JP2015014581A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus which reduces a data amount for temperature compensation and achieves the reduction in size and cost of the apparatus, while suppressing the increase of power consumption.SOLUTION: An imaging apparatus 1 includes an optical system including a lens 2 imaging an infrared ray radiated from an imaging object and an inner cylinder 3 storing the lens 2, a detector 4 converting the infrared ray imaged by the lens 2 into an electrical signal, a heater 6 heating the optical system, a housing 10 storing the optical system, a thermal separation part 8 thermally separating the optical system and the housing 10, and a controller 7 controlling the heater 6, to adjust the temperature of the optical system, in such a state that the optical system and the housing 10 are thermally separated.

Description

  The present invention relates to an imaging apparatus.

  There is an imaging device with a bolometer detector. Such an imaging apparatus images the temperature difference of the imaging object. This image luminance is converted into luminance temperature by using calibration data acquired in advance. However, in addition to the object to be imaged, the image luminance also changes due to temperature changes in the detector itself and the optical system that enters the field of view of the detector. For this reason, the accuracy of the brightness temperature is improved by eliminating the influence of the temperature change of the detector itself and the optical system that enters the visual field of the detector.

  For example, Patent Document 1 describes an imaging device including a temperature compensation device for an infrared sensor. In this imaging apparatus, a variation in image brightness caused by a change in environmental temperature or the like is corrected using a correction table prepared in advance.

  Further, as a structure for compensating for the influence due to temperature fluctuations of the optical system, the one disclosed in Patent Document 2 below is known. This lens device includes a coil spring that presses the lens frame in the direction of the image plane, and a ring-shaped member that is formed from a rod-shaped material having a circular cross section.

JP 2008-185465 A JP 2011-170161 A

  In the imaging apparatus described in Patent Document 1, a range in which the environmental temperature can change is divided into a plurality of temperature regions, and a correction table is prepared for each temperature region. For example, in an earth observation satellite (spacecraft) orbiting a polar orbit at an altitude of 600 km, the environmental temperature changes in a range of approximately −5 degrees to 40 degrees. For this reason, when the imaging device described in Patent Document 1 is mounted on a spacecraft, a large amount of correction table is required in consideration of an uncertain element of a change in environmental temperature, which may increase the number of development steps.

  On the other hand, by controlling the temperature of the imaging device, the influence of the environmental temperature on the image brightness may be reduced. However, in order to control the temperature of the entire imaging apparatus, power consumption increases.

  Furthermore, the lens device described in Patent Document 2 tends to have a complicated structure and increase the size and cost of the device.

  The present invention provides an imaging apparatus having a structure that can reduce the amount of data for temperature compensation while suppressing an increase in power consumption, and can easily reduce the size and cost of the apparatus.

  An imaging apparatus according to an aspect of the present invention includes a lens that forms an infrared ray emitted from an imaging target, an optical system having an inner cylinder that houses the lens, and a detection that converts the infrared ray formed by the lens into an electrical signal. , A heater for heating the optical system, a housing for housing the optical system, a thermal separation unit for thermally separating the optical system and the housing, and the optical system and the housing are thermally separated. And a controller that controls the heater to adjust the temperature of the optical system.

  Calibration data is used to convert an electrical signal obtained by converting infrared rays from the imaging object into a luminance temperature. Different calibration data is used depending on the temperature of the optical system of the imaging apparatus. For this reason, in order to obtain a high-accuracy luminance temperature, it is necessary to obtain a plurality of calibration data in advance according to the temperature range that the optical system can take. According to the imaging apparatus, by controlling the temperature of the optical system, the influence of the environmental temperature on the temperature of the optical system can be reduced, and the temperature range that the optical system can take can be controlled. For this reason, it becomes possible to reduce the data amount of the calibration data used when converting into luminance temperature. Further, the optical system and the housing are thermally separated by the heat separation unit. For this reason, since it is suppressed that the heat of an optical system is transmitted to a housing | casing, the efficiency of the temperature control of the optical system by a heater can be improved. Thereby, power consumption can be reduced. Furthermore, since there is no complicated structure for compensating for the temperature change of the optical system including the lens, it is easy to reduce the size and cost of the entire apparatus.

  The imaging apparatus according to another aspect of the present invention may further include a readout circuit that converts the electrical signal converted by the detector into a luminance temperature. By adopting the above configuration in an imaging device including a readout circuit, the amount of configuration data necessary for luminance temperature conversion can be reduced. Therefore, it is possible to easily reduce the development man-hour of the imaging device.

  In the imaging apparatus according to another aspect of the present invention, the controller may control the heater so that the temperature of the optical system is within a predetermined temperature range. In this case, since the temperature range that the optical system can take can be limited, it is possible to reduce the amount of calibration data used for conversion to the luminance temperature.

  In the imaging device according to still another aspect of the present invention, the heat separation unit may include a heat insulating member that insulates the optical system and the housing, and a heat shield member that shields radiation light from the housing. . In this case, thermal conduction due to conduction between the optical system and the casing can be blocked, and thermal conduction (radiation coupling) due to radiation between the optical system and the casing can be blocked.

  In the imaging device according to still another aspect of the present invention, the inner cylinder may include a gripping part that grips the lens, and a waveguide part that guides infrared rays that have passed through the lens to the detector. You may provide in a waveguide part. In this case, the infrared radiation input to the detector is limited to infrared radiation from the lens, the inner cylinder, and the imaging object. For this reason, when temperature control of the optical system is performed, it is possible to reduce the influence of heat from other than the optical system.

  In the imaging device according to still another aspect of the present invention, the heat insulating member may be provided between the grip portion and the housing. When the optical system is supported by the housing in the grip portion of the inner cylinder, the heat conduction due to the conduction between the optical system and the housing can be blocked by providing a heat insulating member between the grip portion and the housing. it can.

  In the imaging device according to still another aspect of the present invention, the waveguide section may be formed to extend to the vicinity of the detector. By adopting such a configuration, it becomes possible to reduce the influence of heat from other than the optical system.

  In the imaging device according to still another aspect of the present invention, the heater may heat the inner cylinder. In this case, the temperature of the optical system is adjusted by heating the inner cylinder. Further, the configuration in which the temperature of the optical system including the inner cylinder is controlled by the heater eliminates the need to use an expensive lens having a complicated configuration with temperature compensation. Furthermore, the radiant heat from the inner cylinder can be controlled by controlling the temperature of the inner cylinder.

  In the imaging device according to still another aspect of the present invention, the controller may control the heater so that the optical system maintains a set temperature that is set to a temperature higher than the maximum value of the thermal equilibrium temperature of the optical system. By setting the temperature of the optical system to a set temperature that is higher than the thermal equilibrium temperature of the optical system, it is possible to perform thermal control of the optical system using only a heater. Thus, by using a temperature control device only with a heater, the device can be downsized as compared with a conventional temperature control device that requires both cooling and heating.

  In the imaging device according to still another aspect of the present invention, the detector may be an uncooled microbolometer. In this case, even in an imaging apparatus equipped with an uncooled microbolometer, it is possible to reduce the amount of calibration data while suppressing an increase in power consumption.

  According to the present invention, the amount of data for temperature compensation can be reduced while suppressing an increase in power consumption.

1 is an end view schematically showing a configuration of an imaging apparatus according to an embodiment. It is a figure which shows an example of the relationship between the temperature change of a lens, and MTF (Modulation Transfer Function). It is a figure which shows the simulation result of the temperature change of the lens 2 of FIG. 1 at the time of the orbit of the artificial satellite carrying the imaging device 1. FIG. It is a figure which shows the simulation result of the temperature change of the earth-oriented surface of the imaging device 1 at the time of the orbit of the artificial satellite carrying the imaging device 1.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is an end view schematically showing a configuration of an imaging apparatus according to an embodiment. As shown in FIG. 1, the imaging apparatus 1 is an infrared camera that detects infrared rays emitted from a measurement target (imaging target) and images a temperature according to the detected infrared rays. , An inner cylinder 3, a detector 4, a readout circuit 5, a heater 6, a controller 7, a heat separation unit 8, and a housing 10. The imaging device 1 is mounted on a spacecraft such as an artificial satellite. Here, the optical system of the imaging apparatus 1 is a part including the lens 2 and the inner cylinder 3. The main body of the imaging device 1 is a part including a housing 10, a detector 4, a readout circuit 5, and a controller 7.

  The housing 10 is a cylindrical housing that houses the optical system of the imaging apparatus 1 and has an axis X extending along the direction A, for example. The housing 10 includes a support part 11 and a storage part 12. The support part 11 and the accommodating part 12 are arranged along the direction A in that order. The support part 11 is a part that supports the optical system. The support part 11 has an opening 11a at one end in the direction A, and an opening 11b at the other end. The opening diameter of the opening 11a is larger than the opening diameter of the opening 11b. The opening part 11 b is connected to one end of the housing part 12. The accommodating part 12 has an accommodating space for accommodating the optical system, the detector 4, the readout circuit 5, the heater 6 and the controller 7.

  The lens 2 is a lens for imaging infrared rays emitted from the measurement object. The lens 2 is a lens that can transmit infrared rays, and is, for example, a germanium (Ge) lens. The lens 2 is held by the inner cylinder 3.

  The inner cylinder 3 is a cylindrical member that holds the lens 2 and guides infrared rays transmitted through the lens 2 to the detector 4. The inner cylinder 3 has a cylindrical shape with the axis X as an axis, and extends in the direction A from the opening 11 a of the housing 10 to the vicinity of the detector 4. The inner cylinder 3 has a grip portion 31 and a waveguide portion 32. The grip portion 31 and the waveguide portion 32 are arranged along the direction A in that order.

  The grip portion 31 is a portion that grips the lens 2. The grip portion 31 grips the lens 2 such that the peripheral edge of the lens 2 comes into contact with the inner surface, for example. The grip part 31 is supported by the support part 11 via the heat separation part 8. The waveguide unit 32 is a part that guides infrared rays transmitted through the lens 2 to the detector 4. The inner diameter of the waveguide 32 gradually decreases along the direction A. The inner cylinder 3 is provided with a temperature sensor, and outputs the temperature of the optical system (inner cylinder 3) to the controller 7.

  The detector 4 is a thermal infrared sensor that detects infrared rays, and is, for example, an uncooled microbolometer. The detector 4 converts the temperature change of the element inside the detector 4 caused by absorbing infrared rays into an electrical signal, and outputs each electrical signal to the readout circuit 5. The infrared rays detected by the detector 4 have a wavelength of about 8 to 12 μm, for example.

  The readout circuit 5 is a circuit that converts the electrical signal converted by the detector 4 into luminance temperature. The readout circuit 5 converts an electrical signal (image luminance) output from each element of the detector 4 into luminance temperature using calibration data. The calibration data is acquired in advance by, for example, imaging a black body or the like whose temperature is known, and is set in advance for each predetermined temperature range. Note that the readout circuit 5 does not necessarily have to be provided inside the imaging apparatus 1 and may be electrically connected to the detector 4 outside the imaging apparatus 1.

  The heater 6 is a device for heating the optical system. The heater 6 is provided, for example, on the outer peripheral surface of the waveguide portion 32 of the inner cylinder 3 and heats the inner cylinder 3. The heater 6 has a cylindrical shape with the axis X as an axis, for example, and is provided along the outer peripheral surface of the waveguide section 32 around the axis X.

  The controller 7 controls the heater 6 to adjust the temperature of the optical system. The controller 7 controls the heater 6 so that the optical system maintains a predetermined set temperature. That is, the controller 7 controls the heater 6 so that the temperature of the optical system is within a predetermined temperature range with respect to the set temperature. For example, the set temperature is set to a temperature higher than the maximum value of the thermal equilibrium temperature of the optical system of the imaging apparatus 1. The thermal equilibrium temperature is a temperature at which heat input and heat dissipation are balanced. The controller 7 controls the heater 6 by PID (Proportional Integral Derivative) control, for example.

  FIG. 2 is a diagram illustrating an example of the relationship between the temperature change of the lens 2 and the MTF. In FIG. 2, the horizontal axis indicates the temperature change (degree) of the lens, and the vertical axis indicates the normalized MTF of the lens. As shown in FIG. 2, when the temperature change of the lens 2 increases, the MTF deteriorates. That is, since the lens 2 expands or contracts due to temperature change, the lens 2 is out of focus. In order to avoid the degradation of the MTF of the lens 2, the temperature range of the lens 2 may be ± 5 degrees, for example, and is preferably ± 3 degrees. Therefore, for example, the controller 7 sets the set temperature of the optical system to 0 degrees, sets the temperature range to ± 3 degrees, and sets the temperature change rate of the optical system to 0.5 degrees / minute. In the state where the optical system is thermally controlled, optical adjustment (focusing) of the lens 2 is performed, and calibration data is acquired.

  The thermal separation unit 8 is a part for thermally separating the optical system and the main body unit. The heat separation unit 8 thermally separates the optical system and the housing 10, for example. The heat separation unit 8 includes a heat insulating member 81 and a heat shield member 82.

  The heat insulating member 81 is a heat insulating member that blocks heat conduction due to conduction between the optical system and the main body, and insulates the optical system and the housing 10, for example. The heat insulating member 81 is composed of a member having low thermal conductivity, and is composed of, for example, glass epoxy. The heat insulating member 81 is provided between the support part 11 of the housing 10 and the grip part 31 of the inner cylinder 3, for example.

  The heat shield member 82 is a heat shield member that blocks heat conduction (radiation coupling) due to radiation between the optical system and the main body, and shields, for example, radiation light from the housing 10. The heat shield member 82 is made of a heat insulating material having a low emissivity, and is made of, for example, aluminum or gold. The heat shield member 82 is provided in the waveguide section 32 so as to cover the outer surfaces of the heater 6 and the waveguide section 32. The heat shield member 82 is provided on the outer peripheral surface of the waveguide portion 32 by painting or vapor deposition.

  Next, the power consumption of the heater 6 required for temperature control of the lens 2 will be described. First, the simulation result of the temperature change of the lens 2 when the imaging device 1 and the imaging device 100 are mounted on an artificial satellite will be described. The imaging device 100 is an imaging device in which the thermal separation unit 8 is removed from the imaging device 1, and the optical system and the main body are not thermally separated. This simulation was performed under the following conditions.

  The imaging device 1 and the imaging device 100 are provided on an earth-oriented surface that is expected to have a relatively low temperature fluctuation in the outer surface of the artificial satellite, and the housing 10 is thermally coupled to the earth-oriented surface, It was assumed that the surface was insulated. As the orbit, an orbit having an altitude of 628 km, an orbit inclination angle of 90 degrees, and a local time of 12:00 was used. The total mass of the imaging device 1 and the imaging device 100 was 800 g, and the heat generation was 7 W. Moreover, the housing | casing 10 was comprised from aluminum and the mass of the housing | casing 10 was 500 g. The lens 2 is assumed to be a Ge lens, the lens 2 has a mass of 260 g, the infrared reflectance of the lens 2 is 0, the absorptance α is 0.60, and the emissivity ε is 0.55. The earth-oriented surface of the artificial satellite has an aluminum sandwich panel structure, and its mass is 500 g. It was assumed that the outer surface of the artificial satellite was aluminum-deposited Teflon (registered trademark), the solar absorptance α was 0.09, and the infrared emissivity ε was 0.88.

Table 1 below shows the worst low temperature condition and the worst high temperature condition used in the simulation.

Under the above conditions, the temperature change of the lens 2 was simulated by one-node analysis. The opening surface of the lens 2 becomes a heat radiating surface to outer space, and the heat generated by the equipment in the artificial satellite becomes a heat input to the optical system. As heat input to the lens 2 in the imaging device 1, direct solar radiation, albedo, earth infrared radiation, optical system, and radiation from the detector 4 are assumed. For this reason, the heat balance formula of the imaging device 1 is represented by Formula (1). Further, as heat input to the lens 2 in the imaging apparatus 100, the amount of direct solar radiation, albedo, earth infrared radiation, and the amount of heat applied from inside the satellite are assumed. For this reason, the heat balance formula of the imaging device 100 is represented by Formula (2).

  The first term of equation (1) indicates the amount of solar direct solar radiation, the second term indicates albedo, the third term indicates earth infrared radiation, the fourth term indicates radiation from the satellite wall (hood), The fifth term represents the radiation from the optical system, and the sixth term represents the radiation from the detector 4. The first term of Equation (2) indicates the amount of solar direct solar radiation, the second term indicates albedo, and the third term indicates the earth infrared radiation. And the 4th term and 5th term of Formula (2) have shown the calorie | heat amount added from the inside of an artificial satellite.

FIG. 3 is a diagram showing a simulation result of a temperature change of the heat-insulated lens 2 when an artificial satellite equipped with an imaging device orbits the orbit. In the figure, the horizontal axis represents the closest point angle (degrees), and the vertical axis represents the temperature (K) of the lens 2. The graph T _WC1 shows the temperature of the lens 2 under the worst low temperature condition, the graph T _WH1 shows the temperature of the lens 2 under the worst high temperature condition, and the graph T ₁ is heated by the heater 6 with power consumption of 2 _W. The temperature of the lens 2 is shown.

From the results shown in FIG. 3, the temperature of the lens 2 is stabilized at 267.2 K (−6.6 ° C.) in the worst case and 306.0 K (33 ° C.) in the worst case. Since the shape factor between the lens 2 and the surface of the earth is almost zero, there is almost no influence of external heat input. As the result of the graph T ₁ shows, even when the temperature of the lens 2 is T _{WC 1} , the temperature of the lens 2 is controlled to 40 ° C. or more by a heater with a heat amount of about 2 W before it goes around the orbit half. I understand that. Therefore, even if the temperature of the inner cylinder 3 and the detector 4 fluctuates between 0 to 40 ° C., the lens 2 can be controlled to a certain temperature by using the heater 6 having a capacity of about 2 W. It is expected to be. As a result, by using the heater 6 in the imaging device 1, the temperature of the lens 2 can be kept constant while reducing power consumption.

  When the imaging device 1 is mounted on an artificial satellite and orbited in orbit, temperature fluctuations in the orbit occur due to fluctuations in heat input and heat output. The earth-oriented surface, which is the opening surface of the lens 2, becomes a heat radiating surface to outer space, and the heat generated by the device itself in the artificial satellite becomes heat input to the lens 2. In space, it is important to cancel these temperature fluctuations with power saving. Therefore, the imaging device 1 may bias the earth-oriented surface to a low temperature and thermally control the lens 2 thermally coupled to the earth-oriented surface with the heater 6. Specifically, the earth-oriented surface may be biased to a low temperature by providing silver vapor-deposited Teflon (registered trademark) as a heat dissipation material on the earth-oriented surface.

FIG. 4 is a diagram illustrating a simulation result of the temperature change of the earth-oriented surface when the artificial satellite equipped with the imaging device 1 having the earth-oriented surface biased to a low temperature orbits the orbit. In the figure, a graph T _WC2 indicates the temperature of the earth-oriented surface under the worst low temperature condition, and a graph T _WH2 indicates the temperature of the earth-oriented surface under the worst high temperature condition. The horizontal axis indicates the closest point angle (degrees), and the vertical axis indicates the temperature (K) of the earth-oriented surface.

  This result shows that the temperature fluctuation range is 247.4 ± 2.9K in the worst case and 265.8 ± 5.1K in the worst case, and it can be biased to a low temperature. Note that all of the earth-oriented surface may be silver-deposited Teflon (registered trademark), but may be provided on a part of the earth-oriented surface in consideration of a case where the temperature becomes too low. Thus, the upper limit temperature of the thermal control by only the heater 6 can be controlled by biasing the earth-oriented surface to a low temperature.

On the other hand, the graph T ₂ of the 4, the imaging device biasing the earth direction cold, also shows the simulation result of the temperature change of the lens 2 from the housing 10 are not insulated. In this case, it is assumed that the heater 6 built in the imaging apparatus has a power consumption of 19 W. In this way, when the entire imaging device and the earth-oriented surface are thermally coupled, it is necessary to thermally control the entire imaging device, so that temperature fluctuations are canceled and the temperature of the lens 2 is within ± 3K. In order to do so, it can be seen that the heater 6 requires about 19 W of electric power.

  From the above consideration, it is preferable that the imaging device 1 thermally couples the earth-oriented surface and only the optical system including the lens 6. That is, it is preferable that the lens 6 is thermally separated from the housing 10 so that the member that is thermally coupled to the earth-oriented surface is limited to only the optical system including the lens 6. At this time, the earth-oriented surface may be biased to a low temperature.

  Further, a vacuum test was performed using the imaging device 1. When the temperature of the housing 10 was about −4.5 degrees or more, the heater 6 was able to maintain the lens 2 at 35 degrees using 4 W electric power. That is, the temperature difference between the optical system and the main body can be about 40 degrees.

  Next, functions and effects of the imaging device 1 will be described. The image brightness in the imaging device is mainly input from the sensitivity variation of each element (infrared absorption coefficient, resistance value, resistance temperature coefficient, heat capacity value, variation in heat transfer coefficient), detector substrate temperature, and detector periphery. Affected by infrared radiation.

  In a conventional thermal infrared imaging device, the uncooled microbolometer detector has a temperature control mechanism such as a Peltier module, and keeps the thermal radiation of the detector itself constant. However, since the temperature of the optical system is not controlled, calibration data corresponding to the temperature change of the optical system is acquired and corrected. In the conventional thermal infrared imaging device, since the optical system and the camera body are thermally coupled, it is necessary to control the temperature of the entire imaging device in order to control the temperature of the optical system. In order to control the temperature of the entire imaging apparatus, a large amount of power is required, which may not be applicable to a spacecraft that requires power saving.

  On the other hand, according to the imaging apparatus 1, by controlling the temperature of the optical system, the influence of the environmental temperature on the temperature of the optical system can be reduced, and the temperature range that the optical system can take can be controlled. It becomes. Specifically, the controller 7 controls the heater 6 so that the temperature of the optical system is within a predetermined temperature range with respect to the set temperature. This limits the temperature range that the optical system can take. For this reason, it is possible to reduce the amount of calibration data and to reduce the MTF degradation of the lens 2.

  Further, the optical system and the main body are thermally separated by the thermal separation unit 8. For this reason, since it is suppressed that the heat of an optical system is transmitted to a main-body part, the efficiency of the temperature control of the optical system by the heater 6 can be improved. That is, the heater 6 only needs to thermally control only an optical system having a small heat capacity. Thereby, power consumption can be reduced.

  The heat separating unit 8 includes a heat insulating member 81 that insulates the optical system and the housing 10, and a heat shield member 82 that shields radiation light from the housing 10. The heat insulating member 81 is provided between the grip portion 31 and the housing 10, and the heat shield member 82 is provided so as to cover the outer peripheral surface of the waveguide portion 32. For this reason, the thermal conduction due to the conduction between the optical system and the casing 10 can be blocked, and the thermal conduction due to the radiation between the optical system and the casing 10 can be blocked. Therefore, the infrared radiation input to the detector 4 is limited to the infrared radiation from the lens 2, the inner cylinder 3, and the imaging object. That is, it becomes possible to limit the input source of the infrared radiation to the detector 4 to the temperature-controlled optical system and the imaging object. As a result, it is possible to reduce the influence of heat from other than the optical system when controlling the temperature of the optical system.

  In the imaging apparatus 1, the controller 7 may control the heater 6 so that the optical system maintains a set temperature that is set to a temperature that is higher than the maximum value of the thermal equilibrium temperature of the optical system. For example, when mounted on a spacecraft such as an artificial satellite, it is assumed that the thermal equilibrium temperature in outer space is low. In this case, since the set temperature of the optical system becomes higher than the thermal equilibrium temperature, it is possible to perform thermal control of the optical system using only the heater 6 without using a cooling device. In addition, in a vacuum environment of outer space, convection does not occur as in the atmosphere, so that the optical system and the housing can be more completely thermally separated.

  The imaging device according to the present invention is not limited to the above embodiment. For example, the imaging device 1 can be mounted on a microsatellite.

  Further, the imaging device 1 is not limited to a spacecraft, and may be mounted on a security system.

  DESCRIPTION OF SYMBOLS 1 ... Imaging device, 2 ... Lens (optical system), 3 ... Inner cylinder (optical system), 4 ... Detector, 5 ... Reading circuit, 6 ... Heater, 7 ... Controller, 8 ... Thermal separation part, 10 ... Housing , 31 ... gripping part, 32 ... waveguide part, 81 ... heat insulating member, 82 ... heat shielding member.

Claims (10)

An optical system having a lens that forms an infrared ray emitted from the imaging object and an inner cylinder that houses the lens;
A detector that converts the infrared imaged by the lens into an electrical signal;
A heater for heating the optical system;
A housing for housing the optical system;
A thermal separation unit that thermally separates the optical system and the housing;
A controller that adjusts the temperature of the optical system by controlling the heater in a state where the optical system and the housing are thermally separated;
An imaging apparatus comprising: A read circuit for converting the electrical signal converted by the detector into a luminance temperature;
The imaging device according to claim 1.   The imaging apparatus according to claim 1, wherein the controller controls the heater so that a temperature of the optical system falls within a predetermined temperature range. The thermal separation unit is
A heat insulating member for insulating the optical system and the housing;
A heat shield member that shields radiation from the housing;
The imaging device according to claim 1, comprising: The inner cylinder is
A gripping part for gripping the lens;
A waveguide section that guides infrared rays transmitted through the lens to the detector;
With
The imaging device according to claim 4, wherein the heat shield member is provided in the waveguide portion.   The imaging apparatus according to claim 5, wherein the heat insulating member is provided between the grip portion and the housing. The waveguide is formed to extend to the vicinity of the detector,
The imaging device according to claim 5.   The imaging device according to any one of claims 1 to 7, wherein the heater heats the inner cylinder.   9. The controller according to claim 1, wherein the controller controls the heater so that the optical system maintains a set temperature that is set to a temperature larger than a maximum value of a thermal equilibrium temperature of the optical system. The imaging device described.   The imaging device according to any one of claims 1 to 9, wherein the detector is an uncooled microbolometer.

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