JP2016045161A - Distance-measuring apparatus with attachment detection function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a matter attached to a lens.SOLUTION: A distance-measuring apparatus with an attachment detection function of the present invention comprises: light-receiving means and light-emitting means; light-focusing means guiding, to the light-receiving means, reflected light obtained when light emitted from the light-emitting means is reflected by an object; reflection means that is provided on a surface of the light-focusing means and that adjusts the reception intensity of the light-receiving means; and attachment detection means that controls the light reception time of the light-receiving means, or the emission time or emission intensity of the light-emitting means on the basis of a light-receiving signal received from the light-receiving means that has received the light, and that detects whether an attached matter is attached to a front surface of the light-focusing means.SELECTED DRAWING: Figure 1

Description

  The present invention is an apparatus for measuring a distance to an object to be measured, and has an attached matter detection function having a function of detecting attached matter (dirt) attached to the surface of a lens (light collecting means). The present invention relates to a distance measuring device.

  In Patent Document 1, in a TOF (time-of-flight) range imaging system, the presence or absence of contamination on the optical interface is determined based on the amplitude histogram of the amplitude image of the received light wave detected by the imager module. The configured device is described.

  In Patent Document 2, a light guide member is provided on the surface of the lens so that light from the LED is guided to the light guide member. When the LED is turned on, an image obtained by the imaging device and the LED are turned off. An apparatus is described that determines whether or not an adhering substance is attached to a light guide member based on a density difference image with an image obtained by an image pickup device.

Special table 2010-534000 gazette JP 2008-64630 A

  However, in the configuration of Patent Document 1, there is a problem that it is not known whether the obtained amplitude image is caused by reflection by a short-distance object or reflection by dirt, and the dirt cannot be accurately detected. Further, in the configuration of Patent Document 2, in a situation where strong light is incident, a situation in which a density difference image due to the presence or absence of an adhering matter may not be obtained may occur, and the presence or absence of an adhering matter cannot be detected accurately. was there. For example, in an in-vehicle device, examples of situations in which strong light is incident include cases in which strong sunlight is incident during the day, or irradiation light from a headlight of a vehicle at night is incident.

  Accordingly, an object of the present invention is to provide a distance measuring device with an adhering matter detection function capable of accurately detecting an adhering matter adhering to a lens.

  According to the first aspect of the present invention, the light receiving means and the light emitting means, the light irradiated from the light emitting means is reflected by the object, the light collecting means for guiding the reflected light to the light receiving means, and the light receiving intensity at the light receiving means are obtained. Reflecting means provided on the surface of the light collecting means for adjustment, and light receiving time of the light receiving means or irradiation time of the light emitting means based on a light receiving signal received by the light receiving means by irradiating light from the light emitting means Alternatively, it is a distance measuring device with an adhering matter detection function provided with an adhering matter detecting unit that controls irradiation intensity and detects whether or not an adhering matter is attached to the front surface of the light collecting unit.

1 is a partial cross-sectional view of a distance measuring device with an adhering matter detection function according to a first embodiment of the present invention. Enlarged partial cross-sectional view around the reflective member (A) is a figure equivalent to FIG. 1, (b) is a partial front view of a light guide member. Front view of light receiving element for distance measurement and light receiving element for reference light Block diagram showing the electrical configuration of a distance measuring device with an adhering matter detection function Flow chart of adhesion detection control and distance measurement control The figure which shows the voltage of the light reception signal of the light receiving element for reference light Time chart showing irradiation time and light reception time FIG. 4 equivalent view showing the second embodiment of the present invention FIG. 6 equivalent view showing a third embodiment of the present invention. Equivalent to FIG. FIG. 10 equivalent view showing the fourth embodiment of the present invention.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. First, FIG. 1 is a partial cross-sectional plan view showing a schematic configuration of a distance measuring device with an adhering matter detection function of the present embodiment. As shown in FIG. 1, the distance measuring device 1 with an adhering matter detection function includes a case 2, a sensor storage unit 3 disposed in the case 2, and a light receiving element ( A light receiving means) 4, a lens holding portion 5 provided on the right side surface in FIG. 1 of the sensor storage portion 3, and a lens (light collecting means) 6 held by the range holding portion 5.

  As shown in FIG. 4, the light receiving element 4 includes a distance measuring image pickup element (ranging light receiving element) 7 made up of a large number of two-dimensionally arranged pixel arrays, and the right side of the distance measuring image pickup element 7 in FIG. 4. For example, a reference light receiving element 8 made of one pixel is provided at the top of the unit. Each pixel (light receiving element) constituting the distance measuring imaging element 7 has a circuit that receives only AC light emission (for example, pulse light emission) and removes DC light (for example, background light), for example, a background light difference circuit. The reference light receiving element 8 includes a circuit that receives only AC light emission (for example, pulse light emission) and removes DC light (for example, background light), for example, a background light difference circuit.

  A light guide member 9 made of, for example, a glass plate member is attached to the surface (front surface, right side surface in FIG. 1) of the lens 6. The light guide member 9 is disposed so as to be perpendicular to the normal line of the spherical surface of the lens 6. The light guide member 9 is attached to the right end opening of the case 2 in FIG. 1 so as to close the opening. A reference light LED (second light emitting means) 10 is disposed below the sensor housing 3 in FIG. 1 in the case 2 and in the vicinity of the case side wall 2a. A prism 11 is disposed on a portion of the inner surface of the light guide member 9 irradiated with light from the reference light LED 10 in the lower portion in FIG.

  In the case of this configuration, as shown in FIGS. 3A and 3B, the light emitted from the reference light LED 10 is transmitted through the prism 11 to widen the light path, and the light is guided to the light guide member. 9 is configured so as to pass through all positions in the lens 9 (all positions on the surface of the lens 6), that is, an arrangement configuration in which such a light path is formed by the reference light irradiation LED 10, the prism 11, and the light guide member 9. It becomes the composition which becomes. The light guide member 9 and the prism 11 constitute an optical element that adjusts the optical path so that light emitted from the light emitting means passes through all positions on the surface of the light collecting means. A beam splitter or the like may be used instead of the prism 11.

  A reflecting member (reflecting means) 12 is attached to a peripheral edge (lower part in FIG. 1) on the surface of the light guide member 9. As shown in FIG. 2, the reflecting member 12 includes a reflector 13 attached to the surface of the light guide member 9, and a light shield 14 attached to the surface of the light guide member 9 so as to cover the reflector 13. It has. The reflector 13 is made of a material whose refractive index is equal to the refractive index of an adhering substance such as raindrops, earth, and dust, that is, a refractive index of 1.2 to 1.6, and has a hemispherical shape or a truncated cone shape. . Surfaces of the reflector 13 other than the contact surface with the light guide member 9 are covered with a light shield 14. The reflector 13 and the light shield 14 are joined by, for example, an optical contact. The light shield 14 has a function of blocking and absorbing light from the inner surface side and light from the outer surface side.

  In the above configuration, the light emitted from the reference light LED 10 is reflected by the reflecting member 12 and the reflected light is received by the reference light receiving element 8. In the case of this configuration, the reference light receiving element 8 and the reflecting member 12 are disposed at point-symmetrical positions with respect to the center of the lens 6.

  Further, a distance measuring LED (first light emitting means) 15 is disposed on the outer surface of the right end portion in FIG. 1 of the case side wall 2 a of the case 2. The light emitted from the ranging LED 15 is reflected by the object, and the reflected light is configured to be received by the ranging imaging device 7. The reference light LED 10 and the distance measuring LED 15 constitute light emitting means.

  In the case 2, a light shielding plate 31 is disposed between the reference light LED 10 and the light receiving element 4. The right end portion of the light shielding plate 31 is in contact with the light guide member 9. In the case of this configuration, the ranging LED 15, the reference light LED 10, and the light receiving element 4 are configured to be shielded from each other.

  FIG. 5 is a block diagram showing an electrical configuration of the distance measuring device 1 with an adhering matter detection function configured as described above. As shown in FIG. 5, the distance measuring device 1 with an adhering matter detection function includes a control unit 16, a light receiving unit 17 for detection, a light receiving unit 18 for distance measurement, an irradiation unit 19 for detection, and an irradiation for distance measurement. Part 20. The control unit 16 has a function of controlling the entire distance measuring device 1 with an adhering matter detection function, and has functions as an adhering matter detection unit and a control unit. The control unit 16 controls light reception of the detection light receiving unit 17 and the ranging light receiving unit 18 and receives light reception signals from the detection light receiving unit 17 and the ranging light receiving unit 18. The control unit 16 performs irradiation (lighting) control on the detection irradiation unit 19 and the distance measurement irradiation unit 20.

  The detection light receiving unit 17 receives the reference light reception control signal from the control unit 16 to control the exposure time of the reference light reception element 8 and receives the reference light reception signal received by the reference light reception element 8. Output to the control unit 16. The ranging light-receiving unit 18 receives the ranging light-receiving control signal from the control unit 16 and controls the light-receiving time of the ranging image-capturing element 7 and measures the distance received (imaged) by the ranging image-capturing element 7. The received light signal is output to the control unit 16.

  The detection irradiation unit 19 receives the reference light irradiation control signal from the control unit 16 and controls the irradiation (lighting) time of the reference light irradiation LED 10. The distance measurement irradiation unit 20 receives the distance measurement irradiation control signal from the control unit 16 and controls the irradiation (lighting) time of the distance measurement LED 15.

  Next, the operation of the above configuration will be described with reference to FIGS. The flowchart of FIG. 6 shows the content of control of the control part 16 of the distance measuring device 1 with an adhering matter detection function. The time chart of FIG. 8 shows the lighting operation of the ranging LED 15, the lighting operation of the reference light LED 10, and the light receiving (exposure) operation of the ranging imaging element 7 and the reference light receiving element 8.

  As shown in FIG. 8A, the distance measurement LED 15 is turned on (pulsed) for one frame, that is, during each of time t1, time t2, time t3, and time t4. Each time t1 to t4 is, for example, about several us to several ms, and the turn-off time between each time t1 to t4 is, for example, about several us to several hundred us. In this case, during each time t1 to t4, as shown in FIG. 8B, the lighting operation is turned on / off at a short pulse interval T. The pulse interval T is, for example, about several ns to several hundreds ns. The light receiving (exposure) operation of the ranging image pickup device 7 corresponds to the lighting operation of the ranging LED 15 as shown in FIG. 8A, that is, one frame, that is, time t1, time t2, time t3. During each time t4, light is received, and during each time t1 to t4, the light receiving operation is turned on and off at a short pulse interval T as shown in FIG. The light receiving operation of the distance measuring image sensor 7 is set to be delayed by T / 2 every time the time t2, t3, and t4 are advanced with respect to the time t1.

  Further, as shown in FIG. 8A, the lighting operation of the reference light LED 10 is lit (pulse lighting) for a time t5 (the lighting operation is turned on / off at a short pulse interval T). Correspondingly, the light receiving (exposure) operation of the reference light receiving element 8 is received for a time t5 as shown in FIG. 8B (the light receiving operation is turned on and off at a short pulse interval T). ).

  Then, after the lighting operation of the reference light LED 10 (time t5) and the light receiving operation of the reference light receiving element 8 (time t5) are performed once, the lighting operation of the ranging LED 15 (time t1, time t2, time) t3, time t4) and the light receiving operation (time t1, time t2, time t3, time t4) of the distance measuring image sensor 7 are executed N times (that is, for N frames). Further, the reference light LED 10 is not turned on while the distance measuring LED 15 is turned on. During the distance measurement process, the lighting operation of the reference light LED 10 and the light receiving operation of the reference light receiving element 8 for one time, the lighting operation of the ranging LED 15 for N frames, and the imaging for the distance measurement are performed. The light receiving operation of the element 7 is repeatedly executed alternately.

  Next, the contents of the control (attachment detection control and distance measurement control) of the control unit 16 of the distance measuring device 1 with an attachment detection function will be described with reference to the flowchart of FIG. First, in step S10 of FIG. 6, initial setting is executed. Then, the process proceeds to step S20 to irradiate the reference light LED 10 (see time t5 in FIG. 8A). Subsequently, the process proceeds to step S30, and the reference light LED 10 emits light by the reference light receiving element 8 (see FIG. 8A). (See time t5 in FIG. 8A).

  Thereafter, the process proceeds to step S40, and it is determined whether or not the light reception voltage of the reference light receiving element 8 is equal to or higher than a first predetermined value V1 (see FIGS. 7A and 7B). In this case, the reference light receiving element 8 is required to operate between a first predetermined value V1 and a second predetermined value V2 as shown in FIGS. 7A and 7B. ing. When the influence of disturbance light is weak, as shown in FIG. 7A, the received light voltage of the reference light receiving element 8 exists between the first predetermined value V1 and the second predetermined value V2. However, when the influence of disturbance light is strong, the light receiving voltage of the reference light receiving element 8 may be higher than the first predetermined value V1, as shown in FIG. 7B. In such a case, it is necessary to reduce the light receiving voltage of the reference light receiving element 8 so that the light receiving voltage exists between the first predetermined value V1 and the second predetermined value V2. .

  Specifically, in step S40, when the light reception voltage of the reference light receiving element 8 is equal to or higher than the first predetermined value V1, the process proceeds to “YES”, and the process proceeds to step S100 to expose the reference light receiving element 8. (Reception time) is shortened, and the irradiation intensity of the reference light LED 10 is increased. Thereafter, the process returns to step S20 and the above-described processing is repeated. As a result, as shown in FIG. 7B, the light reception voltage of the reference light receiving element 8 is lowered, and the light reception voltage is present between the first predetermined value V1 and the second predetermined value V2. Can be adjusted.

  As a result, in step S40, the light reception voltage of the reference light receiving element 8 becomes smaller than the first predetermined value V1, so the process proceeds to “NO”, and the process proceeds to step S50. In this step S50, it is determined whether or not there is a light receiving voltage of each pixel (light receiving element) in the distance measuring image pickup element 7 equal to or higher than a third predetermined value. Here, when the light receiving voltage of each pixel (light receiving element) in the distance measuring image sensor 7 is higher than the third predetermined value, the process proceeds to “YES”, and the process proceeds to step S110.

  In step S110, it is determined whether or not the number of light receiving voltages of the respective pixels (light receiving elements) in the distance measuring image sensor 7 is equal to or greater than a set number. Here, when an adhering substance is attached to the surface of the lens 6 (light guide member 9), the light reception voltage of each pixel (light receiving element) in the distance measuring image sensor 7 is equal to or greater than a third predetermined value. Since the number of items exceeds the set number, the process proceeds to “YES”, and the process proceeds to step S130. In step S130, a flag (adherent matter detection flag) indicating that the adhering matter has adhered to the surface of the lens 6 (light guide member 9), that is, the adhering matter has been detected, is set to ON. Then, this control (attachment detection process and distance measurement process) is terminated.

  On the other hand, in the above step S110, when there is no deposit on the surface of the lens, the number of light receiving voltages of the respective pixels (light receiving elements) in the distance measuring image sensor 7 that are equal to or greater than a third predetermined value. Is smaller than the set number, the process proceeds to “NO”, and the process proceeds to step S120. In this step S120, the pixels (light receiving elements) in which the light reception voltage of each pixel (light receiving element) in the distance measuring image sensor 7 is not less than the third predetermined value are invalidated (that is, the above-mentioned invalidity at the time of distance measurement). (Do not use the light-receiving voltage from the converted pixels). After this, the process proceeds to step S60.

  In step S50, if there is no pixel (light receiving element) in which the light receiving voltage of each pixel (light receiving element) in the distance measuring image sensor 7 is equal to or greater than the third predetermined value, the process proceeds to “NO”. Proceed to step S60.

  Next, in step S60, the distance measuring LED 15 is irradiated (see the frame (time t1 to t4) in FIG. 8A), and then the process proceeds to step S70, and the distance measuring LED 15 emits light (that is, the object is irradiated). The light that has been irradiated and reflected is received by the distance measuring image sensor 7 (see the frame (time t1 to t4) in FIG. 8A).

  Thereafter, the process proceeds to step S80, and the distance to the object is calculated (ranging) based on the light reception signal received by the ranging image sensor 7. Next, the process proceeds to step S90, and it is determined whether or not the ranging process has been executed N times (N frames). If the distance measurement process has not been executed N times, the process proceeds to “NO”, returns to step S60, and repeats the above process. On the other hand, when the distance measuring process is executed N times in step S90, the process proceeds to “YES”, returns to step S20, and repeats the above process.

  In the present embodiment having the above-described configuration, the reference light LED 10 is installed in the case 2, and the irradiation light is reflected by the reflecting member 12 on the surface of the light guide member 9, and the reflected light passes through the background light difference circuit. It was configured to reach the reference light receiving element 8 included therein. Then, when the distance measuring LED 15 is turned off, light is emitted from the reference light LED 10, and when the reflected light reflected by the reflecting member 12 is received by the reference light receiving element 8, the received light voltage (irradiation of the reference light LED 10 is performed). Exposure (light reception) time or reference of the reference light receiving element 8 (and the distance measuring image pickup element 7) so that the intensity is a predetermined level (between the first predetermined value V1 and the second predetermined value V2). It was comprised so that the irradiation intensity | strength of LED10 for light might be controlled.

  According to this embodiment having the above-described configuration, the object detection can be performed in a state where the influence of disturbance light is reduced by the distance measuring image sensor 7 having the background light difference circuit in the pixel. Further, by always performing optimum exposure control or irradiation control using the reflecting member 12 and the reference light receiving element 8, even when strong disturbance light is incident, the ranging image pickup element 7 and the reference light receiving element. It is possible to adjust the exposure time with respect to 8 or the irradiation intensity with respect to the reference light LED 10, and the deposits can be detected accurately.

  Further, in the present embodiment, when detecting the deposit on the surface of the lens 6 (light guide member 9), the light emitted from the reference light LED 10 is reflected by the deposit and received by the distance measuring image sensor 7. Further, the light receiving voltage of each pixel (light receiving element) in the distance measuring image sensor 7 is higher than a third predetermined value, and the light receiving voltage of each pixel (light receiving element) is a third predetermined value. When the number of the above is equal to or greater than the set number, it is determined that the deposit is attached to the surface of the lens 6 (light guide member 9), and therefore the deposit can be accurately determined. In this case, if it is configured to acquire the arrangement position of the light receiving element whose light reception voltage is equal to or higher than the third predetermined value, it is determined at which position on the lens 6 (the light guide member 9) the attached matter is attached. It is also possible to do.

  Further, in the present embodiment, since the adhering matter detection process is executed once every time the distance measurement process is performed N times, the drive time of the reference light LED 10 in the adhering matter detection process may be reduced. As a result, power consumption can be reduced.

  FIG. 9 shows a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment. In the first embodiment, the distance measuring imaging element 7 and the reference light receiving element 8 are configured as separate semiconductor chips as shown in FIG. 4, but instead of this, in the second embodiment, the distance measuring For example, one light receiving pixel (light receiving element) 21a at the upper right end in FIG. 9 of the distance measuring image sensor 21 is used as the reference light receiving element 21a. .

  The configurations of the second embodiment other than those described above are the same as the configurations of the first embodiment. Therefore, in the second embodiment, substantially the same operational effects as in the first embodiment can be obtained.

  10 and 11 show a third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment. In the third embodiment, step S210 is inserted between step S80 and step S90 as a process for increasing the S / N ratio.

The S / N ratio works as follows: (number of signal photoelectrons per unit time * exposure time) / ((number of signal photoelectrons per unit time + number of disturbing photoelectrons per unit time) * exposure time) ^1/2 . For this reason, for example, if the exposure time is doubled, the S / N ratio is ^2½ times. Therefore, in order to increase the S / N ratio, it is preferable to control the exposure time to be set longer.

  Therefore, in the third embodiment, as an example of the process for increasing the S / N ratio, as shown in FIG. 11, the exposure times of the distance measuring image sensor 7 and the reference light receiving element 8 are set in the first embodiment ( Compared to (see FIG. 3), for example, the time is set to double. In this case, the irradiation time of the ranging LED 15 and the reference light LED 10 is also set to twice as long as that of the first embodiment (see FIG. 3).

  Furthermore, in the third embodiment, the time required for distance detection, that is, the distance detection interval is lengthened by setting the numerical value of the number of times N (N frames) to perform distance measurement larger than that in the first embodiment. As a result, the exposure time used for distance measurement can be increased by the amount of time during which the reference light LED 10 is not irradiated. As a result, the S / N ratio can be further increased.

  The configuration of the third embodiment other than that described above is the same as the configuration of the first embodiment. Therefore, in the second embodiment, substantially the same operational effects as in the first embodiment can be obtained. In particular, according to the third embodiment, since the S / N ratio is set to be large, the distance detection accuracy can be increased.

  FIG. 12 shows a fourth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same structure as 3rd Embodiment. In the fourth embodiment, the determination process in step S110 and the process in step S120 in the third embodiment (see FIG. 10) are omitted, and when the process proceeds to “YES” in step S50, the process proceeds to step S130. Configured.

  The configurations of the fourth embodiment other than those described above are the same as the configurations of the third embodiment. Therefore, in the fourth embodiment, substantially the same operational effects as in the third embodiment can be obtained.

  In each of the above embodiments, the reference light receiving element 8 is configured by one pixel (light receiving element), but may be configured by a plurality of pixels (light receiving elements) instead. In such a configuration, the plurality of pixels may be configured by one semiconductor chip, or the plurality of pixels may be configured by a part of the distance measuring image sensor 7.

  In the drawings, 1 is a distance measuring device with an adhering matter detection function, 2 is a case, 4 is a light receiving element (light receiving means), 6 is a lens (light collecting means), 7 is a distance measuring image sensor, and 8 is a reference light receiving light. Element, 9 is a light guide member, 10 is a reference light LED (second light emitting means), 11 is a prism, 12 is a reflecting member (reflecting means), 13 is a reflector, 14 is a light shield, and 15 is a distance measuring LED. (First light emitting means), 16 is a control unit (attachment detection means, control means), 17 is a light receiving unit for detection, 18 is a light receiving unit for distance measurement, 19 is an irradiation unit for detection, and 20 is an irradiation unit for distance measurement. , 21 are distance measuring image sensors.

Claims (12)

A light receiving means and a light emitting means;
A light collecting means for reflecting the light emitted from the light emitting means by an object and guiding the reflected light to the light receiving means;
Reflecting means provided on the surface of the light collecting means for adjusting the intensity of light received by the light receiving means;
Light is emitted from the light emitting means, and the light receiving time of the light receiving means or the irradiation time or irradiation intensity of the light emitting means is controlled based on the light reception signal received by the light receiving means, and an adhering matter is placed on the front surface of the light collecting means. A distance measuring device with an adhering matter detection function, comprising adhering matter detecting means for detecting whether or not the adhering matter is present.   2. The measurement with an adhering matter detection function according to claim 1, wherein the light receiving means comprises at least one light receiving element, and has a circuit for receiving only AC light emitted from the light emitting means and removing DC light. Distance device.   The distance measuring device with an adhering matter detection function according to claim 1, wherein at least one of the reflecting means is disposed on a front peripheral portion of the light collecting means.   2. The attachment according to claim 1, wherein the reflection means is made of a material having a refractive index equal to a refractive index of a deposit such as raindrop, soil, and dust, that is, a refractive index of 1.2 to 1.6. Distance measuring device with kimono detection function.   The distance measuring device with an adhering matter detection function according to claim 1, wherein the reflecting means has a hemispherical shape or a truncated cone shape.   The distance measuring device with an adhering matter detection function according to claim 1, wherein the reflecting means includes a light shield attached so as to cover a front surface thereof.   2. The deposit according to claim 1, wherein the light emitting means includes a first light emitting means for measuring a distance to an object and a second light emitting means for detecting dirt attached to the light collecting means. Distance measuring device with detection function.   8. The distance measuring apparatus with an adhering matter detection function according to claim 7, wherein the first light emitting means, the second light emitting means, and the light receiving means are shielded from each other.   2. A distance measuring device with an adhering matter detection function according to claim 1, further comprising an optical element for adjusting an optical path so that light emitted from the light emitting means passes through all positions on the surface of the light collecting means. .   8. A control unit for turning off the second light emitting unit while the first light emitting unit is turned on and turning off the first light emitting unit while turning on the second light emitting unit. Ranging device with attached substance detection function as described.   Control means for calculating the SN ratio at that time based on the information of the light reception signal of the light receiving means and controlling the exposure time of the light receiving means or the irradiation time or intensity of the light emitting means according to the SN ratio. The distance measuring device with an adhering matter detection function according to claim 7.   After the adhering matter is detected by the detection control by the adhering matter detecting means, the apparatus comprises a control means for invalidating the light receiving means and continuing the processing if the number of the detected light receiving means is within a predetermined value. The rangefinder with attached matter detection function according to claim 1.

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