JP2012026921A - Optical distance measuring equipment and equipment loaded with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical distance measuring equipment for measuring a distance to each of objects 15 and 16 even when there exists a plurality of objects 15 and 16 in a projecting direction from a light emitting element 11.SOLUTION: The optical distance measuring equipment is provided with: a light emitting element 11; a light collecting part 13 for projection; a condensing part 14 for light reception; and a light receiving element 12. The light receiving element 12 has a light receiving face 12a for receiving optical spots Ls1 and Ls2 condensed by the condensing part 14 for light reception. A plurality of light receiving elements are one-dimensionally or two-dimensionally arrayed in a row on a light receiving face 12a. When the optical spots Ls1 and Ls2 are made incident to the light receiving face 12a, positions x1 and x2 in the light receiving face 12a of the optical spot are searched for each of the optical spots Ls1 and Ls2 based on a signal to be output by each of the plurality of light receiving elements. A distance from the light emitting element 11 to objects 15 and 16 corresponding to each optical spot is calculated by a triangular distance measurement system according to the positions x1 and x2 within the light receiving face of each optical spot.

Description

  The present invention relates to an optical distance measuring device, and more specifically, includes a light emitting element and a light receiving element disposed apart from the light emitting element, and projects light from the light emitting element to an object. The present invention relates to an optical distance measuring device that detects the distance from the light emitting element to the object by a triangular distance measuring method by receiving the reflected light of the light by the light receiving element. Note that the “object” means an object whose distance from the light emitting element is to be measured (the same applies hereinafter).

  The present invention also relates to a device equipped with such an optical distance measuring device.

  Conventionally, as shown in FIG. 6, for example, as an optical distance measuring device 100, one that detects a distance to an object by a triangular distance measuring method is known (for example, Patent Document 1 (Japanese Patent Publication No. 02-19403). Gazette) and Patent Document 2 (Japanese Utility Model Publication No. 07-34334). The optical distance measuring device 100 includes a light emitting element 101 that is a light source such as a light emitting diode, a light projecting condensing unit 103, a light receiving condensing unit 104, and a light receiving element 102.

  In the optical distance measuring device 100, the light L emitted from the light emitting element 101 is condensed by the light projecting condensing unit 103 and is irradiated onto the object 105. A part of the light L ′ reflected by the object 105 is narrowed through the light receiving condensing unit 104 and enters the light receiving surface 102 a of the light receiving element 102 as a light spot Ls.

  The light receiving element 102 is a PSD (Position Sensitive Device), and the light receiving surface 102a is uniformly coated with a material that generates a voltage corresponding to the amount of incident light. When a light spot is incident on the light receiving surface 102a, a voltage corresponding to the amount of light is generated at the portion where the light spot is incident. The potential at a point away from that portion in the light receiving surface is lowered by the resistance of the applied material. Therefore, the position x of the light spot Ls in the light receiving surface 102a can be obtained based on the ratio of the voltages generated at both ends of the light receiving element 102.

  When the distance d from the light emitting element 101 to the object 105 changes, the position x in the light receiving surface 102a on which the light spot Ls enters changes according to the change. Therefore, by obtaining the position x in the light receiving surface 102a on which the light spot Ls is incident, the distance d from the light emitting element 101 to the object 105 can be obtained according to the position x (triangular distance measuring method). ).

Japanese Examined Patent Publication No. 02-19403 No. 07-34334

  Incidentally, when viewed from the optical distance measuring device 100, a plurality of objects may exist in substantially the same direction. For example, when viewed from the optical distance measuring device 100, there is a case where a first semi-transparent object is present and an opaque second object is present behind the first object.

  In such a case, in the conventional optical distance measuring device 100, the light receiving element 102 combines and detects the reflected light from the first object and the reflected light from the second object. The output for the target object cannot be obtained. That is, the conventional optical distance measuring device 100 has a problem in that when there are a plurality of objects in the light projecting direction from the light emitting elements, the distance to each object cannot be measured.

  Therefore, an object of the present invention is to provide an optical distance measuring device that can measure the distance to each object even when there are a plurality of objects in the light projecting direction from the light emitting element. .

  Another object of the present invention is to provide a device equipped with such an optical distance measuring device.

In order to solve the above problems, the optical distance measuring device of the present invention is:
A light emitting element that emits light;
A light condensing part for condensing the light emitted from the light emitting element and irradiating the object;
A light receiving condensing part that condenses the reflected light from the object into a light spot;
A light receiving element disposed apart from the light emitting element and having a light receiving surface for receiving the light spot collected by the light receiving condensing unit, wherein the light receiving surface of the light receiving element includes a plurality of light receiving elements. Arranged side by side in one or two dimensions, each of the plurality of light receiving elements outputs a signal corresponding to the light intensity incident on the light receiving element,
A light spot position calculation unit for determining, for each light spot, the position of the light spot in the light receiving surface for each light spot based on a signal output from each of the light receiving elements when the light spot is incident on the light receiving surface; ,
The distance from the light emitting element to the object corresponding to each light spot is calculated by the triangulation method according to the position in the light receiving surface of each light spot obtained by the light spot position calculation unit. A distance calculation unit is provided.

  In the optical distance measuring device according to the present invention, the light emitted from the light emitting element is condensed by the light condensing unit and irradiated onto the object. The reflected light from the object is narrowed down through the light receiving condensing unit and enters the light receiving surface of the light receiving element as a light spot. A plurality of light receiving elements are arranged one-dimensionally or two-dimensionally on the light receiving surface of the light receiving element, and each of the plurality of light receiving elements outputs a signal corresponding to the light intensity incident on the light receiving element. Therefore, the outputs of the plurality of light receiving elements of the light receiving element represent the light intensity distribution in the light receiving surface as a whole. When the light spot is incident on the light receiving surface, the light spot position calculating unit obtains the position of the light spot in the light receiving surface for each light spot. The distance calculation unit triangulates the distance from the light emitting element to the object corresponding to each light spot according to the position of each light spot obtained by the light spot position calculation unit in the light receiving surface. Calculate using the distance method. Therefore, the optical distance measuring device of the present invention can measure the distances to individual objects even when there are a plurality of objects in the light projecting direction from the light emitting element.

  In addition, if the light spot position calculation unit and the distance calculation unit are configured by hardware including a CPU (Central Processing Unit) and software (computer program) that operates the hardware, individual objects can be obtained. In parallel and substantially simultaneously.

  In the optical distance measuring device according to an embodiment, the light spot position calculation unit obtains the center of gravity of the light intensity distribution of each light spot as the position of the light spot in the light receiving surface.

  In the optical distance measuring device according to this embodiment, the light spot position calculation unit obtains the center of gravity of the light intensity distribution of each light spot as the position of the light spot in the light receiving surface. Therefore, the position of each light spot in the light receiving surface can be obtained with high accuracy.

  In the optical distance measuring device of one embodiment, the light spot position calculation unit obtains the number of the objects according to the number of peaks of the light intensity distribution of the light spot incident on the light receiving surface. To do.

  In the optical distance measuring device of this one embodiment, the light spot position calculation unit obtains the number of objects according to the number of peaks of the light intensity distribution of the light spot incident on the light receiving surface. Therefore, the number of objects whose distance is to be measured can be accurately obtained. It is possible to determine how many light spots are to be obtained within the light receiving surface in accordance with the obtained number of objects.

  In one embodiment, the optical distance measuring device includes a display unit that displays the distances calculated by the distance calculation unit side by side on a display screen for each object corresponding to each of the light spots. .

  In the optical distance measuring device according to the embodiment, the display unit displays the distances obtained by the distance calculation unit side by side on the display screen for each object corresponding to each light spot. Therefore, the user can recognize at a glance the distance from the light emitting element to the object for each object.

  A device according to the present invention includes the optical distance measuring device.

  In the apparatus of the present invention, the distance to each object can be measured by the operation of the optical distance measuring device even when a plurality of objects are present in the light projecting direction from the light emitting element.

  As is clear from the above, in the optical distance measuring device of the present invention and the device on which the optical distance measuring device is mounted, even when there are a plurality of objects in the light projecting direction from the light emitting element, each object is Can be measured.

It is a figure which shows the structure of the optical system which the optical distance measuring device of one Embodiment of this invention has. It is a figure which shows the light intensity distribution in the light-receiving surface which a CMOS imager outputs, when two target objects exist in the light projection direction from a light emitting element. It is a figure which shows the light intensity distribution in the light-receiving surface which a CMOS imager outputs, when one target exists in the light projection direction from a light emitting element. It is a figure which shows the block configuration of the signal processing circuit which the said optical distance measuring device has. It is a figure which illustrates the display content displayed on a liquid crystal display element. It is a figure which shows the personal computer as an apparatus incorporating the said optical distance measuring device. It is a figure which shows the structure and operation state of the conventional optical distance measuring device. FIG.

  FIG. 1 shows a configuration of an optical system included in an optical distance measuring device according to an embodiment of the present invention.

  The optical distance measuring device 10 includes a light emitting element 11, a light projecting condensing unit 13, a light receiving condensing unit 14, and a light receiving element 12.

  The light emitting element 11 is a light source composed of a light emitting diode or a surface emitting laser sealed with a translucent resin (not shown). The light emitting element 11 emits light from the light emitting surface 11a in a certain direction, in this example, the direction in which the objects 15 and 16 are present.

  The light projecting condensing unit 13 includes a lens having a positive refractive power, condenses the light L emitted from the light emitting element 11 and irradiates the objects 15 and 16.

  The light receiving condensing unit 14 includes a lens having a positive refractive power, and condenses the reflected lights L1 and L2 from the objects 15 and 16 into light spots Ls1 and Ls2.

  The light receiving element 12 is a CMOS imager sealed with resin as a separate body from the light emitting element 11, and is spaced apart from the light emitting element 11 in the horizontal direction. The light receiving element 12 has a light receiving surface 12a that receives the light spots Ls1 and Ls2 collected by the light receiving condensing unit 14. In order to perform the triangulation, the light emitting surface 11a of the light emitting element 11 and the light receiving surface 12a of the light receiving element 12 are located at substantially the same height level in substantially the same plane.

  On the light receiving surface 12a of the light receiving element 12, a plurality of photodiodes 12-1, 12-2,..., 12-n are arranged in one dimension (in the x direction in this example) as light receiving elements. The number n of photodiodes is, for example, a number in the range of n = 2000 to 10,000. The plurality of photodiodes 12-1, 12-2,..., 12-n each output a signal corresponding to the light intensity incident on the photodiode. Therefore, the outputs of the plurality of photodiodes 12-1, 12-2,..., 12-n of the light receiving element 12 represent the light intensity distribution in the light receiving surface 12a as a whole (FIG. 2A and FIG. 2B).

  A commercially available “line sensor” can be used as the light receiving element 12.

  FIG. 3 shows a block configuration of the signal processing circuit 20 included in the optical distance measuring device 10. The signal processing circuit 20 includes a light spot position calculation unit 21, a distance calculation unit 22, and a display processing unit 23.

  The light spot position calculation unit 21 is based on signals output from a plurality of photodiodes 12-1, 12-2, ..., 12-n of the light receiving element (CMOS (Complementary Metal Oxide Semiconductor) imager) 12, respectively. Thus, the position of the light spot incident on the light receiving surface 12a in the light receiving surface 12a is obtained.

  In particular, the light spot position calculation unit 21 first obtains the number of objects according to the number of peaks of the light intensity distribution of the light spot incident on the light receiving surface 12a. Thereby, the number of objects can be obtained. Further, it is possible to determine how many light spots are to be obtained in the light receiving surface 12a in accordance with the obtained number of objects. Next, the light spot position calculation part 21 calculates | requires the position x in the light-receiving surface 12a of the light spot for every light spot (that is, for every target object). Here, the position x of the light spot in the light receiving surface 12a can be obtained with high accuracy by calculating the center of gravity of the light intensity distribution of each light spot.

  The distance calculation unit 22 triangulates the distance from the light emitting element 11 to the object corresponding to each light spot according to the position of each light spot in the light receiving surface 12a obtained by the light spot position calculation unit 21. Calculate by the method.

  The display processing unit 23 displays a distance obtained by the distance calculation unit 22 for each object corresponding to each light spot, in this example so as to be displayed side by side on a display screen of a liquid crystal display element (LCD) 19. Image processing to create. In this example, the display processing unit 23 and the LCD 19 constitute a display unit.

  In this example, the signal processing circuit 20 (light spot position calculation unit 21, distance calculation unit 22, and display processing unit 23) includes hardware including a CPU (Central Processing Unit) and software (computer) that operates the hardware. Program).

  The optical distance measuring device 10 operates as follows as a whole.

  (1) First, in FIG. 1, an operation when the object 15 does not exist in the light projecting direction from the light emitting element 11 and only one object 16 exists will be described.

  In this case, the light L emitted from the light emitting element 11 is condensed by the light projecting condensing unit 13 and irradiated onto the object 16. A part of the light L2 reflected by the object 16 is narrowed down through the light receiving condensing unit 14 and enters the light receiving surface 12a of the light receiving element 12 as a light spot Ls2.

  At this time, the light intensity distribution in the light receiving surface 12a represented by the outputs of the plurality of photodiodes 12-1, 12-2,..., 12-n of the light receiving element 12 has one peak Is2 as shown in FIG. It will be shown.

  Here, the light spot position calculation unit 21 in FIG. 3 first has one object according to the number of peaks Is2 of the light intensity distribution of the light spot incident on the light receiving surface 12a. (In this example, it is determined to be the object 16 shown in FIG. 1). Next, the light spot position calculation unit 21 obtains the position x2 of the light spot Ls2 within the light receiving surface 12a.

  Next, the distance calculation unit 22 calculates a distance d2 from the light emitting element 11 to the object 16 shown in FIG. 1 according to the position x2 by a triangulation method.

  The distance d2 to the object 16 obtained by the distance calculation unit 22 is displayed on the display screen of the LCD 19 by the display processing unit 23.

  (2) Next, in FIG. 1, when there is a semi-transparent first object 15 and an opaque second object 16 in the light projecting direction from the light emitting element 11, that is, there are two objects. The operation when doing this will be described.

  In this case, the light L emitted from the light emitting element 11 is condensed by the light projecting condensing unit 13, and is first irradiated to the object 15, and a part of the light L <b> 1 is reflected. The remaining part of the light L is transmitted through the object 15 and is irradiated and reflected on the object 16. The lights L1 and L2 reflected by the objects 15 and 16, respectively, are narrowed down through the light receiving condensing unit 14 and enter the light receiving surface 12a of the light receiving element 12 as light spots Ls1 and Ls2.

  At this time, the light intensity distribution in the light receiving surface 12a represented by the outputs of the plurality of photodiodes 12-1, 12-2,..., 12-n of the light receiving element 12 has two peaks Is1, as shown in FIG. Is2 is shown.

  Here, the light spot position calculation unit 21 in FIG. 3 first determines the number of objects according to the number of peaks Is1 and Is2 of the light intensity distribution of the light spot incident on the light receiving surface 12a being two. Two (in this example, the objects 15 and 16 shown in FIG. 1) are determined. Next, the light spot position calculation part 21 calculates | requires the position in the light-receiving surface 12a of the light spot for each light spot Ls1, Ls2. In this example, the position x1 of the light spot Ls1 in the light receiving surface 12a and the position x2 of the light spot in the light receiving surface 12a are obtained.

  Next, the distance calculation unit 22 triangulates the distances d1 and d2 from the light emitting element 11 to the objects 15 and 16 shown in FIG. 1 according to the positions x1 and x2 of the light spots in the light receiving surface 12a. Calculate using the distance method.

  The distances d1 and d2 to the objects 15 and 16 obtained by the distance calculation unit 22 are displayed side by side on the display screen of the LCD 19 by the display processing unit 23, for example, as shown in FIG. In the example of FIG. 4, identification numbers (“1” and “2”) for identifying the objects 15 and 16 are displayed from the top to the bottom of the screen in the left half of the screen. Corresponding to the display of the left half of the screen, the distances d1 and d2 (in this example, “1.0 m” and “1.5 m”) to the objects 15 and 16 are displayed on the right half of the screen from the top to the bottom. It is displayed towards. Therefore, the user can recognize the distances d1 and d2 from the light emitting element 11 to the objects 15 and 16 at a glance for each of the objects 15 and 16.

  As described above, the optical distance measuring device 10 measures the distances to the individual objects 15 and 16 even when there are a plurality of objects 15 and 16 in the light projecting direction from the light emitting element 11. it can.

  In this example, the light spot position calculation unit 21, the distance calculation unit 22, and the display processing unit 23 are made up of hardware including a CPU (central processing unit) and software (computer program) that operates the hardware. Since it comprises, the distance to each object 15 and 16 can be calculated | required substantially simultaneously in parallel.

  FIG. 5 shows an example in which the optical distance measuring device 10 is built in a personal computer 40 as an example of a device.

  In this example, the personal computer 40 includes a computer main body 41, a display unit 42, a keyboard 43, and a mouse 44. The light emitting element 11 and the light receiving element 12 of the optical distance measuring device 10 are incorporated in the upper edge portion 42 a of the display unit 42. The signal processing circuit 20 (light spot position calculation unit 21, distance calculation unit 22, and display processing unit 23) of the optical distance measuring device 10 includes hardware including a CPU (Central Processing Unit) in the computer main body 41 and its hardware. And software (computer program) for operating the wear. The LCD 19 of the optical distance measuring device 10 corresponds to the display screen of the display unit 42.

  As described above, the optical distance measuring device 10 can be built into the personal computer 40 and compactly incorporated. In the personal computer 40, the distance to each object can be measured by the operation of the optical distance measuring device 10 even when there are a plurality of objects in the light projecting direction from the light emitting element 11. Moreover, the distances to the individual objects can be obtained substantially simultaneously in parallel.

  In this embodiment, the case where the optical distance measuring device 10 includes one object 16 and two objects 15 and 16 is described, but the present invention is not limited to this. Even if there are three or more objects in the light projecting direction of the light-emitting element 11, the optical distance measuring device 10 can move to individual objects by the same operation as described above. Can be measured.

  Further, in the case where the two objects 15 and 16 exist in the light projecting direction of the light emitting element 11, the first object 15 is assumed to be translucent, but the present invention is not limited to this. For example, when the first object 15 is opaque, the edge of the first object 15 exists in the irradiation range of the projecting light collecting unit 13, and the second object 16 exists beyond the edge. In addition, the present invention is applicable.

  In the light receiving element 12, a plurality of photodiodes 12-1, 12-2,..., 12-n are arranged in one dimension (in this example, the x direction). A plurality of photodiodes may be two-dimensionally arranged in the light receiving surface 12 a of the light receiving element 12. As such a light receiving element 12, a commercially available “area sensor” can be used. In such a case, the distance from the light emitting element to each object is measured with higher accuracy by taking into account the difference in the horizontal position and the height position between the light emitting element and the object. be able to.

  In this example, the light receiving element 12 is a CMOS imager, but a CCD (Charge Coupled Device) imager can be used instead.

DESCRIPTION OF SYMBOLS 10 Optical distance measuring device 11 Light emitting element 12 Light receiving element 13 Condensing part for light projection 14 Condensing part for light reception 15 1st target object 16 2nd target object 20 Signal processing circuit Ls1 1st light spot Ls2 2nd Light spot

Claims (5)

A light emitting element that emits light;
A light condensing part for condensing the light emitted from the light emitting element and irradiating the object;
A light receiving condensing part that condenses the reflected light from the object into a light spot;
A light receiving element disposed apart from the light emitting element and having a light receiving surface for receiving the light spot collected by the light receiving condensing unit, wherein the light receiving surface of the light receiving element includes a plurality of light receiving elements. Arranged side by side in one or two dimensions, each of the plurality of light receiving elements outputs a signal corresponding to the light intensity incident on the light receiving element,
A light spot position calculation unit for determining, for each light spot, the position of the light spot in the light receiving surface for each light spot based on a signal output from each of the light receiving elements when the light spot is incident on the light receiving surface; ,
The distance from the light emitting element to the object corresponding to each light spot is calculated by the triangulation method according to the position in the light receiving surface of each light spot obtained by the light spot position calculation unit. An optical distance measuring device comprising a distance calculating unit. The optical distance measuring device according to claim 1.
The optical spot position calculating unit obtains the center of gravity of the light intensity distribution of each light spot as the position of the light spot in the light receiving surface. The optical distance measuring device according to claim 1 or 2,
The optical spot position calculating unit calculates the number of the objects according to the number of peaks of the light intensity distribution of the light spot incident on the light receiving surface. The optical distance measuring device according to any one of claims 1 to 3,
An optical distance measuring device comprising: a display unit that displays the distances calculated by the distance calculation unit side by side on a display screen for each object corresponding to each of the light spots.   An apparatus comprising the optical distance measuring device according to any one of claims 1 to 4.

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