JP2013210357A - Object detection device, object detection method, object detection program, and information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an object detection device capable of certainly determining the presence or absence of a detection object even under a condition that strong external light is incident.SOLUTION: In a proximity sensor S including a light-emitting part 1, a light receiving part 2, and a detection part 10 for detecting a light reception level of light received in the light receiving part 2, when light is received in the light receiving part 2 in the light not-emitted period of the light emitting part 1, a first threshold level for detecting, in the light receiving part 2, the presence or absence of the reception of reflected light R reflecting on a hand H with light emitted from the light emitting part 1 is added with the light reception level detected on the light received in the light receiving part 2 in the light not-emitted period of the light emitting part 1 so as to calculate a second threshold level, and a CPU 12 to determine the presence of the hand H is provided when light equal to or more than the second threshold level is received in the light receiving part 2 in the light emitted period after the light is received in the light receiving part 2 in the light not emitted period of the light emitting part 1.

Description

  The present application belongs to the technical field of an object detection device, an object detection method, an object detection program, and an information recording medium. More specifically, an object detection device and an object detection method that include a light emitting unit and a light receiving unit to detect an object as a detection target, a program for the object detection device, and an information recording medium technology on which the program is recorded Belonging to the field.

  For example, when operating an in-vehicle device mounted on a vehicle, the movement of a human hand is detected by a so-called proximity sensor such as an infrared sensor in consideration of the fact that the interior of the vehicle is not wide and driving safety, etc. In-vehicle devices are controlled according to the contents. In this case, examples of the in-vehicle device include a navigation device and an audio device.

  On the other hand, as an example of a configuration of a conventional proximity sensor, light such as infrared light is emitted from a light emitting unit, and reflected light reflected by a human hand is received by a light receiving unit, thereby receiving a human. Some devices are configured to detect the presence or absence of a hand.

  On the other hand, in the case of a vehicle equipped with an in-vehicle device, the light receiving unit provided in the in-vehicle device is not limited to reflected light from a human hand, or other light such as sunlight or light from a bright streetlight. Light may enter. In this case, depending on the level of incident external light, it may be determined that there is a human hand despite the absence of the human hand due to the incident of the external light on the light receiving unit. In this case, there is a problem that the in-vehicle device malfunctions.

  Therefore, as a technique for solving this problem, a technique disclosed in Patent Document 1 below has been developed. In the technique disclosed in Patent Document 1, the level of the external light is detected by an illuminance sensor provided separately from the light receiving unit, and the detected external light level is equal to or higher than a predetermined illuminance threshold. Is configured to turn off the function of the proximity sensor itself.

JP 2010-199706 A (FIG. 2, FIG. 13A, FIG. 13B, etc.)

  However, in the technique described in Patent Document 1, the proximity sensor itself does not function when the level of external light is equal to or greater than the illuminance threshold. For example, when strong sunlight is inserted into the vehicle. However, the proximity sensor does not function, and as a result, the in-vehicle device cannot be operated. On the other hand, the situation in which sunlight is inserted as described above is a situation that can frequently occur during operation of a vehicle on a sunny day, for example, and it is inconvenient that the in-vehicle device cannot be operated in such a case. There is also a possibility of problems in safe operation.

  Therefore, the present application has been made in view of the above-described problems, and an example of the problem is an object detection apparatus that can accurately determine the presence or absence of a detection target even under a situation where strong external light is incident. And an object detection method, a program for the object detection apparatus, and an information recording medium on which the program is recorded.

  In order to solve the above-mentioned problem, an invention according to claim 1 is an object detection apparatus comprising: a light emitting unit; a light receiving unit; and a detection unit that detects a light reception level of light received by the light receiving unit. When the light receiving unit receives light during the non-light emitting period of the light emitting unit, the light receiving unit detects the presence or absence of reflected light reflected from the detection target by the light emitted from the light emitting unit. Calculating means for calculating a second threshold level by adding the received light level detected for the light received by the light receiving unit in the non-light emitting period to the preset first threshold level; and the non-light emitting period In the light emission period in which the light emitting unit emits light after light is received by the light receiving unit, the detection is performed when light of the calculated second threshold level or higher is received by the light receiving unit. Comprising a determining unit that there is an elephant product, the.

  In order to solve the above-described problem, an invention according to claim 5 is an object detection apparatus comprising: a light emitting unit; a light receiving unit; and a detection unit that detects a light reception level of light received by the light receiving unit. In the object detection method to be executed, when light is received by the light receiving unit during the non-light emitting period of the light emitting unit, whether or not the reflected light reflected by the detection target is received by the light emitted from the light emitting unit is determined. Calculation for calculating a second threshold level by adding the received light level detected for the light received in the light receiving unit during the non-light emitting period to a first threshold level set for detection in the light receiving unit And a light emission period in which the light emitting unit emits light after light is received by the light receiving unit during the non-light emitting period, and the light having the calculated second threshold level or more is transmitted to the light receiving unit. When received it is, including a determination step of determining that there is the detection target.

  In order to solve the above-described problem, an invention according to claim 6 is an object detection apparatus including a light emitting unit, a light receiving unit, and a detection unit that detects a light reception level of light received by the light receiving unit. When the light receiving unit receives light during the non-light-emitting period of the light emitting unit, the computer included is configured to determine whether the light emitted from the light emitting unit is reflected by the detection target or not. Calculating means for calculating a second threshold level by adding the received light level detected for the light received by the light receiving unit in the non-light emitting period to a first threshold level set in advance for detection in In the light emission period in which the light emitting unit emits light after the light receiving unit receives light in the non-light emitting period, the light receiving unit receives light of the calculated second threshold level or higher. When said determination means that there is a detection object, to function as a.

  In order to solve the above-mentioned problem, in the invention described in claim 7, the object detection program described in claim 6 is recorded so as to be readable by the computer described in claim 6.

It is a block diagram which shows the schematic structure of the object detection apparatus which concerns on embodiment. It is a block diagram etc. which show schematic structure of the proximity sensor which concerns on an Example, (a) is the said block diagram, (b) is a figure which illustrates a detection range. It is a flowchart which shows the detection process which concerns on an Example. It is a figure explaining the detection process which concerns on an Example. It is a figure which illustrates the change of the drive current of the light emission part in the detection process which concerns on an Example.

  Next, the form for implementing this application is demonstrated using FIG. FIG. 1 is a block diagram showing a schematic configuration of the object detection apparatus according to the embodiment.

  As shown in FIG. 1, the object detection apparatus S according to the embodiment includes an object detection unit including a light emitting unit 1, a light receiving unit 2, and a detection unit 10 that detects a light reception level of light received by the light receiving unit 2. The apparatus S includes a light emitting unit 1, a light receiving unit 2, and a detection unit 10, and a calculation unit 11 and a determination unit 12.

  In this configuration, the calculation unit 11 reflects light IR such as infrared light emitted from the light emitting unit 1 to the detection target H when light is received by the light receiving unit 2 during the non-light emitting period of the light emitting unit 1. The light receiving level detected for the light received by the light receiving unit 2 during the non-light emitting period is added to a preset first threshold level for detecting whether the reflected light R is received by the light receiving unit 2 The second threshold level is calculated. In this case, the light receiving unit 2 may receive, for example, sunlight or light from a strong streetlight in addition to the reflected light R.

  As a result, the determination unit 12 causes the light receiving unit 2 to emit light that is equal to or higher than the calculated second threshold level in the light emitting period in which the light emitting unit 1 emits light after the light receiving unit 2 receives light during the non-light emitting period of the light emitting unit 1. 2, it is determined that there is a detection object H.

  As described above, according to the processing of the object detection device S according to the embodiment, when light is received by the light receiving unit 2 during the non-light emitting period of the light emitting unit 1, the light reception level of the light is set to the first threshold level. And the second threshold level is calculated, and it is determined that there is the detection target H when light of the second threshold level or higher is received in the light emission period after light is received in the non-light emission period. Therefore, the presence or absence of the detection target H can be accurately determined even under a situation where light other than the reflected light R from the detection target H is incident.

  Next, specific examples corresponding to the above-described embodiment will be described with reference to FIGS. In addition, the Example demonstrated below is an Example at the time of applying embodiment with respect to the proximity sensor which detects presence of the human hand as the detection target H using infrared light.

  FIG. 2 is a block diagram illustrating a schematic configuration of the proximity sensor according to the embodiment, and FIG. 3 is a flowchart illustrating detection processing according to the embodiment. FIG. 4 is a diagram illustrating a detection process according to the embodiment, and FIG. 5 is a diagram illustrating a change in driving current of the light emitting unit in the detection process according to the embodiment. At this time, in FIG. 2, the same member numbers as the respective constituent members in the object detection apparatus S are used for the respective constituent members in the examples corresponding to the respective constituent members in the object detection apparatus S according to the embodiment shown in FIG. 1. ing.

As illustrated in FIG. 2A, the proximity sensor S according to the embodiment is a proximity sensor that detects a human hand H as the detection target H by infrared light IR. Proximity sensor S according to the specific embodiment is driven by a pulsed drive current I _L to be described later, a light emitting unit 1 which emits infrared light IR of the detection, infrared light emitted from the light emitting portion 1 The light receiving unit 2 that receives the reflected light R (which is of course infrared light) reflected by the hand H, the light emitting unit 1 and the light receiving unit 2 are driven, and the threshold level according to the embodiment is set. And a CPU 12 as an example of the determination unit 12 according to the embodiment that outputs, for example, a predetermined command corresponding to the detection result of the presence or absence of the hand H as the proximity sensor S according to the embodiment. ing. In addition, the sensor driver D is an example of a detection unit 10 according to the embodiment that detects the light reception level of reflected light R in the light receiving unit 2 and infrared light in external light described later based on an output signal from the light receiving unit 2. The detection unit 10 and a calculation unit 11 as an example of the calculation unit 11 according to the embodiment that calculates the threshold level according to the example based on the detection result in the detection unit 10 are configured.

  In this configuration, the light emitting unit 1 and the light receiving unit 2 are specifically disposed on a planar base B as shown in FIG. With this arrangement, the light emitting unit 1 and the light receiving unit 2 form a detection region A as the proximity sensor S1. At this time, the sensor driver 10 emits infrared IR from the light emitting unit 1 through processing described later, and causes the light receiving unit 2 to receive the reflected light R reflected by the hand H. Thereby, it is detected whether or not the hand H to be detected exists in the detection area A as infrared light. Specifically, the sensor driver D indicates that the presence of the hand H is detected in the detection area A when the light receiving unit 2 detects that the reflected light R having a level equal to or higher than a threshold level described later is received. A detection signal is output to the CPU 12. Accordingly, the CPU 12 outputs, for example, a command corresponding to the detected hand H based on the detection signal.

  Next, the detection process in the proximity sensor S according to the embodiment will be specifically described with reference to FIGS.

As shown in FIG. 3, first, the sensor driver D monitors whether or not the power of the proximity sensor S is turned on (step S1). When the power is not turned on in the monitoring in step S1 (step S1; NO), the sensor driver D continues monitoring as it is. On the other hand, when the power is turned on in the monitoring in step S1 (step S1; YES), the sensor driver D drives the light emitting unit 1 and the light receiving unit 2 (step S2). Emitting portion 1 as described above at this time, the pulsed drive current I _L from the sensor driver D _(see above Fig. 4), intermittently infrared light at intervals corresponding to a pulse period in the drive current I _L Emits IR light. Here, the value of the drive current I _L in accordance with the embodiment (i.e. emission power. Hereinafter, the same), in its initial state is the level L1 exemplified on FIG.

  Next, the sensor driver D sets a first threshold level TH1 as a threshold when detecting whether or not the reflected light R is received by the light receiving unit 2 (step S3). When the reflected light R having a level equal to or higher than the first threshold level TH1 is received by the light receiving unit 2, the first threshold level TH1 has a hand H in the detection range A in the CPU 12 to which the result is output. It is a predetermined threshold level that is determined to be present. The first threshold level TH1 is a threshold level determined by the same determination method as that of the conventional proximity sensor. A specific value as the first threshold level TH1 is set in advance based on, for example, normal light emission intensity in the light emitting unit 1, sensitivity as the light receiving unit 2, and the like. The data indicating the first threshold level TH1 is stored in advance in a non-volatile manner such as a ROM (not shown) of the CPU 12, for example, and is read and used by the sensor driver D as necessary.

Then sensor driver D is non-light emission period in pulsed drive current I _L (e.g., non-emission period between the emission period T1 and the light-emitting period T2 on Figure 4), the light emitted from the light-emitting portion 1 Wait (step S4). Then, the detection unit 10 of the sensor driver D detects the light reception level of the infrared light in the external light that is incident on the light reception unit 2 during the standby non-light emission period (step S5). The external light at this time is, for example, the above-mentioned sunlight or light from a strong street lamp. The detection result in step S5 is output to the calculation unit 11. As a result, the calculation unit 11 calculates the second threshold level TH2 by adding the first threshold level TH1 to the external light reception level detected in step S5 (step S6).

Here, the processing from step S3 to step S6 will be specifically described with reference to FIG. 4. For example, when the first threshold level TH1 is the level LV as illustrated in FIG. 4 (see step S3 in FIG. 3). When the external light receiving level illustrated in FIG. 4 in the non-emission period between the emission period T1 of the drive current I _L on FIG. 4 and the light emitting period T2 is received (see FIG. 3 step S4 and S5), calculating unit 11 calculates a level obtained by adding the level LV to the light receiving level of the ambient light as the second threshold level TH2 _-1. Similarly, when the external light receiving level illustrated in FIG. 4 in the non-emission period between the emission period T2 of the drive current I _L and the light-emitting period T3 is to have been received (see FIG. 3 step S4 and S5), calculated part 11 calculates a level obtained by adding the level LV to the light receiving level of the ambient light as a new second threshold level TH2 _-2. These calculated values of the second threshold level TH2 are temporarily stored, for example, in a RAM (not shown) in the CPU 12, for each calculation. When no external light is received by the light receiving unit 2 during the non-light-emitting period, the light reception level of external light in step S6 is zero. In this case, the second threshold level TH2 is the same as the original first threshold level TH1. It becomes.

When the second threshold level TH2 at each of the non-emission period is calculated (step S6), and then the sensor driver D is the value of the drive current I _L in the light-emitting period immediately after the non-light emission period, on FIG. 4, for example The level is set to the exemplified level L2 (step S7).

Here, when the second threshold level TH2 set by the process of step S6 is higher than the first threshold level TH1 similar to the conventional case, the sensor driver D according to the embodiment sets the set second threshold level TH2. The intensity of the infrared light IR in the light emitting unit 1 is increased in correspondence with the relationship between the first threshold level TH1 and the original first threshold level TH1. For example, when illustrated on FIG. 4, the sensor driver D, when the second threshold level TH2 _-1 is calculated / set, level L2 values of the drive signal I _L from the level L1 exemplified above in FIG. 4, for example by increasing to raise the intensity of the infrared light IR to a level corresponding to the drive signal I _L level L2. Sensor driver D Similarly, when the second threshold level TH2 _-2 is calculated / set, by increasing the level L2 illustrate the value of the drive signal I _L on FIG. 4, for example to a level L3 , increase the intensity of the infrared light IR to a level corresponding to the drive signal I _L level L3. This is because the fact that the threshold level used for detecting the presence or absence of the hand H increases to the second threshold level TH2 means that the presence of the hand H is not detected unless the stronger reflected light R is received. emission level parts 1 and remains at a level corresponding to the drive signal I _L of the same level L1 in the case of the first threshold level TH1, the hand H is located at a position closer than the position to be originally detected Otherwise it will not be detected.

Specifically, the sensor level D is, for example, proportional to the difference between the second threshold level TH2 and the first threshold level TH1 in order to keep the distance from the proximity sensor S where the presence of the hand H is detected constant. as the intensity of the second threshold after the level TH2 is set infrared light IR is increased, the value of the drive current I _L of the process in step S7, the set is increased for example from level L1 to level L2. In this regard, in FIG. 4, the difference between the second threshold level TH2 ₋₁ (see step S6 in FIG. 3) set in the non-light emission period between the light emission period T1 and the light emission period T2 and the original first threshold level TH1. And the difference between the second threshold level TH2 _-2 set in the non-light emission period between the light emission period T2 and the light emission period T3 and the second threshold level TH2 _-1 set immediately before is the light emission the difference between the level L1 of the drive current I _L which has been set at the level L2 and the previous emission period T1 of set driving current I _L in the period T2, the drive current I _L which is set in the light emission period T3 and T4 It is set so as to match the ratio of the difference between the level L2 of the drive current I _L which has been set at the level L3 and the previous emission period T2. Note in Figure 5, an example of a change in the drive current I _L in the actual light emitting portion 1, the wavelength of the infrared light IR 890 nm, temperature 25 ° C., are shown for the case of the driving voltage 5V. 5, for example at the level of the drive current I _L in the light emitting period T1 illustrated in FIG. 4 is a level that is illustrated in dotted lines, increasing the driving current I _L in the issuing period T2 to a level illustrated by a dashed line ( (See the upward arrow in FIG. 5). In FIG. 5, the received light level of the infrared light in the external light is illustrated by a broken line with an error width (flicker width) of about 20 μA.

When the value of the drive current I _L is determined at step S7 is set, then the sensor driver D causes the light emitting portion 1 by using the drive current I _L of the value set by the processing of step S7 (step S8 ). Thereby, the detection unit 10 receives the reflected light R corresponding to the light emission of the light emitting unit 1 and detects the light reception level. Thereby, the sensor driver D determines whether or not the light reception level exceeds the second threshold level TH2 (step S9). If it is determined in step S9 that the light reception level does not exceed the second threshold level TH2 (step S9; NO), the sensor driver D returns to step S4 and repeats the processing described above. On the other hand, if the light reception level exceeds the second threshold level TH2 in the determination in step S9 (step S9; YES), the sensor driver D outputs a message to that effect to the CPU 12. As a result, the CPU 12 determines that the hand H is present in the detection range A (step S10), and performs processing such as outputting a predetermined command previously associated with the presence of the hand H. Do.

Here, the processing of the above step S9 and step S10 will be specifically described with reference to FIG. 4. For example, when there is a hand H in the detection range A in the issue period T3 as illustrated in FIG. It reflected light R of the light-receiving level exceeds a second threshold level TH2 _-2 which is set by the processing of the previous step S6 is received in the light-receiving unit 2 (FIG. 3 step S9; see YES). The light reception level of the reflected light R at this time is consequently detected in the non-light emission period between the light emission period T2 and the light emission period T3 (see step S6 in FIG. 3). Is the added light reception level. Thereby, the CPU 12 determines that the hand H exists within the detection range A in the light emission period T3 (step S10 in FIG. 3).

As illustrated in FIG. 4, when the hand H no longer exists within the detection range A after the light emission period T3 has elapsed (see step S9 in FIG. 3; NO), in the next light emission period T4, the second threshold level 2 ₋ The reflected light R having a light receiving level exceeding ₂ is not received, and therefore it is determined that the hand H does not exist within the detection range A. After that, when the external light itself disappears, the second threshold level TH2 becomes equal to the original first threshold level TH1 in the light emission period T5 as illustrated in FIG. At this time, when the second threshold level TH2 as the threshold level TH according to the embodiment returns to the original first threshold level TH1, in the process of step S7 in FIG. 3 corresponding to the timing, the value of the drive current _IL is also Returned to the original level L1 and set (see the light emission period T5 in FIG. 4).

  After the process of step S10, the sensor driver D determines whether or not the power of the proximity sensor S1 is turned off (step S11). If the power is not turned off in the determination in step S11 (step S11; NO), the sensor driver D proceeds to the process in step S4. On the other hand, when the power is turned off in the determination of step S11 (step S11; YES), the sensor driver D and the CPU 12 end the detection process according to the embodiment.

  As described above, according to the detection process according to the embodiment, the light reception level when the outside light (infrared light) other than the reflected light R is incident on the light receiving unit 2 in the non-light emission period is detected. When the second threshold level TH2 is calculated by adding the first threshold level TH1 to the received light level, and the presence or absence of the hand H is detected in the light emission period after the non-light emission period in which the external light is incident, Since it is determined that the hand H is present when the reflected light R equal to or higher than TH is received, the presence or absence of the hand H can be accurately determined even under conditions where external light other than the reflected light R is incident.

Further, the light-emitting portion 1 is driven by a pulsed drive current I _L, duration drive current I _L is zero level is the non-emission period, the drive current I _L after was the zero level is a light-emitting portion 1 Since the period when the light emission level is reached is the light emission periods T1 to T5, the calculation of the second threshold level TH2 based on the light reception level of the latest external light and the hand H of the light emission period T and the light emission period T are continued. Since the presence / absence can be determined, the presence / absence of the hand H can be more accurately determined even when there is external light other than the reflected light R.

  Furthermore, since the light emission power of the light emitting unit 1 in the light emission period when external light is incident is higher than the light emission power when there is no external light, the threshold level TH is increased due to the presence of external light. Can be prevented from being shortened.

  Furthermore, the relationship between the light emission power of the light emitting unit 1 when external light is incident and the light emission par when there is no external light corresponds to the relationship between the second threshold level TH2 and the first threshold level TH1. Therefore, the detectable distance of the hand H can be made constant regardless of the presence or absence of external light.

  In the above-described embodiments and examples, the case where the detection process shown in the flowchart of FIG. 3 is executed by the sensor driver D has been described. However, the CPU 12 may be configured to execute the detection process. it can.

In the above-described embodiments and examples, the level of the drive signal _IL is also changed at a timing corresponding to the change of the threshold level TH (see FIG. 4). However, the value of the threshold level TH is changed. may be also a constant level of the drive signal I _L.

  In the above-described embodiments and examples, the case where the detection target H is a human hand H has been described. However, the detection target H is not limited to the hand H, and may be an object that can reflect infrared light IR. For example, the presence of any object in the detection range A can be determined.

Further, in the above-described embodiments and examples, the case where the present application is applied to the proximity sensor S for controlling the vehicle-mounted device has been described. However, in addition to this, on / off and brightness of general household lighting are controlled. The present application can also be applied to the detection of the presence of the hand H by a non-contact type switch such as an infrared type. In this case, the emission of infrared light from the light emitting portion as the switch does not need to be pulsed as in the case according to the drive current I _L as described above. In this case, the light emission from the light emitting unit is stopped at a predetermined timing in a state where there is external light, the infrared light reception level in external light is detected, and the presence or absence of the hand H is determined with a threshold level obtained by adding the values. It can be configured to detect.

  Furthermore, a program corresponding to the flowchart shown in FIG. 3 is recorded on a recording medium such as a flexible disk or a hard disk, or obtained via a network such as the Internet, and this is stored in a general-purpose microcomputer or the like. By reading and executing, it is possible to cause the microcomputer or the like to function as the sensor driver D and the CPU 12 according to the embodiment.

DESCRIPTION OF SYMBOLS 1 Light emission part 2 Light reception part 10 Detection means (detection part)
11 Calculation means (calculation unit)
12. Determination means (CPU)
D Sensor driver H Object to be detected (hand)
S Object detection device (proximity sensor)
A Detection area

Claims (7)

In an object detection apparatus comprising: a light emitting unit; a light receiving unit; and a detection unit that detects a light reception level of light received by the light receiving unit.
When the light receiving unit receives light during the non-light emitting period of the light emitting unit, the light receiving unit detects whether or not the reflected light reflected by the detection object is emitted from the light emitting unit. Calculating means for calculating a second threshold level by adding the received light level detected for light received by the light receiving unit during the non-light emitting period to a first threshold level set in advance;
The detection is performed when light exceeding the calculated second threshold level is received by the light receiving unit in a light emitting period in which the light emitting unit emits light after light is received by the light receiving unit during the non-light emitting period. Determining means for determining that there is an object;
An object detection apparatus comprising: The object detection apparatus according to claim 1,
The light emitting unit is a light emitting unit driven by a pulsed drive signal,
The non-light emitting period is a period in which the drive signal is at a zero level,
The object detection device according to claim 1, wherein the light emission period is a period in which the drive signal is at a level causing the light emitting unit to emit light after the non-light emission period. In the object detection device according to claim 1 or 2,
The light emission level of the light emitting unit in the light emitting period after light is received by the light receiving unit during the non-light emitting period is the light emitting period after the light is not received by the light receiving unit during the non-light emitting period. An object detection apparatus characterized by being higher than the light emission level. The object detection device according to claim 3,
The light emission level of the light emitting unit in the light emitting period after light is received by the light receiving unit during the non-light emitting period, and the light emitting period after the light is not received by the light receiving unit during the non-light emitting period. The relationship between the light emission level corresponds to the relationship between the second threshold level and the first threshold level. In an object detection method executed in an object detection device comprising: a light emitting unit; a light receiving unit; and a detection unit that detects a light reception level of light received by the light receiving unit.
When the light receiving unit receives light during the non-light emitting period of the light emitting unit, the light receiving unit detects whether or not the reflected light reflected by the detection object is emitted from the light emitting unit. A calculation step of calculating a second threshold level by adding the received light level detected for light received by the light receiving unit in the non-light emitting period to a first threshold level set in advance;
The detection is performed when light exceeding the calculated second threshold level is received by the light receiving unit in a light emitting period in which the light emitting unit emits light after light is received by the light receiving unit during the non-light emitting period. A determination step of determining that there is an object;
An object detection method comprising: A computer included in an object detection device comprising: a light emitting unit; a light receiving unit; and a detection unit that detects a light reception level of light received by the light receiving unit.
When the light receiving unit receives light during the non-light emitting period of the light emitting unit, the light receiving unit detects whether or not the reflected light reflected by the detection object is emitted from the light emitting unit. A calculating means for calculating a second threshold level by adding the received light level detected for the light received by the light receiving unit in the non-light emitting period to a preset first threshold level; and
The detection is performed when light exceeding the calculated second threshold level is received by the light receiving unit in a light emitting period in which the light emitting unit emits light after light is received by the light receiving unit during the non-light emitting period. Determining means for determining that there is an object;
An object detection program that functions as a computer program.   An information recording medium in which the object detection program according to claim 6 is recorded so as to be readable by the computer according to claim 6.