JP5845858B2 - Object detection apparatus and object detection method - Google Patents

Description

  The present invention relates to an object detection apparatus and an object detection method, and more particularly to an object detection apparatus and an object detection method for detecting an object using a two-dimensional image.

  “Imaging spectrometer”, [online], [searched April 27, 2011], Internet <URL: http://www.ryoden.co.jp/fa/system/fa28_4.html> (Non-patent document 1 ) Discloses instruments used in the fields of industrial and research spectroscopic analysis. That is, in the imaging spectrometer, the light at each point in the line-shaped area is dispersed by a special prism and a grating structure. Then, by combining an ordinary lens, a black and white two-dimensional camera, and an imaging spectrometer, an imaging spectrometer capable of detecting the wavelength distribution of the line area is realized. Light intensity data is obtained for 256 to 1024 wavelengths at each point in the line area.

“Imaging Spectrometer”, [online], [Search April 27, 2011], Internet <URL: http://www.ryoden.co.jp/fa/system/fa28_4.html>

  When trying to analyze a planar area using the imaging spectrometer described in Non-Patent Document 1, the analysis object or imaging spectrometer is moved, and the position of the line area to be measured is changed repeatedly. Acquire a spectrum. For this reason, the imaging spectroscope described in Non-Patent Document 1 is not suitable for an application for analyzing a wide area and an application for which an analysis of a planar area needs to be performed at high speed.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an object detection apparatus and an object detection method capable of detecting an object in a wider range and at a higher speed.

  In order to solve the above-described problem, an object detection apparatus according to an aspect of the present invention includes an imaging unit for imaging a two-dimensional image with respect to a plurality of wavelength bands selected in advance according to physical properties of a detection target, A detection unit for detecting a substance in each pixel of the two-dimensional image, and the imaging unit includes an imaging element unit having a plurality of imaging elements for outputting an electric signal indicating the intensity of received light, and a receiving unit. Wavelength light having a plurality of wavelength selection filters for transmitting the light in the plurality of wavelength bands and irradiating the image sensor part, and reflecting the received light to the wavelength filter part. And a reflection unit that can switch the wavelength selection filter to which the reflected light is irradiated by changing the optical path of the reflected light.

  When a detection target such as a person is recognized by its shape, for example, data of several tens of pixels is required to express the shape. When detecting a substance in each pixel of a two-dimensional image, if there is a detection result of the substance of about one pixel or several pixels by appropriately selecting the wavelength band used for the detection, the detection target from the background of the two-dimensional image The inventors of the present application have found that and the position can be extracted. In other words, even if the imaging range is wide, it is possible to ensure the accuracy of specifying the detection target and its position. Since it does not depend on the shape, it is possible to specify the target even when the entire target cannot be detected. There is little need to change the focal length in order to increase the number of pixels used for recognizing the detection target, and the movement of the detection target can be easily tracked. In addition, by selecting the wavelength band according to the physical property of the detection target, it becomes unnecessary to analyze the images of each of the many wavelength bands, so that the planar area can be analyzed at high speed. In addition, a two-dimensional image corresponding to the transmission wavelength band can be obtained, and various substances can be detected by appropriately selecting the transmission wavelength band in the wavelength filter unit.

  Preferably, the detection unit detects a substance in the pixel based on an evaluation value calculated by combining a part or all of the intensity values for the plurality of wavelength bands in one pixel.

  With such a configuration, it is possible to appropriately evaluate the characteristics of the detection target and the like with respect to the wavelength without obtaining images in a large number of wavelength bands, and the target detection process can be performed more accurately. In addition to the evaluation value of the target pixel itself, the intensity value, the evaluation value, and the substance discrimination result of the surrounding pixels can be used for detecting the substance in the target pixel.

  Preferably, at least some of the plurality of wavelength bands are included in the infrared region.

  With such a configuration, it is possible to more appropriately evaluate the substance contained in the detection target or its background.

  Preferably, the imaging element unit is divided into a plurality of regions for receiving light of the plurality of wavelength bands, and the wavelength selection filter transmits light of the corresponding wavelength band to the corresponding region. Irradiate.

  With such a configuration, the configuration of the wavelength filter unit can be simplified as compared with a configuration in which, for example, a wavelength selection filter for each imaging element is provided in the wavelength filter unit.

  As one embodiment, the pixel includes a plurality of subpixels corresponding to the plurality of wavelength bands, and each of the subpixels includes a wavelength selection filter for selecting a corresponding wavelength band, and the wavelength selection filter. And an imaging device for receiving the transmitted light.

  In order to solve the above-described problem, an object detection method according to an aspect of the present invention includes a step of capturing a two-dimensional image with respect to a plurality of wavelength bands selected in advance according to a physical property of a detection target; Detecting the substance in each pixel of the pixel, and in the step of capturing the two-dimensional image, the wavelength selection of the irradiation destination of the reflected light by reflecting the received light and changing the optical path of the reflected light The filters are switched, and the light of the plurality of wavelength bands is transmitted through the wavelength selection filter and irradiated to the plurality of imaging elements.

  According to the present invention, it is possible to detect an object in a wider range and at a higher speed.

It is a functional block diagram of the object detection apparatus which concerns on embodiment of this invention. It is a figure which shows notionally the imaging | photography of the detection target by the target detection apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the light-receiving part in the target detection apparatus which concerns on embodiment of this invention. It is a figure which shows notionally the image processing by the light-receiving part in the target detection apparatus which concerns on embodiment of this invention. It is a figure which shows the reference example of the permeation | transmission wavelength band of the wavelength filter part in the light-receiving part of a target detection apparatus. It is a figure which shows the object detection operation | movement by the object detection apparatus which concerns on embodiment of this invention. It is a figure which shows the object detection operation | movement by the object detection apparatus which concerns on embodiment of this invention. It is a figure which shows the example of a structure of the light-receiving part in the target detection apparatus which concerns on embodiment of this invention. It is a figure which shows the other structural example of a target detection apparatus. It is the flowchart which determined the operation | movement procedure at the time of the target detection apparatus which concerns on another structural example performing a target detection process. It is a functional block diagram of the detection part in the object detection apparatus which concerns on another structural example. It is the flowchart which defined an example of the operation | movement procedure at the time of the determination part in the detection part of the target detection apparatus which concerns on another structural example performing a substance determination process.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a functional block diagram of an object detection apparatus according to an embodiment of the present invention. The target detection device 101 can be used for a monitoring device, and further for detecting an intruder in a monitoring area and capturing an image of the intruder.

  With reference to FIG. 1, the target detection apparatus 101 includes an imaging unit 11 and a detection unit 12. The imaging unit 11 includes an optical system 21 and a light receiving unit 22.

  The imaging unit 11 captures a two-dimensional image for a plurality of wavelength bands selected in advance according to the physical property of the detection target. A hyperspectral (HS) camera can be used for this imaging. In the present embodiment, the HS camera captures electromagnetic waves in a target wavelength range including at least the near infrared range. The target wavelength range is, for example, 900 nm to 1800 nm, and includes the plurality of wavelength bands selected in advance. These wavelength bands are selected, for example, up to 10 wavelength bands.

  Here, the reason why the number of wavelength bands to be selected is 10 or less is that if it is larger than that, it becomes difficult to discriminate substances at a high speed (almost real time) with a constant resolution, which is not suitable for monitoring applications. In addition, even if the number of wavelength bands to be selected is 10 or less, the number of substances to be identified and the accuracy can be sufficiently secured. In consideration of practicality of a monitoring device or the like, it is preferable to select the 2-6 wavelength band, and it is more preferable to select the 3-5 wavelength band.

  The HS camera is installed in a diagonally downward direction at a place where the target area can be photographed, for example, at the top of a pillar near the target area. When the target area cannot cover the entire monitoring area or when a blind spot occurs, a plurality of HS cameras can be installed.

  In the imaging unit 11, the light receiving unit 22 includes a plurality of pixels P. The plurality of pixels P each output an electric signal indicating the reception intensity of the electromagnetic wave in each selected wavelength band.

  The light receiving unit 22 captures a two-dimensional image of the target area using an electrical signal output from the plurality of pixels P.

  In the present embodiment, the detection unit 12 determines a substance for each pixel P based on the two-dimensional image captured by the light receiving unit 22. The detection unit 12 only needs to be able to determine a substance according to the detection target of the target detection apparatus 101. When the target detection apparatus 101 is used as a monitoring apparatus, it is only necessary to be able to determine, for example, human skin and other substances. The substance determination is not limited to each pixel P but may be performed for each pixel group, and may be performed for each pixel group in a partial region and for each pixel group in the remaining region.

  FIG. 2 is a diagram conceptually illustrating imaging of a detection target by the target detection device according to the embodiment of the present invention.

  Referring to FIG. 2, the optical system 21 receives light from the monitoring area and irradiates the light receiving unit 22.

  The light receiving unit 22 creates a two-dimensional image based on the light (infrared rays here) received from the optical system 21. A target TG, here a person, is detected based on the two-dimensional image, and an image of the target TG in the monitoring area is taken.

  FIG. 3 is a diagram illustrating a configuration of the light receiving unit in the target detection device according to the embodiment of the present invention.

  With reference to FIG. 3, the light receiving unit 22 includes a wavelength filter unit 31 and an imaging element unit 32.

  The image sensor section 32 includes a plurality of image sensors R arranged in a matrix. The imaging element R is a light receiving element using, for example, InGaAs. The image sensor R outputs an electrical signal indicating the intensity of the received light.

  The wavelength filter unit 31 includes a plurality of wavelength selection filters F arranged in a lattice shape. The wavelength selection filter F is provided corresponding to the image sensor R, and transmits light in the corresponding wavelength band among the plurality of wavelength bands for substance discrimination and irradiates the corresponding image sensor R.

  Specifically, the wavelength filter unit 31 that is aligned with each image sensor R in the image sensor unit 32 is disposed immediately above the image sensor unit 32. The wavelength filter unit 31 is integrated with the image sensor unit 32, for example. The vertical and horizontal sizes of the light receiving surface of the wavelength filter unit 31 substantially coincide with the light receiving surface of the imaging element unit 32. Each image sensor R outputs an electrical signal indicating the intensity of light in the wavelength band transmitted by the corresponding wavelength selection filter F.

  FIG. 4 is a diagram conceptually illustrating image processing by the light receiving unit in the target detection device according to the embodiment of the present invention.

  FIG. 5 is a diagram illustrating a reference example of the transmission wavelength band of the wavelength filter unit in the light receiving unit of the target detection device.

  Referring to FIG. 5, wavelength filter unit 31 is provided with a plurality of wavelength selection filters F that transmit light in a plurality of wavelength bands for substance discrimination and are adjacent to each other. In the present embodiment, a set of these six wavelength selection filters constitutes a wavelength selection filter unit for one pixel. Each wavelength selection filter constitutes a wavelength selection filter unit for one subpixel.

  It is preferable that at least some of the plurality of wavelength bands are included in the infrared region, and further in the near infrared region. More specifically, the wavelength filter unit 31 includes a plurality of sets of wavelength selection filters that respectively transmit light having wavelengths of 940 nm band, 1100 nm band, 1200 nm band, 1300 nm band, 1500 nm band, and 1600 nm band, for example. Each wavelength band may have a width of ± several tens of nm with respect to the center wavelength, for example.

  Here, the wavelength filter unit 31 having different transmission characteristics in a mosaic shape can be created by applying, for example, a photonic crystal. This filter plate is arranged according to the image sensor. As a method of providing the wavelength selection filter F for each image sensor R, for example, a method similar to an RGB filter for CMOS (Complementary Metal Oxide Semiconductor) or CCD (Charge Coupled Device) can be considered.

  The pixel P includes a plurality of subpixels SP respectively corresponding to a plurality of wavelengths. In the example shown in FIGS. 4 and 5, as described above, one pixel P is constituted by the six sub-pixels SP, and calculation is performed for each pixel P to determine the substance of the image in the pixel P. Then, by displaying the pixels P determined to be human skin separately from the other pixels P, for example, a human-type spectrum image can be obtained.

  The detection unit 12 detects a substance in the pixel P based on an evaluation value calculated by combining some or all of intensity values for a plurality of wavelength bands in one pixel P. More specifically, the detection unit 12 compares the intensities of the plurality of selection lights in the pixel P in the two-dimensional image, and determines the substance in the pixel P based on the comparison result. The detection unit 12 determines the substance for each pixel P based on the electrical signals output from the plurality of light receiving elements R corresponding to the pixel P.

  6 and 7 are diagrams illustrating an object detection operation by the object detection device according to the embodiment of the present invention.

  Referring to FIGS. 6 and 7, in order to determine that a person is a person from a shape, such as pattern matching, at least several tens of pixels are required to represent the shape on an image, and there is a camera. If movement in the direction is also determined, more pixels are required. This is because when an intruder approaches the camera, the object will not appear in the image due to a difference in shape unless the object moves considerably. In FIG. 6, AR is a pixel area required for detecting a human in a general recognition process of a visible image. In the example of the visible image in FIG. 6, since the size on the human image is equivalent to the area AR, it can be recognized as a human by image processing. On the other hand, in the example of the visible image in FIG. 7, since the size on the human image is smaller than the area AR, it is difficult to recognize the human being from the shape, and the recognition accuracy is lowered. In order to accurately recognize a human at this distance, it is necessary to zoom in on the target candidate and increase the size of the candidate image.

  On the other hand, the object detection apparatus 101 uses a two-dimensional spectrum image. In this spectral image, there is no need for shape to recognize a person. For this reason, as shown in FIG. 7, even when the distance between the optical system 21 and the monitoring area is 100 m, if there is an image IMG of one to several pixels, the target is selectively extracted from the background. be able to. Since it does not depend on the shape, the entire object need not be included in the image, and the presence of the object can be specified from the determination result for a part of the object. For this reason, if the resolution is equivalent to that of the visible image, the presence of a farther object can be detected, and the need for zooming up for object recognition is reduced.

  As described above, the target detection apparatus 101 can recognize the presence of a target from the detection results of a small number of pixels, and thus can perform target detection more accurately over a wide range.

  Further, movement in the camera direction can be detected by a slight increase in the number of pixels accompanying the movement. In FIG. 6, the image IMG is illustrated with three pixels for simplicity, but in reality, the image IMG is configured with more pixels, and the movement is detected before a person approaches 100 m to 25 m. Can do. If the number of pixels corresponding to the image IMG increases by about several pixels as the object moves in the camera direction, the movement can be detected and the object can be tracked.

  In a general recognition process for a visible image, a difference between the previous and subsequent frames is calculated in order to detect the amount of movement of the detection target. At this time, in order to recognize the difference in the size of the detection target between the frames, an amount of information that can be recognized that the same shape object has become large is necessary. The above differences are necessary. For this reason, in the configuration using a normal wide-angle camera, when the detection target gradually approaches, it is difficult to detect the amount of movement of the detection target.

  On the other hand, since the target detection apparatus 101 does not depend on the shape, it is possible to recognize a difference in the size of the detection target between frames by increasing or decreasing a small number of pixels. Thereby, even when the detection target approaches gradually, the detection target can be accurately detected.

  In addition, when a zoom camera is used to secure an amount of information for detecting the amount of movement of a detection target in normal image processing, it becomes difficult to track an intruder because the field of view is narrowed.

  In contrast, the object detection apparatus 101 can recognize a difference in the size of the detection object between frames with a small number of pixels, and thus can perform wide-angle imaging. This makes it possible to easily track an intruder without moving the camera lens.

  Furthermore, in the target detection device according to the embodiment of the present invention, the imaging unit 11 captures a two-dimensional image for a plurality of bands of wavelengths selected in advance according to the physical property of the detection target, as described above. Since it is not necessary to perform analysis processing on each of the two-dimensional images having a large number of wavelengths, it is possible to detect an object at a higher speed over a wide range.

  Furthermore, in the target detection device according to the embodiment of the present invention, the detection unit 12 uses the pixel based on the evaluation value calculated by combining some or all of the intensity values for a plurality of wavelengths in one pixel P. The substance in P is detected.

  With such a configuration, it is possible to more appropriately evaluate the detection target and the substances contained in the background. In addition to the evaluation value of the pixel itself, the intensity value, the evaluation value, and the substance discrimination result of the surrounding pixels can be used for detecting the substance in one pixel. For example, the intensity values of a plurality of pixels may be averaged, and the evaluation value may be calculated from the average value.

  In the target detection device according to the embodiment of the present invention, at least a part of the plurality of wavelength bands is included in the infrared region.

  With such a configuration, an appropriate wavelength band can be selected as the selection light, and substance discrimination can be performed more accurately.

  In the target detection device, as described above, the pixel P can include a plurality of sub-pixels SP respectively corresponding to a plurality of wavelength bands. However, the object detection apparatus according to the embodiment of the present invention employs different filter configurations.

  FIG. 8 is a diagram illustrating an example of the configuration of the light receiving unit in the target detection device according to the embodiment of the present invention.

  Referring to FIG. 8, the light receiving unit 22 includes a wavelength filter unit 31, an image sensor unit 32, and a reflection unit 33. The wavelength filter unit 31 and the imaging element unit 32 are integrated, for example.

  The image sensor unit 32 includes a plurality of image sensors for outputting an electrical signal indicating the intensity of received light.

  The wavelength filter unit 31 transmits a plurality of wavelength bands λ1 to λ4 for substance discrimination among the light received from the optical system 21, and irradiates the image sensor unit 32 with a plurality of wavelength selection filters FL1 to FL1. Has FL4.

  The reflection unit 33 reflects the light received from the monitoring area and irradiates the wavelength filter unit 31. The reflection unit 33 can switch the wavelength selection filter F to which the reflected light is irradiated by changing the optical path of the reflected light. Specifically, the reflecting unit 33 is a reflecting plate provided with an optical path changing mechanism. This optical path changing mechanism is realized using, for example, MEMS (Micro Electro Mechanical Systems).

  More specifically, the image sensor section 32 is divided into a plurality of regions for receiving light in a plurality of wavelength bands for substance discrimination. The imaging element unit 32 is divided into, for example, four parts, and transmits light in different wavelength bands for each divided region.

  The wavelength selection filters FL <b> 1 to FL <b> 4 transmit light in the corresponding wavelength band and irradiate the corresponding region in the imaging element unit 32.

  With such a configuration, a two-dimensional image corresponding to the transmission wavelength band can be obtained for each of the regions in the imaging element unit 32. By appropriately selecting the transmission wavelength band in the wavelength filter unit 31, various substances can be detected.

  In addition, in the imaging element unit 32, the light from the optical system 21 is irradiated onto a reflection plate that can change the reflection destination of the light, and the reflected light is sequentially irradiated to each divided wavelength region in the imaging element unit 32. A two-dimensional image corresponding to the transmission wavelength band can be obtained for each wavelength region. Further, for example, the configuration of the wavelength filter unit can be simplified as compared with a configuration in which the wavelength selection filter for each imaging element is provided in the wavelength filter unit.

  In FIG. 8, the imaging element unit 32 is configured to be divided into each wavelength region, but is not limited thereto. There may be a configuration in which a plurality of imaging element units are provided, and each imaging element unit is irradiated with light of a different wavelength band from the reflection unit 33.

  In the above-described embodiment, the target detection device is used alone as a monitoring device, but the present invention is not limited to this, and for example, it can be combined with a visible telephoto camera.

  FIG. 9 is a diagram illustrating another configuration example of the target detection apparatus.

  Referring to FIG. 9, target detection apparatus 101 according to the present embodiment includes HS camera 51, telephoto camera 52, and control apparatus 53.

  The control device 53 detects an intruder based on the spectrum image captured by the HS camera 51 and automatically notifies the user, or controls the telephoto camera 52 to capture an enlarged visible image of the intruder. can do.

  More specifically, the telephoto camera 52 is, for example, a PTZ camera equipped with a pan / tilt function and a zoom function. The HS camera 51 and the telephoto camera 52 perform shooting by receiving reflected sunlight from the monitoring area.

  In this example, the telephoto camera 52 is provided for the user to visually confirm the intruder immediately or after the fact, and is not necessary for the purpose of detecting the intruder. Further, it is not essential to automatically track the intruder by the telephoto camera 52, and the user may manually operate the telephoto camera 52.

  In addition, the object detection apparatus 101 may be configured to further include a light irradiator that irradiates halogen light or infrared light toward the monitoring area in order to enable photographing at night.

  FIG. 10 is a flowchart defining an operation procedure when the target detection apparatus according to the example of FIG. 9 performs the target detection process. Hereinafter, an example using five wavelength bands will be described.

  Referring to FIG. 10, first, the HS camera 51 captures the entire monitoring area. This photographing is performed continuously or intermittently (step S1).

  Next, the light receiving unit 22 creates a two-dimensional image of each wavelength band of 1100 nm band, 1200 nm band, 1300 nm band, 1500 nm band, and 1600 nm band. For example, the light receiving unit 22 reflects the light received from the monitoring area and changes the wavelength selection filter to which the reflected light is irradiated by changing the optical path of the reflected light. Then, light in a plurality of wavelength bands is transmitted through the wavelength selection filter and irradiated to the plurality of image sensors (step S2).

  Next, the detection unit 12 determines a substance in each pixel P of the two-dimensional image based on the two-dimensional image captured by the light receiving unit 22 (step S3).

  When notifying a user of target detection automatically, next, the detection part 12 specifies the detection target in an monitoring area, here an intruder, and its position based on a discrimination | determination result (step S4). This specification can be performed based on whether or not “human skin” is included in the discrimination result of the substance in each pixel, for example. If “human skin” is included in the substance discrimination result for a certain pixel, the pixel position may be specified as the position of the intruder, or the intruder may be determined from a combination of substance discrimination results for a plurality of pixels. You may specify. For example, when a pixel discrimination result of “human skin” and a “fiber” pixel are adjacent, the position of the pixel group may be specified as the position of the intruder. The position of the pixel group can be determined by the center of gravity of the constituent pixels. Even if the entire body of the intruder is not detected, it may be determined that there is an intruder if there is one pixel or several pixels of “human skin”.

  The detection unit 12 can also individually specify detection targets in the monitoring area. For example, when the intruder A is wearing a covering surface and the intruder B is not wearing a covering surface, the substance of the intruder A's face is a fiber, while the substance of the intruder B's face is It becomes human skin. Moreover, when the materials of the clothes worn by the intruder A and the intruder B are different, the substances of the body parts of the intruders A and B are different from each other. The detection unit 12 can also distinguish the intruders A and B individually based on the difference in substances.

  If an intruder is detected by the detection unit 12 (YES in step S4), the telephoto camera 52 is controlled to capture an enlarged image of the intruder (step S5).

  More specifically, photographing by the telephoto camera 12 is performed with the position of the intruder specified by the detection unit 12, that is, the pixel P detected by the intruder as the center of the field of view. If the attachment angle of the HS camera is determined, the approximate distance to the object can be estimated, and the focal length can be adjusted accordingly. The photographed enlarged image is recorded in, for example, the target detection device 101 and displayed on a display unit such as a liquid crystal display installed in a remote monitoring center. The object detection device 101 can also warn the intruder by sound or light in parallel with the intruder's photographing by the telephoto camera 12.

  On the other hand, when the intruder is not detected by the detection unit 12 (NO in step S4), the monitoring area is shot, the spectrum image is created, the substance is determined, and the intruder is detected again, and the monitoring is continued. (Steps S1 to S4).

  FIG. 11 is a functional block diagram of a detection unit in the target detection apparatus according to the example of FIG.

  Referring to FIG. 11, in this example, detection unit 12 includes a reflectance calculation unit 91, a normalization index calculation unit 92, a secondary differential value calculation unit 93, and a determination unit 94.

  The detection unit 12 can calculate the reflectance of the plurality of selection lights in the pixel P of the two-dimensional image, and can determine the substance in the pixel P of the two-dimensional image based on the calculated reflectance of the plurality of selection lights. .

  More specifically, the reflectance calculation unit 91 is based on the two-dimensional image received from the light-receiving unit 22 and uses the wavelength components of the 1100 nm band, 1200 nm band, 1300 nm band, 1500 nm band, and 1600 nm band in the pixel P of the two-dimensional image. The reflectances R1100, R1200, R1300, R1500, and R1600 are calculated. When irradiating infrared light, the reflectance can be calculated from the emission luminance of the infrared light source and the intensity value of each pixel. When using natural light, the reflectance may be calculated separately by measuring the illuminance.

The normalization index calculation unit 92 uses the reflectances R1100, R1200, R1300, R1500, and R1600 calculated by the reflectance calculation unit 91 to calculate normalization indexes ND1 to ND5 defined by the following expressions.
ND1 = (R1500-R1200) / (R1500 + R1200)
ND2 = (R1300-R1200) / (R1300 + R1200)
ND3 = (R1600-R1300) / (R1600 + R1300)
ND4 = (R1300-R1100) / (R1300 + R1100)
ND5 = (R1500-R1300) / (R1500 + R1300)

The secondary differential value calculation unit 93 calculates the secondary differential value of the function of the reflectance and wavelength. Specifically, the secondary differential value calculation unit 93 uses the reflectances R1100, R1200, R1300, R1500, and R1600 calculated by the reflectance calculation unit 91, and uses the approximate two defined by the following formula. Next derivative values der1 and der2 are calculated. der1 is a secondary difference by R1200, R1300, and R1500. Also, der2 is a secondary difference by R1100, R1200, R1500. der1 and der2 are represented by the following equations.
der1 = [{(R1500-R1300) / (R1500 + R1300)} / 200]-[{(R1300-R1200) / (R1300 + R1200)} / 100]
der2 = [{(R1500-R1200) / (R1500 + R1200)} / 300]-[{(R1200-R1100) / (R1200 + R1100)} / 100]

  The determination unit 94 determines a substance in the pixel P of the two-dimensional image based on the reflectances R1100, R1200, R1300, R1500, R1600, the normalization indices ND1 to ND4, and the second derivative values der1 and der2.

  FIG. 12 is a flowchart that defines an example of an operation procedure when the determination unit in the detection unit of the target detection device according to the embodiment of the present invention performs the substance determination process.

  Referring to FIG. 12, first, determination unit 94 determines whether or not the values of reflectances R1100, R1200, R1300, R1500, and R1600 are approximately zero. For example, when the reflectance value is less than a predetermined value (for example, 0.02), it is determined that the reflectance is approximately 0, and the reflectance value is greater than or equal to the predetermined value. Is determined not to be approximately zero. Determination unit 94 determines that glass is present when the values of reflectances R1100, R1200, R1300, R1500, and R1600 are all approximately 0 (NO in step S11).

  On the other hand, when any one of the reflectances R1100, R1200, R1300, R1500, and R1600 is not approximately 0 (YES in step S11), the determination unit 94 adds the normalized indices ND5 and ND3 to the secondary differential value der1. It is determined whether the value “der1 × (ND5 + ND3)” multiplied by the sum is greater than 0 (step S12).

  If “der1 × (ND5 + ND3)” is greater than 0 (YES in step S12), the determination unit 94 determines whether the value of the normalized index ND1 is greater than 0 (step S13).

  When the value of the normalization index ND1 is greater than 0 (YES in step S13), the determination unit 94 determines that there is an animal or fabric.

  On the other hand, when the value of the normalization index ND1 is 0 or less (NO in step S13), the determination unit 94 determines whether the value of the secondary differential value der2 is greater than 0 (step S14).

  The determination unit 94 determines that human skin exists when the value of the secondary differential value der2 is greater than 0 (YES in step S14).

  On the other hand, the determination part 94 determines with a plant existing, when the value of the secondary differential value der2 is 0 or less (it is NO at step S14).

  If the value of “der1 × (ND5 + ND3)” is 0 or less (NO in step S12), the determination unit 94 determines whether the value of the normalization index ND3 is greater than 0 (step S15). ).

  If the value of the normalized index ND3 is greater than 0 (YES in step S15), the determination unit 94 determines whether the value of the normalized index ND2 is greater than 0 (step S16).

  The determination unit 94 determines that asphalt exists when the value of the normalization index ND2 is 0 or less (NO in step S16).

  On the other hand, when the value of the normalization index ND2 is greater than 0 (YES in step S16), the determination unit 94 determines that concrete is present.

  Further, when the value of the normalization index ND3 is 0 or less (NO in step S15), the determination unit 94 determines whether the value of the normalization index ND4 is greater than 0 (step S17).

  The determination unit 94 determines that concrete is present when the value of the normalization index ND4 is greater than 0 (YES in step S17).

  On the other hand, when the value of the normalization index ND4 is 0 or less (NO in step S17), the determination unit 94 determines that glass is present.

  In each of the above steps for determining whether or not it is greater than 0, a threshold value other than 0 may be set according to the physical properties of the determination target substance.

  When the determination unit 94 determines that human skin is present, the detection unit 12 can determine that an intruder exists in the monitoring area. For example, when the determination unit 94 determines that glass is present, the detection unit 12 can determine that a vehicle is present in the monitoring area.

  In addition, the situation where the human skin is not exposed because the intruder into the monitoring area wears a covering surface and gloves is also assumed. Assuming such a case, for example, in the target detection device 101, the threshold value and the wavelength are set so that a substance such as a chemical fiber worn only by a human can be detected. Thereby, when the determination unit 94 determines that the chemical fiber is present, the detection unit 12 can determine that an intruder exists in the monitoring area.

  It is also possible to detect the material of clothing worn by humans by setting a threshold and wavelength that can detect the type of fiber such as wool, cotton, nylon (registered trademark), and polyester.

  Assuming that the object detection device 101 only detects humans, it may be configured to perform only the separation of substances related to humans.

  Although the object detection device according to the embodiment of the present invention is used for the purpose of detecting an intruder in the monitoring area, the object detection apparatus is not limited to such an object, but for the purpose of detecting some object. Widely applicable.

  For example, the detection target may be a bicycle traveling on a general road or a highway, a blind person with a cane, or the like. Moreover, it is applicable also to the use which detects the growing state of the crop in a fixed area.

  In addition to the purpose of intrusion detection, the object detection device according to the embodiment of the present invention can also be used as a monitoring device that monitors a person or an object for purposes other than intrusion detection. For example, it can be considered to be used as a monitoring device for monitoring traffic conditions at intersections or a monitoring device for detecting and photographing a car license plate.

  Further, in the object detection device according to the embodiment of the present invention, the object detection is performed without being noticed by a person in the dark and at night by providing the light irradiator that irradiates halogen light or infrared light as described above. It can also be used for the purpose.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 11 Image pick-up part 12 Detection part 13 Target image acquisition part 21 Optical system 22 Light receiving part 31 Wavelength filter part 32 Image pick-up element part 33 Reflection part 51 HS camera 52 Telephoto camera 53 Control apparatus 91 Reflectance calculation part 92 Normalization parameter | index calculation part 93 Two Next derivative calculation unit 94 Judgment unit 101 Target detection device P pixel SP sub pixel R Image sensor F, FL1 to FL4 Wavelength selection filter

Claims (4)

An imaging unit for imaging a two-dimensional image for a plurality of wavelength bands selected in advance according to the physical property of the detection target;
A detection unit for detecting a substance in each pixel of the two-dimensional image,
The imaging unit
An image sensor section having a plurality of image sensors for outputting an electrical signal indicating the intensity of received light;
Of the received light, a wavelength filter unit having a plurality of wavelength selection filters for transmitting the light in the plurality of wavelength bands and irradiating the image sensor unit, respectively,
Receiving reflected light is irradiated to the wavelength filter unit was, and saw including a reflective portion capable of switching the irradiation target of the wavelength selective filter of said reflected light by changing the optical path of the reflected light,
The image sensor unit is divided into a plurality of regions for receiving light in the plurality of wavelength bands,
The said wavelength selection filter is a target detection apparatus which permeate | transmits the light of the said corresponding wavelength band, and irradiates to the said corresponding | compatible area | region .   The target according to claim 1, wherein the detection unit detects a substance in the pixel based on an evaluation value calculated by combining a part or all of the intensity values for the plurality of wavelength bands in one pixel. Detection device.   The target detection apparatus according to claim 1, wherein at least a part of the plurality of wavelength bands is included in an infrared region. Imaging a two-dimensional image for a plurality of wavelength bands preselected according to the physical properties of the detection target;
Detecting a substance in each pixel of the two-dimensional image,
In the step of capturing the two-dimensional image, the received light is reflected, and a wavelength selection filter to which the reflected light is irradiated is changed by changing an optical path of the reflected light, and the light of the plurality of wavelength bands is Irradiate each of the wavelength selective filters and irradiate an image sensor unit having a plurality of image sensors ,
The image sensor unit is divided into a plurality of regions for receiving light in the plurality of wavelength bands,
In the step of capturing the two-dimensional image , a target detection method in which the wavelength selection filter transmits light in the corresponding wavelength band and irradiates the corresponding region .

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