JP2020067360A - Measurement device, method for measuring distance, program, and recording medium - Google Patents

Abstract

To provide a measurement device which can measure an accurate distance regardless of the distance to an object.SOLUTION: The present invention includes: a division unit for dividing a light which has been emitted to a predetermined region and has been reflected by an object in the predetermined region into a first reflected light RL1 and a second reflected light RL2; a first light collecting lens 22A on the optical path for the first reflected light; a first light receiving unit 23A on the optical path for the first reflected light having traveled through the first light collecting lens; a second light collecting lens 22B on the optical path for the second reflected light; a second light receiving unit 23B on the optical path for the second reflected light having traveled through the second light collecting lens; and a distance calculating unit 33 for calculating the distance to the object on the basis of at least one of the result of light reception by the first receiving unit and the result of light reception by the second receiving unit, the numerical aperture of the first collecting lens being larger than that of the second light collecting unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a distance measuring device.

  There is known a distance measuring device that measures a distance to an object by irradiating the object with laser light and receiving and analyzing laser light reflected by the object (for example, Patent Document 1). . In such a distance measuring device, for example, laser light reflected by an object is condensed by a lens, and the condensed laser light is received by a light receiving element.

JP, 2005-129646, A

  In the distance measuring device as described above, the light receiving optical system is usually set so that the reflected light from the object at a long distance is condensed on the light receiving element. When focusing light, defocus and spherical aberration occur. Therefore, the light receiving element cannot receive the reflected light from the object at a short distance in a sufficiently condensed state, and there is a problem that an accurate distance to the object cannot be obtained.

  In particular, when a line-shaped laser beam (line beam) is emitted and a reflected light is received using a line sensor in which a plurality of light receiving elements are arranged in a line, reflected light from an object at a short distance is reflected by a lens. There is a problem in that the light to be received by each light receiving element is projected to the adjacent light receiving element due to the aberration generated when converging.

  As described above, when the target object exists at a short distance, the light receiving element cannot receive the reflected light in a sufficiently condensed state, and the distance to the target object cannot be accurately calculated. As.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a distance measuring device capable of performing accurate distance measurement regardless of the distance to an object.

  The invention according to claim 1 is a distance measuring device, wherein light emitted toward a predetermined area and reflected by an object in the predetermined area is converted into first reflected light and second reflected light. A branching portion for branching, a first condenser lens provided on the optical path of the first reflected light, and a first condenser lens provided on the optical path of the first reflected light that has passed through the first condenser lens. No. 1 light receiving section, a second condenser lens provided on the optical path of the second reflected light, and a second condenser lens provided on the optical path of the second reflected light that has passed through the second condenser lens. And a distance calculation unit that calculates a distance to the object based on at least one of the light reception result of the first light reception unit and the light reception result of the second light reception unit. The numerical aperture of the first condenser lens is larger than the numerical aperture of the second condenser lens.

  The invention according to claim 7 includes a branching part for branching the light, a first condenser lens provided on one optical path of the light branched by the branching portion, and the first condenser lens. A first light receiving portion provided on an optical path of light, and a second condenser lens having a numerical aperture smaller than that of the first condenser lens provided on the other optical path of the light branched by the branching portion. A second light receiving portion provided on the optical path of the light passing through the second condenser lens, and up to the object based on the light receiving result of the first light receiving portion or the second light receiving portion. A distance calculating unit that calculates a distance, and a distance measuring method executed by a distance measuring device, wherein the branching unit emits light toward a predetermined region and reflects light reflected by an object in the predetermined region, Branching into a first reflected light and a second reflected light; A step of collecting the first reflected light; a step of collecting the second reflected light by the second collecting lens; and a step of collecting the first light receiving part by the first collecting lens. Receiving the condensed first reflected light and generating a first received light signal; and the second light receiving section collecting the second reflected light condensed by the second condenser lens. Receiving light and generating a second light receiving signal; and determining the approximate distance to the object based on the first light receiving signal or the second light receiving signal by the distance calculation unit. The distance calculation unit calculates the distance to the object based on a summed signal obtained by summing the first received light signal and the second received light signal, when the approximation process is equal to or more than a threshold value. , If the estimated distance is less than the threshold value, based on the second received light signal, Characterized in that it comprises the steps of: calculating a distance to the object Te.

  The invention according to claim 8 is a program, which splits light emitted toward a predetermined region and reflected by an object in the predetermined region into first reflected light and second reflected light. A diverging section, a first condenser lens that condenses the first reflected light, and a first condensing lens that receives the first reflected light that has passed through the first condensing lens and generates a first received light signal. One light receiving portion, a second condenser lens having a numerical aperture smaller than that of the first condenser lens and condensing the second reflected light, and the second condenser lens that passes through the second condenser lens. A computer mounted on a distance measuring device having a second light receiving section that receives two reflected lights and generates a second light receiving signal, based on the first light receiving signal or the second light receiving signal. And a step of determining an approximate distance to the object, and if the approximate processing is equal to or more than a threshold, The distance to the object is calculated based on a summed signal obtained by adding the first received light signal and the second received light signal, and based on the second received light signal when the estimated distance is less than the threshold value. And calculating a distance to the target object.

  The invention according to claim 9 is a recording medium, wherein light emitted toward a predetermined region and reflected by an object in the predetermined region is branched into first reflected light and second reflected light. A branching portion, a first condensing lens that condenses the first reflected light, and the first reflected light that has passed through the first condensing lens to receive a first light reception signal. A first light receiving portion, a second light collecting lens that has a numerical aperture smaller than that of the first light collecting lens and collects the second reflected light, and the second light collecting lens that passes through the second light collecting lens. A computer mounted on a distance measuring device having a second light receiving section for receiving a second reflected light and generating a second light receiving signal, and applying the first light receiving signal or the second light receiving signal to the computer. Determining an approximate distance to the object based on the above, and if the approximate processing is a threshold value or more, Of the received light signal and the second received light signal are combined to calculate a distance to the object, and when the estimated distance is less than the threshold value, based on the second received light signal. And a step of calculating a distance to the object, a program for executing the step is recorded.

3 is a block diagram showing the configuration of the distance measuring apparatus according to the first embodiment. FIG. It is a schematic diagram which shows reception of the reflected light when a target object is in a long distance. It is a schematic diagram which shows the light reception of the reflected light when a target object is in a short distance. It is a figure which shows the waveform of the light reception signal when a target object is in a long distance. It is a figure which shows the waveform of the light reception signal when a target object is in a short distance. It is a schematic diagram which shows the mode of light reception of the reflected light from the several target object in a long distance. It is a figure which shows the waveform of the light reception signal in case a some object is in a long distance. It is a schematic diagram which shows the case where the 1st light-receiving part received the reflected light from the some target object in a short distance. It is a figure which shows the example of the 1st received light signal when a some object is in a short distance. It is a schematic diagram which shows the case where the reflected light from the some target object in a short distance is received by the 2nd light-receiving part. It is a figure which shows the example of the 2nd light reception signal when a some object is in a short distance. FIG. 7 is a diagram showing an example of a beam splitter of the second embodiment. 7 is a schematic diagram showing reception of reflected light from a long-distance object in Embodiment 2. FIG. 7 is a schematic diagram showing reception of reflected light from an object at a short distance in Embodiment 2. FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail. In the following description of each embodiment and the accompanying drawings, substantially the same or equivalent parts are designated by the same reference numerals.

  FIG. 1 is a block diagram showing the configuration of the distance measuring device 100 of this embodiment. The distance measuring device 100 emits laser light toward a predetermined area, receives the laser light reflected by the object OJT in the predetermined area, and measures the distance to the object OJT based on the light reception result. It is a distance device. The distance measuring device 100 includes a light projecting unit 11, a beam splitter 20, a first light receiving processing unit 21A, a second light receiving processing unit 21B, and a distance measuring unit 30.

  The light projecting unit 11 includes a light source 12 that emits laser light, a light emission driving unit 13 that drives the light source 12, and a light projecting lens 14 that is provided on the optical path of the laser light emitted from the light source 12. The light source 12 is composed of, for example, a plurality of emitters (multi-emitters) arranged in a line shape, and emits a line-shaped laser light (that is, a line beam) obtained by combining the laser lights emitted from the plurality of emitters. The light transmitting unit 11 emits the laser light emitted from the light source 12 toward a predetermined area.

  The beam splitter 20 is provided on the optical path of the reflected light RL that is the laser light reflected by the object OJT in the predetermined area. The beam splitter 20 is composed of, for example, a half mirror, and reflects a part of the reflected light RL and transmits another part of the reflected light RL so that the reflected light RL becomes a first reflected light RL1 and a second reflected light RL2. Branch to. For example, in the present embodiment, a part of the reflected light RL is reflected as the first reflected light RL1, and another part of the reflected light RL is transmitted as the second reflected light RL2.

  The first light reception processing unit 21A is a signal processing unit that receives the first reflected light RL1 and generates a first light reception signal RS1. The first light receiving processing unit 21A includes a first light receiving lens 22A and a first light receiving unit 23A.

  The first light receiving lens 22A is a condensing lens that condenses the incident light, and is configured as, for example, a convex lens. The first light receiving lens 22A is provided on the optical path of the first reflected light RL1 which is a part of the reflected light RL reflected by the beam splitter 20. The first light receiving lens 22A has a numerical aperture NA1 (NA: Numerical Aperture).

  The first light receiving unit 23A is configured as a line sensor in which a plurality of light receiving elements that convert the intensity of the received light into an electric signal are arranged in a line. Each of the light receiving elements forming the first light receiving section 23A is formed of, for example, an APD (Avalanche Photodiode). The first light receiving unit 23A is provided on the optical path of the first reflected light RL1 that has passed through the first light receiving lens 22A, and receives the first reflected light RL1 and converts it into an electrical signal. The first received light signal RS1 is generated. Each of the light receiving elements of the first light receiving unit 22A takes into consideration the numerical aperture NA1 of the first light receiving lens 22A and the first light receiving lens 22A from a distance that can be regarded as infinity as viewed from the first light receiving lens 22A. It is arranged at a position where the light incident on is condensed.

  The second light reception processing unit 21B is a signal processing unit that receives the second reflected light RL2 and generates a second light reception signal RS2. The second light receiving processing unit 21B includes a second light receiving lens 22B and a second light receiving unit 23B.

The second light receiving lens 22B is a condensing lens that condenses the incident light, and is configured as, for example, a convex lens. The second light receiving lens 22B is provided on the optical path of the second reflected light RL2 which is a part of the reflected light RL transmitted by the beam splitter 20. The second light receiving lens 22B has a numerical aperture NA2 that is smaller than the numerical aperture NA1 of the first light receiving lens 22A. That is, in the distance measuring apparatus 100 of the present embodiment, the numerical aperture NA1 of the first light receiving lens 22A is larger than the numerical aperture NA2 of the second light receiving lens NA2, and the second light receiving section 23B has a linear light receiving element. Are arranged as a plurality of line sensors. Each of the light receiving elements forming the second light receiving section 23B is formed of, for example, an APD. The second light receiving unit 23B is provided on the optical path of the second reflected light RL2 that has passed through the second light receiving lens 22B, and receives the second reflected light RL2 and converts it into an electric signal. The second received light signal RS2 is generated. Each light receiving element of the second light receiving portion 22B is incident on the first light receiving lens 22A from a position at a short distance that cannot be regarded as infinity, in consideration of the numerical aperture NA2 of the second light receiving lens 22B. It is arranged at a position where the collected light is condensed.

  The distance measuring unit 30 is a signal processing unit that performs processing calculation for calculating the distance to the object OJT based on the first light receiving signal RS1 or the second light receiving signal RS2. The distance measuring section 30 includes an approximate distance determining section 31, a used light receiving element determining section 32, and a distance calculating section 33.

  The approximate distance determining unit 31 receives the first light receiving signal RS1 from the first light receiving unit 23A and the second light receiving signal RS2 from the second light receiving unit 23B, and receives the first light receiving signal RS1 and the second light receiving signal RS2. The approximate distance to the object OJT is determined based on at least one of the light reception signals RS2. For example, the approximate distance determination unit 31 determines whether or not the object OJT is located at a long distance (e.g., 10 m or more) that is equal to or larger than a predetermined distance that can be regarded as infinity when viewed from the first light receiving lens 22A.

  Based on the approximate distance determined by the approximate distance determining unit 31, the used light receiving element determining unit 32 uses the light receiving result of either the first light receiving unit 23A or the second light receiving unit 23B to reach the object OJT. Is calculated. For example, when the approximate distance is a predetermined distance or more, the used light receiving element determination unit 32 determines that the first light receiving signal RS1 and the second light receiving unit 23B which are the light receiving results of the first light receiving unit 23A. It is determined that the distance to the object OJT is calculated based on the summed signal obtained by summing the resulting second light reception signal RS2. On the other hand, when the estimated distance is a short distance less than the predetermined value, the used light receiving element determination unit 32 determines the object OJT based on the second light reception signal RS2 which is the light reception result by the second light reception unit 23B. It is determined to calculate the distance.

  The distance calculation unit 33, based on the summed signal obtained by summing the first light receiving signal RS1 and the second light receiving signal RS2, or the second light receiving signal RS2, according to the determination result by the used light receiving element determination unit 32, The distance to the object OJT is calculated.

  Next, the reception of the reflected light RL (that is, the reception of the first reflected light RL1 and the second reflected light RL2) by the distance measuring apparatus 100 of the present embodiment will be described. The reflected light RL, which is the laser light reflected by the object OJT in the predetermined region, is partially reflected by the beam splitter 20 and the other part is transmitted through the beam splitter 20, whereby the first reflected light RL1. And the second reflected light RL2. The first reflected light RL1 is condensed by the first light receiving lens 22A, and the second reflected light RL2 is condensed by the second light receiving lens 22B. At this time, the manner of condensing the first reflected light RL1 is such that the reflected light RL seen from the first light receiving lens 22A and the length of the optical path of the first reflected light RL1 (that is, the distance to the object OJT). Depends on

  FIG. 2A shows a case where the lengths of the optical paths of the reflected light RL and the reflected light RL1 are distances that can be regarded as infinity as viewed from the first light receiving lens 22A, that is, the reflected light RL exists at a long distance that can be regarded as infinity. It is a figure which shows typically the aspect of condensing when it is the reflected light RL from the target object OJT which is doing. Here, the light receiving element 24A is shown as one of the light receiving elements forming the first light receiving section 23A, and the light receiving element 24B is shown as one of the light receiving elements forming the second light receiving section 23B.

  The reflected light RL from a distance that can be regarded as infinity enters the beam splitter 20 in a state close to parallel light, that is, in a state in which the diameter of the light flux is substantially constant. For this reason, the first reflected light RL1 enters the first light receiving lens 22A and is condensed with the diameter of the light flux being substantially constant. Therefore, the light receiving element 24A receives the first reflected light RL1 which is sufficiently condensed by the first light receiving lens 22A. Further, the second reflected light RL2 also enters the second light receiving lens 22B and is condensed with the diameter of the light flux being substantially constant. Therefore, the light receiving element 24B receives the second reflected light RL2 that is sufficiently condensed by the second light receiving lens 22B.

  On the other hand, FIG. 2B shows that the lengths of the optical paths of the reflected light RL and the first reflected light RL1 are such a short distance that they cannot be regarded as infinity when viewed from the first light receiving lens 22A, that is, the reflected light RL is It is a figure which shows typically the aspect of condensing when it is the reflected light from the object OJT which exists in a comparatively short distance.

  The reflected light RL from a short distance, which cannot be regarded as infinity, is incident on the beam splitter 20 in such a state that the diameter of the light beam spreads. Therefore, the first reflected light RL1 is incident on the first light receiving lens 22A in such a state that the diameter of the light beam spreads. Since the first light receiving lens 22A is set so that light from infinity is condensed on the light receiving element, the first reflected light RL1 is not sufficiently condensed due to the influence of spherical aberration and defocus. Is incident on the light receiving element 24A.

  On the other hand, the second reflected light RL2 also enters the second light receiving lens 22B in such a state that the diameter of the light beam spreads, but the second light receiving lens 22B has a small numerical aperture NA2. Generally, if there is a wavefront aberration due to defocus (hereinafter referred to as defocus aberration) and a spherical aberration, the diameter of the focused spot becomes large, which leads to deterioration of the imaging performance. However, these wavefront aberrations have the property of becoming larger as the numerical aperture increases, and under a sufficiently small numerical aperture, the deterioration of the imaging performance can be minimized. The pinhole photograph produces a clear image without blurring because the numerical aperture is sufficiently small. The second reflected light RL2 is condensed by a lens having a small numerical aperture, and therefore enters the light receiving element 24B in a sufficiently condensed state.

  Therefore, in the distance measuring apparatus 100 of the present embodiment, regarding the reflected light RL from the object OJT at a long distance that can be regarded as infinity, the light receiving result by the first light receiving unit 23A and the second light receiving unit 23B are used. The distance to the object OJT is calculated using both the light reception result. On the other hand, for the reflected light RL from the object OJT at a short distance that cannot be considered to be infinity, the distance to the object OJT is calculated using only the light reception result by the second light receiving unit 23B.

  Specifically, first, the approximate distance determining unit 31 determines the approximate distance to the object OJT based on the light receiving signal RS1 from the first light receiving unit 23A or the light receiving signal RS2 from the second light receiving unit 23B. . For example, when the reflected light RL is the reflected light from the object OJT at such a long distance that it can be regarded as infinity, the light reception signal RS2 has a signal waveform as shown in FIG. 3A. Here, the horizontal axis represents the elapsed time after the emission light OL is emitted, and the vertical axis represents the signal level of the light reception signal RS2. The received light signal RS2 based on the reflected light RL from a long distance has a signal waveform that rises later than the reference timing RT. Therefore, the approximate distance determination unit 31 determines that the object OJT is located at a long distance that is equal to or greater than a predetermined value and can be regarded as infinity.

  On the other hand, when the reflected light RL is the reflected light from the object OJT at a short distance that cannot be regarded as infinity, the light reception signal RS2 has a signal waveform as shown in FIG. 3B. The reception signal RS2 based on the reflected light RL from a short distance has a signal waveform that rises earlier than the reference timing RT. Therefore, the approximate distance determination unit 31 determines that the elephant OJT is located at such a short distance that the reflected light RL cannot be regarded as infinity.

  The used light receiving element determination unit 32 adds up the first light reception signal RS1 and the second light reception signal RS2 in the calculation of the distance to the object OJT by the distance calculation unit 33 based on the determined approximate distance. It is determined whether the signal is used or only the second light receiving signal RS2 is used. For example, when the approximate distance is a long distance, the used light receiving element determination unit 32 determines to calculate the distance using the summed signal obtained by adding the first light receiving signal RS1 and the second light receiving signal RS2. When the approximate distance is a short distance, the used light receiving element determination unit 32 determines to calculate the distance using only the second light receiving signal RS2.

  The distance calculation unit 33 calculates the distance to the object OJT based on the determination result of the used light receiving element determination unit 32 and based on the second light reception signal RS2 or the summed signal. That is, when the object OJT is at a long distance, the distance calculation unit 33 calculates the distance using the summed signal. When the object OJT is in the short distance, the distance calculation unit 33 calculates the distance using only the second light reception signal RS2.

  FIG. 4A is a schematic diagram showing how reflected light is received from a plurality of objects OJA, OJB, and OJC at a long distance that can be regarded as infinity. Since the reflected light from a long distance is sufficiently condensed by the first light receiving lens 22A having a large numerical aperture, the reflected light from the objects OJA, OJB, and OJC constitutes the first light receiving portion 23A. The light is received by each of the plurality of light receiving elements.

  FIG. 4B is a diagram showing a waveform of a light reception signal of reflected light received from each light receiving element of the first light receiving unit 23A from a long distance. As described above, since the reflected light from a long distance is received by each light receiving element of the first light receiving unit 23A in a state of being collected by the first light receiving lens 22A, it is easy to distinguish each light receiving signal. Is.

  Therefore, when the object is at a long distance, it is possible to obtain a sufficient reception signal by using both the light reception result of the first light receiving unit 23A and the light reception result of the second light receiving unit 23B, so that it is possible to accurately obtain It is possible to calculate the distance.

  On the other hand, FIG. 5A is a schematic diagram showing a case where reflected light from a plurality of objects OJA, OJB, and OJC at a short distance that cannot be regarded as infinity is received by the first light receiving unit 23A. The reflected light from a short distance is not sufficiently condensed on each light receiving element of the first light receiving portion 23A due to the influence of the spherical aberration of the first light receiving lens 22A having a large numerical aperture, the spot becomes large, and the adjacent light The light-receiving element is exposed.

  FIG. 5B is a diagram showing a waveform of a received light signal of reflected light from a short distance received by each light receiving element of the first light receiving unit 23A. As described above, the reflected light from a short distance is not sufficiently condensed on each light receiving element of the first light receiving section 23A and protrudes to the adjacent light receiving element, so that it is difficult to distinguish each light receiving signal. Is. Therefore, when the target object is at a short distance, it is not possible to accurately determine the distance to the target object OJT using the light reception result of the first light receiving unit 23A.

  FIG. 6A is a schematic diagram showing a case where reflected light from a plurality of objects OJA, OJB, and OJC at a short distance similar to the case of FIG. 5A is received by the second light receiving unit 23B. Since the numerical aperture NA2 of the second light receiving lens 22B is small, even reflected light from a short distance is condensed by the second light receiving lens 22B and received by each light receiving element of the second light receiving section 23B.

  FIG. 6B is a diagram showing a waveform of a light reception signal of reflected light from a short distance received by each light receiving element of the second light receiving section 23B. As described above, since the reflected light from a short distance is received by each light receiving element of the second light receiving unit 23B in a state of being collected by the second light receiving lens 22B, it is possible to distinguish each light receiving signal. Is.

  Therefore, when the object is at a short distance, the distance is calculated without being affected by the spherical aberration and defocus of the first light receiving lens 22A by using only the light receiving result of the second light receiving unit 23B. It becomes possible.

  As described above, in the distance measuring apparatus 100 of the present embodiment, when the object OJT is at such a long distance that it can be regarded as infinity, the light receiving result by the first light receiving unit 23A and the light receiving by the second light receiving unit 23B are received. The distance is calculated using both of the results, and when the object OJT is at a short distance that cannot be regarded as infinity, the distance is calculated using both of the light reception results of the second light receiving unit 23B. . With such a configuration, it is possible to accurately measure the distance regardless of the distance to the object OJT.

  Further, in the distance measuring apparatus 100 of the present embodiment, the beam splitter 20 formed of a half mirror splits the reflected light RL into the first reflected light RL1 and the second reflected light RL2, and the branched reflected light is the first reflected light RL1. The light receiving section 23A and the second light receiving section 23B are configured to receive light. Therefore, the reflected light RL from a short distance can be received with a reduced amount of light, and the sensitivity of the light receiving elements of the first light receiving unit 23A and the second light receiving unit 23B can be reduced.

  Next, a distance measuring device according to a second embodiment of the present invention will be described. The distance measuring apparatus according to the present embodiment is different from the distance measuring apparatus 100 according to the first embodiment in that the beam splitter 20 is formed of a holed mirror instead of a half mirror. Further, in the distance measuring apparatus of the present embodiment, the numerical aperture NA1 of the first light receiving lens 22A and the numerical aperture NA2 of the second light receiving lens 22B may be the same value.

  FIG. 7 is a diagram showing an example of the surface of the beam splitter 20 of this embodiment. The beam splitter 20 of this embodiment has an opening AP near the center. Further, a reflection region RP having a predetermined reflectance is formed on the periphery of the opening AP.

  As shown in FIG. 1, a part of the reflected light RL incident on the beam splitter 20 passes through the opening AP and becomes the reflected light RL2. On the other hand, another part of the reflected light RL is reflected by the reflection region RP to become the reflected light RL1. As a result, the reflected light RL is branched into the first reflected light RL1 and the second reflected light RL2 having an outer edge smaller than that of the first reflected light RL1.

  FIG. 8A shows a case where the lengths of the optical paths of the reflected light RL and the reflected light RL1 are distances that can be regarded as infinity as viewed from the first light receiving lens 22A, that is, the reflected light RL exists at a long distance that can be regarded as infinity. It is a figure which shows typically the aspect of condensing when it is the reflected light from the object OJT which is doing. Here, the light receiving element 24A is shown as one of the light receiving elements forming the first light receiving section 23A, and the light receiving element 24B is shown as one of the light receiving elements forming the second light receiving section 23B.

  The reflected light RL from a distance that can be regarded as infinity enters the beam splitter 20 in a state close to parallel light, that is, in a state in which the diameter of the light flux is substantially constant. For this reason, the first reflected light RL1 enters the first light receiving lens 22A and is condensed with the diameter of the light flux being substantially constant. Therefore, the light receiving element 24A receives the first reflected light RL1 which is sufficiently condensed by the first light receiving lens 22A. Further, the second reflected light RL2 also enters the second light receiving lens 22B and is condensed with the diameter of the light flux being substantially constant. Therefore, the light receiving element 24B receives the second reflected light RL2 that is sufficiently condensed by the second light receiving lens 22B.

  On the other hand, FIG. 8B shows that the lengths of the optical paths of the reflected light RL and the reflected light RL1 are such a short distance that they cannot be regarded as infinity when viewed from the first light receiving lens 22A, that is, the reflected light RL is relatively close. It is a figure which shows typically the aspect of condensing when it is the reflected light from the object OJT which exists in the distance.

  The reflected light RL from a short distance, which cannot be regarded as infinity, is incident on the beam splitter 20 in such a state that the diameter of the light beam spreads. Therefore, the first reflected light RL1 is incident on the first light receiving lens 22A in such a state that the diameter of the light beam spreads. Since the first light receiving lens 22A is set so that light from infinity is condensed on the light receiving element, the first reflected light RL1 is not sufficiently condensed due to the influence of spherical aberration and defocus. Is incident on the light receiving element 24A.

  On the other hand, the second reflected light RL2 also enters the second light receiving lens 22B in such a state that the diameter of the light beam spreads, but the second light receiving lens 22B is set to have a small numerical aperture NA2. The second reflected light RL2 is incident on the light receiving element 24B in a sufficiently condensed state.

  The first light receiving lens 22A and the second light receiving lens 22B of the present embodiment have the same numerical aperture, for example, but the size of the outer edge of the incident reflected light (that is, the size of the diameter of the light beam) is different. . In the distance measuring apparatus 100 of the present embodiment, the reflected light RL has the first reflected light RL1 having a relatively large outer edge and a large substantial numerical aperture, and the reflected light RL having a relatively small outer edge and a substantial numerical aperture. It is split into a small second reflected light RL2. That is, the second reflected signal RL2 having a small outer edge is incident on the second light receiving lens 22B, and the substantial numerical aperture is reduced. Therefore, the second reflected light RL2 is received by the light receiving element 24B in a substantially condensed state.

  On the other hand, the first reflected signal RL1 having a large outer edge is incident on the first light receiving lens 22A, and the substantial numerical aperture is increased. Therefore, the first reflected light RL1 is incident on the light receiving element 24A in a state where it is not sufficiently condensed due to the influence of defocus and spherical aberration. That is, the first reflected light RL1 incident on the light receiving element 24A overflows to the adjacent light receiving element.

  Similar to the first embodiment, the approximate distance determining unit 31 of the present embodiment is based on the light receiving signal RS1 from the first light receiving unit 23A or the light receiving signal RS2 from the second light receiving unit 23B. , The approximate distance to the object OJT is determined.

  The used light receiving element determination unit 32 adds up the first light reception signal RS1 and the second light reception signal RS2 in the calculation of the distance to the object OJT by the distance calculation unit 33 based on the determined approximate distance. It is determined whether the signal is used or only the second light receiving signal RS2 is used. For example, when the approximate distance is a long distance, the used light receiving element determination unit 32 determines to calculate the distance using the summed signal obtained by adding the first light receiving signal RS1 and the second light receiving signal RS2. When the approximate distance is a short distance, the used light receiving element determination unit 32 determines to calculate the distance using only the second light receiving signal RS2.

  The distance calculation unit 33 calculates the distance to the object OJT based on the determination result of the used light receiving element determination unit 32 and based on the second light reception signal RS2 or the summed signal. That is, when the object OJT is at a long distance, the distance calculation unit 33 calculates the distance using the summed signal. When the object OJT is in the short distance, the distance calculation unit 33 calculates the distance using only the second light reception signal RS2.

  In the distance measuring apparatus 200 of the present embodiment, similar to the first embodiment, since both the first light receiving signal RS1 and the second light receiving signal RS2 are used for calculating the distance for the long-distance object OJT, the distance is accurately calculated. It is possible to calculate the distance. Further, since only the light reception result (second light reception signal RS2) of the second reflected light RL2 having a small outer edge is used for the calculation of the distance for the short-distance object OJT, the spherical aberration of the lens and the defocused light of the reflected light are used. It is possible to calculate the distance without being affected by the focus.

  Therefore, according to the distance measuring device 200 of the present embodiment, it is possible to perform accurate distance measurement regardless of the distance to the object.

  Note that the embodiment of the present invention is not limited to the one shown in the above example. For example, in the first embodiment, the configuration in which the numerical aperture NA1 of the first light receiving lens 22A is larger than the numerical aperture NA2 of the second light receiving lens 22B has been described. In addition, in the second embodiment, the configuration in which the beam splitter 20 including the perforated mirror splits the reflected light RL into the first reflected light RL1 having a large outer edge and the second reflected light RL2 having a small outer edge has been described. However, these configurations can be combined. In other words, a perforated mirror may be used to branch the reflected light so that the outer edges have different sizes, and the branched reflected light may be received through light receiving lenses having different numerical apertures.

  Further, in the above-described embodiment, the case where the first light receiving portion 23A and the second light receiving portion 23B are each configured as a line sensor in which a plurality of light receiving elements are arranged in a line has been described. The configurations of the unit 23A and the second light receiving unit 23B are not limited to this. For example, the first light receiving unit 23A and the second light receiving unit 23B may each be configured by a single light receiving element. The first light receiving unit 23A and the second light receiving unit 23B may each be composed of a plurality of light receiving elements arranged in a two-dimensional array.

  Further, in the above embodiment, the case where the light source 12 is composed of a plurality of emitters (multi-emitters) arranged in a line and emits a line-shaped laser beam has been described. However, the configuration of the light source 12 and the shape of the emitted laser light are not limited to this. For example, the light source 12 may be configured as a single emitter.

  Further, in the second embodiment, the configuration in which the reflected light RL is split into the first reflected light RL1 and the second reflected light RL2 by using the perforated mirror having the circular opening in the central portion has been described. However, the branching portion for branching the reflected light RL is not limited to such a perforated mirror, and it is possible to branch so that the outer edge of the first reflected light RL1 is larger than the outer edge of the second reflected light RL2. It should be configured in.

  In addition, the series of processes described in the above embodiments can be performed by computer processes according to a program stored in a recording medium such as a ROM.

100 distance measuring device 11 light emitting unit 12 light source 13 light emission drive unit 14 light emitting lens 20 beam splitter 21A first light receiving processing unit 21B second light receiving processing unit 22A first light receiving lens 22B second light receiving lens 23A first light receiving Section 23B Second light receiving section 24A Light receiving element 24B Light receiving element 30 Distance measuring section 31 Approximate distance determination section 32 Used light receiving element determination section 33 Distance calculation section

Claims (9)

A branching unit for branching the light emitted toward the predetermined region and reflected by the object in the predetermined region into first reflected light and second reflected light;
A first condenser lens provided on the optical path of the first reflected light;
A first light receiving portion provided on the optical path of the first reflected light that has passed through the first condenser lens;
A second condenser lens provided on the optical path of the second reflected light;
A second light receiving portion provided on the optical path of the second reflected light that has passed through the second condenser lens;
A distance calculation unit that calculates a distance to the object based on at least one of a light reception result of the first light receiving unit and a light reception result of the second light receiving unit;
Have
The distance measuring device, wherein the numerical aperture of the first condenser lens is larger than the numerical aperture of the second condenser lens.   The distance measuring device according to claim 1, wherein an aperture of the first condenser lens is larger than an aperture of the second condenser lens.   The focal length of the said 1st condensing lens is smaller than the focal length of the said 2nd condensing lens, The ranging device of Claim 1 or 2 characterized by the above-mentioned. The first light receiving unit receives the first reflected light that has passed through the first condenser lens and generates a first received light signal,
The second light receiving unit receives the second reflected light that has passed through the second condenser lens to generate a second light receiving signal,
The distance calculation unit calculates a distance to the object based on a summed signal obtained by summing the first light reception signal and the second light reception signal, or the second light reception signal.
The distance measuring device according to any one of claims 1 to 3, wherein:   The distance calculation unit determines an approximate distance to the object based on the first received light signal or the second received light signal, and based on the combined signal when the estimated distance is equal to or greater than a threshold value. The distance to the target object is calculated, and when the approximate distance is less than the threshold value, the distance to the target object is calculated based on the second light reception signal. Ranging device. It has an emission part for emitting the line-shaped light,
The measuring device according to claim 1, wherein each of the first light receiving unit and the second light receiving unit is a line sensor in which a plurality of light receiving elements are arranged in a line. Distance device. A branching part for branching the light, a first condensing lens provided on one optical path of the light branched by the branching part, and a first condensing lens provided on the optical path of the light passing through the first condensing lens. No. 1 light receiving part, a second condensing lens having a numerical aperture smaller than that of the first condensing lens provided on the other optical path of the light branched by the branching part, and the second condensing lens A second light receiving unit provided on the optical path of the light passing through, and a distance calculating unit that calculates the distance to the object based on the light receiving result of the first light receiving unit or the second light receiving unit, A distance measuring method executed by a distance measuring device having:
A step in which the branching portion branches the light emitted toward the predetermined area and reflected by the object in the predetermined area into first reflected light and second reflected light;
The first condensing lens condensing the first reflected light;
The second condensing lens condensing the second reflected light;
A step in which the first light receiving section receives the first reflected light focused by the first focusing lens to generate a first light receiving signal;
A step in which the second light receiving section receives the second reflected light focused by the second focusing lens to generate a second light receiving signal;
A step in which the distance calculation unit determines an approximate distance to the object based on the first received light signal or the second received light signal;
When the distance calculation unit is equal to or more than the threshold value, the distance calculation unit calculates a distance to the object based on a summed signal obtained by summing the first light reception signal and the second light reception signal, Calculating a distance to the object based on the second received light signal when the estimated distance is less than the threshold;
A distance measuring method comprising: A branching portion for branching light emitted toward a predetermined area and reflected by an object in the predetermined area into first reflected light and second reflected light, and condensing the first reflected light. A first condenser lens, a first light receiving section that receives the first reflected light that has passed through the first condenser lens, and generates a first received light signal; And a second condenser lens having a small numerical aperture for condensing the second reflected light, and the second reflected light passed through the second condenser lens to receive a second received light signal. A second light receiving unit for generating, and a computer mounted on the distance measuring device,
Determining an approximate distance to the object based on the first received light signal or the second received light signal,
When the approximate processing is equal to or more than a threshold value, the distance to the object is calculated based on a summed signal obtained by adding the first received light signal and the second received light signal, and the approximate distance is the threshold value. If it is less than, a step of calculating a distance to the object based on the second received light signal,
A program characterized by causing to execute. A branching portion for branching light emitted toward a predetermined area and reflected by an object in the predetermined area into first reflected light and second reflected light, and condensing the first reflected light. A first condenser lens, a first light receiving section that receives the first reflected light that has passed through the first condenser lens, and generates a first received light signal; And a second condenser lens having a small numerical aperture for condensing the second reflected light, and the second reflected light passed through the second condenser lens to receive a second received light signal. A second light receiving unit for generating, and a computer mounted on the distance measuring device,
Determining an approximate distance to the object based on the first received light signal or the second received light signal,
When the approximate processing is equal to or more than a threshold value, the distance to the object is calculated based on a summed signal obtained by adding the first received light signal and the second received light signal, and the approximate distance is the threshold value. If it is less than, a step of calculating a distance to the object based on the second received light signal,
A recording medium for recording a program for executing.