JPH08105961A - Distance detection device and size detection device for heat source - Google Patents

Abstract

PURPOSE: To detect a distance up to a heat source and the size thereof via the application of relatively simple constitution. CONSTITUTION: A heat source distance and size detection device 100 is mounted on a vehicle or the like. A heated surface image acquisition section 4 collects the heated surface image of a monitor zone. A heat source area calculation section 5 calculates the heat source area S of the heated surface image occupied by a heat source. An area variation calculation section 6 calculates the time differential S' of the area S. A speed data acquisition section 7 collects the data of speed (v) (vehicle speed) from an array sensor 3. Also, a distance calculation section 8 calculates a distance (x) up to the heat source, according to the formula of (x=-2.v.S/S'). A size calculation section 9 calculates the size So of the heat source, according to the formula of (So=S.x$.x/C1) where C1 is a constant depending on the device 100. Furthermore, a dangerous degree judgement section 10 calculates the degree of danger on the basis of the distance (x) and the heat source size S, and outputs a warning signal (a), when the degree exceeds a threshold value. A buzzer 11 sounds an alarm on the basis of the warning signal (a).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat source distance detector and size detector. In particular, fields in which information on the distance to the heat source or the size of the heat source is required (for example, forward monitoring systems used for moving bodies such as automobiles, identification of intruders and small animals in intruder monitoring systems, etc.)
The present invention relates to a distance detecting device and a size detecting device for a heat source useful for the above.

[0002]

2. Description of the Related Art FIG. 13 shows a block diagram of an example of a conventional heat source detection device. This heat source detection device 1000 is
A lens 1 that collects infrared rays from a monitoring field of view, a chopper 2 that chops the infrared rays that have passed through the lens 1 at a predetermined cycle, and an array sensor 3 in which a plurality of pyroelectric infrared sensing elements that sense the infrared rays are two-dimensionally arranged. And a thermal image acquisition unit 4 that acquires a thermal image based on the output value of each pyroelectric infrared sensing element of the array sensor 3, and a pixel that exceeds the predetermined threshold value by checking each pixel value of the thermal image. A heat source determination unit 60 that determines the presence of a heat source based on the presence or absence of a pixel having a value;
The heat source determination unit 60 includes a buzzer 11 that sounds a warning sound when it determines that “there is a heat source”.
FIG. 14 is an explanatory diagram of an installation example of the heat source detection device 1000. The heat source detection device 1000 is attached near the front grill of an automobile or the like, and has a traveling direction as a monitoring area. H is a heat source that has entered the monitoring area.

FIG. 15 is an exemplary view of a thermal image. This thermal image G is an image composed of 30 × 30 pixels. There are a plurality of pixels (filled portions in FIG. 15) in which the output value of the corresponding pyroelectric infrared sensing element exceeds a predetermined threshold value, and these pixels are adjacent to each other. From this, it can be determined that the heat source H exists in the monitoring area, the buzzer 11 sounds, and an alarm that the heat source exists in the traveling direction is issued.

[0004]

In the above conventional heat source detection device 1000, it is possible to determine whether or not the heat source exists in the monitoring area. However, there is a problem that the distance to the heat source is unknown. In addition, there is a problem that the true size of the heat source is unknown. Then, the 1st objective of this invention is to provide the distance detection apparatus of the heat source which can know the distance to a heat source. A second object of the present invention is to provide a heat source size detection device capable of knowing the true size of the heat source.

[0005]

According to a first aspect of the present invention, the present invention provides an array sensor having a plurality of two-dimensionally arranged infrared sensing elements, and a thermal image acquisition means for acquiring a thermal image of a monitoring area by the array sensor. A heat source area calculation means for calculating a heat source area occupied by a heat source in the thermal image; a speed acquisition means for acquiring a relative speed of the array sensor with respect to the heat source; and an area change index for calculating a change index of the heat source area. There is provided a heat source distance detecting device comprising: a calculating unit; and a distance calculating unit that calculates a distance to the heat source based on the speed and the area change index.

In a second aspect, the present invention is an array sensor having a plurality of infrared sensing elements arranged two-dimensionally, a thermal image acquisition means for acquiring a thermal image of a monitoring area by the array sensor, and the thermal image of the thermal image. A heat source area calculation means for calculating a heat source area occupied by a heat source, and a change index from a heat source area when the distance from the array sensor to the heat source is a first distance to a heat source area when the distance is the second distance. Area change index calculating means for calculating, and the first distance and the second
And a distance calculation unit that calculates a distance to the heat source based on the distance difference of the distance and the area change index. According to a third aspect, the present invention provides a distance detection device for a heat source according to the second aspect, wherein a reflecting means provided in an optical path from the array sensor to the heat source and a reflecting means are operated to operate the reflecting means. An optical path length switching means for switching between a first optical path length and a second optical path length, wherein the difference between the first optical path length and the second optical path length is the distance difference. A distance detection device is provided.

In a fourth aspect, the present invention is an infrared intensity detecting means for detecting infrared intensity from a heat source in a monitoring area, and a speed acquiring means for acquiring a relative speed of the infrared intensity detecting means with respect to the heat source. An intensity change index calculating means for calculating an infrared intensity change index of the heat source, and a distance calculating means for calculating a distance to the heat source based on the speed and the intensity change index. A distance detection device is provided.

In a fifth aspect, the present invention provides an infrared intensity detecting means for detecting infrared intensity from a heat source in a monitoring area, and a distance from the infrared intensity detecting means to the heat source is a first distance. Intensity change index calculating means for calculating an index of change from the infrared intensity of the infrared intensity to the infrared intensity at the second distance, and the intensity change index based on the distance difference between the first distance and the second distance and the intensity change index. Provided is a distance detecting device for a heat source, which is provided with a distance calculating means for calculating a distance to a heat source. According to a sixth aspect, the present invention provides a heat source distance detecting device according to the fifth aspect, wherein a reflecting means provided in an optical path from the array sensor to the heat source and a reflecting means operated to operate the reflecting means. An optical path length switching means for switching between a first optical path length and a second optical path length, wherein the difference between the first optical path length and the second optical path length is the distance difference. A distance detection device is provided.

According to a seventh aspect, the present invention provides a heat source distance detecting device according to any one of the first to third aspects, and the size of the heat source based on the heat source area and the distance to the heat source. Provided is a heat source size detection device characterized by comprising a size calculation means for calculating the size.

According to an eighth aspect, the present invention provides a heat source distance detecting device according to any one of the fourth to sixth aspects, and a heat source area calculation for calculating a heat source area occupied by a heat source in the thermal image. There is provided a heat source size detection device comprising: a heat source area; and a size calculation unit that calculates a size of the heat source based on a distance to the heat source.

[0011]

In the heat source distance detecting device according to the first aspect, the heat source area S occupied by the heat source in the thermal image of the monitoring area is calculated, and further the change index of the heat source area S is calculated.
The area change index is, for example, the area change amount S ′ (time differential value of the heat source area S). At the same time, the relative velocity v of the array sensor with respect to the heat source is measured. Then, based on the velocity v and the area change amount S ′, the distance x to the heat source is calculated by x = −2 · v · S / S ′ (1). The above equation (1) is derived as follows.
The heat source area S is proportional to the size So of the heat source and is inversely proportional to the square of the distance x to the heat source. Therefore, with C1 as an appropriate coefficient, S = C1 · So / (x · x) (2) is there. On the other hand, the area change amount S ′ is the time derivative of the heat source area S, and S ′ = ΔS / Δt (3) When this equation (3) is modified and equation (2) is considered, S ′ = ΔS / Δt = (ΔS / Δx) · (Δx / Δt) = (− 2 · C1 · So / (x · x · x) )) · V = (− 2 · S / x) · v (4) By modifying the equation (4), the equation (1) is obtained.
From the above, the distance x to the heat source can be known. The speed of the heat source is Vh, and the speed of the array sensor is Va.
Then, v = Vh + Va.

On the other hand, as the area change index, for example, the area change ratio R may be used. That is, when the heat source area at time t1 is S1 and the heat source area at time t2 is S2, the distance x to the heat source is R = S2 / S1 x = v (t1-t2) / (√ {R} -1 ) (5) may be used for calculation.

The above equation (5) is derived as follows. Since S1 = C1 · So / (x1 · x1) and S2 = C1 · So / (x2 · x2), R = S2 / S1 = (x1 · x1) / (x2 · x2). When transformed, x1 = x2√ {R} (6) On the other hand, the area change amount S'is S '= (S1-S2) / (t1-t2) = {(S1-S2) / (x1-x2 )} {(X1-x2) / (t1-t2)} = {(S1-S2) / (x1-x2)} v (7) When formula (7) is arranged, 1 / (t1−t2) = v / (x1−x2) (8) By substituting equation (6) into equation (8) and rearranging, x2 = v (t1-t2) / (√ {R} -1) (9). As a result, the equation (5) is derived.

Transforming the equation (9), x2 = v (t1-t2) / (√ {R} -1) = v {(t1-t2) / (S1-S2)} / {(√ {S2 / S1} -1) / (S1-S2)} = -v {1 / S '} / {1 / {√ {S1} ・ (√ {S1} + √ {S2})}} = -v ・ (S1 + √ {S1 · S2}) / S ′ = − v · S1 (1 + √ {S2 / S1}) / S ′ = − v · S1 (1 + √ {R}) / S ′ (10) The distance x2 may be calculated from this equation (10). Further, if the interval between the time t1 and the time t2 is short, R = 1 approximately. Therefore, the above equation (10) is expressed as x2 = −v · S1 (1 + √ {1}) / S ′ = − 2 · v · S1 / S ′, which agrees with the equation (1).

In the heat source distance detecting device according to the second aspect, the distance from the array sensor to the heat source is the first distance x.
The heat source area S1 when 1 is calculated, and then the heat source area S2 when the distance from the array sensor to the heat source is the second distance x2 is calculated. Further, a change index from the heat source area S1 to the heat source area S2 is calculated. The area change index is, for example, the area change ratio R = S2 / S1. Then, based on the distance difference L between the first distance and the second distance and the area change index, the distance x to the heat source is calculated by x = L / (√ {R} -1) (11) To do. Equation (11) above is L = v in Equation (5) above.
It is introduced as (t1-t2). If it is easier to obtain the distance difference L than to obtain the velocity v, it is preferable to use the equation (11).

In the heat source distance detecting device according to the third aspect, the reflecting means is provided in the optical path from the array sensor to the heat source, and the reflecting means is operated to operate the first optical path length and the second optical path length. Switch between and. Then, the difference between the first optical path length and the second optical path length is defined as the distance difference L. When it can be considered that the heat source is stationary, this allows the distance x to the heat source to be known.

In the heat source distance detecting device of the fourth aspect, the infrared intensity I of the heat source is calculated, and further, the change index of the infrared intensity I is calculated. The intensity change index is, for example, an intensity change amount I ′ (a time derivative of the infrared intensity I). At the same time, the relative velocity v of the array sensor with respect to the heat source is measured. Then, based on the speed v and the intensity change amount I ′, the distance x to the heat source is calculated by x = −2 · v · I / I ′ (12). The above equation (12) is derived as follows.
The infrared intensity I is proportional to the heat Io of the heat source and inversely proportional to the square of the distance x from the heat source. Therefore, with C2 being an appropriate coefficient, I = C2 · Io / (x · x) (13) . On the other hand, the intensity change amount I ′ is a time derivative of the infrared intensity I, and I ′ = ΔI / Δt (14) By transforming the equation (14) and considering the equation (13), I '= ΔI / Δt = (ΔI / Δx) · (Δx / Δt) = (− 2 · C2 · Io / (x · x · x) )) * V = (-2 * I / x) * v ... (15). By transforming this equation (15), equation (12) is obtained.
From the above, the distance x to the heat source can be known.

On the other hand, for example, the intensity change ratio r may be used as the intensity change index. That is, the infrared intensity at time t1 is I1, and the infrared intensity at time t2 is I.
When it is set to 2, the distance x to the heat source may be calculated by r = I2 / I1 x = v (t1-t2) / (√ {r} -1) (16). The above equation (16) is derived as follows. I1 = C2 · Io / (x1 · x1) I2 = C2 · Io / (x2 · x2) Therefore, r = I2 / I1 = (x1 · x1) / (x2 · x2). When transformed, x1 = x2√ {r} (17) On the other hand, the intensity change amount I ′ is I ′ = (I1−I2) / (t1−t2) = {(I1−I2) / (x1−x2 )} {(X1-x2) / (t1-t2)} = {(I1-I2) / (x1-x2)} v (18) When formula (18) is rearranged, it becomes 1 / (t1-t2) = v / (x1-x2) (19). Substituting equation (17) into equation (19) and rearranging yields x2 = v (t1-t2) / (√ {r} -1) (20). This leads to Eq. (16).

When the equation (20) is modified, x2 = v (t1-t2) / (√ {r} -1) = v {(t1-t2) / (I1-I2)} / {(√ { I2 / I1} -1) / (I1-I2)} = -v {1 / I '} / {1 / {√ {I1} ・ (√ {I1} + √ {I2})}} = -v ・(I1 + √ {I1 · I2}) / I ′ = − v · I1 (1 + √ {I2 / I1}) / I ′ = − v · I1 (1 + √ {r}) / I ′ (21) Therefore, the distance x2 may be calculated from the equation (21).

If the interval between the time t1 and the time t2 is short, r = 1 approximately, so x2 = -v.I1 (1 + √ {1}) / I '=-2.v.I1 / It becomes I ', which agrees with the equation (12).

In the heat source distance detecting device according to the fifth aspect, the infrared ray intensity I1 is calculated when the distance from the infrared ray intensity detecting means to the heat source is the first distance x1, and then,
The distance from the infrared intensity detecting means to the heat source is the second distance x
The infrared intensity I2 when it is 2 is calculated. Further, a change index from the infrared intensity I1 to the infrared intensity I2 is calculated. This intensity change index is, for example, intensity change ratio r = I2
/ I1. Then, based on the distance difference L between the first distance and the second distance and the strength change index, the distance x to the heat source is calculated by x = L / (√ {r} -1) (22) To do. The above formula (22) is L = v in the above formula (16).
It is introduced as (t1-t2). When it is easier to obtain the distance difference L than to obtain the velocity v, it is preferable to use the equation (22).

In the heat source distance detecting device according to the sixth aspect, the reflecting means is provided in the optical path from the infrared intensity detecting means to the heat source, and the reflecting means is operated to operate the first optical path length and the second optical path. Switch between optical path length. Then, the difference between the first optical path length and the second optical path length is defined as the distance difference L. When it can be considered that the heat source is stationary, this allows the distance x to the heat source to be known.

In the heat source size detection device according to the seventh and eighth aspects, the size calculation means calculates the heat source size So from the heat source area S and the distance x to the heat source, So = S -X * x / C1 ... (23) is used for calculation. The coefficient C1 may be obtained in advance by measuring a standard heat source. The above equation (23) is derived by modifying the above equation (2).

[0024]

The present invention will be described in more detail with reference to the embodiments shown in the drawings. The present invention is not limited to this.

[First Embodiment] FIG. 1 is a block diagram showing the configuration of a heat source distance / size detecting device 100 according to a first embodiment of the present invention. This heat source distance / size detection device 100 includes a lens 1 that collects infrared rays from a monitoring field of view, a chopper 2 that chops the infrared rays that have passed through the lens 1 at a predetermined cycle, and a plurality of pyroelectric type sensors that detect infrared rays. It is provided with an array sensor 3 in which infrared sensing elements are two-dimensionally arranged, and a thermal image acquisition unit 4 which acquires a thermal image based on the output value of each pyroelectric infrared sensing element of the array sensor 3. Further, a heat source area calculation unit 5 for calculating a heat source area S occupied by a heat source in the thermal image,
An area change amount calculation unit 6 that calculates a change amount S ′ of the heat source area S with respect to time t, a speed acquisition unit 7 that acquires a speed v from a speedometer of an automobile, the heat source area S, and the area change amount S ′. And a distance calculation unit 8 that calculates a distance x to the heat source from the velocity v, a size calculation unit 9 that calculates a size So of the heat source from the heat source area S and the distance x, the distance x and the heat source And a buzzer 11 for emitting a warning sound by the warning signal a. The risk judgment unit 10 outputs a warning signal a when the danger level exceeds a threshold value. ing.

FIG. 2 shows an installation example of the distance / size detecting device 100. The lens 1, the chopper 2 and the array sensor 3 are housed in a predetermined housing and attached to the front grill FG of the automobile C. Further, the thermal image acquisition unit 4, the heat source area calculation unit 5, the area change amount calculation unit 6,
The speed acquisition unit 7, the distance calculation unit 8, the size calculation unit 9, the risk determination unit 10, and the buzzer 11 are housed in a predetermined housing and installed in the dashboard DB.

FIG. 3 is an explanatory diagram of the monitoring field of view of the distance / size detecting device 100. The front of the car C is the surveillance field of view. A person H and the sun T are included as heat sources in the surveillance field of view. Let the size of the person H be So. The speed of car C is v
And The distance between the vehicle C and the person H at time t1 is x1, and the distance between the vehicle C and the person H at time t2 is x2.

FIG. 4 shows the distance / size detecting device 100.
It is a flowchart which shows operation | movement. In step P1, the thermal image G is acquired by the thermal image acquisition unit 4. This thermal image G is an image composed of 30 × 30 pixels. Figure 5
The thermal image G is illustrated as an example. At time t1, FIG.
The thermal image G1 of (a) is obtained. There are a plurality of pixels (filled portions in FIG. 5) in which the output value of the corresponding pyroelectric infrared sensing element exceeds a predetermined threshold value, and there are two adjacent portions. The heat source at one location is the person H, and the heat source at the other location is the sun T. In step P2, the heat source area calculator 5 calculates the heat source area S. From the thermal image G1 in FIG. 5A, the heat source area S1 and the heat source area S
T is obtained. After this step P2,
Return to 1. In step P1 of the second time, at time t2, the thermal image G2 of FIG. 5B is obtained. In the second step P2, the heat source area S2 and the heat source area ST are obtained from the thermal image G2 in FIG. 5B. The heat source area ST where the heat source is the sun T is constant regardless of the time t. After step P2, the process returns to step P1 and the above operation is repeated. On the other hand, after the two thermal images G are obtained, step P3 and subsequent steps are executed in parallel with the repetition of steps P1 and P2.

In step P3, the area change amount calculation unit 6 calculates the area change amount S '. That is, S '= [Delta] S / [Delta] t = (S1-S2) / (t1-t2) (24). The area change amount S ′ of the heat source area ST where the heat source is the sun T is “0”. In Step P4, the speed acquisition unit 7 acquires the moving speed of the automobile C as the speed v. In step P5, the distance calculator 8 calculates the distance x2 to the heat source. That is, x2 = −2 · v · S1 / S ′ (25). When S '= 0, the value of x2 is set to a sufficiently large value without calculating the equation (25). That is, for the heat source (sun T) applied to the heat source area ST, a sufficiently large value is set for x2. In Step P6, the size calculation unit 9 calculates the size So of the heat source. That is, the size So of the heat source is calculated by So = S2 * x2 * x2 / C1 (26). When S '= 0, the value of So is set to a sufficiently large value without calculating the equation (26).

At step P7, the risk determination section 10
Distance x2 to heat source is a predetermined safety threshold (eg 20m)
If it is shorter and the size So of the heat source is larger than a predetermined minimum threshold value (for example, 300 cm 2), it is determined as “dangerous”, and if not so, it is determined as “not dangerous”.
If it is determined to be "dangerous", the process proceeds to step P8, and if it is determined to be "not dangerous", the process ends. Since a sufficiently large value is set for x2 for the heat source (sun T) applied to the heat source area ST, it is determined to be “non-dangerous”. In step P8, the buzzer 11 is sounded to warn. Then, the process ends.

The above-mentioned heat source distance / size detecting device 100
According to, the distance x2 to the heat source and the size So of the heat source
Can be known and a warning is issued according to the degree of danger. Therefore, the car C can be safely operated.

Second Embodiment FIG. 6 is a block diagram showing the configuration of a heat source distance / size detecting device 200 according to a second embodiment of the present invention. This heat source distance / size detection device 200 includes a lens 1 that collects infrared rays from a surveillance field of view, a chopper 2 that chops the infrared rays that have passed through the lens 1 at a predetermined cycle, and a plurality of pyroelectric types that detect infrared rays. The infrared sensor comprises an array sensor 3 having a two-dimensional array. The lens 1, the chopper 2, and the array sensor 3 are installed on the conveyor 31 and moved to a first position (position indicated by a broken line in FIG. 6) and a second position (position indicated by a solid line in FIG. 6). To be made.

Further, the heat source distance / size detecting device 20
0 is a thermal image acquisition unit 4 that acquires a thermal image based on the output value of each pyroelectric infrared sensing element of the array sensor 3, a heat source area calculation unit 5 that calculates the heat source area of the heat source, and the first An area change ratio calculator 26 that calculates an area change ratio R = S2 / S1 of the heat source area S2 in the thermal image acquired at the second position with respect to the heat source area S1 in the thermal image acquired at the position; and the first position. From the heat source to the second
From the position to the heat source, the distance calculation unit 28 that calculates the distance x to the heat source based on the distance difference L and the area change ratio R, and the size So of the heat source from the heat source area S and the distance x. And a distance calculation unit 9 for calculating the distance x
And the size So of the heat source, the presence / absence of an intruder is determined, and when the intruder is present, an intruder determination unit 3 that outputs a warning signal a
0 and a buzzer 11 that emits a warning sound by the warning signal a
Is provided.

FIG. 7 shows an installation example of the distance / size detecting device 200. The distance / size detection device 200 is mounted above the entrance D of a house, commercial facility, research facility, etc., and the area in front of the entrance D is a monitoring area. H is a heat source existing in the monitoring area.

FIG. 8 is a flow chart showing the operation of the distance / size detection device 200. In step Q1, the thermal image acquisition unit 4 acquires a thermal image G at the first position or the second position. This thermal image G is an image composed of 30 × 30 pixels.

FIG. 9 illustrates the thermal image G. At the first position, the thermal image G1 of (a) is obtained. At the second position, the thermal image G2 of (b) is obtained. Pixels (filled portions in FIG. 9) in which the output value of the corresponding pyroelectric infrared sensing element exceeds a predetermined threshold value are heat sources H. In step Q2, the heat source area calculation unit 5 calculates the heat source area S. The heat source area S1 is obtained from the thermal image G1 of FIG. From the thermal image G2 of FIG. 9B, the heat source area S2
Is obtained. In step Q3, the conveyor 31 changes the positions of the lens 1, the chopper 2, and the array sensor 3. That is, the position is changed from the first position to the second position or from the second position to the first position. Then, the process returns to step Q1. After the thermal image G1 at the first position and the thermal image G2 at the second position are obtained, the above step Q1 is performed.
Steps Q4 and thereafter are executed in parallel with the repetition of Q3.

In step Q4, the area change ratio calculation unit 26
The area change ratio R is calculated by. That is, R = S2 / S1 (27). In step Q5, the distance calculator 28 calculates the distance x to the heat source. That is, x = L / (√ {R} -1) (28). When R = 1, the value of x is set to a sufficiently large value without calculating the equation (28). In step Q6,
The size calculation unit 9 calculates the size So of the heat source. That is, the size So of the heat source is calculated by So = S2 · x · x / C1 (29). When R = 1, the value of So is set to a sufficiently large value without calculating the equation (29).

In step Q7, the intruder determination unit 10
If the distance x to the heat source is shorter than a predetermined safety threshold value (for example, 5 m) and the size So of the heat source is larger than a predetermined minimum threshold value (for example, 500 square cm), it is determined to be an “intruder”, and otherwise. Is determined to be “not an intruder”. For example, when a person is in the vicinity of the entrance D, it is determined as "intruder", but when a small animal is in the vicinity of the entrance D, it is determined as "not an intruder". If it is determined to be "intruder", the process proceeds to step Q8, and if it is determined to be "not intruder", the process ends. In step Q8, the buzzer 11 sounds,
Warning. Then, the process ends.

Distance and size detection device 200 for the above heat sources
According to the method, the distance x to the heat source and the size So of the heat source can be known, and a warning distinguishing between humans and small animals is issued. Therefore, it is useful as a highly reliable intrusion monitoring device.

[Third Embodiment] FIG. 10 is a block diagram showing the configuration of a heat source distance / size detecting device 300 according to a third embodiment of the present invention. This heat source distance / size detection device 300 includes a mirror 40, a moving device 4 and a moving device 4.
1 moves to the first position (broken line in FIG. 10) and the second position (solid line in FIG. 10) to change the distance from the heat source to the array sensor 3 to the first distance and the second distance. It is supposed to switch. Other configurations are the same as those in the second embodiment.

[Fourth Embodiment] FIG. 11 is a block diagram showing the configuration of a heat source distance / size detection device 400 according to a fourth embodiment of the present invention. This heat source distance / size detection device 400 includes an infrared intensity calculation unit 45, an intensity change amount calculation unit 46, and a distance calculation unit 48 instead of the area change amount calculation unit 6 and the distance calculation unit 8 of the first embodiment. It has. The infrared intensity calculator 45 calculates the infrared intensity I of the heat source based on the output value of the pyroelectric infrared sensing element corresponding to the heat source portion of the thermal image. That is, the infrared intensity I1 of the heat source is calculated from the thermal image G1 at the time t1. Further, the infrared intensity I2 of the heat source is calculated from the thermal image G2 at the time t2. The intensity change amount calculation unit 46 calculates the change amount I ′ of the infrared intensity I with respect to time t according to I ′ = (I1−I2) / (t1−t2) (30). The distance calculator 48 calculates the distance x2 to the heat source by: x2 = −2 · v · I1 / I ′ (31) Other configurations are the same as those in the first embodiment.

[Fifth Embodiment] FIG. 12 is a block diagram showing the construction of a heat source distance / size detection device 500 according to a fifth embodiment of the present invention. This heat source distance / size detection device 500 has an infrared intensity calculation unit 45, an intensity change ratio calculation unit 56, and a distance calculation unit 5 instead of the area change ratio calculation unit 26 and the distance calculation unit 28 of the second embodiment.
Eight. The infrared intensity calculator 45 calculates the infrared intensity I of the heat source based on the output value of the pyroelectric infrared sensing element corresponding to the heat source portion of the thermal image. That is, the infrared intensity I1 of the heat source is calculated from the thermal image G1 at the time t1. In addition, the thermal image G2 at time t2
From this, the infrared intensity I2 of the heat source is calculated. The intensity change ratio calculating unit 56 calculates the intensity change ratio r by r = I2 / I1 (32). The distance calculator 58
Calculates the distance x to the heat source by x = L / (√ {r} -1) (33). Other configurations are the same as those in the second embodiment.

[0043]

According to the heat source distance detecting device of the present invention, the distance to the heat source can be known with a relatively inexpensive structure. In particular, it is useful for a forward monitoring system for moving bodies such as automobiles. Further, according to the heat source size detection device of the present invention, the size of the heat source can be known with a relatively inexpensive configuration. In particular, it is useful for an intruder surveillance system that needs to distinguish between humans and small animals.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a distance / size detecting device for a heat source according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an installation example of the distance / size detection device of FIG.

FIG. 3 is an explanatory diagram showing a monitoring field of view of the distance / size detection device of FIG.

FIG. 4 is a flowchart showing the operation of the distance / size detection device of FIG.

FIG. 5 is an exemplary diagram of a thermal image.

FIG. 6 is a configuration block diagram of a heat source distance / size detection device according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram showing an installation example of the distance / size detection device of FIG.

8 is a flowchart showing the operation of the distance / size detection device of FIG.

FIG. 9 is an exemplary diagram of a thermal image.

FIG. 10 is a configuration block diagram of a heat source distance / size detection device according to a third embodiment of the present invention.

FIG. 11 is a configuration block diagram of a heat source distance / size detection device according to a fourth embodiment of the present invention.

FIG. 12 is a configuration block diagram of a heat source distance / size detection device according to a fifth embodiment of the present invention.

FIG. 13 is a configuration block diagram of an example of a conventional heat source detection device.

14 is an explanatory diagram of an installation example of the heat source detection device of FIG.

FIG. 15 is a view showing an example of a thermal image.

[Explanation of symbols]

100, 200, 300, 400, 500 Heat source distance / size detection device 1 Lens 2 Chopper 3 Array sensor 4 Thermal image acquisition unit 5 Heat source area calculation unit 6 Area change amount calculation unit 7 Speed acquisition unit 8, 28, 48, 58 distance calculation unit 9 size calculation unit 10 risk determination unit 11 buzzer 26 area change ratio calculation unit 30 intruder determination unit 31 conveyor 40 mirror 41 moving device 45 infrared intensity calculation unit 46 intensity change amount calculation unit 56 intensity change ratio calculation Department

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Claims (8)

[Claims] 1. An array sensor having a plurality of infrared sensing elements arranged two-dimensionally, a thermal image acquisition means for acquiring a thermal image of a monitoring region by the array sensor, and a heat source area occupied by a heat source in the thermal image is calculated. Heat source area calculation means, speed acquisition means for acquiring the relative speed of the array sensor with respect to the heat source, area change index calculation means for calculating a change index of the heat source area, based on the speed and the area change index A heat source distance detecting device, comprising: a distance calculating unit that calculates a distance to the heat source. 2. An array sensor having a plurality of infrared sensing elements arranged two-dimensionally, a thermal image acquisition means for acquiring a thermal image of a monitoring region by the array sensor, and a heat source area occupied by a heat source in the thermal image is calculated. Heat source area calculation means, and area change index calculation means for calculating a change index from the heat source area when the distance from the array sensor to the heat source is the first distance to the heat source area when the distance is the second distance. And a distance calculation unit that calculates a distance to the heat source based on the distance difference between the first distance and the second distance and the area change index. 3. The heat source distance detecting device according to claim 2, wherein a reflecting means provided in an optical path from the array sensor to the heat source and a first optical path length by operating the reflecting means. An optical path length switching device for switching between a second optical path length and a distance detecting device for a heat source, wherein the difference between the first optical path length and the second optical path length is the distance difference. 4. An infrared intensity detecting means for detecting infrared intensity from a heat source in a monitoring area, a speed obtaining means for obtaining a relative speed of the infrared intensity detecting means with respect to the heat source, and an index of change in infrared intensity of the heat source. A heat source distance detecting device, comprising: a strength change index calculating means for calculating; and a distance calculating means for calculating a distance to the heat source based on the speed and the strength change index. 5. An infrared intensity detecting means for detecting infrared intensity from a heat source in the monitoring area, and a second distance from the infrared intensity when the distance from the infrared intensity detecting means to the heat source is a first distance. Intensity change index calculation means for calculating a change index to the infrared intensity, and a distance for calculating the distance to the heat source based on the distance difference between the first distance and the second distance and the intensity change index. A heat source distance detecting device comprising: a calculating unit. 6. The heat source distance detecting device according to claim 5, wherein a reflecting means provided in an optical path from the infrared intensity detecting means to the heat source and a first optical path by operating the reflecting means. An optical path length switching unit for switching between a long optical path length and a second optical path length, wherein the difference between the first optical path length and the second optical path length is the distance difference. . 7. The heat source distance detecting device according to claim 1, and a size calculating means for calculating the size of the heat source based on the heat source area and the distance to the heat source. A device for detecting the size of a heat source, which is provided. 8. The heat source distance detection device according to claim 4, a heat source area calculation means for calculating a heat source area occupied by a heat source in the thermal image, the heat source area and the heat source. A heat source size detection device comprising size calculating means for calculating the size of the heat source based on the distance to the heat source.