the 3D measurement data integrated with a texture.

  In the monitoring system using the laser radar method disclosed in Patent Document 2, an object is recognized by irradiating an object with a laser. Specifically, the monitoring system irradiates the laser while changing the turning and elevation, measures the time until the reflected light returns, and calculates the distance to the object.

  In the three-dimensional measurement apparatus using the method based on the detection principle of triangulation disclosed in Patent Document 3, the laser light emitted from a single light projecting laser is reflected by a polygon mirror that rotates at a constant speed. Irradiate the surface of the object to be measured. Thereby, scanning in the X direction (direction along the rotation direction of the polygon mirror) is performed on the object to be measured. On the other hand, the object to be measured is moved at a constant speed in the Y direction perpendicular to the X direction. As a result, scanning in the XY direction is performed on the object to be measured.

Then, the laser reflected light reflected from the surface of the object to be measured is received by a PSD (Position Sensitive Device; position detection element) through a light receiving condenser lens. Since the light spot position detected by the PSD changes according to the surface unevenness of the object to be measured, the amount of unevenness of the object to be measured at the location being scanned can be obtained using the amount of change.
JP 2005-165468 A JP 2003-337172 A Japanese Patent Laid-Open No. 10-54708

  However, when an object is recognized by a method using a stereo image as in the three-dimensional image display device disclosed in Patent Document 1, it takes time to perform image processing, and high-speed sampling becomes difficult. In addition, in this method, it is possible to recognize only the feature points of the recognized object, and it is difficult to obtain position information on the entire screen. Furthermore, this method requires two auxiliary lights for use in dark places and two cameras for obtaining a stereo image, which increases the cost of the visual device itself.

Further, when an object is recognized by a laser radar system as in the monitoring system disclosed in Patent Document 2, the object is determined by the time from when the laser is scanned onto the object until the laser reflected light returns. Therefore, the measurement resolution is low (for example, several tens of mm). In addition, since the two-dimensional scanning is performed, the measurement frequency is slow. Furthermore, if it is attempted to increase the measurement frequency, the processing time becomes longer because the number of scans increases.

  Further, as in the three-dimensional measurement apparatus disclosed in Patent Document 3 described above, when an object is recognized by a method based on triangulation, the measurement frequency becomes slow because of two-dimensional scanning. Further, if the measurement frequency is increased, the processing time becomes longer because the number of scans increases. Furthermore, in order to increase the processing speed, it is necessary to increase the number of rotations of the polygon mirror. However, there is a limit in the apparatus configuration, and the speed cannot be increased beyond the limit.

  Therefore, an object of the present invention is to provide a visual device capable of realizing high resolution and high processing speed.

  In order to achieve the above object, the present invention has the following features.

  1st invention is a visual device which measures the distance with the said object by receiving the reflected light of the light irradiated with respect to the object. The visual device includes a light source, an optical element, and a light receiving unit. The optical element changes the direction of the reflecting surface that reflects the light emitted from the light source, thereby scanning the direction in which the light is irradiated in the main scanning direction. The light receiving unit receives at least a part of the scattered light reflected by the surface of the object when the light irradiated by the optical element is irradiated on the object. The light source includes a plurality of light emitting elements and a light emission control unit. The plurality of light emitting elements are provided apart from each other, and each emits light toward a reflecting surface of the optical element. The light emission control unit sequentially causes one of the plurality of light emitting elements to emit light.

  In a second aspect based on the first aspect, the optical element is a polygon mirror. The polygon mirror has a plurality of side surfaces serving as reflection surfaces around a rotation axis provided in the sub-scanning direction, and changes the direction of the reflection surface by rotating in the main scanning direction around the rotation axis.

  In a third aspect based on the second aspect, the plurality of side surfaces of the polygon mirror are inclined at different angles with respect to the rotation axis.

  According to a fourth invention, in any one of the first to third inventions, the plurality of light emitting elements are arranged in a row apart from each other in the sub-scanning direction perpendicular to the main scanning direction.

  According to a fifth invention, in any one of the first to third inventions, the plurality of light emitting elements are arranged in a row apart from each other in the main scanning direction.

  According to a sixth invention, in any one of the first to third inventions, the plurality of light emitting elements are arranged apart from each other in an oblique lattice shape.

  According to a seventh invention, in any one of the first to third inventions, a polarizing section is further provided. The polarizing unit is provided between the plurality of light emitting elements and the optical element, and separates the light emitted from the light emitting element into two orthogonal polarization components, and enters the reflecting surface of the optical element. The light receiving unit includes two light receiving elements that separately receive two polarized components separated by the polarizing unit.

In an eighth aspect based on any one of the first to third aspects, the light receiving section includes a condenser lens and a position detection section. The position detection unit detects the light spot position of the scattered light collected through the condenser lens. The visual device further includes a distance calculation unit. The distance calculation unit calculates the distance to the object at the light position based on the light spot position detected by the position detection unit and the light position irradiated by the optical element.

  In a ninth aspect based on the eighth aspect, the light receiving section further includes a zoom mechanism. The zoom mechanism increases the focal length until the scattered light is enlarged and collected by the position detection unit.

  In a ninth aspect based on the ninth aspect, the apparatus further includes a return light detection unit, an approximate distance measurement unit, a range selection unit, and a light reception control unit. When the light irradiated by the optical element is irradiated on the object, the return light detection unit detects the light reflected by the surface of the object and returning to the optical element. Based on the position of the light irradiated by the optical element and the time from when the light source emits the light until the return light detection unit detects the light returning to the optical element, the approximate distance measuring unit reaches the object at the position of the light. Calculate the approximate distance. The range selection unit selects a reflection range of the scattered light to be detected by the position detection unit for the light spot position according to the approximate processing for each light position calculated by the approximate distance measurement unit. The light reception control unit sets the condensing direction in which the condensing lens collects the scattered light and the enlargement factor of the zoom function according to the reflection range selected by the range selecting unit, and based on the condensing direction and the enlargement factor. The focal length of the zoom function is changed by changing the direction of the light receiving unit.

  According to an eleventh aspect of the present invention, in any one of the first to third aspects, the plurality of light emitting elements are spaced apart from each other at equal intervals, and the emitted light is focused on or near the reflecting surface of the optical element. Provided.

  According to the first aspect of the invention, the plurality of light emitting elements sequentially emit light, and are reflected by the reflecting surface of the optical element, so that the direction in which the light emitting element is provided and the main scanning direction in which the optical element is scanned are moved. It is possible to sequentially irradiate light with the extended wide range as a scanning range. In addition, it is possible to realize high-speed processing and high resolution by increasing the timing of light emission / quenching of a plurality of light-emitting elements. Therefore, it is possible to realize high resolution and high processing speed without being affected by the device configuration limit of the optical element.

  According to the second aspect of the invention, the polygon mirror is rotated with the side surface of the polygon mirror as the reflection surface, thereby moving the direction of irradiating light emitted from the light source in the main scanning direction with high accuracy and high speed. Can do.

  According to the third aspect of the invention, by scanning the light emitted from the light source on each side of the polygon mirror, the light moving in the main scanning direction is moved in the sub-scanning direction on each side of the polygon mirror for scanning. It can move, and irradiation of a wider range of light becomes possible.

  According to the fourth aspect of the present invention, the plurality of light emitting elements arranged in the sub-scanning direction sequentially emit light, and the direction in which the optical element is irradiated with light is scanned and moved in the main scanning direction. It is possible to sequentially irradiate light with a wide range expanded in the sub-scanning direction as a scanning range.

  According to the fifth aspect, the plurality of light emitting elements arranged in the main scanning direction sequentially emit light, and the direction of irradiating light with the optical element is scanned in the main scanning direction, thereby moving in the main scanning direction. It is possible to sequentially irradiate light with the extended wide range as a scanning range. Further, since the scanning direction in which each light emitting element is irradiated differs from the main scanning direction, the scanning range for each light emitting element can be narrowed, and a wide range of scanning in the main scanning direction can be performed in a short time. .

According to the sixth aspect of the invention, by arranging a plurality of light emitting elements side by side in a slanted lattice shape, the separation distance between the light emitting elements in the sub-scanning direction and the main scanning direction can be further reduced even if there is a restriction on the apparatus space. Since it can be shortened, the resolution in each direction can be further reduced.

  According to the seventh aspect, the number of installed light emitting elements can be halved with respect to the required number of light emitting elements. In addition, since the light receiving elements that receive two orthogonal polarization components are separately configured, measurement using the respective polarization components can be performed simultaneously. Therefore, the measurement frequency can be doubled to further speed up the processing.

  According to the eighth aspect of the invention, since the distance to the object is calculated by the method based on the triangulation, the measurement resolution can be increased and high-precision measurement can be performed.

  According to the ninth aspect of the invention, it is possible to enlarge a part of the scanning range and perform distance measurement with higher accuracy.

  According to the tenth aspect of the present invention, the approximate distance to the object for detecting the time difference from when the light is irradiated until the return light returns is calculated, and a range to be noted is set based on the approximate distance, Precise measurement within the range is performed. Thus, by performing the two-stage distance calculation, it is possible to achieve both the detection of the measurement object for a wide range and the highly accurate distance measurement.

  According to the eleventh aspect, a plurality of light emitting elements are spaced apart from each other at equal intervals, and the light emitted from each light emitting element is calculated by focusing the light emitted on or near the reflecting surface of the optical element. Becomes easy, and light can be irradiated to the object at a uniform interval.

(First embodiment)
Hereinafter, the visual device according to the first embodiment of the present invention will be described with reference to FIGS. Typically, the visual device is used for a machine vision system, a manipulator, or the like. FIG. 1 is a schematic diagram illustrating an example of the overall configuration of the visual device. FIG. 2 is a schematic diagram showing an example of the configuration of the light irradiation unit 1 included in the visual device. FIG. 3 is a view of an example of the configuration of the light irradiation unit 1 as seen from the side surface direction. FIG. 4 is a block diagram illustrating an example of the configuration of the visual device. FIG. 5 is a diagram illustrating an example of timings at which each of the LDs (Laser Diodes) 11 to LD14 emits light. FIG. 6 is a diagram illustrating an example of the position of the spot SP irradiated by the LD 11 to LD 14 emitting light.

  In FIG. 1, the visual device according to the first embodiment generally includes a light irradiation unit 1, a position detection unit 2, and a condenser lens 3. Spot light (for example, laser light) emitted from the light irradiation unit 1 is scanned within a preset scanning range and projected onto the surface of the measurement object. In FIG. 1, light projected on the surface of the measurement object is shown as a spot SP. A part of the scattered light reflected by the surface of the measurement object is condensed on the position detection unit 2 via the condenser lens 3. The position detection part 2 is comprised by PSD (Position Sensitive Device; position detection element), for example.

  Here, the light spot position of the scattered light condensed on the position detection unit 2 moves according to the distance between the light irradiation unit 1 and the spot SP irradiated on the surface of the measurement object. Specifically, the position of the light spot moves according to the distance between the light irradiation unit 1 and the measurement object, the shape of the measurement object, the unevenness of the surface, and the like. The distance to the measurement object, the shape of the measurement object, and the amount of surface irregularities can be calculated based on the light spot position using, for example, the principle of triangulation. Omitted.

  Next, a configuration example of the light irradiation unit 1 will be described. 2 and 3, the light irradiation unit 1 includes a polygon mirror 10 and a plurality of LD11 to LD14.

  The polygon mirror 10 is a polygonal column that rotates in a direction A in the drawing at a constant speed around a predetermined rotation axis, and forms a reflecting surface on the side surface. In FIG. 2, the polygon mirror 10 is comprised by the hexagonal prism as an example. The polygon mirror 10 may be a polygonal column having five or less side surfaces (reflection surfaces), or may be a polygonal column having seven or more side surfaces (reflection surfaces).

  Each of the laser diodes 11 to 14 emits laser light to the same reflecting surface of the polygon mirror 10. Preferably, the LD 11 to LD 14 are installed so that the emitted laser beams converge on or near the same reflecting surface of the polygon mirror 10. Here, in the example shown in FIG. 2, four LDs 11 to LD 14 that are spaced apart at a predetermined interval are formed, and the LDs 11 to LD 14 are arranged in parallel to the rotation axis of the polygon mirror 10. Then, LD11, LD12, LD13, and LD14 are arranged in this order from the top shown in FIG. The number of LDs installed and the direction of installation are not limited to this, but other LD setting examples will be described later.

  The laser light emitted from the LD 11 is reflected by any reflecting surface of the polygon mirror 10, and the reflected light is projected outside the light irradiation unit 1. And the direction of the reflected light of LD11 projected outside the light irradiation unit 1 changes to the rotation direction of the polygon mirror 10 according to the direction of the reflective surface which the laser beam reflected. Here, when attention is paid to one reflecting surface of the polygon mirror 10, the polygon mirror 10 rotates at a constant speed in the direction A in the figure. Therefore, the laser beam of the LD 11 can enter from the direction of the reflected light reflected by the reflecting surface arranged at the position closest to the negative direction A in the figure and can enter the laser beam from the LD 11 to the position on the most positive side in the figure A. The range up to the direction of the reflected light reflected by the arranged reflecting surface is the scanning range of the LD 11 in the rotation direction of the polygon mirror 10 (scanning angle described later; see FIG. 6). As described above, the spot position (spot SP11) where the reflected light of the LD 11 is irradiated on the surface of the measurement object moves in the B direction in the drawing according to the rotation of the polygon mirror 10. The direction in which the spot SP11 moves (the direction in which the polygon mirror 10 rotates) is defined as the main scanning direction.

  Since LD11 to LD14 are arranged in parallel to the rotation axis of the polygon mirror 10, and each laser beam is installed so as to converge on or near the same reflecting surface of the polygon mirror 10, LD12 to LD14. The scanning range and the scanning direction in the main scanning direction are the same as those of the LD 11 described above. That is, the spot positions (spots SP12 to SP14) where the reflected light of the LD12 to L14 is irradiated on the surface of the measurement object also move in the B direction in the drawing according to the rotation of the polygon mirror 10, respectively. That is, each of the spots SP11 to SP14 moves in the B direction (that is, the main scanning direction) in accordance with the rotation of the polygon mirror 10.

  However, since LD11 to LD14 are arranged in a row apart in the direction of the rotation axis, the direction in which each reflected light is projected to the outside of the light irradiation unit 1 also shifts in the direction of the rotation axis according to the separation distance. It will be. Hereinafter, the rotation axis direction in which the LD11 to LD14 are separated and arranged is referred to as a sub-scanning direction. That is, the sub-scanning direction is a direction perpendicular to the main scanning direction.

For example, the spot position (spot SP11) where the reflected light of the LD 11 is irradiated on the surface of the measurement object is relatively lower than the spot positions (spots SP12 to SP14) of the reflected light of the other LD12 to LD14. As a result, as shown in FIG.
The spots SP11 to SP14 are irradiated separately from the bottom in the sub-scanning direction in the order of the spots SP11, SP12, SP13, and SP14. Since each of the spots SP11 to SP14 moves in the B direction (that is, the main scanning direction) in accordance with the rotation of the polygon mirror 10, it is expanded in the main scanning direction and the sub scanning direction with respect to the measurement object. It is possible to irradiate the spots SP11 to SP14 over a wide scanning range.

  Next, the configuration of the visual device will be described. In FIG. 4, the visual device includes an LD driver 15 to 18, a control unit 19 a, an analog signal processing circuit 21, an x coordinate AD (analog digital) in addition to the position detection unit 2, polygon mirror 10, and LD 11 to LD 14 described above. Conversion unit) 22, y coordinate AD 23, motor 101, motor driver 102, and encoder 103.

  The LD drivers 15 to 18 control light emission of the LD 11 to LD 14 based on instructions from the control unit 19a. In addition, the timing which each LD11-LD14 light-emits is mentioned later.

  The analog signal processing circuit 21 processes the analog signal indicating the light spot position (x, y) of the scattered light obtained from the position detector 2 and outputs an analog signal indicating the x coordinate of the light spot position to the AD 22. The analog signal indicating the y coordinate of the light spot position is output to the AD 23. The AD 22 converts the analog signal indicating the x coordinate of the light spot position output from the analog signal processing circuit 21 into a digital signal and outputs the digital signal to the control unit 19a. Further, the AD 23 converts an analog signal indicating the y coordinate of the light spot position output from the analog signal processing circuit 21 into a digital signal, and outputs the digital signal to the control unit 19a.

  The motor 101 rotates the polygon mirror 10 at a constant speed around the rotation axis. The motor driver 102 controls driving of the motor 101 based on an instruction from the control unit 19a. Then, the encoder 103 outputs the rotation angle of the polygon mirror 10 around the rotation axis (or the rotation angle around the drive axis of the motor 101) to the control unit 19a.

  The control part 19a is comprised by DSP (digital signal processor), for example, and performs the various processes mentioned later by executing a predetermined program. Note that a program for executing these processes is stored in advance in a storage area (for example, a memory, a hard disk, an optical disk, etc.) provided in the control unit 19a, and the control unit 19a is turned on. This is executed by the control unit 19a.

  The control unit 19a instructs the motor driver 102 to rotate the motor 101. Moreover, the control part 19a calculates the timing which makes LD11-LD14 light-emit based on the rotation angle obtained from the encoder 103, and controls the action | operation of LD driver 15-18 according to the said calculation result. Further, the control unit 19a calculates the distance between the surface position of the spot SP irradiated to the surface of the measurement object and the light irradiation unit 1 based on the light spot position obtained from the AD 22 and AD 23, and calculates the calculation. The result is output to another apparatus (for example, a host computer) as a measurement result of the measurement object.

An example of the timing at which the control unit 19a causes the LD11 to LD14 to emit light will be described. In FIG. 5, the control unit 19 a controls each light emission timing so that any one of the LDs 11 to LD14 emits light. Specifically, the control unit 19a sequentially repeats light emission / extinction of LD11 to LD14 in the order of LD11 light emission → LD11 light emission → LD12 light emission → LD12 light emission → LD13 light emission → LD13 light emission → LD14 light emission → LD14 light off → LD11 light emission. Thus, the respective light emission timings are controlled. The frequency at which each of LD 11 to LD 14 emits / extinguishes (hereinafter referred to as the lighting frequency) is preferably set to the same lighting frequency = FL (Hz).

  Thus, the main scanning direction described above is obtained by rotating the polygon mirror 10 while irradiating the LD 11 to LD 14 sequentially at the same lighting frequency and irradiating the reflected light using any one surface of the polygon mirror 10. Further, the laser beam can be sequentially irradiated with a wide range expanded in the sub-scanning direction as a scanning range. For example, as shown in FIG. 6, the LD 11 to LD 14 sequentially repeat light emission / extinction to perform scanning in the sub-scanning direction, and at the same time, the polygon mirror 10 rotates in the A direction (see FIG. 2) at a constant speed. Thus, scanning is performed while moving in the main scanning direction. That is, in reality, the spots SP11 to SP14 generated by the sequential light emission of the LD11 to LD14 are not completely irradiated in parallel to the sub-scanning direction but are inclined in the main scanning direction.

  In FIG. 6, the numerical values in the circles of the spots SP indicate the light emission order. Here, the interval in the main scanning direction between the two spots SP in which the light emission order is continuous depends on the time difference at which the LD in which the light emission order is continuous starts to emit light and the rotational speed of the polygon mirror 10. Specifically, the interval Pa in the main scanning direction between the spots SP11 and SP12 where light emission continues depends on the time difference from when the LD 11 emits light until the LD 12 emits light, and the rotational speed of the polygon mirror 10. That is, the interval Pa can be shortened by shortening the time difference between the LD 11 emitting light and the LD 12 emitting light or by reducing the rotational speed of the polygon mirror 10.

  Further, the interval in the main scanning direction of the spots SP in which the light emission order continues in the same LD depends on the lighting frequency FL of the LD and the rotational speed of the polygon mirror 10. Specifically, the interval Pb in the main scanning direction between the spot SP11 and the next light emitting spot SP11 is the time difference (lighting frequency FL) from when the LD 11 emits light until the LD 11 emits light again, and the rotation of the polygon mirror 10. Depends on speed. That is, the interval Pb can be shortened by shortening the lighting frequency FL or slowing the rotational speed of the polygon mirror 10.

  Further, the interval in the sub-scanning direction between the two spots SP in which the light emission order is continuous depends on the separation distance in which the LDs in which the light emission order is continuous are arranged. Specifically, the distance Pc in the sub-scanning direction between the spot SP11 and the spot SP12 depends on the distance between the LD 11 and the LD 12 that is spaced from the LD 11 in the sub-scanning direction. That is, the distance Pc can be shortened by shortening the distance between the LD11 and the LD12.

  Further, by setting the interval Pa, the interval Pb, and the interval Pc described above, the number (resolution) of the spots SP irradiated to the scanning range is determined. For example, if m spots SP are irradiated to the scanning range, the resolution in the main scanning direction is m / 4 points, and the resolution in the sub-scanning direction is the number of LDs, that is, four points. As described above, the number and interval of the spots SP with respect to the scanning range are adjusted by adjusting the number of LDs installed, the timing at which a plurality of LDs emit / extinguish, the distance between the LDs, and the rotation speed of the polygon mirror 10. It is possible to adjust the resolution for the scanning range, the time required for sequentially irradiating the entire scanning range with laser light (measurement time), and the like.

When laser light sequentially emitted from the light irradiation unit 1 is projected for each spot SP on the surface of the measurement object, a part of the scattered light reflected by the surface of the measurement object is a condensing lens. The light is condensed on the position detection unit 2 via 3. The position detection unit 2 outputs an analog signal indicating the light spot position of the scattered light collected on the position detection unit 2 to the analog signal processing circuit 21. In accordance with the acquired analog signal, the analog signal processing circuit 21 generates an analog signal indicating the x coordinate and an analog signal indicating the y coordinate of the light spot position, and outputs them to AD 22 and AD 23, respectively. The AD 22 and AD 23 convert the acquired analog signal indicating the x-coordinate and analog signal indicating the y-coordinate into digital signals and output them to the control unit 19a. As described above, the light spot position of the scattered light collected on the position detector 2 moves according to the distance between the light irradiation unit 1 and the spot SP irradiated on the surface of the measurement object. Based on the light spot position, the control unit 19a calculates the distance to the measurement object at the spot SP, the shape of the measurement object, and the unevenness of the surface.

  As described above, according to the visual device according to the first embodiment, the number of LDs to be installed, the timing at which the plurality of LDs emit / extinguish, the distance between the LDs, and the rotational speed of the polygon mirror 10 are adjusted. Thus, the number and interval of the spots SP with respect to the scanning range can be adjusted, and the resolution for the scanning range, the measurement time for the entire scanning range, and the like can be easily adjusted. In addition, according to the visual device, it is possible to increase the processing speed and high resolution by increasing the timing at which a plurality of LDs emit / extinguish light, and to increase the rotation speed of the polygon mirror 10. Not required. Therefore, high resolution and high speed processing can be realized without being affected by the limitations of the apparatus configuration such as the polygon mirror 10.

  Here, with reference to FIG. 7A and FIG. 7B, the visual apparatus according to the first embodiment is compared with the method disclosed in Patent Document 1 (hereinafter referred to as a conventional method). FIG. 7A is a diagram illustrating an arrangement example of the spots SP irradiated by the visual device according to the first embodiment. FIG. 7B is a diagram illustrating an example of spot arrangement according to a conventional method. In FIGS. 7A and 7B, the numerical values in the spot circles indicate the light emission order.

  The polygon mirrors used for both are assumed to have four surfaces (that is, a quadrangular prism) and rotate at a rotational speed of 250 rps. Moreover, the spot arrangement of both uses the example in which 4 × 4 = 16 spots are irradiated. Then, in the visual device according to the first embodiment, it is assumed that the LD 11 to LD 14 irradiate the laser beam 16 times a total of four times on the one side surface using only one side surface of the polygon mirror. Further, in the conventional method, it is assumed that a single LD irradiates a laser beam four times on one side surface for a total of 16 times using all four side surfaces of the polygon mirror.

  When the visual device according to the first embodiment irradiates the laser beam under the above-described conditions, the entire optical system emits light (for example, from the irradiation of the spot SP11 to the next irradiation of the spot SP12). The time interval is 0.0625 μs (frequency pulse 16 kHz). In addition, the light emission interval (for example, the time interval from when the LD 11 emits light until the LD 11 emits light again) after the LD emits light again emits the same LD is 0.25 μs (lighting frequency FL = 4 kHz). Become. The total scanning range measurement frequency for irradiating 16 spots is 1 kHz (total scanning time 1 μs).

  On the other hand, when laser light is irradiated using the conventional method under the above-described conditions, the light emission interval of the entire optical system is 0.25 μs (frequency pulse 4 kHz), and the light emission interval in a single LD is the same (lighting frequency FL). = 4 kHz). The total scanning range measurement frequency for irradiating 16 spots is 250 Hz (total scanning time 4 μs).

  As described above, when the number of polygon mirror surfaces, the driving conditions, the number of spots (resolution), and the light emission interval (lighting frequency FL) for one LD are the same, the visual device according to the first embodiment is compared. It can be seen that the entire scanning range measurement frequency (total scanning time) and the light emission interval of the entire optical system in FIG.

Note that the polygon mirror 10 may be formed on each side surface at different inclination angles with respect to the rotation axis. As shown in FIG. 8, it is assumed that the i-th surface among the plurality of side surfaces of the polygon mirror 10 is formed with an inclination angle θi with respect to the rotation axis. In this case, the laser light incident on the i-th surface from each of LD11 to LD14 is reflected in the elevation direction (or depression direction) by an angle αi corresponding to the inclination angle θi and projected onto the measurement object. . That is, by changing the inclination angle θi to a different angle for each side surface of the polygon mirror 10, the vertical angle at which the laser light is projected from the light irradiation unit 1 is changed, that is, the light projection direction with respect to the sub-scanning direction for each side surface. Can be changed.

  For example, it is assumed that the polygon mirror 10 is an n prismatic body having n side surfaces (first surface to nth surface), and the n side surfaces have different inclination angles. In this case, as shown in FIG. 9, the sub-scanning direction of the laser light reflected from the first surface to the n-th surface can be changed for each side surface. In FIG. 9, the numerical value in the spot SP circle indicates the side number of the reflected polygon mirror 10.

  For example, a region to be scanned by being reflected by the second surface of the polygon mirror 10 is formed below the region to be scanned by being reflected by the first surface of the polygon mirror 10. Then, a region to be reflected and scanned by the third surface of the polygon mirror 10 is formed below the region to be scanned by being reflected by the second surface of the polygon mirror 10 and adjacent in the sub-scanning direction. Hereinafter, similarly, a region to be scanned in the sub-scanning direction is formed, and the polygon mirror 10 is positioned below the region to be scanned by being reflected by the n−1th surface of the polygon mirror 10 and adjacent to the sub-scanning direction. A region to be scanned by being reflected by the nth surface is formed. As described above, by using the polygon mirrors 10 having different inclination angles on the side surfaces and setting the regions to be reflected and scanned on the side surfaces sequentially shifted in the sub-scanning direction, the scanning further expanded in the sub-scanning direction. The spots can be irradiated with spots SP11 to SP14.

Here, a specific example using the polygon mirrors 10 having different inclination angles as described above will be described. For example, a polygon having the number of side surfaces of the polygon mirror 10 and a ratio between the scanning time determined by the rotational speed of the polygon mirror 10 and the scanning time of the actual image area, that is, the ratio of the time during which the polygon mirror 10 can be effectively irradiated. It is assumed that the scanning efficiency of the mirror 10 is 0.7 and the side surfaces are formed with different inclination angles. Then, 13 LDs spaced apart in the sub-scanning direction are arranged in a row, and the resolution in the main scanning direction (the number of spots SP in the main scanning direction) in the scanning range is set to 200 points. In this case, the resolution in the sub-scanning direction in the scanning range (the number of spots SP in the sub-scanning direction) is LD installation number × number of surfaces of the polygon mirror 10 = 78 points. And if the response time of the position detector 2 is 400 kHz,
Lighting frequency FL: 30.9 kHz
Rotation speed of polygon mirror 10: 2300 rpm
Full scan range measurement frequency: 18Hz
Scan angle: 84 °
Spacing Pa: 0.0006 rad
It becomes. Here, the scanning angle is an angle range of the laser light reflected from the polygon mirror 10 and projected in the main scanning direction.

In addition, the aspect which forms the area | region scanned with respect to a subscanning direction is not restricted to what was shown in FIG. For example, as shown in FIG. 10, using polygon mirrors 10 having different inclination angles on the side surfaces, an area to be scanned is set for each LD to be irradiated, and the areas are set to be adjacent to each other in the sub-scanning direction. It doesn't matter. Also in FIG. 10, the numerical value in the circle of the spot SP indicates the side number of the reflected polygon mirror 10. Specifically, the interval Pc in the sub-scanning direction (see FIG. 6) between two spots SP in which the light emission order is continuous is set to be relatively large. Then, the polygon mirror 10 is arranged so that one spot SP fills the space Pc.
Set the inclination angle of each side. That is, each of the polygon mirrors 10 is arranged with a relatively small inclination angle difference from the inclination angle difference between the side surfaces of the polygon mirror 10 used in the mode shown in FIG. By forming the side surface, it is possible to form a scanning region as shown in FIG.

  Further, the LD 11 to LD 14 may be arranged in a row apart from each other in the main scanning direction. Hereinafter, a configuration example of the light irradiation unit 1 including the LDs 11 to LD14 arranged in the main scanning direction will be described with reference to FIGS. FIG. 11 is a schematic diagram illustrating an example of the configuration of the light irradiation unit 1 including the LD 11 to LD 14 arranged in the main scanning direction. FIG. 12 is a view of an example of the configuration of the light irradiation unit 1 including the LDs 11 to LD14 arranged in the main scanning direction as seen from the top surface direction. FIG. 13 is a diagram illustrating an example of the position of the spot SP irradiated when the LD 11 to LD 14 arranged in the main scanning direction emit light.

  In FIG. 11 and FIG. 12, the polygon mirror 10 is a polygonal column that rotates in the direction A in the figure at a constant speed around a predetermined rotation axis as described above, and forms a reflecting surface on its side surface. LD 11 to LD 14 each emit laser light to the same reflecting surface of polygon mirror 10. Preferably, the LD 11 to LD 14 are installed so that the emitted laser beams converge on or near the same reflecting surface of the polygon mirror 10. Here, in the example shown in FIG. 11, it is composed of four LDs 11 to LD14 that are spaced apart by a predetermined interval, and LD11 to LD14 are arranged in a row (sub-scanning direction) perpendicular to the rotation axis of the polygon mirror 10. ing. Then, LD11, LD12, LD13, and LD14 are arranged in this order from the left shown in FIG.

  The laser light emitted from the LD 11 is reflected by any reflecting surface of the polygon mirror 10, and the reflected light is projected outside the light irradiation unit 1. The spot position (spot SP11) where the reflected light of the LD 11 projected to the outside of the light irradiation unit 1 is irradiated on the surface of the object to be measured is the B direction (main scanning) in accordance with the rotation of the polygon mirror 10. Direction).

  Further, the spot positions (spots SP12 to SP14) where the reflected light of the LDs 12 to L14 is irradiated on the surface of the measurement object also move in the direction B in the figure according to the rotation of the polygon mirror 10, respectively. That is, each of the spots SP11 to SP14 moves in the B direction (that is, the main scanning direction) in accordance with the rotation of the polygon mirror 10. Here, since LD11 to LD14 are arranged apart from each other in the sub-scanning direction and the respective laser beams are installed so as to converge on or near the same reflecting surface of the polygon mirror 10, the main LD12 to LD14 are arranged. Even if the scanning angle in the scanning direction is the same, the scanning direction in which each scans with respect to the main scanning direction differs according to the separation distance.

  For example, the spot position (spot SP11) where the reflected light of the LD 11 is irradiated on the surface of the measurement object is relatively in the main scanning positive direction side than the spot positions (spots SP12 to SP14) of the reflected light of the other LD12 to LD14. It becomes. As a result, as shown in FIG. 11, the spots SP11 to SP14 of the LD11 to LD14 are irradiated separately from the left in the order of the spots SP11, SP12, SP13, and SP14 in the main scanning direction. Since each of the spots SP11 to SP14 moves in the B direction in the figure (that is, the main scanning direction) according to the rotation of the polygon mirror 10, a wide range in which the main scanning direction is further expanded with respect to the measurement object. The spots SP11 to SP14 can be irradiated to the scanning range.

In this manner, the polygon mirror 10 is rotated while the LD 11 to LD 14 arranged in the main scanning direction are sequentially emitted at the same lighting frequency, and the reflected light is irradiated using any one surface of the polygon mirror 10. Thus, it is possible to sequentially irradiate the laser beam with a wide range expanded in the main scanning direction as a scanning range. For example, as shown in FIG. 13, the polygon mirror 10 rotates in the direction A (see FIG. 11) at a constant speed while the LD 11 to LD 14 sequentially repeat light emission / extinction, so that each spot SP moves in the main scanning direction. Scanning is performed. However, since the scanning directions in which the spots SP11 to SP14 are irradiated are different from each other with respect to the main scanning direction, the scanning range for each of the spots SP11 to SP14 can be narrowed. Scanning is possible.

  In FIG. 13, the numerical values in the circles of the spots SP indicate the light emission order. In the example shown in FIG. 13, the scanning ranges irradiated by the LD 11 to LD 14 are set adjacent to each other so as not to overlap each other. Here, the interval in the main scanning direction between the two spots SP in which the light emission order is continuous is the separation distance of the LD in which the light emission order is continuous, the time difference at which the LD in which the light emission order is continuous, and the rotation speed of the polygon mirror 10. Depends on and. Specifically, the interval Pa in the main scanning direction between the spot SP11 and the spot SP12 where light emission continues is the distance between the LD11 and LD12, the time difference from when the LD11 emits light until the LD12 emits light, and the polygon mirror 10 Depends on the rotation speed. That is, by shortening the distance between the LD 11 and the LD 12 installed, shortening the time difference between the LD 11 emitting light and the LD 12 emitting light, or reducing the rotational speed of the polygon mirror 10, The interval Pa can be shortened.

  Further, the interval in the main scanning direction of the spots SP in which the light emission order continues in the same LD depends on the lighting frequency FL of the LD and the rotational speed of the polygon mirror 10. Specifically, the interval Pb in the main scanning direction between the spot SP11 and the next light emitting spot SP11 is the time difference (lighting frequency FL) from when the LD 11 emits light until the LD 11 emits light again, and the rotation of the polygon mirror 10. Depends on speed. That is, the interval Pb can be shortened by shortening the lighting frequency FL or slowing the rotational speed of the polygon mirror 10.

  Further, by setting the interval Pa and the interval Pb described above, the number (resolution) of the spots SP irradiated to the scanning range is determined. For example, if m spots SP are irradiated to the scanning range, the resolution in the main scanning direction is m points. As described above, the number and interval of the spots SP with respect to the scanning range are adjusted by adjusting the number of LDs installed, the timing at which a plurality of LDs emit / extinguish, the distance between the LDs, and the rotation speed of the polygon mirror 10. It is possible to adjust the resolution for the scanning range, the time required for sequentially irradiating the entire scanning range with laser light (measurement time), and the like.

  As is clear from comparison with FIG. 6, when LD11 to LD14 are arranged in the main scanning direction, the scanning range in the subscanning direction is larger than when LD11 to LD14 are arranged in the subscanning direction. Although there is no expansion, the scanning angle for each LD becomes narrow. This is because when the LD 11 to LD 14 are arranged in the main scanning direction, the scanning range in the main scanning direction can be divided and scanned for each LD. Specifically, when LD 11 to LD 14 are arranged in the main scanning direction, the range in the main scanning direction that each LD scans is (the entire range in the main scanning direction to be scanned) / (number of LDs). Thus, since the scanning angle to be scanned is narrowed by the rotation of the polygon mirror 10, it is possible to use a polygon mirror having a relatively large number of surfaces (for example, 20 or 24 side surfaces), and the polygon mirror itself. The size can be reduced.

  In addition, the polygon mirror 10 in the case where the LD 11 to LD 14 are arranged in the main scanning direction may also form the respective side surfaces at different inclination angles with respect to the rotation axis. By making the inclination angle different for each side surface of the polygon mirror 10, the vertical angle at which the laser light is projected from the light irradiation unit 1 is changed, that is, the light projection direction with respect to the sub-scanning direction is changed for each side surface. be able to.

  For example, it is assumed that the polygon mirror 10 is an n prismatic body having n side surfaces (first surface to nth surface), and the n side surfaces have different inclination angles. In this case, as shown in FIG. 14, the sub-scanning direction of the laser light reflected from the first surface to the n-th surface can be changed for each side surface. In FIG. 14, the numerical value in the spot SP circle indicates the side number of the reflected polygon mirror 10.

  For example, a region to be scanned by being reflected by the second surface of the polygon mirror 10 is formed below the region to be scanned by being reflected by the first surface of the polygon mirror 10. Then, a region to be reflected and scanned by the third surface of the polygon mirror 10 is formed below the region to be scanned by being reflected by the second surface of the polygon mirror 10 and adjacent in the sub-scanning direction. Hereinafter, similarly, a region to be scanned in the sub-scanning direction is formed, and the polygon mirror 10 is positioned below the region to be scanned by being reflected by the n−1th surface of the polygon mirror 10 and adjacent to the sub-scanning direction. A region to be scanned by being reflected by the nth surface is formed. As described above, by using the polygon mirrors 10 having different inclination angles on the respective side surfaces and setting the regions to be reflected and scanned on the respective side surfaces sequentially shifted in the sub-scanning direction, the scanning range expanded in the sub-scanning direction. The spots SP11 to SP14 can be irradiated.

  In addition, a plurality of LDs may be arranged in parallel in a slanted lattice pattern in a separated manner in the main scanning direction and the sub-scanning direction. Hereinafter, with reference to FIG. 15, a configuration example of the light irradiation unit 1 in which a plurality of LDs are arranged side by side in an oblique lattice shape will be described. FIG. 15 is a schematic diagram showing an example of the configuration of the arrangement positions of a plurality of LDs arranged side by side in an oblique lattice shape.

  In FIG. 15, the light irradiation unit 1 includes 12 LDs. In the example of FIG. 15, in the above-described four LD11 to LD14 arranged in the sub-scanning direction (see FIGS. 2 and 3), eight LD11m1 to LD14m1 and LD11m2 to LD14m2 are arranged at positions to compensate for the interval in the sub-scanning direction. Each is installed.

  For example, when a new LD is inserted in the sub-scanning direction between the LD 11 and the LD 12 to shorten the separation distance in the sub-scanning direction, it is not possible to additionally install the LD due to restrictions on the apparatus space. There is. In this case, the LD may be additionally installed by shifting to a position perpendicular to the sub-scanning direction and at the same distance from the polygon mirror 10.

  In the example of FIG. 15, two LD11m1 and LD11m2 are installed between the separation distance P between the LD11 and the LD12. Specifically, the LD 11m1 is installed so that the distance in the sub-scanning direction from the LD 11 to the LD 11m1 is P / 3. The LD 11m2 is installed so that the distance in the sub-scanning direction from the LD 11m1 to the LD 11m2 is P / 3. The separation distance in the sub-scanning direction from the LD 11m2 to the LD 12 is P / 3.

Further, similarly to between LD11 and LD12, two LD12m1 and LD12m2 are installed between the separation distance P between LD12 and LD13, and two LD13m1 and LD13m2 are installed between the separation distance P between LD13 and LD14. To do. Then, the LD 14m1 is installed so that the separation distance in the sub-scanning direction from the LD 14 to the LD 14m1 is P / 3, and the LD 14m2 is installed so that the separation distance in the sub-scanning direction from the LD 14m1 to the LD 14m2 is P / 3. To do. LD 11 to LD 14, LD 11 m 1 to LD 14 m 1, and LD 11 m 2 to LD 14 m 2 each emit laser light to the same reflecting surface of the polygon mirror 10. Preferably, LD11 to LD14, LD11m1 to LD14m1, and LD11m2 to LD14m2 are installed so that the emitted laser beams converge on or near the same reflecting surface of the polygon mirror 10, respectively. In this way, by newly installing a new LD so as to compensate for the gap P, a plurality of LDs are arranged side by side in the form of a diagonal lattice.

  And the control part 19a controls each light emission timing so that any one among LD11-LD14, LD11m1-LD14m1, and LD11m2-LD14m2 may light-emit. Specifically, the control unit 19a performs LD11 emission → LD11 extinction → LD12 emission → LD12 extinction → LD13 emission → LD13 extinction → LD14 emission → LD14 extinction → LD11m1 emission → LD11m1 extinction → LD12m1 emission → LD12m1 extinction → LD13m1 emission → LD13m1 Light extinction → LD14m1 light emission → LD14m1 light emission → LD11m2 light emission → LD11m2 light emission → LD12m2 light emission → LD12m2 light emission → LD13m2 light emission → LD14m2 light emission → LD14m2 light emission → LD11 light emission → LD11 light emission, LD11m1, LD11m1 The respective light emission timings are controlled so that the LD 14m2 repeats light emission / extinction. The lighting frequencies at which each of LD11 to LD14, LD11m1 to LD14m1, and LD11m2 to LD14m2 emits / extinguishes are preferably set to the same lighting frequency = FL (Hz).

  By arranging a plurality of LDs in an oblique grid in this way, the separation distance between the LDs in the sub-scanning direction can be further shortened even if there is a restriction on the device space. Can be further refined. For example, when the lattice arrangement is applied to the arrangement example of the spots SP shown in FIG. 6, the interval Pc in the sub-scanning direction can be shortened.

  Further, an optical fiber and a lens may be provided for each LD between the LD 11 to LD 14 and the polygon mirror 10. The optical fiber guides the laser beam emitted from the LD to the lens. And a lens makes the laser beam radiate | emitted from an optical fiber into parallel light, and injects into the side surface of the polygon mirror 10. FIG. With this configuration, the distance between the light sources can be set short, and the downsizing of the apparatus and restrictions on the apparatus space can be reduced.

  Further, the LD 11 to LD 14 may be configured by combining an LD array and a microlens array. For example, the LD array is configured by an LD bar or the like in which an LD is made into a one-dimensional array. Then, the microlens array converts the laser beams emitted from the LD array into parallel beams and converges them on or near the same reflecting surface of the polygon mirror 10. As described above, by combining the optical system with the LD array and the microlens array, the separation distance of the light sources can be set short, and the size reduction of the apparatus and restrictions on the apparatus space are reduced.

Further, the laser beam emitted from the LD may be separated into two orthogonal polarization components (P-polarized light and S-polarized light) and emitted. For example, as shown in FIG. 16, a polarizing filter 104a and a mirror 105a are provided between the LD 11 and the polygon mirror 10. The polarizing filter 104a allows the S-polarized component of the laser light emitted from the LD 11 to pass through the side surface of the polygon mirror 10 and reflects the P-polarized component to enter the mirror 105a. The mirror 105a reflects the P-polarized component and makes it incident on the same side surface of the polygon mirror 10 as the S-polarized component. Similarly, a polarizing filter 104b and a mirror 105b are provided between the LD 13 and the polygon mirror 10. The position detection unit 2 and the condensing lens 3 are provided with a P-polarized component light receiving unit and a S-polarized component light receiving unit, respectively, so that the scattered light reflected by the measurement object is separately reflected by the respective polarized component light. Receive light. By configuring the light source in this way, the laser light of the P-polarized component and the laser light of the S-polarized component can be separated and emitted from one LD, and two light sources can be realized with one LD. . Therefore, the light irradiation unit 1 can be configured by halving the number of LDs installed with respect to the required number of light sources. For example, in the example of FIG. 16, for the required number of four light sources, it can be realized by two LDs of LD11 and LD13, and LD12 and LD14 are not necessary. In addition, a light receiving unit that receives two orthogonal polarized components (P-polarized light and S-polarized light) is separately configured, and measurement using each polarized component can be performed simultaneously. Therefore, in the example of FIG. 16, the measurement frequency can be doubled to further speed up the processing.

(Second Embodiment)
The visual device according to the second embodiment of the present invention will be described below with reference to FIGS. FIG. 17 is a schematic diagram illustrating an example of the configuration of the light irradiation unit 1 included in the visual device. FIG. 18 is a block diagram illustrating an example of the configuration of the visual device. FIG. 19 is a top view for explaining the zoom function and the light receiving direction adjustment function provided to the position detection unit 2. FIG. 20 is a flowchart illustrating an example of the operation of the visual device. Note that the visual device according to the second embodiment is obtained by adding a zoom function to the visual device according to the first embodiment described above. Therefore, in the description of the visual device according to the second embodiment, the same components as those of the visual device according to the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 17, the light irradiation unit 1 included in the visual device according to the second embodiment includes a half mirror 41 disposed between the LD 11 to LD 14 and the polygon mirror 10, and reflected light reflected by the half mirror 41. And a photodiode 40 for detection. The half mirror 41 passes the laser light irradiated from the LD 11 to LD 14 to the polygon mirror 10 as it is. On the other hand, the half mirror 41 reflects the light incident on the polygon mirror 10 from the outside, which is guided from the polygon mirror 10 to the LD 11 to LD 14, and causes the light to enter the photodiode 40. That is, the scattered light (returned light) reflected from the LD 11 to LD 14 by the polygon mirror 10 and irradiated to the measurement object and reflected by the measurement object and returning to the light irradiation unit 1 is again the polygon mirror 10 and the half mirror 41. And is incident on the photodiode 40. Then, the photodiode 40 outputs a signal indicating that the return light is incident to the control unit 19b (see FIG. 18). Therefore, the distance to the measurement object can be obtained by detecting the time difference between the light emission timing of LD11 to LD14 and the timing of incidence on the photodiode 40 (time delay method).

  In FIG. 18, the visual device according to the second embodiment includes a control unit 19b, a motor 24, an encoder 25, a motor driver 26, and a zoom lens 31 in addition to the components described above.

  For example, as shown in FIG. 19, the motor 24 changes the direction of the position detection unit 2 with reference to the light receiving direction adjustment axis provided in the position detection unit 2 using the driving force applied from the motor driver 26. Thus, the direction in which the position detection unit 2 detects scattered light is changed. The motor driver 26 controls driving of the motor 24 based on an instruction from the control unit 19b. Then, the encoder 25 outputs a signal indicating the direction in which the position detection unit 2 is detecting scattered light to the control unit 19b.

  The zoom lens 31 enlarges the scattered light reflected by the measurement object and causes the scattered light to enter the position detection unit 2. The magnification at which the zoom lens 31 expands the scattered light is adjusted by the control unit 19b. The zoom function may be realized by the condensing lens 3 using the condensing lens 3. For example, the focal length of the condenser lens 3 is changed by changing the distance between the condenser lens 3 and the position detector 2. That is, by changing the distance between the condensing lens 3 and the position detection unit 2 to be long, the focal length of the condensing lens 3 is increased, and the scattered light is enlarged and incident on the position detection unit 2. The measurement resolution becomes higher. In this way, the zoom function is realized by adjusting the position of the condenser lens 3, and in this case, another zoom lens 31 is not necessary.

  In addition to the function of the control unit 19a described above, the control unit 19b is configured to change the direction in which the position detection unit 2 detects scattered light, adjust the zoom function of the zoom lens 31, and enter the photodiode 40. It has a distance calculation function by the time delay method using scattered light. Hereinafter, an example of the operation of the control unit 19b will be described with reference to FIG. Note that each step of the flowchart shown in FIG. 20 is performed by the control unit 19b executing a predetermined program. Note that a program for executing these processes is stored in advance in a storage area provided in the control unit 19b, for example, and is executed by the control unit 19b when the power of the control unit 19b is turned on. The

  In FIG. 20, the control unit 19b sequentially causes the LD11 to LD14 to emit light while rotating the polygon mirror 10 (step S51). Then, based on the signal from the photodiode 40, it is determined whether or not there is return light from the outside (step S52). And control part 19b advances processing to the following step S53, when there is return light. On the other hand, when there is no return light, the control unit 19b proceeds to the next step S54.

  In step S53, the control unit 19b performs measurement at the spot SP irradiated with the laser beam based on the time difference from when any of the laser diodes 11 to 14 emits the laser beam until the photodiode 40 detects the return beam. Calculate the distance to the object. Note that the distance calculated in step S53 is calculated by the time delay method, so that the measurement resolution is low (for example, several tens of mm), and the control unit 19b calculates the calculated distance as an approximate distance ( Coarse distance). Then, the control unit 19b stores the calculated distance in a predetermined storage area in association with the spot SP where the return light is detected, and proceeds to the next step S54.

  In step S54, the control unit 19b determines whether or not the laser beam irradiation has been completed for the entire scanning range. Then, when the irradiation for the entire scanning range is completed, the process proceeds to the next step S55. On the other hand, the control part 19b returns to the said step S51, and repeats a process, when irradiation with respect to the whole scanning range is not complete | finished.

  In step S55, the control unit 19b selects a region of interest within the scanning range based on the distance for each spot SP calculated in step S53, and advances the treatment to the next step. Here, the region of interest is a region where a more detailed distance is to be calculated (region to be magnified) within the scanning range, and the shape of the region on which the measurement object exists and the surface of the measurement object are complex. Some surface areas are selected. The attention area may be selected based on a predetermined algorithm. For example, the attention area is set so that the spot SP indicating the average value or the median value of the calculated distances is included, or is calculated for each adjacent spot SP. The attention area is set so as to expand the area where the distance difference is equal to or greater than the threshold value, or the attention area is set so as to include all the spots SP whose distances are calculated.

Next, the control unit 19b controls the motor driver 26 based on the signal obtained from the encoder 25, and changes the direction in which the position detection unit 2 detects the scattered light to the direction of the region of interest selected in step S55. (Step S56). For example, as shown in FIG. 19, the control unit 19b determines the direction of the position detection unit 2 around the light reception direction adjustment axis so that the direction in which the position detection unit 2 receives light is the direction of the attention area selected in step S55. Adjust the light reception direction. Next, the control unit 19b adjusts the position of the zoom lens 31 to increase the detection accuracy of the position detection unit 2 for the attention area selected in Step S55 (Step S57). For example, as illustrated in FIG. 19, the control unit 19b determines that the amount of movement of the light spot position of the scattered light collected on the position detection unit 2 is the distance between the light irradiation unit 1 and the measurement target in the region of interest. The position of the zoom lens 31 is adjusted so as to expand according to the shape of the measurement object in the region of interest, the unevenness of the surface, and the like. That is, the control unit 19b adjusts the position of the zoom lens 31 so that the movement amount of the light spot position that moves according to the distance change in the spot SP is enlarged in the attention area. And the control part 19b advances a process to the next step.

  Next, the control unit 19b sequentially causes the LD11 to LD14 to emit light while rotating the polygon mirror 10 (step S58). Then, the control unit 19b calculates the distance to the measurement object in the spot SP irradiated with the laser beam in step S58 based on the information indicating the light spot position obtained from the position detection unit 2, and the like. Data indicating the distance is output to the device (step S59), and the process proceeds to the next step. In the distance calculation process in step S59, in addition to using information from the position detection unit 2 using a method based on a triangulation detection principle, the process is expanded with respect to the region of interest. ing. Therefore, it is possible to calculate the distance to the measurement object with a relatively high measurement resolution as compared with step S53, and it is also possible to measure the detailed shape of the measurement object and the surface unevenness amount.

  Next, the control unit 19b determines whether or not the irradiation of the laser light on all the attention areas has been completed (step S60). And when irradiation with respect to all the attention ranges is complete | finished, the process by the said flowchart is complete | finished. On the other hand, the control part 19b returns to said step S58, and repeats a process, when irradiation with respect to all the attention ranges is not complete | finished.

  In the above description, the position detection unit 2 is provided with a zoom function and a light receiving direction adjustment function to achieve precise measurement within the region of interest. However, the position detection unit 2 may be provided with a zoom function in other configurations. You may give it. Hereinafter, another example of the zoom function of the position detection unit 2 will be described with reference to FIGS. 21 and 22. FIG. 21 is a schematic structural diagram illustrating another example of the zoom function provided to the position detection unit 2. FIG. 22 is a top view for explaining the relationship between the measurement area of the position detection unit 2 and the region of interest.

  In FIG. 21, in another example of the zoom function, a prism 32 and a diaphragm 33 are provided in addition to the position detection unit 2 and the zoom lens 31. Here, in the zoom function described with reference to FIG. 19 and the like, the measurement resolution of the position detection unit 2 is increased by increasing the focal length of the zoom lens 31, that is, by increasing the distance between the zoom lens 31 and the position detection unit 2. Is high. Therefore, since it is necessary to secure the light receiving area even when the focal length of the zoom lens 31 is increased, the light receiving area (detector) of the position detection unit 2 is increased. In another example of the zoom function, by including the prism 32 and the diaphragm 33, the zoom function can be provided without increasing the light receiving area of the position detection unit 2.

  Specifically, a diaphragm 33 that opens around the optical axis of the zoom lens 31 is provided outside the zoom lens 31 that is closest to the object to be measured. As a result, the scattered light of the measurement object enters the zoom lens 31 through the diaphragm 33. A pair of prisms 32 is provided between the zoom lens 31 and the position detection unit 2. The prisms 32 are arranged on the left and right sides with a predetermined gap around the optical axis of the zoom lens 31. Then, an external region that passes through the gap of the prism 32 and is directly received by the position detection unit 2 is defined as a region B. In addition, the regions on both sides of the region B in which the traveling direction is changed by the pair of prisms 32 are referred to as a region A and a region C, respectively.

Here, as shown in FIG. 21, the prism 32 is formed so that the traveling direction of the incident light is bent inward (to the gap). As a result, the scattered light incident from the region A via the diaphragm 33 is bent inward in one of the prisms 32 via the zoom lens 31 and is received from the light receiving surface of the position detection unit 2 that receives light from the region B. Incident on the same light receiving surface. That is, the scattered light from the region A can be received by the light receiving surface (detector) of the position detection unit 2 for receiving the scattered light from the region B. Similarly, the scattered light incident from the region C through the diaphragm 33 is also bent inward at the other side of the prism 32 via the zoom lens 31 and received from the region B by the light receiving surface of the position detector 2. Incident on the same light receiving surface. That is, the scattered light from the region C can be received by the light receiving surface (detector) of the position detection unit 2 for receiving the scattered light from the region B. As described above, even if the focal length is increased by the zoom lens 31, the pair of prisms 32 that change the traveling direction of the light are installed between the zoom lens 31 and the position detection unit 2 to detect the position. The measurement resolution of the position detection unit 2 can be increased without increasing the light receiving area of the unit 2. Note that the region B and the region A may partially overlap. In addition, the region B and the region C may partially overlap.

  Moreover, as shown in FIG. 22, the position detection part 2 can receive the scattered light from each area | region AC. Specifically, even if the attention area α is set in the area A, the attention area β is set in the area B, or the attention area γ is set in the area C, they exist in the attention areas α to γ. Scattered light reflected by the measurement object to be measured is received by the position detector 2. That is, the measurement resolution can be increased even if the light receiving direction adjustment function of the position detector described with reference to FIG. 19 is not provided. As described above, in another example of the zoom function, the zoom function can be realized without increasing the light receiving area of the position detecting unit 2, and the light receiving direction adjusting function of the position detecting unit 2 is not necessary.

  Next, a processing operation using another example of the zoom function will be described. In the processing operation using another example of the zoom function, the operation in step S56 in the flowchart described with reference to FIG. 20 is not necessary, and the processing operation from step S51 to step S55 is the same. Therefore, with reference to FIG. 20, the processing operation after step S57 using another example of the zoom function will be described. A control unit having a function of controlling another example of the zoom function will be described as a control unit 19c. In addition to the function of the control unit 19a described above, the control unit 19c adjusts the zoom function of the zoom lens 31 shown in FIG. 21, and calculates the distance by the time delay method using scattered light incident on the photodiode 40. , And the position where the scattered light is reflected has a function of determining one of the areas A to C.

  In FIG. 20, the control unit 19c adjusts the position of the zoom lens 31 after selecting a region of interest in step S55, and increases the detection accuracy of the position detection unit 2 for the region of interest selected in step S55 (step S55). S57). At this time, as described with reference to FIG. 22, the position detection unit 2 can receive the scattered light from the regions A to C, and the detection accuracy of the regions A to C can be adjusted simultaneously by adjusting the position of the zoom lens 31. Will change. Therefore, the control unit 19c determines in which of the areas A to C the attention area selected in step S55 and pays attention to the area including the attention area, and determines the position of the zoom lens 31. adjust. And the control part 19c advances a process to the next step.

Next, the control unit 19c causes the LD11 to LD14 to emit light sequentially while rotating the polygon mirror 10 (step S58). Then, the control unit 19c calculates the distance to the measurement object in the spot SP irradiated with the laser beam in step S58 based on the information indicating the light spot position obtained from the position detection unit 2, and the like. Data indicating the distance is output to the device (step S59), and the process proceeds to the next step. Here, the control unit 19c calculates the approximate distance to the measurement object in step S53. In step S57, it is also determined which of the areas A to C the current attention area is included in. Therefore, the control unit 19c can determine from which region of the regions A to C the light spot position obtained by the position detection unit 2 in step S59 is the scattered light. In the distance calculation process in step S59, in addition to using information from the position detection unit 2 using a method based on a triangulation method, the process is expanded with respect to the region of interest. ing. Therefore, it is possible to calculate the distance to the measurement object with a relatively high measurement resolution as compared with step S53, and it is also possible to measure the detailed shape of the measurement object and the surface unevenness amount.

  Next, the control unit 19c determines whether or not the irradiation of the laser light on all the attention areas has been completed (step S60). And when irradiation with respect to all the attention ranges is complete | finished, the process by the said flowchart is complete | finished. On the other hand, the control part 19b returns to said step S58, and repeats a process, when irradiation with respect to all the attention ranges is not complete | finished.

  Thus, according to the visual device according to the second embodiment, the time delay for obtaining the distance to the measurement object by detecting the time difference between the light emission timing of the LD 11 to LD 14 and the timing of incidence on the photodiode 40. The approximate distance to the measurement object is calculated by the method. Then, a region of interest is set based on the approximate measurement result, and a precise measurement within the region of interest is performed. Thus, by performing the two-step distance calculation, it is possible to achieve both the detection of the measurement object for a wide range and the detailed distance measurement.

  Needless to say, the various modifications described in the first embodiment can also be applied to the visual device according to the second embodiment.

  In addition, the visual device according to the first embodiment and the second embodiment described above includes a polygon mirror having a reflective surface formed on its side surface, but uses other optical components that reflect laser light. It doesn't matter. For example, a polarizer (galvanometer mirror) that changes the rotation angle of the mirror by attaching a mirror to the shaft and giving a predetermined electric signal may be used instead of the polygon mirror.

Moreover, although the visual apparatus which concerns on 1st Embodiment mentioned above and 2nd Embodiment used the example comprised by PSD (position detection element) as the position detection part 2, the light of scattered light by another system is used. The point position may be detected. For example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide).
The light spot position of the scattered light may be detected using a semi-conductor (complementary metal oxide semiconductor).

  The visual devices according to the first and second embodiments are typically used for machine vision systems, manipulators, and the like, but may be used for other purposes. For example, it may be used for a sensor for monitoring the front and periphery of a moving body such as an automobile, a three-dimensional scanner for three-dimensionally measuring the surface shape of a measurement object, and the like.

  The visual device according to the present invention can realize high resolution and high processing speed, and is useful for machine vision systems, manipulators, peripheral monitoring sensors for moving objects, three-dimensional scanners, and the like.

Schematic diagram showing an example of the overall configuration of the visual device according to the first embodiment of the present invention Schematic diagram showing an example of the configuration of the light irradiation unit 1 of FIG. The figure which looked at an example of the structure of the light irradiation unit 1 of FIG. 1 from the side surface direction The block diagram which shows an example of a structure of the visual device of FIG. The figure which shows an example of the timing which LD11-LD14 of FIG. 2 light-emits, respectively The figure which shows an example of the position of spot SP irradiated when LD11-LD14 of FIG. 2 light-emits, respectively. The figure which shows the example of arrangement | positioning of the spot SP irradiated by the visual device which concerns on 1st Embodiment. The figure which shows the example of arrangement of the spot by the conventional method The figure which shows an example of the polygon mirror 10 in which the i-th surface is formed inclining by inclination-angle (theta) i with respect to the rotating shaft. The figure which shows an example of spot SP of the laser beam reflected in the 1st surface-the nth surface of the polygon mirror 10, respectively. The figure which shows the other example of the spot SP of the laser beam reflected in the 1st surface-the nth surface of the polygon mirror 10, respectively. Schematic diagram showing an example of the configuration of the light irradiation unit 1 including LD11 to LD14 arranged in the main scanning direction. The figure which looked at an example of the structure of the light irradiation unit 1 provided with LD11-LD14 arranged in the main scanning direction from the upper surface direction. The figure which shows an example of the position of spot SP irradiated when LD11-LD14 arranged in the main scanning direction each light-emits. The figure which shows an example of spot SP of the laser beam reflected in the 1st surface-the nth surface of the polygon mirror 10, respectively. Schematic diagram showing an example of a configuration of arrangement positions of a plurality of LDs arranged side by side in an oblique lattice shape The figure which shows an example of the optical system which provided the polarizing filter 104a and the mirror 105a between LD11 and the polygon mirror 10 Schematic which shows an example of a structure of the light irradiation unit 1 contained in the visual apparatus which concerns on the 2nd Embodiment of this invention. The block diagram which shows an example of a structure of the visual device of FIG. A top view for explaining a zoom function and a light receiving direction adjustment function provided to the position detection unit 2 The flowchart which shows an example of operation | movement of the visual apparatus of FIG. Schematic structure diagram showing another example of a zoom function to be given to the position detection unit 2 Top view for explaining the relationship between the measurement area of the position detector 2 and the region of interest

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light irradiation unit 10 ... Polygon mirror 11-14 ... LD
15 to 18: LD driver 19 ... control unit 21 ... analog signal processing circuit 22, 23 ... AD
24, 101 ... Motor 25, 103 ... Encoder 26, 102 ... Motor driver 104 ... Polarizing filter 105 ... Mirror 2 ... Position detector 3 ... Condensing lens 31 ... Zoom lens 32 ... Prism 33 ... Aperture 40 ... Photodiode 41 ... Half mirror

Claims (11)

A visual device that measures the distance to an object by receiving reflected light of the light irradiated to the object,
A light source;
An optical element that scans and moves the direction of irradiation of the light in the main scanning direction by changing the direction of the reflecting surface that reflects the light emitted from the light source;
A light receiving unit that receives at least a part of the scattered light reflected by the surface of the object when the light irradiated by the optical element is irradiated on the object;
The light source is
A plurality of light emitting elements that are spaced apart from each other and emit light toward the reflecting surface of the optical element;
And a light emission control unit that sequentially emits one of the plurality of light emitting elements.   The optical element has a plurality of side surfaces serving as the reflection surface around a rotation axis provided in the sub-scanning direction, and the direction of the reflection surface by rotating in the main scanning direction around the rotation axis The visual device according to claim 1, wherein the visual device is a polygon mirror that changes the angle.   The visual device according to claim 2, wherein the plurality of side surfaces of the polygon mirror are inclined at different angles with respect to the rotation axis.   4. The visual device according to claim 1, wherein the plurality of light emitting elements are arranged separately from each other in a sub-scanning direction perpendicular to the main scanning direction. 5.   The visual device according to any one of claims 1 to 3, wherein the plurality of light emitting elements are arranged in a row apart from each other in the main scanning direction.   The visual device according to any one of claims 1 to 3, wherein the plurality of light-emitting elements are arranged in parallel with each other in a diagonal lattice pattern. A polarization unit provided between the plurality of light emitting elements and the optical element, each of which separates light emitted from the light emitting element into two orthogonal polarization components and enters the reflection surface of the optical element; In addition,
The visual device according to claim 1, wherein the light receiving unit includes two light receiving elements that separately receive two polarization components separated by the polarizing unit. The light receiving unit is
A condenser lens;
A position detection unit that detects a light spot position of the scattered light collected through the condenser lens,
The visual device further includes a distance calculation unit that calculates the distance to the object at the light position based on the light spot position detected by the position detection unit and the light position irradiated by the optical element. The visual device according to any one of claims 1 to 3.   The visual device according to claim 8, wherein the light receiving unit further includes a zoom mechanism that increases a focal length until the scattered light is enlarged and collected by the position detection unit. When the light irradiated by the optical element is irradiated to the object, a return light detection unit that detects light that is reflected by the surface of the object and returns to the optical element;
Based on the position of the light irradiated by the optical element and the time from when the light source emits light until the return light detection unit detects the light returning to the optical element, an estimate to the object at the position of the light An approximate distance measuring unit for calculating the distance;
In accordance with the approximate processing for each light position calculated by the approximate distance measurement unit, the range selection unit that selects the reflection range of scattered light to be detected by the position detection unit as the light spot position;
In accordance with the reflection range selected by the range selection unit, a condensing direction in which the condensing lens collects scattered light and an enlargement factor of the zoom function are set, and the light reception is performed based on the condensing direction and the enlargement factor. The visual device according to claim 9, further comprising: a light receiving control unit that changes a focal length of the zoom function by changing a direction of the unit.   4. The visual device according to claim 1, wherein the plurality of light emitting elements are spaced apart from each other at equal intervals, and are provided at positions where light emitted from each of the light emitting elements is focused on or near a reflection surface of the optical element. .

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