JP2007333576A - Object identification device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily identify a radiation object from a reflection object. <P>SOLUTION: A device includes: an electric wave imaging part 200 for detecting the radiant quantity in an area of electric waves radiated from objects A, B and generating an electric wave radiation intensity image based on the detection result; an image computing part 300 for storing the electric wave radiation intensity image in time series, and comparing two or more stored electric wave radiation intensity images to compute a time-series deviation of the electric wave radiation intensity image; and a recognition processing means (a radiation amount computing part 400 and an object identification processing part 500) for recognizing the objects A, B based on an electric wave radiation intensity image generated by the electric wave imaging part 300 and the time-series deviation information computed by the image computing part 300, wherein the recognition processing means determines that the reflection object having a large reflectance exists in a part of the electric wave radiation intensity image where the time-series deviation is larger than a predetermined value, and excludes the reflection object from the electric wave radiation intensity image to identify the reflection object from the radiation object. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an object identification device, and more particularly to an object identification device for identifying a radiating object and a reflecting object.

  Conventionally, an apparatus for observing an object around a car has been developed. As an external environment recognition device mounted on a vehicle, there are generally a device that measures the amount of radio wave reflection like a radar device and a device that observes the amount of heat radiation like a far-infrared camera. A radar device is mainly used as a device for detecting a vehicle, and a far-infrared camera is used as a device for detecting a pedestrian.

The radar device detects the presence of an object by transmitting a radio wave and detecting a reflected signal having an intensity equal to or greater than a predetermined value, and observes the distance to the object from a time difference between transmission and reception. A far-infrared camera is suitable for detecting a far-infrared ray radiated from an object and detecting a thing close to a human body temperature. In addition, a method for detecting a vehicle by detecting a high-temperature portion with a far-infrared camera has been proposed (see, for example, Patent Document 1).
JP 2002-98509 A

  By the way, in the case of a method of observing the amount of reflection such as radio radar, the object to be observed is determined based on the strength of the amount of reflection, but the reflection characteristics tend to largely depend on the surface properties of the object. It is difficult to accurately identify. In addition, the observation of the radiation amount of a far-infrared camera, etc. is passive and is not affected by the surface properties, and the physical properties of the observation object can be determined from the shape and radiation amount of the radiation object. Radiation from other radiating objects is reflected on the surface of the reflecting object, and erroneous detection occurs.

  In the method disclosed in Patent Document 1, a high temperature part such as an exhaust pipe of an automobile is detected as an automobile, but the detected part is very small and may be shielded by a vehicle body or the like. There is a problem that the high temperature part is not detected in front of a vehicle such as an oncoming vehicle and is not detected.

  In addition, in response to bad weather, a device for observing the amount of radiation in the radio wave region using a radio wave imaging device has been studied. In the radio wave region, the reflectivity of metal is almost “1” and the emissivity and transmittance are almost “ Because it is close to “0”, the amount of radiation of the metal itself is not observed, and the radiation of other objects present in the surroundings is reflected by the metal surface and observed, and the metal may be misrecognized as if it were a radiation object. is there. In general road environments, there are many environments in which objects with high reflectivity such as metal and radiation objects such as human bodies coexist, and there is also a problem that erroneous detection of objects occurs due to observation of the virtual image.

  An object of the present invention is to provide an object identification device that can easily identify a radiation object and a reflection object.

  In order to solve the above problems, the feature of the present invention is to measure the time variation of the amount of radio wave radiation radiated from an object, and in a spatial region where the time variation fluctuates with a deviation greater than a predetermined value, It is to determine that there is an object made of a large material.

  That is, the present invention includes a radio wave radiation intensity image generating unit that detects a radiation amount in a radio wave region radiated from an object and generates a radio wave radiation intensity image based on the detection result, and the radio wave radiation intensity image generating unit. Image calculation means for accumulating the generated radio wave emission intensity images in time series and comparing the accumulated radio wave emission intensity images to calculate a time series deviation of the radio wave emission intensity images; and A radio wave radiation intensity image generated by the intensity image generation means and a recognition processing means for recognizing the object based on time-series deviation information calculated by the image calculation means, and the recognition processing means includes the radio wave radiation intensity. It is determined that there is a reflective object having a high reflectivity in a portion where the time-series deviation is larger than a predetermined value in the image, and the reflection object is excluded from the radio wave radiation intensity image. It is characterized by identifying a large emitting body of the object and emissivity.

  According to the present invention, it is determined that there is a reflective object having a high reflectance in a portion where the time-series deviation is larger than a predetermined value in the radio wave radiation intensity image, and the reflective object is excluded from the radio wave radiation intensity image. Therefore, it is possible to easily distinguish the reflecting object and the radiating object.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram of an object identification device according to the first embodiment. As shown in FIG. 1, the object detection apparatus 100 includes a radio wave imaging unit 200, an image calculation unit 300, a radiation amount calculation unit 400, and an object recognition processing unit 500.

  The radio wave imaging unit 200 detects radiation from the object A (symbol 10) and the object B (symbol 11) existing in the front space, and acquires a radiation intensity image in the radio wave region. The image calculation unit 300 accumulates (stores) the radiation intensity image acquired by the radio wave imaging unit 200 a predetermined number of times, compares the plurality of accumulated radiation intensity images, calculates the variation of the radiation intensity image, and calculates the radiation intensity. Find the deviation image. The radiation amount calculation unit 400 generates a radiation intensity distribution image in which spatial regions are classified for each radiation intensity from the radiation intensity image acquired by the radio wave imaging unit 200, and extracts a region where a radiation object exists. Further, the object recognition processing unit 500 detects the object A, which is a radiation object, and the reflection object from the radiation intensity deviation image obtained by the image computation unit 300 and the radiation intensity distribution image detected by the radiation amount computation unit 400. A certain object B is detected.

  Here, the function of each part will be described in more detail.

  The radio wave imaging unit 200 includes a dielectric lens 201 that transmits radio wave radiation to be observed, an imaging array unit 202 in which radio wave receiving elements 204 that observe radio wave radiation are arranged in a matrix, and the amount of thermal noise observed in each array element Are arranged in a matrix and are composed of a signal conversion unit 203 that generates a thermal noise image.

  FIG. 2 is a diagram for explaining an operation image of the radio wave imaging unit 200. Thermal noise radiated from a certain forward direction is collected by the dielectric lens 201 and received by one radio wave receiving element 204. The radio wave receiving element 204 includes a receiving antenna 205, a detection unit 206, and a signal amplification unit 207. The radio wave receiving element 204 is matched with the observation wavelength, and outputs a signal intensity of only a desired wavelength component from the thermal noise signal. By arranging the radio wave receiving elements 204 in a matrix and combining the received signal intensity output from each radio wave receiving element, an intensity image of radio wave radiation as shown in FIG. 3 can be generated.

  As shown in FIG. 1, the image calculation unit 300 includes a radio wave image storage unit 301 that stores an intensity image of radio wave radiation output from the radio wave imaging unit 200, and a space of the intensity image stored in the radio wave image storage unit 301. A spatial calculation processing unit 302 that performs a calculation for obtaining a deviation of intensity variation with respect to time change for each region, performs spatial calculation for each spatial region, and outputs an intensity variation deviation image.

  The radiation amount calculation unit 400 divides the spatial region for each radiation amount intensity from the radio wave radiation intensity image output from the radio wave imaging unit 200 and outputs the positions and shapes of the objects A and B and the radiation amount.

  The object recognition processing unit 500 detects the position and shape of an object made of a material having high reflection characteristics in the radio wave region from the radiation intensity deviation image obtained by the image calculation unit 300, and is output from the radiation amount calculation unit 400. From the information on the radiating object, the information on the radiating object that overlaps the spatial position of the object having a large reflection characteristic is determined to be a false image due to reflection, and the radiating object and the reflecting object are classified to perform identification processing.

  In this embodiment, the radio wave imaging unit 200 constitutes a radio wave radiation intensity image generation unit, the image computation unit 300 constitutes an image computation unit, and the radiation amount computation unit 400 and the object recognition processing unit 500 constitute a recognition processing unit. Yes.

  Here, radiation from an object will be described.

Generally, radiant energy (electromagnetic waves) determined according to the temperature is emitted from the surface of an object at a certain temperature. Assuming that the emissivity of an object is ε and the energy radiated from a black body at a certain temperature is E 0, the energy E radiated from an object at a certain temperature is expressed by the following equation (1).
E = ε × E0 (1)

The energy radiated from a black body can be calculated by Planck's radiation law, but the emissivity varies depending on the type of object, surface condition, and measurement conditions (temperature, wavelength, detection angle of the object identification device with respect to the object, etc.). It is known. The emissivity of a substance is equal to the rate at which the substance absorbs radiation, and the relationship of the following equation (2) is established between the reflectance and transmittance of the object.
"Reflectance" + "Absorption (radiation) rate" + "Transmittance" = 1 (2)

  As a device for observing the amount of radiation, there are a far-infrared camera and a radio wave imaging device.

  These radiation observation devices are passive and are not affected by the surface properties.The physical properties of the observation object can be judged from the shape and radiation amount of the radiating object. May be erroneously detected due to reflections.

  For vehicles, it is preferable to cope with bad weather, and devices using radio wave imaging devices are being studied. However, in the radio wave region, the reflectivity of metal is almost “1” and the emissivity and transmittance are almost “0”. Therefore, it is difficult to observe the radiation amount of the metal itself. When an object with high reflectivity such as metal is actually observed, the radiation of other objects present in the surroundings is reflected and observed on the metal surface. That is, the radiation of the object A in FIG. 1 may be reflected on the surface of the object B, and the object B may be erroneously recognized as if it is a radiation object. In general road environments, there are many environments in which highly reflective objects such as metals and radiation objects such as human bodies coexist, and false detection of objects has occurred due to observation of the virtual image.

  In this embodiment, in the passive radiation amount observation using the radio wave imaging device for observing the radio wave radiation amount, by extracting a region such as a metal having the characteristics of emissivity 0 and reflectance 1 in the radio wave region, The erroneous detection due to the reflection is suppressed.

  That is, in this embodiment, a radio wave image storage unit 301 that accumulates a radiation intensity image output from the radio wave imaging unit 200 for a certain period of time, and a spatial calculation process that calculates a deviation in intensity variation with respect to time change for each pixel of the radiation intensity image. The unit 302 is provided, and it is determined that an object having a high reflectance in the observation radio wave region exists in the region that fluctuates with a deviation of a predetermined value or more, and is excluded from the radiant object identification process from the radiation intensity image. It is possible to detect the reflected object separately.

  3 and 4 show examples of observation results.

FIG. 3 is an image obtained when the object A having a high emissivity and the object B having a high reflectivity are observed with a radio wave imaging apparatus in a moving state, and FIG. 3A shows the image at time t ₀ . , (B) shows the one at time t ₀ + Δt, and (c) shows the one at time t ₀ + 2Δt. In this embodiment, the object A is a utility pole and the object B is a vehicle. As the image images, a telephone pole image A ′ and a vehicle image B ′ are displayed.

  As shown in FIG. 3, in the case of an object A (image A ') having a high emissivity, there is almost no change (change in light and shade of the image) with respect to time, and a uniform radiation amount can be observed. However, in the case of the object B having a high reflectance (image B ′), the radiation of the object B is not observed, and the radiation is reflected from the surrounding objects (that is, a large change in shading of the image is observed). When observed in a state, as shown in FIG.

  Therefore, it is possible to determine whether or not the object is a reflection object by detecting the time variation of the radiation amount observed in the radiation intensity image and obtaining the deviation.

  The image calculation unit 300 observes a temporal change as shown in FIG. 4 from the radiation image as shown in FIG. 3, calculates a variation deviation of the radiation amount, and generates a radiation amount fluctuation deviation image as shown in FIG. . In FIG. 5, the image A ′ of the object A (electric pole) is light and the image B ′ of the object B (vehicle) is dark.

  The object recognition processing unit 500 detects that an object having a large reflection characteristic exists in a spatial region having a deviation equal to or larger than a predetermined threshold from the radiation amount variation deviation image output from the image calculation unit 300. In the corresponding spatial region, By excluding the radiation object information output from the radiation amount calculation unit 400, a recognition process for separating the radiation object and the reflection object is performed, and the identified object information is transmitted to the vehicle control device 600 (vehicle control CPU or the like). Output. It is also possible to output object information obtained by extracting only radiation objects and object information obtained by extracting only reflection objects.

  FIG. 6 shows an operation flow of the object identification device according to the present embodiment.

  First, the radiation from the objects A and B in front of the object identification device 100 is observed by the radio wave imaging unit 200 to acquire a radio wave radiation image (step S1), and the radio wave radiation image is calculated with the image calculation unit 300 and the radiation amount calculation. Output to the unit 400.

  The image calculation unit 300 stores radio wave radiation images as an array (step S4) and checks whether a predetermined number of radio wave radiation images are stored (step S5). When a predetermined number of radio wave radiation images are stored, a variation deviation is calculated for each pixel, and a deviation image that displays only pixels where a deviation equal to or greater than a threshold is observed is generated (step S6). (If a predetermined number of radio wave radiation images are not stored, the process proceeds to step S7 without generating a deviation image.)

  On the other hand, the radiation amount calculation unit 400 classifies regions by the intensity of the radiation amount of the radio wave radiation image acquired in step S1 (step S2), the radiation amount for each classified region, and the position and size of the object. Are extracted and output (step S3).

  In the object recognition processing unit 500, it is determined whether or not there is a region that shows a variation greater than a threshold in the intensity deviation image from the deviation image from the image calculation unit 300 and the radiator information from the radiation amount calculation unit 400 (step S7) If present, the region in the intensity deviation image is excluded from the radiation image (step S8). If not present, the radiation object is determined from the radiation amount information (step S9). And a vehicle control signal is output with respect to the vehicle control apparatus 600 after the process by step S8 or step S9 (step S10).

  As described above, in this embodiment, by adding a function of observing the variation of the radiation amount to the radio wave imaging unit 200 and performing the recognition by separating the radiation object and the reflection object, more accurate object recognition is possible. Become.

  When the object to be observed is a three-dimensional object such as an automobile, a portion having a small surface curvature such as a corner of the vehicle body and a portion having a large surface curvature are mixed. When this is observed by the radio wave imaging unit 200, as shown in FIG. 7, in a portion with a small curvature, peripheral radiation in a narrow range is observed, so that the intensity fluctuation is small (lightness is thin), but the surface such as the corner of the vehicle body In the part with a large curvature, the radiation variation deviation is observed to be larger (darker and darker) than the other parts. Accordingly, in the object recognition processing unit 500, the threshold value for determining the variation deviation of the radiation amount variation deviation image output from the image calculation unit 300 is set in two stages, and in the region where it is determined that the radiation amount variation exists with the first threshold value. Then, a part having a larger variation is specified with a second threshold value (second predetermined value) larger than the first threshold value (predetermined value). Thereby, the edge part of a reflective object can be detected and it becomes possible to perform more stable shape identification in the identification of a reflective object.

  FIG. 8 shows an operation flow for detecting a three-dimensional object.

  This is an operation of extracting a part having a larger variation from the deviation image generated by the image calculation unit 300 using the second threshold value. In FIG. 8, steps S1 to S10 are the same as the operation flow of FIG.

  It is determined whether or not there is a variation deviation exceeding the second threshold in the deviation image generated in step S6 (step S11). If there is a variation deviation exceeding the second threshold, a three-dimensional object flag is added to the region where the variation deviation exists surrounded by the part (step S12), and if there is no variation deviation exceeding the second threshold, the variation deviation. A plane object flag is added to the area (step S13). And a result is output to vehicle control CPU (step S10).

  The above operation has been described on the premise that the variation deviation of the radiation intensity is observed when the vehicle equipped with the object identification device and the preceding vehicle to be observed have a relative speed. The same effect can be obtained in the same manner even in a situation where the vehicle speed is not zero or a situation where the ground vehicle speed of the host vehicle is not zero.

  In addition, since the radio wave imaging apparatus does not radiate electromagnetic waves, there is no limitation on the observation band to be used. However, in order to observe objects up to a longer distance, the influence of atmospheric propagation attenuation is low, or the band is 90 to 100 GHz. It is preferable to set the band.

  As described above, according to the present embodiment, using a radio wave imaging apparatus that observes radiation from an object in the radio wave region, the reflection physical property of the object observed from the temporal variation of the radiation image is determined, and the radiation object and the reflection object are detected. Recognition processing can be performed, and object identification independent of surface properties and shapes can be performed.

  The first embodiment is a technique that uses a passive radiation amount observing means to prevent detection of a metal region having reflectivity “1” and emissivity “0” and false detection due to reflection on the metal surface.

  In the passive method, the metal area occupied on the detection screen can be known, but it cannot be determined whether the metal area is a small signboard that exists nearby or a large vehicle that exists far away. Therefore, in order to make the information of the metal area detected in the first embodiment more useful, the present embodiment further includes a built-in or separate radar device up to the metal area detected in the first embodiment. A function for measuring the distance and calculating the projected area of the object is provided.

  FIG. 9 is a block diagram of the object identification device according to this embodiment. In the present embodiment, in addition to the configuration of the first embodiment, a radio wave radar device 700 and an object area calculation unit 800 are provided.

  The radio wave radar apparatus 700 includes a transmission antenna 701, an oscillator 702, a power distributor 703, a reception antenna 704, a mixer unit 705, and an FFT processing calculation unit 706. The frequency-modulated transmission signal from the oscillator 702 is distributed and output to the mixer unit 705 and the transmission antenna 701 by the power distributor 703. The transmission signal transmitted from the transmission antenna 701 is reflected by the object B, and the reflected signal is detected by the reception antenna 704. The detected reflected signal is multiplied by the transmission signal by the mixer unit 705, and an IF signal having a differential frequency for transmission and reception is output. The FFT operation processing unit 706 detects the amount of time delay required for propagation by performing frequency analysis of the IF signal, and outputs the distance to the object B.

  The object area calculation unit 800 calculates the projection area of the object B using the metal area detected in the first embodiment and the distance output from the radio wave radar device 700 and outputs the result to the object recognition processing unit 500. .

  In the object recognition processing unit 500, in addition to the information on the radiation object (object A) and the reflection object (object B) obtained in the first embodiment, information on the projected area of the reflection object (object B) is used to reflect the object. The identification of the object (object B) can be determined more accurately.

  In the present embodiment, the radio wave radar apparatus 700 constitutes a radar apparatus, and the object area calculation unit 800 constitutes a projected area calculation unit.

  FIG. 10 shows an operation flow of the object identification device according to this embodiment. Here, the differences in operation from the first embodiment will be mainly described. After acquiring the radio wave radiation image by the radio wave imaging unit 200 (step S1), electromagnetic waves are transmitted and received forward from the radio wave radar device 700, and the distance to the front object is measured by the FFT processing calculation unit 706 ( In step S21, the measurement result is output to the object area calculation unit 800 (step S22).

  The object area calculation unit 800 determines whether or not the area information of the reflective object input from the object identification device 100 matches the orientation information of the reflective object input from the radar device 700 (step S23). First, the projected area of the reflecting object is calculated from the area information of the variation deviation image and the distance information from the radar (step S24), and the calculation result is output to the vehicle control device 600. If not, only radar information is output to the vehicle control device 600 (step S25).

  In the description of the operation flow, the output signal from the radio wave radar device 700 is alternately performed so as not to affect the radio wave region observed by the radio wave imaging unit 200. However, the output signal is used across the frequency region. For example, they may be operated in parallel. Also. Although the radio wave radar device 700 is used as the radar device, an optical radar using a near infrared laser that does not affect the radio wave imaging unit 200 may be used.

  As described above, according to the present embodiment, in addition to the process of observing the time variation in the radiation amount observation, the distance information in the radar apparatus is used, so that an object having a large reflectance and an object having a large radiation ratio are mixed. Even in the situation, it is possible to more accurately identify the reflective object by detecting the projected area of the reflective object without erroneously detecting a difference in physical properties.

  Each of the embodiments described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in each of the embodiments is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

It is a block block diagram of the object identification device by Example 1. It is a figure which shows the structure of the array element in a radio wave imaging part. Shows the image of the radio emission image of the radiation object and reflecting object to be detected by the radio wave imaging unit, figure, FIG. In (b) the time t ₀ + Delta] t in (a) the time t _0, (c) the time It is a figure in t ₀ + 2Δt. It is a figure explaining the time change of the radio wave radiation | emission of the radiation | emission object and reflection object in FIG. It is an image figure of the fluctuation deviation image at the time of observing a solid thing. It is an operation | movement flowchart of the object identification apparatus by Example 1. FIG. It is an image figure of the fluctuation deviation image at the time of observing a solid thing. It is an operation | movement flowchart which detects that it is a solid object. It is a block block diagram of the object identification device by Example 2. It is an operation | movement flowchart of the object identification device by Example 2.

Explanation of symbols

10 Object A (radiating object)
11 Object B (reflective object)
DESCRIPTION OF SYMBOLS 100 Object identification apparatus 200 Radio wave imaging part 201 Dielectric lens 202 Imaging array part 203 Signal conversion part 205 Reception antenna 206 Detector 207 Signal amplifier 300 Image calculating part 301 Radio wave image memory | storage part 302 Spatial arithmetic processing part 400 Radiation amount calculating part 500 Object Recognition processing unit 600 Vehicle control device 700 Radio wave radar device 701 Transmitting antenna 702 Oscillator 703 Power distributor 704 Receiving antenna 705 Mixer unit 706 FFT processing unit 800 Object area calculation unit

Claims (5)

Radio wave intensity image generation means for detecting the amount of radiation in the radio wave area radiated from the object and generating a radio wave radiation intensity image based on the detection result, and radio wave radiation intensity generated by the radio wave radiation intensity image generation means An image calculating means for storing images in time series and comparing a plurality of stored radio wave radiation intensity images to calculate a time series deviation of the radio wave radiation intensity images, and generated by the radio wave radiation intensity image generating means Recognition processing means for recognizing the object based on the radio wave radiation intensity image and time-series deviation information calculated by the image calculation means,
The recognition processing unit determines that a reflective object having a high reflectance exists in a portion where the deviation in time series is larger than a predetermined value in the radio wave radiation intensity image, and excludes the reflective object from the radio wave radiation intensity image. Thus, an object identification apparatus that distinguishes between a reflective object and a radiation object having a high emissivity. A second predetermined value that is larger than the predetermined value is set,
The recognition processing means determines that there is a three-dimensional object composed of a material having a large reflection characteristic in a portion of the radio wave radiation intensity image where the time-series deviation is larger than the second predetermined value. The object identification device according to claim 1.   The object recognition apparatus according to claim 1, wherein the recognition processing unit does not apply object recognition based on a radio wave radiation amount in an area where it is determined that a reflective object is present. A radar device for detecting the distance to the reflective object;
A projected area calculating means for calculating a projected area of the reflecting object from a size on the radio wave radiation intensity image;
The recognition processing means determines the type of the reflecting object from the distance to the reflecting object detected by the radar device and the size of the projected area at the distance calculated by the projected area calculating means. The object identification device according to claim 1. 5. The object identification device according to claim 1, wherein the radio wave radiation intensity image generation unit detects a radio wave in a 30 to 40 GHz band or a 90 to 100 GHz band radiated from an object.

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