JPH0672400A - Full-bore calibration system for visible infrared radiometer - Google Patents

Abstract

PURPOSE:To make calibration of the light quantity in a visible infrared radiome ter with full bore of the light receiving system through composite usage of various light sources ranging from visible to infrared ray. CONSTITUTION:The measuring light 102 and calibration light 103 including three calibrating beams (a, b, c) are put in parallel beams by a reflex mirror 3 as three different light sources are installed in the light source part 5 arranged at the focus of the reflex mirror. Generally the calibration light is a little dislocated from the parallel beams due to different positions of the light source, but can be led to a radiometer optical part 4 by changing the rotaional angle of the calibration light incident to a scanning mirror 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-calibration calibration system for visible infrared radiometers, and in particular, it is mounted on a spacecraft such as an artificial satellite to perform an optical passive objective scanning surface for the earth, The present invention relates to a total aperture calibration system for a visible infrared radiometer that enables optical calibration of a visible infrared radiometer that obtains visible and infrared radiation amounts as measurement light over the entire diameter of a light receiving optical system.

[0002]

2. Description of the Related Art In the conventional calibration of a visible range radiometer, calibration light is emitted to a part of the aperture of a light receiving optical system of the radiometer.

Further, when performing calibration over the entire diameter of the light receiving system, a flat plate black body is used, so that the calibration is limited to the infrared region.

[0004]

The above-mentioned conventional calibration method has the following drawbacks.

(1) In the visible range, since the calibration light can be emitted only to a certain part of the light receiving optical system, if the local deterioration of the transmittance of the light receiving optical system occurs, the calibration cannot be performed.

(2) When attempting to calibrate the entire diameter of the light-receiving optical system in the visible range, it is necessary to arrange it separately from the one for infrared light, which has a drawback that the size becomes large and it is not practical.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a total aperture calibration system for a visible infrared radiometer, which makes optical calibration over the entire aperture of a receiving optical system extremely easy.

[0008]

A full-calibration calibration system for a visible infrared radiometer according to the present invention is equipped with a spacecraft as a platform, and optically and passively scans a scanning object such as the earth to make visible and infrared rays. In the calibration system that calibrates the light receiving system of the visible infrared radiometer that acquires the measurement light by the calibration light, a plurality of calibration lights are collimated to the rotary scanning mirror of the plane mirror configuration that acquires the measurement light by scanning the object surface. A reflecting mirror as a collimating mirror having a curved mirror configuration for projecting light as a light source, and a light source unit arranged at a focal position of the reflecting mirror and projecting a plurality of light source lights to the reflecting mirror to reflect and emit the plurality of calibration lights. And a configuration capable of performing optical calibration over the entire diameter of the light receiving system of the visible infrared radiometer with one rotation of the rotary scanning mirror.

Further, the total aperture calibration system for visible / infrared radiometer of the present invention has a constitution in which the plurality of light source lights are mixed with various wavelength regions from visible to infrared.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing the structure of an embodiment of the present invention. The embodiment shown in FIG. 1 is configured as a plane mirror, and a rotary scanning mirror 1 that rotates 360 degrees about a rotation axis 101, and a reflecting mirror as a collimating mirror that receives light from a light source and sends the reflected light as parallel light. 2, a light source unit 4 having a plurality of light sources, and a radiometer optical unit 3 having a light receiving optical system for receiving the measurement light 102 reflected by the rotary scanning mirror 1 or the calibration light 103 reflected by the reflecting mirror 2. It has a configuration provided.

Next, the operation of this embodiment will be described.

As shown in FIG. 1, the measuring light 102 is reflected at the wavy line display position of the rotary scanning mirror 1 and measured by the radiometer optical section 4.

On the other hand, by rotating the rotary scanning mirror 1 around the rotary shaft 101, the calibration light 103 from the light source unit 4 is converged by the reflecting mirror 2, and the radiometer optical unit 4 is shown via the rotary scanning mirror 1 shown by the solid line. Is projected on.

By arranging the light source unit 5 at the focal position of the reflecting mirror which is a collimating mirror, it is possible to obtain parallel light having a luminous flux which covers the entire diameter of the light receiving optical system of the radiometer.

As the reflecting mirror 2, a curved mirror made of silver or aluminum is used to ensure a high reflectance from visible to infrared.

From the light source unit 4, light source light 104 of three kinds of wavelength regions is projected on the reflecting mirror 2, and three calibration lights (1) a, calibration light (2) b, and calibration light as parallel lights, respectively. (3) The calibration light 103 including c is emitted from the reflecting mirror 2.

FIG. 2 is a plan view showing the incident states of the measurement light and the calibration light of FIG. 1. In this embodiment, the calibration light 103 is composed of three types of calibration light (1) a having different wavelength regions, and calibration light. Using the light (2) b and the calibration light (3) c, the light is projected onto the rotary scanning mirror 2 from different directions by the reflecting mirror 2 and is reflected and reflected on the light receiving surface of the light receiving optical system of the radiometer optical unit 3. It reaches, but at this time it is set to receive light at a solid angle that covers the entire aperture.

Further, the measuring light 102 by scanning the object plane is also
The light is reflected by the rotating scanning mirror 2 and received by the radiometer optical section 3.

In this way, the rotary scanning mirror 1 is attached to the rotary shaft 1
By rotating around 01, light from any direction on the plane can be guided to the radiometer optical section 3. Further, the measurement light 102 can also be acquired from a wide range of about 90 degrees by rotating the rotary scanning mirror 2.

Since the measuring light 102 also has a field angle although it is almost parallel, it changes the rotation angle of the rotary scanning mirror 1 by a small amount and guides it to the radiometer optical section 4.

FIG. 3 is a plan view showing the structure of the light source section 4 of FIG. 1, and also shows the reflecting mirror 2.

As shown in FIG. 3, if the light source section 4 using the calibration light (1) light source 5, the calibration light (2) light source 6 and the calibration light (3) light source 7 is arranged at the focal point of the reflecting mirror, it is rotated. Scanning mirror 1
It is possible to irradiate the radiometer optical section 3 with the calibration light from a plurality of light sources by using one reflecting mirror 2 by changing the rotation angle of.

Calibration light (1) light source 5, (2) light source 6,
(3) The light source 7 includes a halogen lamp as a visible light source,
Various light sources such as a mercury lamp can be arranged, and a hollow black body or the like can be arranged as an infrared light source. The arrangement order does not matter.

In this way, the measurement light d, the calibration light (1) a, the calibration light (2) b, and the calibration light (3) c are introduced into the radiometer optical section 3 during one rotation of the scanning mirror.

The calibration light is for calibrating the light quantity,
It does not calibrate geometrically. Therefore, some aberration is allowed, and the angle of view of the calibration light can be widened. That is, the focus position can have a certain size, and various light sources can be arranged.

[0027]

As described above, according to the present invention, in a visible infrared radiometer having a rotary scanning mirror for scanning an object surface, a reflecting mirror (collimator) having a curved surface for projecting reflected light to the rotary scanning mirror. Mirror) and a plurality of light sources for projecting a plurality of calibration lights on this reflecting mirror, so that optical calibration over the entire aperture of the light receiving optical system of the visible infrared radiometer can be performed using various light sources. It is possible to perform measurement including one rotation while rotating, and it is possible to significantly improve the calibration accuracy.

[Brief description of drawings]

FIG. 1 is a plan view showing the configuration of an embodiment of the present invention.

FIG. 2 is a plan view showing an incident state of measurement light and calibration light of FIG.

FIG. 3 is a plan view showing a configuration of a light source unit 4 of FIG.

[Explanation of symbols]

 1 Rotating Scanning Mirror 2 Reflecting Mirror 3 Radiometer Optical Section 4 Light Source Section 5 Calibration Light (1) Light Source 6 Calibration Light (2) Light Source 7 Calibration Light (3) Light Source 101 Rotation Axis 102 Measurement Light 103 Calibration Light a Calibration Light (1 ) B Calibration light (2) c Calibration light (3)

Claims (2)

[Claims] 1. A light receiving system of a visible infrared radiometer, which mounts a spacecraft as a platform and optically and passively scans a scanning object such as the earth to obtain visible and infrared measurement light, is calibrated by calibration light. In the calibration system described above, a reflecting mirror as a collimating mirror having a curved mirror configuration for projecting a plurality of calibration beams as parallel light with respect to a rotary scanning mirror having a flat mirror configuration for acquiring the measurement light by scanning an object surface, and the reflecting mirror. And a light source unit for projecting a plurality of light source lights to the reflecting mirror to reflect and emit the plurality of calibration lights, and the optical system over the entire diameter of the light receiving system of the visible infrared radiometer. A full-calibration calibration system for a visible infrared radiometer, characterized in that the calibration can be performed by one rotation of the rotary scanning mirror. 2. The total aperture calibration system for a visible infrared radiation type according to claim 1, wherein the plurality of light sources are configured so that various wavelength regions from visible to infrared are mixed. .