JP2009278249A - Monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a moving object body distinguishable from the background of a railroad crossing without being affected by sunshine even in a state where sunlight passed through the atmosphere in fine weather impinges directly on the object, in order to solve the problem that the temperature of the pavement rises above the body temperature under blazing heat of summer and radiation intensity of the human body and an object are equalized for 8-15 μm and becomes indistinguishable. <P>SOLUTION: A monitoring system includes an infrared bandpass optical filter of light of wavelength of 1.4 μm or 1.9 μm which glass transmits but moisture vapor absorbs using an infrared glass lens, and a solid-state imaging element having sensitivity of light in wavelength of 1.4 μm or 1.9 μm, wherein an image is imaged by using the lighting consisting of an array of laser diodes having an emission light of a band which glass transmits but steam absorbs, and an image is imaged from short distance by removing the bandpass optical filter and using the halogen lamp lighting at the time of rainfall. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement of a monitoring system having an imaging device using an infrared solid-state imaging device.

  Since the definitions of near infrared, mid infrared, and far infrared vary depending on the purpose and industry, the following is a quantitative distinction between infrared rays using the approximate wavelength of transparency in the atmosphere.

FIG. 4 is a schematic diagram showing a conventional operation, and is an outline of transparency of visible light and infrared light in the atmosphere. In FIG. 4, the sunlight has a specific wavelength of 0.4 μm to 1.3 μm (short wavelength side of visible light and near infrared) and 1.5 μm to 1.8 μm (center wavelength of near infrared), which are called atmospheric windows. It passes through the atmosphere of 1.8 km at 2 μm-2.6 μm (long infrared side long wavelength side), 3 μm-4.2 μm, 4.4 μm-5 μm (middle infrared) and 8-15 μm (far infrared). 1.4 μm and 1.9 μm are absorbed by water vapor and change greatly with humidity, but are halved within about 100 m. (See Non-Patent Document 1)
By the way, in 8-15 micrometers (far infrared rays), a radiation intensity and the object temperature of about 30 degreeC are proportional, and sunlight is a low level. (See Non-Patent Document 2)
That is, in a monitoring system having an imaging device using an infrared solid-state imaging device of 5 μm or less, it is difficult to distinguish between a background and a moving object due to the influence of sunlight when directly hitting a subject. Therefore, as shown in FIG. 3 of the block diagram showing the entire configuration of the conventional imaging apparatus, the 8-15 μm far-infrared transmission such as 8-15 μm solid-state imaging device and chalcogenide (S, Se, Te, Ge, As, Sb) etc. An imaging device is used that uses an optical system and outputs an image by color-coding the 8-15 μm radiant intensity of a subject by temperature.

  However, in clear weather in summer, the pavement surface temperature that has been exposed to direct sunlight rises above body temperature, and the radiant intensity of 8-15 μm between the human body and the subject becomes equal to or greater, making it indistinguishable. Specifically, the background 19 having the same temperature as the body temperature in FIG. 3 of the block diagram showing the entire configuration of the conventional imaging apparatus cannot be distinguished from the person 6. In 2007, temperatures over 40 ° C were recorded several times at multiple locations such as Kumagaya. So there are also 20 backgrounds that are hotter than body temperature.

  Therefore, the sensor 17 for detecting the intruding object is used in combination with the imaging device 13 using the visible light glass lens 12 and the visible light solid-state imaging device and the 8-15 μm far-infrared imaging device 11.

By the way, infrared rays of 1400 nm or more are not transmitted by the vitreous fluid of the eye, so the output is unlikely to be sent to the retina, and even though the surface of the cornea may be damaged, it is output by the eye focusing function The density is never increased. Therefore, no damage will occur unless the output is very large. Therefore, based on the new IEC 60825-1 modified 2 standard, the power level limits for Class 1 and Class 1M laser systems are IEC / CDRH Class 1 near infrared 850nm 0.78mW and near infrared 1550nm 10mW It has become. (See Non-Patent Document 3)
In some cases, the energy intensity of a wavelength with little absorption by CO2 and the energy intensity of a CO2 absorption band wavelength are measured to obtain the radiation energy from the measurement object. (See Patent Document 1)
RDHudson.Jr `` INFRADRED SYSTEM ENGINEERINGS '' (John Willey & Son.1969) Architectural Institute of Japan Planning Series 459 IEC 60825-1 JP 5-306695

  Using a single-system solid-state imaging device, it is possible to distinguish between the background and moving objects in a railroad crossing without being affected by sunlight, even when sunlight that has passed through the atmosphere under the hot summer sun continues to hit the subject directly. It is the object of the present invention to attach and detect.

  In order to achieve the above object, in the present invention, at least one infrared bandpass optical filter of about 1.4 μm and about 1.9 μm of an absorption band of water vapor transmitted through glass and an infrared ray made of glass and sensitivity to the above infrared rays are used. A solid-state imaging device comprising: a solid-state imaging device having a light source; and an illumination that generates the infrared rays (parallel laser diode or LED or halogen lamp, etc.), and images a subject within 100 m with the infrared rays. Monitoring system.

  Also, in the above, when there is infrared illumination that passes through the atmosphere (such as LED or halogen lamp), and rain, fog, and other aerial water vapor are close to saturated water vapor, an infrared band-pass optical filter in the water vapor absorption band The generation of about 1.4 μm and about 1.9 μm of the water vapor absorption band through which the glass permeates is stopped, the infrared illumination of about 1 μm to about 2 μm is used, and the infrared light of about 1 μm to about 2 μm is used within 30 m. A monitoring system is characterized by imaging a subject.

  In the monitoring system of the present invention, when sunlight directly hits a subject, the sunlight illuminates and shoots at about 1.4 μm and about 1.9 μm of the absorption band of water vapor that does not pass through the atmosphere of 1.8 km. 1.4 μm and 1.9 μm change greatly with humidity without being affected by light, but are halved within approximately 100 m. Therefore, it is easy to detect moving objects by distinguishing the background from moving objects within approximately 100 m. .

  In addition, when rain, fog, or other aerial water vapor is close to saturated water vapor, the attenuation of 1.4 μm and 1.9 μm is severe, but sunlight does not directly hit the subject, so the infrared bandpass optics of the water vapor absorption band Remove the filter, stop the generation of about 1.4 μm and about 1.9 μm of the water vapor absorption band that passes through the glass, and use the infrared illumination of about 1 μm to about 2 μm that passes through the atmosphere, and the mid-infrared that passes through the atmosphere By picking up an image of a subject within 30 m, it is possible to distinguish between a short-distance background and a moving object without being affected by water vapor, and to easily detect the moving object.

  As a result, a sensor for detecting an intruding object and an 8-15 μm far-infrared imaging device are not required.

  In addition, since a glass optical system similar to that of visible light can be used, an image with little flare and ghost and high contrast and modulation can be obtained, and an imaging device using a visible light solid-state imaging device and a glass lens becomes unnecessary.

  As described above, using a single-system solid-state imaging device, even when sunlight that has passed through the atmosphere under the hot summer sun hits the subject directly, it is not affected by sunlight and can be distinguished from short-distance backgrounds and moving objects. It becomes possible to attach.

  An embodiment of the present invention will be described with reference to FIG. 1 which is a block diagram showing the overall configuration of an imaging apparatus according to an embodiment of the present invention, and FIG. 2 which is a schematic diagram showing the operation of the embodiment of the present invention.

  The major difference between FIG. 1 of the block diagram showing the overall configuration of the imaging apparatus of one embodiment of the present invention and FIG. 3 of the block diagram showing the overall configuration of the conventional imaging apparatus is a parallel laser of 1.4 μm or 1.9 μm. A detection system consisting of a diode or LED, a halogen lamp, and an imaging device, with a solid-state imaging device of 8-15 μm and a far-infrared transmission optical system of 8-15 μm such as chalcogenide (S, Se, Te, Ge, As, Sb) This is because the functions of three detection systems, that is, an imaging apparatus to be used, an imaging apparatus using a solid-state imaging element for visible light and a glass lens, and a sensor for detecting an intruding object are provided.

  FIG. 1 is a block diagram showing the overall configuration of an image pickup apparatus according to an embodiment of the present invention. 3 is a moving object image processing device for detecting intruders and detecting suspicious behavior, 4 is a video display device (picture monitor), 5 is a recording device, 6 is a moving object such as a person, and 7 is an infrared imaging device. It is a background of a road surface of a railroad crossing, etc., 8 is a laser diode or LED illumination of 1.4 μm or 1.9 μm, 9 is an optical bandpass filter (Band that transmits at least one near infrared ray of 1.4 μm or 1.9 μm) Pass Filter: BPF). Reference numeral 18 denotes near-infrared illumination that passes through the atmosphere, such as a halogen lamp or LED. No. 8 may be a halogen lamp with an optical BPF that transmits only near infrared rays of at least one of 1.4 μm and 1.9 μm.

  In FIG. 2 which is a schematic diagram showing the operation of one embodiment of the present invention, (a) is an outline of the transparency of visible light and infrared rays in the atmosphere, (b) is an outline of the permeability in infrared glass, (c ) Is an outline of the near-infrared spectral sensitivity of the individual image sensor.

  FIG. 2A, which is a schematic diagram showing the operation of one embodiment of the present invention, is an enlarged view of 5 μm or less of FIG. 4 showing the conventional operation. 2A and 2B, which are schematic diagrams showing the operation of one embodiment of the present invention, the near-infrared transmission optical system made of glass having a thickness of 2 μm or less is 1.4 μm and 1.9 μm. It can be seen that there is room for transmission of near infrared rays.

  FIG. 2C of the schematic diagram showing the operation of one embodiment of the present invention is an outline of the near-infrared spectral sensitivity of the solid-state imaging device, and the chain line is an example of spectral sensitivity of the imaging device in which a photodiode made of Si silicon is deeply formed. The solid line is an example of spectral sensitivity focusing on 1.7 μm of an imaging device made of InGaAs indium gallium arsenide, and the dotted line is an example of spectral sensitivity focusing on 2.2 μm of an imaging device made of InGaAs. Here, an image pickup element of 1.4 μm can be picked up even if it is an image pickup element made of Si and formed with a photodiode deeply by a frame transfer CCD or a horizontal overflow drain CCD. In order to reduce dark current variations and deterioration with time, which are likely to occur in deep photodiodes, it is preferable to reduce crystal defects in the CCD image sensor, reduce electric field concentration, and cool the CCD image sensor.

  FIG. 1 is a block diagram showing the overall configuration of an image pickup apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the operation of the embodiment of the present invention. Because it uses 1.4μm or 1.9μm, which does not pass through and halves within about 100m, it is not affected by the sun at all, and it is stably distinguished from the background such as the road surface of railroad crossings within about 100m. Can be detected.

  By the way, since the light of 1.4 μm or more is not transmitted by the vitreous fluid of the eye, its output is unlikely to be sent to the retina, and even though the surface of the cornea may be damaged, the focusing function of the eye Does not increase the power density. Therefore, no damage will occur unless the output is very large. However, illumination in which a number of diffused laser diodes or LEDs with low directivity are arranged in parallel is preferable.

  In addition, when rain, fog, or other aerial water vapor is close to saturated water vapor, the attenuation of 1.4 μm and 1.9 μm is severe, but sunlight does not directly hit the subject, so the infrared absorption of water vapor is 1.4 μm. Alternatively, remove 9 of the 1.9 μm transmission filter, stop emission of the 1.4 μm or 1.9 μm illumination 8, and use an infrared illumination 18 such as a halogen lamp or LED of about 1 μm to about 2 μm that passes through the atmosphere, Detects moving objects such as people by imaging within 30m with near infrared rays that pass through the atmosphere, without being affected by water vapor, and distinguishing backgrounds such as road surfaces within a short distance crossing and moving objects such as people Becomes easier.

  As a result, a sensor for detecting an intruding object and an 8-15 μm far-infrared imaging device are not required.

  In addition, since a glass optical system similar to that of visible light can be used, an image with little flare and ghost and high contrast and modulation can be obtained, and an imaging device using a visible light solid-state imaging device and a glass lens becomes unnecessary.

  As described above, using a single-system solid-state imaging device, even in the state where sunlight that has passed through the atmosphere under the summer sun hits the subject directly, it is not affected by sunlight, such as the road surface in a short-distance railroad crossing A background and a moving object such as a person can be distinguished from each other.

  For this reason, the moving object image processing apparatus 3 for detecting intruders and detecting suspicious behaviors, such as InGaAs, Si, etc., without referring to the sensor for detecting the intruding object and the information about the 8-15 μm far-infrared imaging device, is used. It is only necessary to input and process the video signal of the near infrared imaging device 2 using the 2 μm detection imaging device to the moving object image processing device 3 such as intruder detection or suspicious behavior detection, and the monitoring system is simple and stable. .

1 is a block diagram showing the overall configuration of an imaging apparatus according to an embodiment of the present invention. Schematic diagram showing the operation of one embodiment of the present invention ((a) Outline of transmission of visible light and infrared light in the atmosphere (b) Outline of transmission in infrared glass (c) Near-infrared spectroscopy of individual imaging device (Summary of sensitivity) The block diagram which shows the whole structure of the conventional imaging device Schematic diagram showing conventional operation

Explanation of symbols

1: Near-infrared transmission optical system 2 [mu] m or less made of glass 2: Near-infrared imaging device 3 or 14 using 1-2 [mu] m detection imaging device such as InGaAs: Moving object image processing device 4, 15 for detecting intruders or detecting suspicious behavior : Video display device (picture monitor)
5, 16: Recording device 6: Moving object 7: Background
19: Background of temperature equivalent to body temperature 20: Background higher than body temperature 8: Near-infrared illumination of at least one of 1.4 μm or 1.9 μm 9: Transmits only near-infrared of at least one of 1.4 μm or 1.9 μm Optical bandpass filter (BPF)
10: 8-15 μm far-infrared transmission optical system 11 such as chalcogenide 11: Far-infrared imaging device 12: glass-made visible light transmission optical system 13: visible light imaging device 17: sensor 18: Near-infrared illumination that passes through the atmosphere such as halogen lamps and LEDs

Claims (2)

A solid-state imaging device comprising a glass infrared optical system, at least one infrared band-pass optical filter having a water vapor absorption band of about 1.4 μm and about 1.9 μm, and a solid-state imaging device having sensitivity to the infrared rays. And an illumination that generates the infrared rays, and images a subject within 100 m with the infrared rays. 2. The monitoring system according to claim 1, further comprising an infrared illumination that passes through the atmosphere, and when rain, fog, or other airborne water vapor is close to saturated water vapor, the infrared bandpass optical filter of the water vapor absorption band is removed, and glass Stops the generation of about 1.4 μm and about 1.9 μm in the absorption band of water vapor that passes through, and uses an infrared illumination of about 1 μm to about 2 μm to image a subject within 30 m with an infrared of about 1 μm to about 2 μm. A monitoring system characterized by that.