JP7264474B2 - Object detection device and object detection method - Google Patents

Description

The present invention mainly relates to an object detection device that measures the distance to an object.

The object detection device of Patent Document 1 includes an optical sensor having light emitting means and light receiving means. The object detection device compares data from the light receiving means with pre-stored data. When the object detection device determines that the difference between the two data is equal to or greater than a predetermined value, it shortens the light emission period of the light emitting means and performs the same determination process a plurality of times. When the difference between the two data repeatedly reaches or exceeds a predetermined value in a plurality of determination processes, a warning signal is output. On the other hand, if the difference between the two data repeatedly does not reach the predetermined value or more in the determination process a plurality of times, there is a high possibility of malfunction, so the original state is restored.

The distance measuring device of Patent Document 2 includes a light emitting unit and a light receiving unit, and creates a distance image of a subject including a person. The distance measuring device sets the power saving mode when there is no person in the distance image, and sets the high definition mode when there is a person in the distance image. In the high-definition mode, the number of pulses emitted by the light-emitting unit is larger and the pulse amplitude is larger than in the power-saving mode.

The distance measuring device of Patent Document 3 includes a device that measures the distance to an object using a TOF (Time of Flight) method, and a device that measures the distance to the object using a triangulation method. The distance measuring device outputs the distance measured by either the TOF method or the triangulation method according to the distance to the object.

JP-A-09-237385 JP 2019-049480 A JP 2017-181279 A

In the distance measuring device of Patent Document 3, by constantly performing both the TOF method effective for long-distance distance measurement and the triangular distance measurement method effective for short-distance distance measurement, the object detection range is widened. can do. However, the method of Patent Document 3 always requires two methods of light projection and light reception, resulting in high power consumption. Therefore, there is a demand for an apparatus that can detect a wide range of objects while suppressing power consumption. Note that the object detection device of Patent Literature 1 is a device for detecting the presence or absence of an object, so it is not configured to detect objects in a wide range from short to long distances. Further, the distance measuring device of Patent Document 2 is configured to switch the accuracy of distance detection according to the presence or absence of a person, and is not configured to detect objects over a wide range from short to long distances.

SUMMARY OF THE INVENTION The present invention has been made in view of the circumstances described above, and its main object is to provide an object detection apparatus that can detect a wide range of objects while suppressing power consumption.

Means and Effects for Solving Problems

The problems to be solved by the present invention are as described above. Next, the means for solving the problems and the effects thereof will be described.

According to the aspect of the present invention, an object detection device having the following configuration is provided. That is, this object detection device includes a light projecting section, a light receiving section, a calculating section, and a control section. The light projecting section includes a light projecting element, and is capable of transmitting a long distance light projecting signal and a short distance light projecting signal. The light-receiving section includes a light-receiving element, and receives reflected light of the long-distance projection signal or the short-distance projection signal reflected by an object. The calculator calculates the distance to the object based on the reflected light received by the light receiver. The control unit executes the long-distance mode while the received light level of the reflected light of the long-distance projection signal is equal to or less than a threshold, and the received light level of the reflected light of the long-distance projection signal exceeds the threshold. Execute close-range mode if In the long-distance mode, the light projecting unit transmits the long-distance light projection signal in a first period and does not transmit the short-distance light projection signal, and the calculation unit calculates the reflected light of the long-distance light projection signal. The distance to the object is calculated based on the received light level of . In the short-distance mode, the light projecting section transmits at least the short-distance light projection signal in a second period shorter than the first period, and the calculation section calculates the reflected light of the short-distance light projection signal The distance to the object is calculated using a triangulation method. The light projecting section transmits the long distance light projection signal in addition to the short distance light projection signal in the short distance mode. In the short-distance mode, the controller maintains the short-distance mode while the received light level of the reflected light of the long-distance projection signal exceeds the threshold, and When the received light level of the reflected light becomes equal to or less than the threshold, the mode is switched to the long-distance mode.

Accordingly, in the long-distance mode, since the long-distance projection signal is transmitted in the first period longer than the second period, it is possible to roughly calculate the distance to the object while suppressing power consumption. Also, while it is detected that the received light level of the reflected light of the long-distance projection signal has exceeded the threshold value (the distance to the object has decreased), the short-distance mode is enabled. In close-range mode, the distance to an object can be calculated accurately because it uses a triangulation method. By configuring as described above, it is possible to widen the detection range while suppressing power consumption. Moreover, in addition to the detection result by the triangulation method, the detection result based on the light reception level can be obtained, and when the distance to the object becomes long, the short distance mode can be switched to the long distance mode.

In the object detection device described above, it is preferable that the signal level of the long-distance projection signal is higher than the signal level of the short-distance projection signal.

As a result, compared to the case where the signal level is the same in the long-distance mode and the short-distance mode, it is possible to increase the detection distance in the long-distance mode and reduce the power consumption in the short-distance mode.

In the object detection device described above, it is preferable that the light projecting section uses the common light projecting element to transmit the long distance light projection signal and the short distance light projection signal.

This makes it possible to reduce the device cost of the optical system, such as the lens and the light projecting element, as compared with the case where separate light projecting elements are used for the long distance mode and the short distance mode.

It is preferable that the object detection device has the following configuration. That is, the light-receiving section includes a pair of light-receiving elements. The calculation unit calculates the distance to the object using the sum of the detection values of the pair of light receiving elements in the long distance mode, and calculates the difference between the detection values of the pair of light receiving elements in the short distance mode. Alternatively, the ratio is used to calculate the distance to the object.

As a result, distance measurement based on the received light level of reflected light in the long distance mode and triangular distance measurement method distance measurement in the short distance mode can be performed appropriately.

It is preferable that the object detection device has the following configuration. That is, the light receiving section has a first electrode and a second electrode, and includes a PSD (Position Sensitive Detector) that detects an optical signal corresponding to the position and amount of light applied. The calculator calculates the distance to the object using the sum of the detected values of the first electrode and the second electrode of the light receiving element in the long distance mode, and calculates the distance to the object in the short distance mode. and the difference or ratio of the detection values of the second electrode to calculate the distance to the object.

This makes it possible to calculate the distance to the object with a simple configuration.

It is preferable that the object detection device has the following configuration. That is, the light receiving section includes a CCD (Charge Coupled Device) sensor including a plurality of light receiving elements. The calculation unit calculates the distance to the object using the sum of the detection values of the plurality of light receiving elements in the long distance mode, and calculates the peak position of the detection values of the plurality of light receiving elements in the short distance mode. is used to calculate the distance to the object.

As a result, the distance to the object can be calculated with higher accuracy than when using the PSD.

It is preferable that the object detection device has the following configuration. That is, the light receiving section includes a one-dimensional sensor in which the light receiving elements are linearly arranged. The calculation unit calculates the distance to the object using the sum of the detection values of the light receiving elements in the long distance mode, and calculates the distance to the object using the peak position of the detection values of the light receiving elements in the short distance mode. Calculate the distance to an object.

As compared with the case of using a pair of light receiving elements, detection is performed with the multi-divided light receiving elements, so the distance to the object can be calculated with high accuracy.

It is preferable that the object detection device has the following configuration. That is, the light-receiving section includes a two-dimensional sensor in which the light-receiving elements are arranged in a plane. The calculation unit calculates the distance to the object using the sum of the detection values of the light receiving elements in the long distance mode, and calculates the distance to the object using the peak position of the detection values of the light receiving elements in the short distance mode. Calculate the distance to an object.

As a result, the distance to the object can be calculated with higher accuracy than when using a one-dimensional sensor.

FIG. 2 is a diagram showing an overview of an object detection device and how the position of reflected light changes as an object moves; 1 is a block diagram showing the configuration of an object detection device; FIG. Graph showing drive current and photoelectric conversion voltage. Timing chart of the object detection device. The schematic diagram which shows the structure of the object detection apparatus of a modification.

Embodiments of the present invention will now be described with reference to the drawings. First, an overview of the object detection device 1 will be described with reference to FIG.

The object detection device 1 includes a light projecting unit 10 that transmits light (projection signal) and a light receiving unit 20 that receives reflected light reflected by the object 100 . The object detection device 1 detects the presence of the object 100 and calculates the distance to the object 100 based on the reflected light received by the light receiving unit 20 . The object detection device 1 is mounted in a device or the like that cancels a sleep state when, for example, a person as the object 100 approaches.

However, the target object 100 is not limited to a person, and may be a creature other than a person, or a machine such as a vehicle or an autonomous mobile body. Also, the distance to the object 100 is not limited to canceling the sleep state, and may be used for other purposes.

Next, a detailed configuration of the object detection device 1 will be described with reference to FIGS. 2 and 3. FIG.

As shown in FIG. 2 , the object detection device 1 has a signal processing section 30 . The signal processing unit 30 changes the light projection signal transmitted by the light projection unit 10, analyzes the reflected light received by the light receiving unit 20, and outputs the analysis results.

The signal processing unit 30 includes a control unit 31 , an oscillation circuit 32 , and a driving circuit 33 as components for controlling the light projecting unit 10 . The control unit 31 sets either the long-distance mode or the short-distance mode based on the input signal (details will be described later). The control unit 31 causes the light projecting unit 10 to project different types of signals according to the set mode. The oscillation circuit 32 generates a current signal that changes periodically in order to cause the light projecting section 10 to emit light at a predetermined cycle according to the mode set by the control section 31 . The driving circuit 33 supplies a current signal for driving to the light projecting section 10 based on the current signal of the oscillation circuit 32 .

The light projecting section 10 includes a light projecting element 11 and a light projecting lens 12 . The light projecting element 11 is an element that converts a current signal into light (projection signal), and is an LED (light emitting diode), for example. The light projecting element 11 intermittently emits light in a predetermined cycle based on the current signal supplied from the driving circuit 33 . An example of the current signal input from the drive circuit 33 to the light projecting element 11 is shown in FIG. 3(a). When the current signal shown in FIG. 3A is input to the light projecting element 11, the light projecting element 11 transmits a one-pulse light projection signal. The light projection signal transmitted by the light projecting element 11 is focused by the light projection lens 12, and when the target object 100 exists nearby, the target object 100 is irradiated with the light projection signal.

As shown in FIG. 4A, the light projecting section 10 is configured to be capable of transmitting a long distance light projection signal and a short distance light projection signal. The signal level Pf of the long-distance projection signal is higher than the signal level Pn of the short-distance projection signal. However, both signal levels may be the same. The first period T1 of the long-distance projection signal is longer than the second period T2 of the short-distance projection signal. The long-distance light projection signal transmits one pulse during the first period T1. The short-distance projection signal transmits a plurality of pulses in a third period T3 during the second period T2 (only one pulse may be transmitted). Although the pulse width of the long-distance projection signal and the pulse width of the short-distance projection signal are the same, they may be different.

The light projection unit 10 can transmit only the long-distance projection signal, transmit only the short-distance projection signal, or transmit by switching between the two. In this embodiment, only the long-distance projection signal is transmitted in the long-distance mode, and the long-distance projection signal and the short-distance projection signal are switched and transmitted in the short-distance mode. Alternatively, only the short-distance projection signal may be transmitted in the short-distance mode.

In this embodiment, the common light projecting element 11 is used to transmit the long-distance light projection signal and the short-range light projection signal. Therefore, the number of light projecting elements 11 included in the object detection device 1 can be reduced. Alternatively, the light projecting element that transmits the long distance light projection signal and the light projecting element that transmits the short distance light projection signal may be separate.

As shown in FIG. 1 , part of the reflected light (scattered reflected light) of the light projection signal applied to the object 100 is received by the light receiving section 20 . The light receiving section 20 includes a light receiving lens 21 , a first light receiving element 22 and a second light receiving element 23 . In this embodiment, the second light receiving element 23 is the light receiving element closer to the light projecting element 11 of the pair of light receiving elements. Reflected light from the object 100 is condensed by the light receiving lens 21 and applied to the first light receiving element 22 and the second light receiving element 23 . The first light receiving element 22 and the second light receiving element 23 are elements that convert light (reflected light) into current signals, and are photodiodes, for example. Hereinafter, the current signal and voltage signal based on the reflected light are referred to as light receiving signals.

The signal processor 30 includes a calculator 34 that calculates the distance to the object 100 based on the received light signal. As shown in FIG. 2 , the calculator 34 includes conversion circuits 41 and 42 , an addition circuit 43 , a subtraction circuit 44 , a switcher 45 , a comparison circuit 46 and a determination circuit 47 .

The conversion circuit 41 converts the light receiving signal of the first light receiving element 22 from a current signal to a voltage signal (see FIG. 3B). The conversion circuit 42 converts the light receiving signal of the second light receiving element 23 from a current signal to a voltage signal (see FIG. 3(c)). The adder circuit 43 adds the light receiving signal of the first light receiving element 22 and the light receiving signal of the second light receiving element 23 and outputs a total signal (see FIG. 3D) indicating the sum of the light receiving signals. The subtraction circuit 44 subtracts the light receiving signal of the second light receiving element 23 from the light receiving signal of the first light receiving element 22 and outputs a difference signal (see FIG. 3(e)) indicating the difference between the light receiving signals. The difference signal may be a signal obtained by subtracting the logarithmic value of the light receiving signal of the second light receiving element 23 from the logarithmic value of the light receiving signal of the first light receiving element 22 . In this case, subtraction of logarithms becomes division and can be regarded as a signal ratio.

The sum signal and difference signal are each used to calculate the distance to the object 100 . First, a method of calculating the distance to the object 100 by the light receiving level method using the total signal will be described. This method is performed using the reflected light of the long-distance projection signal when the long-distance mode is set. Here, the closer the object 100 is located, the higher the level of reflected light received (the amount of reflected light received by the light receiving unit 20). Also, the magnitude of the received light level of the reflected light corresponds to the magnitude of the voltage of the total signal. Therefore, the magnitude of the voltage of the total signal is a value that correlates with the distance to the object 100 .

Next, a method of calculating the distance to the object 100 by triangulation using the difference signal will be described. This method is performed using the reflected light of the short-range projection signal in a situation where the object 100 is located relatively close. As shown in FIG. 1, as the object 100 approaches, the direction of the reflected light detected by the light receiving unit 20 also changes. The condensing position (imaging position) of the light also changes. For example, as shown in FIG. 1, when the distances to the object 100 are D1, D2, and D3, the condensing positions are P1, P2, and P3, respectively. There is a correlation between the distance to the object 100 and the change in the focal position of the reflected light. In addition, the ratio of the light receiving levels of the first light receiving element 22 and the second light receiving element 23 changes according to the change in the condensing position of the reflected light. That is, the magnitude of the voltage of the differential signal is a value that is correlated with the distance to the object 100 .

The object detection device 1 detects whether or not the distance to the object 100 is shorter than a predetermined distance (distance D2 in FIG. 1) in the long distance mode, and detects whether or not the distance to the object 100 is shorter than the distance D2 in FIG. 1 in the short distance mode. It detects whether or not it is closer than another predetermined distance (distance D3 in FIG. 1). On the other hand, the object detection device 1 does not display or notify the specific distance to the object 100 . In this case as well, the object detection apparatus 1 determines the distance by calculating a value that is correlated with the distance to the object 100, and therefore "calculates the distance to the object 100". shall be Note that the object detection device 1 may display or notify the specific distance to the target object 100 .

The total signal and the differential signal are input to the switch 45 . The switch 45 outputs either the total signal or the difference signal to the comparison circuit 46 according to the output of the control section 31 . Specifically, the control unit 31 outputs a total signal to the comparison circuit 46 with respect to the light reception signal of the reflected light of the long-distance light projection signal. On the other hand, the control unit 31 outputs a difference signal to the comparison circuit 46 with respect to the received light signal of the reflected light of the short-distance light projection signal.

When the total signal is input, the comparison circuit 46 compares the total signal with the voltage V1 and outputs a comparison result (for example, difference). This voltage V1 corresponds, for example, to the distance D2 in FIG. That is, the comparison circuit 46 calculates whether or not the distance to the object 100 is shorter than the distance D2, and outputs the result. When the difference signal is input, the comparison circuit 46 compares the difference signal with the voltage V2 and outputs a comparison result (for example, difference). This voltage V2 corresponds to distance D3 in FIG. 1, for example. That is, the comparison circuit 46 calculates whether or not the distance to the object 100 is shorter than the distance D3, and outputs the result. The determination circuit 47 outputs a signal indicating the result of comparison by the comparison circuit 46 to the control section 31 and the output circuit 48 . The output circuit 48 is a circuit for outputting the determination result of the determination circuit 47 to the outside.

The control unit 31 changes the light projection signal based on the output from the determination circuit 47 . Specifically, when the distance to the object 100 is longer than the distance D2 (when the voltage of the total signal is smaller than the voltage V1), the control unit 31 sets the long distance mode and Only the distance projection signal is transmitted from the projection unit 10. - 特許庁Further, when the distance to the target object 100 is shorter than the distance D2 (when the voltage of the total signal is higher than the voltage V1), the control unit 31 sets the short-distance mode and performs long-distance projection as described above. Both the signal and the short-distance projection signal are transmitted from the light projecting part 10 while being switched. The reason why the long-distance projection signal is transmitted even in the short-distance mode is to shift from the short-distance mode to the long-distance mode when the received light level of the long-distance projection signal becomes low. That is, when the voltage of the total signal becomes smaller than the voltage V1 in the short-distance mode, the short-distance mode is changed to the long-distance mode.

Next, the process (object detection method) when the object 100 at the distance D3 gradually approaches the object detection device 1 will be described with reference to FIGS. 4(b) and 4(c). Also, the output signals shown in FIGS. 4B and 4C are signals that turn ON when the distance to the object 100 is shorter than the distance D3.

When the distance to the object 100 is the distance D1, the voltage of the total signal of the reflected light of the long-distance projection signal is smaller than V1. Therefore, the control unit 31 sets the long-distance mode, and the light projection unit 10 transmits a long-distance projection signal as shown in FIG. 4(b). Further, the calculation unit 34 performs distance measurement by the light receiving level method (long-distance distance measurement process).

After that, when the object 100 approaches the object detection device 1 and the distance to the object 100 becomes shorter than the distance D2, the voltage of the total signal of the reflected light of the long-distance projection signal becomes larger than V1. Therefore, since the controller 31 sets the short-distance mode, the light projection section 10 transmits both the long-distance projection signal and the short-distance projection signal, as shown in FIG. 4(c). Further, the calculation unit 34 performs distance measurement by the triangulation method based on the reflection of the short-distance projection signal (short-distance distance measurement process).

When the distance to the object 100 is shorter than the distance D2 and longer than the distance D3, the voltage of the difference signal of the reflected light of the short-distance projection signal is smaller than V2. Therefore, the output signal remains OFF. After that, the distance to the object 100 becomes shorter than the distance D3, so that the voltage of the difference signal of the reflected light of the short-distance projection signal becomes larger than V2. As a result, as shown in FIG. 4(c), the output signal is switched from OFF to ON. The short-distance projection signal includes a plurality of pulses, and the output signal is switched from OFF to ON at the timing when the voltage of the differential signal of the reflected waves of all or most of the pulses exceeds the voltage V2. Thereby, malfunction can be suppressed.

By performing the processing as described above, when the target object 100 is located far away, the short-distance projection signal is not transmitted, thereby suppressing power consumption. In particular, since the short-distance projection signal has a short period, the reduction in power consumption is large. Further, in the long-distance mode, by calculating the distance to the object 100 using the light reception level method instead of the triangulation method, the object 100 at a farther distance can be detected. On the other hand, when the object 100 is located nearby, a short-distance projection signal is transmitted. Since the short-distance projection signal has a short period, when the distance to the object becomes shorter than the distance D3, it can be detected immediately. Further, by calculating the distance to the object 100 using the triangulation ranging method instead of the light receiving level method, the distance to the object 100 can be calculated accurately.

Next, a modification of the above embodiment will be described with reference to FIG. In the description of this modified example, the same or similar members as those of the above-described embodiment may be denoted by the same reference numerals in the drawings, and the description thereof may be omitted.

In the above embodiment, the light receiving section 20 has a configuration in which two independent light receiving elements are combined. Alternatively, for example, a one-dimensional PSD (Position Sensitive Detector) may be used. A one-dimensional PSD has a first electrode and a second electrode at both ends of a light receiving surface, and outputs a current signal that is inversely proportional to the distance between the first electrode and the second electrode according to the position and amount of light irradiated. be. These two current signals are substantially the same as the two current signals in the above embodiment, and are processed in the same way. Note that the PSD may be two-dimensional.

In the modification shown in FIG. 5A, the light receiving section 20 includes a one-dimensional CCD sensor 24 in which CCDs (Charge Coupled Devices) are linearly arranged (arranged in a row) as light receiving elements. From the signal output by the one-dimensional CCD sensor 24, the light receiving signal for each light receiving element can be extracted individually. Therefore, a total signal can be generated by adding all light receiving signals of all (a plurality of) light receiving elements. This total signal is used in the same manner as in the above embodiments. That is, the distance to the object 100 can be calculated in the long-distance mode in the same manner as in the above-described embodiment by performing calculation by the received light level method using this total signal.

Also, in this modification, the peak position of the received light level (the position where the received light level is highest, the central position of the distribution of the received light level) is calculated based on the received light signal of each light receiving element instead of the difference signal. Since this peak position corresponds to the condensing position of the reflected wave, the distance to the object 100 can be calculated in the short distance mode in the same manner as in the above-described embodiment by performing triangulation using the peak position. can be calculated.

In the modification shown in FIG. 5B, the light receiving section 20 includes a two-dimensional CCD sensor 25 in which CCDs as light receiving elements are arranged in a plane (arranged in two orthogonal directions). From the signal output by the two-dimensional CCD sensor 25, the light receiving signal for each light receiving element can be extracted individually. Therefore, similarly to the modification shown in FIG. 5A, the distance to the object 100 can be calculated in both the short distance mode and the long distance mode.

As described above, the object detection device 1 of the embodiment includes the light projecting section 10 , the light receiving section 20 , the calculating section 34 and the control section 31 . The light projecting unit 10 includes a light projecting element 11, and is capable of transmitting a long distance light projection signal and a short distance light projection signal. The light receiving unit 20 includes light receiving elements (the first light receiving element 22 and the second light receiving element 23, etc.), and receives the light reflected by the object 100 from the long-distance projection signal or the short-distance projection signal. receive light. The calculator 34 calculates the distance to the object 100 based on the reflected light received by the light receiver 20 . The control unit 31 executes the long-distance mode while the received light level of the reflected light of the long-distance projection signal is equal to or less than the threshold, and the short-distance mode is executed when the received light level of the reflected light of the long-distance projection signal exceeds the threshold. run mode. In the long-distance mode, the projection unit 10 transmits a long-distance projection signal at the first period T1, and the calculation unit 34 calculates the distance to the object 100 based on the received light level of the reflected light of the long-distance projection signal. do. In the short-range mode, the light projecting unit 10 transmits at least the short-range light projection signal in a second cycle T2 shorter than the first cycle T1, and the calculation unit 34 triangulates the reflected light of the short-range light projection signal. A distance method is used to calculate the distance to the object 100 .

Accordingly, in the long-distance mode, since the long-distance projection signal is transmitted in the first cycle T1 longer than the second cycle T2, it is possible to roughly calculate the distance to the object 100 while suppressing power consumption. Also, while it is detected that the received light level of the reflected light of the long-distance projection signal has exceeded the threshold value (the distance to the object has decreased), the short-distance mode is enabled. In close-range mode, the distance to an object can be calculated accurately because it uses a triangulation method. By configuring as described above, it is possible to widen the detection range while suppressing power consumption.

Further, in the object detection device 1 of the above embodiment, the signal level of the long-distance projection signal is higher than the signal level of the short-distance projection signal.

As a result, compared to the case where the signal level is the same in the long-distance mode and the short-distance mode, it is possible to increase the detection distance in the long-distance mode and reduce the power consumption in the short-distance mode.

Further, in the object detection device 1 of the above-described embodiment, the light projecting section 10 uses the common light projecting element 11 to transmit the long distance light projection signal and the short distance light projection signal.

This makes it possible to reduce the device cost of the optical system such as the lens and the light projecting element, as compared with the case where separate light projecting elements 11 are used for the long distance mode and the short distance mode.

Further, in the object detection device 1 of the above embodiment, the light projecting section 10 transmits a long distance light projection signal in addition to the short distance light projection signal in the short distance mode.

This makes it possible to obtain a detection result based on the light receiving level in addition to the detection result obtained by the triangulation method.

Further, in the object detection device 1 of the above-described embodiment, in the short distance mode, the control unit 31 maintains the short distance mode while the reflected light of the long distance projection signal exceeds the threshold value. When the reflected light of the optical signal becomes equal to or less than the threshold, the mode is switched to the long-distance mode.

Thereby, when the distance to the object 100 becomes long, it is possible to switch from the short distance mode to the long distance mode.

Further, in the object detection device 1 of the above embodiment, the light receiving section 20 includes a pair of light receiving elements (the first light receiving element 22 and the second light receiving element 23). The calculation unit 34 calculates the distance to the object 100 using the sum of the detection values of the pair of light receiving elements in the long distance mode, and uses the difference or the ratio of the detection values of the pair of light receiving elements in the short distance mode. , the distance to the object 100 is calculated.

As a result, distance measurement based on the received light level of reflected light in the long distance mode and triangular distance measurement method distance measurement in the short distance mode can be performed appropriately.

Further, as described above, the light receiving section 20 of the object detection device 1 may be provided with a PSD or CCD sensor. Further, the object detection device 1 may include a one-dimensional sensor in which light receiving elements are linearly arranged, or a two-dimensional sensor in which light receiving elements are arranged in a plane.

Accordingly, the object detection device 1 can be realized using various devices.

Although the preferred embodiments and modifications of the present invention have been described above, the above configuration can be modified as follows, for example.

The one-dimensional CCD sensor 24 and the two-dimensional CCD sensor 25 can also use CMOS (Complementary Metal Oxide Semiconductor) instead of CCD.

The signal processing unit 30 shown in FIG. 2 is an example, and may have another configuration. For example, the signal processing section 30 may be further provided with another device (for example, an amplifier).

Reference Signs List 1 object detection device 10 light projecting unit 11 light projecting element 20 light receiving unit 21 light receiving lens 22 first light receiving element 23 second light receiving element 24 one-dimensional CCD sensor (one-dimensional sensor, CCD sensor)
25 two-dimensional CCD sensor (two-dimensional sensor, CCD sensor)
30 signal processing unit 31 control unit 34 calculation unit

Claims (9)

a light projecting unit configured to include a light projecting element and capable of transmitting a long distance light projecting signal and a short distance light projecting signal;
a light-receiving unit configured to include a light-receiving element for receiving light reflected by an object from the long-distance projection signal or the short-distance projection signal;
a calculation unit that calculates a distance to the object based on the reflected light received by the light receiving unit;
executing the long-distance mode while the received light level of the reflected light of the long-distance projection signal is equal to or less than a threshold, and executing the short-distance mode when the received light level of the reflected light of the long-distance projection signal exceeds the threshold; a control unit that executes
with
In the long-distance mode, the light projecting unit transmits the long-distance light projection signal in a first period and does not transmit the short-distance light projection signal, and the calculation unit calculates the reflected light of the long-distance light projection signal. calculating the distance to the object based on the received light level of
In the short-distance mode, the light projecting section transmits at least the short-distance light projection signal in a second period shorter than the first period, and the calculation section calculates the reflected light of the short-distance light projection signal calculating the distance to the object using a triangulation method,
The light projecting unit transmits the long distance light projection signal in addition to the short distance light projection signal in the short distance mode,
In the short-distance mode, the controller maintains the short-distance mode while the received light level of the reflected light of the long-distance projection signal exceeds the threshold, and The object detection device , wherein the mode is switched to the long-distance mode when the received light level of the reflected light is equal to or less than the threshold value . The object detection device according to claim 1,
An object detection device, wherein the signal level of the long-distance projection signal is higher than the signal level of the short-distance projection signal. The object detection device according to claim 1 or 2,
The object detection device, wherein the light projecting unit uses the common light projecting element to transmit the long-distance light projection signal and the short-distance light projection signal. The object detection device according to any one of claims 1 to 3 ,
The light receiving unit includes a pair of light receiving elements,
The calculation unit calculates the distance to the object using the sum of the detection values of the pair of light receiving elements in the long distance mode, and calculates the difference between the detection values of the pair of light receiving elements in the short distance mode. or calculating the distance to the object using a ratio. The object detection device according to any one of claims 1 to 3 ,
The light receiving unit has a first electrode and a second electrode, and includes a PSD (Position Sensitive Detector) that detects a light signal according to the position and amount of irradiated light,
The calculator calculates the distance to the object using the sum of the detected values of the first electrode and the second electrode of the light receiving element in the long distance mode, and calculates the distance to the object in the short distance mode. and a difference or a ratio of the detection values of the second electrode to calculate the distance to the object. The object detection device according to any one of claims 1 to 3 ,
The light receiving unit includes a CCD (Charge Coupled Device) sensor configured to include a plurality of light receiving elements,
The calculation unit calculates the distance to the object using the sum of the detection values of the plurality of light receiving elements in the long distance mode, and calculates the peak position of the detection values of the plurality of light receiving elements in the short distance mode. and calculating the distance to the object. The object detection device according to any one of claims 1 to 3 ,
The light receiving unit includes a one-dimensional sensor in which the light receiving elements are linearly arranged,
The calculation unit calculates the distance to the object using the sum of the detection values of the light receiving elements in the long distance mode, and calculates the distance to the object using the peak position of the detection values of the light receiving elements in the short distance mode. An object detection device that calculates a distance to an object. The object detection device according to any one of claims 1 to 3 ,
The light receiving unit includes a two-dimensional sensor in which the light receiving elements are arranged in a plane,
The calculation unit calculates the distance to the object using the sum of the detection values of the light receiving elements in the long distance mode, and calculates the distance to the object using the peak position of the detection values of the light receiving elements in the short distance mode. An object detection device that calculates a distance to an object. In an object detection method for detecting an object using a light projecting section including a light projecting element and a light receiving section including a light receiving element,
A long-distance light projection signal is transmitted from the light projection unit at the first cycle, reflected light of the long-distance light projection signal is received by the light receiving unit, and the distance to the object is determined based on the received light level of the reflected light. a long-distance ranging step of calculating a distance;
When the received light level of the reflected light of the long distance light projection signal exceeds a threshold, at least the short distance light projection signal is transmitted from the light projecting unit in a second period shorter than the first period, a short distance measuring step of receiving the reflected light of the distance projection signal with the light receiving unit and calculating the distance to the object using a triangulation method for the reflected light;
including
wherein the light projecting unit transmits the long distance light projection signal in addition to the short distance light projection signal in the short distance measuring step;
In the short-distance ranging step, while the received light level of the reflected light of the long-distance projection signal exceeds the threshold, the short-distance ranging step is maintained, and the reflection of the long-distance projection signal is maintained. An object detection method, characterized in that, when the received light level becomes equal to or less than the threshold value, the process is switched to the long-distance ranging step, and the short-distance projection signal is not transmitted in the long-distance ranging step.

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