JP2007336288A - Obstacle detection system and obstacle detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the omission of the detection of obstacles beforehand by adjusting timing for performing NUC (Non-Uniformity Correction). <P>SOLUTION: Parallax images imaged by a plurality of far-infrared imaging apparatuses for imaging surroundings of a vehicle time sequentially are acquired to detect the existence of obstacles in an image. A far-infrared imaging apparatus stores an offset correction value for correcting an output value of a plurality of imaging elements each arranged in a matrix form with respect to a prescribed temperature, and a gain correction value for correcting a difference in an output value with respect to a predetermined variation rate of a temperature in each imaging element. The stored offset correction value in each imaging element is updated on the basis of image data obtained by imaging the surface of a shutter for opening and closing an opening through which light is made incident on an imaging element. One far-infrared imaging apparatus starts to update the offset correction value when a time corresponding to one frame of image data elapses after the other far-infrared imaging apparatus updates the offset correction value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an obstacle detection system and an obstacle detection method in which the brightness value between parallax images is adjusted to maintain high obstacle detection accuracy by correcting the output brightness value of a far-infrared imaging device that images the outside. About.

  In order to ensure the safety of traveling of vehicles such as automobiles, many obstacle detection systems that detect the presence of obstacles such as pedestrians and bicycles using far-infrared imaging devices such as night vision have been developed. Usually, two far-infrared imaging devices are installed at a predetermined position in front of the vehicle, and the distance to the obstacle detected by stereo vision is calculated.

  For example, from an image captured by the left and right far-infrared imaging devices, an area where an obstacle, for example, a human being is present is detected by pattern matching with a predetermined reference pattern, and a distance to the area is calculated by stereo vision. Vehicle safety is ensured by notifying the driver when the distance is within a predetermined distance.

  The far-infrared imaging device is composed of a plurality of imaging elements, A / D-converts luminance values output from the imaging elements, and outputs them as digital signals. When images are taken by far-infrared imaging devices arranged separately on the left and right, even if the target is the same, the amount of heat to be detected is different and the output value is different. Therefore, in order to accurately calculate the distance to the obstacle detected by stereo vision, the luminance values of the imaging data of the same object are the same so that the same object can be reliably detected. It is necessary to correct the output value of the far-infrared imaging device so that

For example, Non-Patent Document 1 discloses NUC (Non-Uniformity Correction), which is a representative example of a method for correcting the non-uniformity of sensitivity that differs for each image sensor, and the response characteristics of the image sensor are linear. Assuming that there is an offset, an offset correction value for correcting an output value for a predetermined temperature for each image sensor and a gain correction value for correcting a difference in output value for a predetermined temperature change rate for each image sensor are calculated. The output value from the infrared imaging device is corrected.
“Real-time implementation of two-point non-uniformity correction for IR-CCD imagery”, SPIE Proc., Vol. 2598, p. 44-50, 1995

  However, in the conventional correction method of the output value of the imaging device, the absolute temperature is accurately grasped and the offset correction value is not calculated. Therefore, even when the same object is imaged, it depends on the surrounding environment. The output values may be different and may be an area indicating an obstacle or may not be an area indicating an obstacle. Therefore, even when the same obstacle is imaged by the imaging devices arranged on the left and right sides of the vehicle, it may not be determined that the object is the same, and there is a risk of detection omission of an obstacle or erroneous detection. There was a problem that there was.

  Further, when far-infrared imaging devices are installed on the left and right sides of the vehicle, it is impossible to capture an image with the far-infrared imaging device while NUC is performed with one far-infrared imaging device. Therefore, when NUC is performed simultaneously with the left and right far-infrared imaging devices, there is a possibility that an image to be captured does not exist and an obstacle detection failure occurs.

  The present invention has been made in view of such circumstances, and provides an obstacle detection system and an obstacle detection method capable of preventing an obstacle from being detected in advance by adjusting the timing of performing NUC. The purpose is to do.

  In order to achieve the above object, an obstacle detection system according to a first aspect of the present invention acquires parallax images captured by a plurality of far-infrared imaging devices that image the periphery of a vehicle in time series, and detects obstacles in the image. In the obstacle detection system for detecting presence, the far-infrared imaging device includes a plurality of imaging elements arranged in a matrix, an offset correction value for correcting an output value for a predetermined temperature for each imaging element, and each imaging element. A means for storing a gain correction value for correcting a difference in output value with respect to a predetermined rate of temperature change, and an image data stored based on image data obtained by imaging the surface of a shutter that opens and closes an opening for entering the image sensor. Means for updating the offset correction value for each element, and one far infrared imaging device updates the offset correction value after the other far infrared imaging device has updated the offset correction value. If older than a time corresponding to the over arm, characterized in that you have to start updating of the offset correction value.

  In the obstacle detection system according to the second invention, in the first invention, when one far infrared imaging device updates the offset correction value, the other far infrared imaging device uses the captured image data. The one far-infrared imaging device extracts an obstacle detected before starting to update the offset correction value, and stores a change in the position of the extracted obstacle in time series. Features.

  The obstacle detection method according to the third aspect of the present invention is an obstacle detection method that acquires parallax images captured by a plurality of far-infrared imaging devices that image the periphery of a vehicle in time series and detects the presence of an obstacle in the image. In the object detection method, in the far-infrared imaging device, an offset correction value for correcting an output value for a predetermined temperature for each of a plurality of imaging elements arranged in a matrix and an output value for a predetermined temperature change rate for each imaging element The gain correction value for correcting the difference between the image pickup devices is stored, and the stored offset correction value for each image pickup device is updated based on the image data obtained by picking up the surface of the shutter that opens and closes the opening that enters the image pickup device. This far-infrared imaging device updates the offset correction value when a time corresponding to one frame of image data has elapsed after another far-infrared imaging device has updated the offset correction value. Characterized in that it starts to.

  In the first invention and the third invention, parallax images captured by a plurality of far-infrared imaging devices that image the periphery of the vehicle in time series are acquired, and the presence of an obstacle in the image is detected. The far-infrared imaging device includes an offset correction value for correcting an output value for a predetermined temperature for each of a plurality of image sensors arranged in a matrix and a gain correction for correcting a difference between output values for a predetermined temperature change rate for each image sensor. The value is stored, and the stored offset correction value for each image sensor is updated based on the image data obtained by imaging the surface of the shutter that opens and closes the opening that enters the image sensor. One far-infrared imaging device starts updating the offset correction value when a time corresponding to one frame of image data has elapsed after the other far-infrared imaging device has updated the offset correction value. In this way, after updating the offset correction value in one far-infrared imaging device, it is possible to acquire image data for at least one frame from a plurality of far-infrared imaging devices. Ranging up to is possible. In addition, even when the offset correction value is being updated by one far-infrared imaging device, the image captured by the other far-infrared imaging device can be acquired, and the captured image is interrupted. Can be avoided and a safe obstacle detection system can be realized.

  In the second invention, when one far-infrared imaging device updates the offset correction value, the other far-infrared imaging device updates the offset correction value from the captured image data. The obstacle detected before starting is extracted, and the change of the position of the extracted obstacle is stored in time series. Even when NUC is executed, an image of at least one far-infrared imaging device can be acquired, and the movement position of an obstacle that has already been detected is tracked (tracked) based on the previous image data. Thus, the detected obstacle can be monitored even when the offset correction value is being updated by one of the far-infrared imaging devices, and a safer obstacle detection system can be realized.

  According to the present invention, after updating the offset correction value in one far-infrared imaging device, it is possible to acquire image data for at least one frame from a plurality of far-infrared imaging devices, up to an obstacle by stereo vision. Ranging is possible. In addition, even when the offset correction value is being updated by one far-infrared imaging device, the image captured by the other far-infrared imaging device can be acquired, and the captured image is interrupted. Can be avoided and a safe obstacle detection system can be realized.

  FIG. 1 is a schematic diagram showing a configuration of an obstacle detection system according to an embodiment of the present invention. In the present embodiment, a case will be described as an example in which the presence of an obstacle in front of the vehicle, such as a pedestrian or a bicycle, is detected based on an image captured by a far-infrared imaging device during traveling. The far infrared imaging device is an imaging device using infrared light having a wavelength of 7 to 14 micrometers.

  In FIG. 1, reference numerals 1 and 2 denote far-infrared imaging devices that image pedestrians at night, people on bicycles, and the like. The far-infrared imaging devices 1 and 2 are juxtaposed in a substantially horizontal direction at an appropriate length in the front grill of the vehicle. Image data captured by the far-infrared imaging devices 1 and 2 is transmitted to the detection device 3 connected via the video cable 7 corresponding to an analog video system such as NTSC or a digital video system.

  In addition to the far-infrared imaging devices 1 and 2, the detection device 3 is connected to a display device 4 having an operation unit via a cable 8 corresponding to a video system such as NTSC, VGA, DVI, etc. An output device such as an alarm device 5 that emits an audible warning by a sound effect or the like is connected via an in-vehicle LAN cable 6 compliant with CAN.

  FIG. 2 is a block diagram showing a configuration of the far-infrared imaging device 1 (2) of the obstacle detection system according to the embodiment of the present invention. The image pickup unit 11 includes image pickup elements that convert optical signals into electric signals in a matrix. As an imaging device for infrared light, an infrared sensor such as a vanadium oxide bolometer type using a micromachining technique or a BST (Barium-Strontium-Titanium) pyroelectric type sensor is used. The image capturing unit 11 reads an infrared light image around the vehicle as a luminance signal, and transmits the read luminance signal to the signal processing unit 12.

  The signal processing unit 12 is an LSI, converts the luminance signal received from the image imaging unit 11 into a digital signal such as an RGB signal, and performs processing for correcting variations in the imaging device, correction processing for a defective device, gain control processing, and the like. And stored in the image memory 13 as image data.

  The image capturing unit 11 reads an infrared light image around the vehicle as a luminance signal, and transmits the read luminance signal to the signal processing unit 12 that is an LSI substrate. FIG. 3 is a block diagram showing the configuration of the signal processing unit 12 of the far-infrared imaging device 1 (2) according to the embodiment of the present invention. The signal processing unit 12 is an A / D conversion unit 121, an NUC (Non-Uniformity Correction) processing unit 122, a BPR (Bad-Pixel Replacement) processing unit 123, and a nonvolatile memory such as a flash memory. It is composed of a certain RAM 125.

  The signal processing unit 12 converts the luminance signal received from the image capturing unit 11 into a digital signal by the A / D conversion unit 121, and outputs the luminance signal output for each image sensor by the NUC (Non-Uniformity Correction) processing unit 122. to correct.

In the NUC processing unit 122, as a correction coefficient by calibration, an offset correction value for correcting an output value for a predetermined temperature for each image sensor, and an output value difference for a predetermined temperature change rate for each image sensor as necessary. A gain correction value to be corrected is calculated to correct the luminance signal. For example, when the output luminance value for each image sensor arranged in a matrix of i rows and j columns is V _ij , the NUC processing unit calculates the luminance value for each image sensor by performing the calculation shown in (Equation 1). Correct to _ij . In the present embodiment, “calibration” means processing for correcting variations in output luminance values from the image sensor by imaging an object having a substantially uniform temperature distribution such as a black body furnace. .

In (Equation 1), G _ij indicates a gain correction value, and O _ij indicates an offset correction value. For example, an output for each image sensor when an object having a uniform temperature distribution such as a black body furnace or a shutter is imaged. This is a value calculated based on the luminance value.

  In the present embodiment, a plate-like shutter 72 having a substantially uniform temperature distribution on the surface is provided so as to be able to open and close between the objective lens 71 and the image pickup unit 11, and the shutter 72 is closed. The offset correction value is corrected as needed based on the output luminance value for each image sensor when the image is picked up. In FIG. 2, a mechanical plain shutter is taken as an example. However, the shutter may have any configuration as long as the temperature distribution on the surface is uniform.

  The LSIs 16 of the signal processing units 12 of the two far-infrared imaging devices 1 and 2 perform data communication with each other via the detection device 3 or by directly connecting a communication line, and the two far-infrared imaging devices 1, 2, the average value of the luminance values output when the shutters 72 and 72 are imaged is matched between the two. For example, when the far-infrared imaging device 1 is a master device that serves as a reference for updating the offset correction value, and the far-infrared imaging device 2 is a slave device that updates the offset correction value depending on the master device, the far-infrared imaging device The LSI 16 of 2 closes the shutter 72 at the time of executing calibration, and offset correction is performed so that the average value of the luminance values captured by the far-infrared imaging device 2 matches the average value of the luminance values captured by the far-infrared imaging device 1. The value is updated and stored in the RAM 125 of the far infrared imaging device 2.

  In order to detect the surface temperature of the shutters 72, 72, means for detecting the surface temperature, for example, a sensor such as a thermocouple, a thermopile, or a diode type temperature sensor, is attached to the surface of the shutters 72, 72 on the image pickup unit 11 side. Alternatively, the offset correction value and the gain correction value may be calculated so that the absolute values of the surface temperature are made uniform.

  The NUC processing unit 122 of the signal processing unit 12 corrects the luminance signal output for each image sensor based on the stored offset correction value and gain correction value. The image sensor includes an image sensor in which defects are generated at a predetermined rate. Therefore, the LSI 16 uses a BPR (Bad-Pixel Replacement) processing unit 123 to set the output value of the image sensor having a defect to a value representative of the output value of the surrounding image sensor, for example, the image sensor having the defect. Is corrected to the average value of the output values of the surrounding image sensors excluding the output value of.

  The communication interface unit 14 is an LSI, and outputs video data to the detection device 3 via a video cable 7 compatible with an analog video system such as NTSC or a digital video system. Needless to say, it is not essential to temporarily store the image data in the image memory 13, and the image data may be directly transmitted to the detection device 3 via the communication interface unit 14.

  FIG. 4 is a block diagram showing the configuration of the detection device 3 of the obstacle detection system according to the embodiment of the present invention. The imaging device interface unit 31 a inputs video signals from the far-infrared imaging devices 1 and 2, and outputs an average value of output luminance values of images captured by the shutter 72 between the far-infrared imaging devices 1 and 2 during calibration. Forward. When the image data is digitized, the image data is transferred via a digital video cable 7. When the image data is analog data, the image data is transferred by connecting a separate communication line. The imaging device interface unit 31a stores the image data input from the far infrared imaging devices 1 and 2 in the image memory 32 in synchronization with one frame unit. The video output unit 31 b outputs image data to the display device 4 such as a liquid crystal display via the video cable 8, and the communication interface unit 31 c outputs an alarm device 5 such as a buzzer and a speaker via the in-vehicle LAN cable 6. An output signal such as a synthesized sound is transmitted.

  The image memory 32 is an SRAM, flash memory, SDRAM or the like, and stores image data input from the far-infrared imaging device 1 via the imaging device interface unit 31a.

  The LSI 33 that performs image processing reads the image data stored in the image memory 32 in units of frames, and specifies an obstacle candidate region based on the image data acquired from the far-infrared imaging device 1. The LSI 33 extracts a feature amount from the obstacle candidate region, and determines whether an obstacle exists based on the extracted feature amount. The RAM 331 stores data generated during the arithmetic processing and the calculated time-series position data of the obstacle.

  Hereinafter, timing control of calibration processing in the far-infrared imaging devices 1 and 2 will be described. FIG. 5 is a flowchart showing a processing procedure of the LSI 16 of the signal processing unit 12 of the far-infrared imaging device 1 (master device) of the obstacle detection system according to the embodiment of the present invention.

  The LSI 16 of the signal processing unit 12 of the far-infrared imaging device 1 (master device) issues a calibration execution instruction or obtains it from the detection device 3 (step S501), and the predetermined time T1 has elapsed from the start of the previous calibration. It is determined whether or not the time has elapsed (step S502). The predetermined time T1 is set as a time more than twice the time T2 obtained by adding at least the time α corresponding to one frame of image data to the time ΔT required for calibration after the far-infrared imaging device 1 starts calibration. To do.

  FIG. 6 is a diagram schematically showing a waiting time (predetermined time) T1 in the far-infrared imaging device 1 (master device) and a waiting time T2 in the far-infrared imaging device 2 (slave device) described later. (1) and (2) in FIG. 6 show the time axes of the processing of the far-infrared imaging devices 1 and 2, respectively, and the hatched portion shows the calibration execution time zone. The far-infrared imaging device 2 that is a slave device until the time ΔT required for calibration and the time α corresponding to one frame elapse after the calibration is started in the far-infrared imaging device 1 that is a master device. The LSI 16 of the far-infrared imaging device 2 controls so as not to execute the calibration.

  In other words, when the calibration is executed simultaneously by the left and right far-infrared imaging devices 1 and 2, the shutters 72 and 72 are closed, and the surrounding images are interrupted. Therefore, since the obstacle detection process by the detection device 3 is also interrupted, safety during calibration execution cannot be ensured.

  Therefore, in the present embodiment, calibration is executed alternately, and at least the time corresponding to one frame of image data from the end of calibration in the far infrared imaging device 1 to the start of calibration in the far infrared imaging device 2. Leave an interval. By doing in this way, the detection apparatus 3 can always acquire any one image data.

  In addition, the detection device 3 can execute only a so-called tracking process that tracks the trend of an obstacle that has already been detected during a period in which only one image data is acquired. Therefore, it is necessary for the detection device 3 to execute an obstacle detection process immediately before entering the tracking process. Therefore, in the present embodiment, by controlling to leave at least a time interval of one frame of image data from the end of calibration in the far-infrared imaging device 1 to the start of calibration in the far-infrared imaging device 2, The detection device 3 can always acquire image data for one frame or more during a period in which calibration is not executed, and can execute an obstacle detection process.

  Similarly, the detection apparatus 3 is calibrated by providing a time interval of at least one frame of image data from the end of calibration in the far-infrared imaging apparatus 2 to the start of calibration in the far-infrared imaging apparatus 1. The image data for one frame or more can be acquired without fail during the period during which no obstacle is executed, and the obstacle detection process can be executed. Therefore, in the far-infrared imaging device 1, a time obtained by adding a time α corresponding to at least one frame of image data to a time ΔT required for calibration from the time when calibration is performed to the time when calibration is performed again. By providing a time interval that is at least twice as long as T2, the detection device 3 can continue to detect obstacles even when calibration is performed alternately.

  The LSI 16 waits until the predetermined time T1 has elapsed since the start of the previous calibration (step S502: NO), and if the LSI 16 determines that the predetermined time T1 has elapsed (step S502: YES), the LSI 16 Then, the timing means such as the built-in timer is reset to start timing (step S503). The LSI 16 transmits information indicating that the calibration is started to the far-infrared imaging device 2 (slave device) (step S504).

  The LSI 16 sends an instruction to close the shutter 72 to an actuator (not shown) that controls the operation of the shutter 72 (step S505). The actuator that has received the closing instruction closes the shutter 72.

  The LSI 16 acquires image data obtained by imaging the surface of the shutter 72 with the shutter 72 closed (step S506), and calculates an average luminance value (step S507). Based on the calculated average luminance value, the LSI 16 calculates an offset correction value that makes the variation of each image sensor uniform, and stores it in the RAM 125 (step S508).

  The LSI 16 transmits the offset correction value stored in the RAM 125 to the far-infrared imaging device 2 (slave device) (step S509), and opens the shutter 72 to an actuator (not shown) that controls the operation of the shutter 72. An instruction is transmitted (step S510). The actuator that has received the opening instruction opens the shutter 72.

  FIG. 7 is a flowchart showing a processing procedure of the LSI 16 of the signal processing unit 12 of the far-infrared imaging device 2 (slave device) of the obstacle detection system according to the embodiment of the present invention. The LSI 16 of the signal processing unit 12 of the far-infrared imaging device 2 (slave device) issues a calibration execution instruction or obtains it from the detection device 3 (step S701), and calibration from the far-infrared imaging device 1 (master device). In step S702, it is determined whether or not information indicating that the communication has started is received. The LSI 16 waits until it receives information indicating that calibration has started (step S702: NO), and if it determines that the LSI 16 has received information indicating that calibration has started (step S702: YES) The LSI 16 resets the time measuring means such as a built-in timer and starts time counting (step S703).

  The LSI 16 determines whether or not the predetermined time T2 has elapsed (step S704), and the LSI 16 waits until the predetermined time T2 has elapsed (step S704: NO). If the LSI 16 determines that the predetermined time T2 has elapsed (step S704: YES), the LSI 16 sends an instruction to close the shutter 72 to an actuator (not shown) that controls the operation of the shutter 72 (step S704). S705). The actuator that has received the closing instruction closes the shutter 72.

  The LSI 16 acquires image data obtained by imaging the surface of the shutter 72 with the shutter 72 closed (step S706), and calculates an average luminance value (step S707). Based on the calculated average luminance value, the LSI 16 calculates an offset correction value that makes the variation of each image sensor uniform (step S708).

  The LSI 16 receives the offset correction value calculated by the far-infrared imaging device 1 (master device) (step S709), and determines whether or not the received offset correction value substantially matches the calculated offset correction value. (Step S710). If the LSI 16 determines that the two do not match (step S710: NO), the LSI 16 stores the offset correction value received from the far-infrared imaging device 1 (master device) in the RAM 125 (step S711). As a result, the luminance values output by the far-infrared imaging device 1 and the far-infrared imaging device 2 can be made to substantially match.

  When the LSI 16 determines that the two are substantially the same (step S710: YES), the LSI 16 stores the calculated offset correction value in the RAM 125 (step S712). The LSI 16 sends an instruction to open the shutter 72 to an actuator (not shown) that controls the operation of the shutter 72 (step S713). The actuator that has received the opening instruction opens the shutter 72.

  The timing for updating the offset correction values of the far-infrared imaging devices 1 and 2 may be a fixed time interval, or the detection device 3 detects that the temperature change in the surrounding environment has exceeded a predetermined range. An instruction may be transmitted when the information is recognized via a device (not shown).

  As described above, according to the present embodiment, after updating the offset correction value in the far-infrared imaging device 1 (master device), image data for at least one frame is transferred from the left and right far-infrared imaging devices 1 and 2. Obstacles can be detected including distance measurement up to the obstacle by stereo vision. Further, even when the offset correction value is being updated by the far-infrared imaging device 1 (master device) or the far-infrared imaging device 2 (slave device), the image captured by the other far-infrared imaging device is reliably acquired. Therefore, it is possible to avoid a situation in which the captured image is interrupted, and a safe obstacle detection system can be realized.

  In the above-described embodiment, the LSI 16 of the signal processing unit 12 of the far-infrared imaging devices 1 and 2 performs the offset correction value calculation processing. However, the present invention is not limited to this, and for example, the detection device 3 It goes without saying that the LSI 33 may perform the calculation process.

It is a mimetic diagram showing composition of an obstacle detection system concerning an embodiment of the invention. It is a block diagram which shows the structure of the far-infrared imaging device of the obstruction detection system which concerns on embodiment of this invention. It is a block diagram which shows the structure of the signal processing part of the far-infrared imaging device which concerns on embodiment of this invention. It is a block diagram which shows the structure of the detection apparatus of the obstacle detection system which concerns on embodiment of this invention. It is a flowchart which shows the procedure of the process of LSI of the signal processing part of the far-infrared imaging device (master apparatus) of the obstacle detection system which concerns on embodiment of this invention. It is a figure which shows typically waiting time T1 in a far-infrared imaging device (master device) and waiting time T2 in a far-infrared imaging device (slave device). It is a flowchart which shows the procedure of the process of LSI of the signal processing part of the far-infrared imaging device (slave device) of the obstacle detection system which concerns on embodiment of this invention.

Explanation of symbols

1 Far-infrared imaging device (master device)
2 Far-infrared imaging device (slave device)
DESCRIPTION OF SYMBOLS 3 Detection apparatus 4 Display apparatus 5 Alarm apparatus 11 Image pick-up part 12 Signal processing part 13 Image memory 14 Communication interface part 15 Internal bus 16 LSI
121 A / D converter 122 NUC processor 123 BPR processor 125 RAM

Claims (3)

In an obstacle detection system that acquires parallax images captured by a plurality of far-infrared imaging devices that image the periphery of a vehicle in time series, and detects the presence of an obstacle in the image,
The far-infrared imaging device is:
A plurality of imaging devices arranged in a matrix;
Means for storing an offset correction value for correcting an output value for a predetermined temperature for each image sensor and a gain correction value for correcting a difference in output value for a predetermined temperature change rate for each image sensor;
Means for updating an offset correction value for each stored image sensor based on image data obtained by imaging the surface of a shutter that opens and closes an opening for entering the image sensor; and
One far-infrared imaging device starts updating the offset correction value when a time corresponding to one frame of image data has elapsed after the other far-infrared imaging device has updated the offset correction value. Obstacle detection system characterized by   When one far-infrared imaging device updates the offset correction value, the other far-infrared imaging device uses the captured image data before the one far-infrared imaging device starts updating the offset correction value. 2. The obstacle detection system according to claim 1, wherein the detected obstacle is extracted and changes in the position of the extracted obstacle are stored in time series. In the obstacle detection method for acquiring parallax images captured by a plurality of far-infrared imaging devices that image the periphery of a vehicle in time series, and detecting the presence of an obstacle in the image,
In the far infrared imaging device,
Storing an offset correction value for correcting an output value for a predetermined temperature for each of a plurality of image sensors arranged in a matrix and a gain correction value for correcting a difference in output value for a predetermined temperature change rate for each image sensor;
Based on the image data obtained by imaging the surface of the shutter that opens and closes the opening for entering the image sensor, the stored offset correction value for each image sensor is updated.
One far-infrared imaging device starts updating an offset correction value when another far-infrared imaging device has updated an offset correction value and a time corresponding to one frame of image data has elapsed. Obstacle detection method.

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