JPH0566156A - Scanning radiometer - Google Patents

Abstract

PURPOSE:To change moment visual field and automatically vary space resolution by using a diaphragm opening of opening variable type, and changing its size by a variable opening mechanism. CONSTITUTION:A signal processing part 7 has a means for setting the opening size (a) of a diaphragm opening 5 to O-d (the diameter of the light receiving surface of a detector 4) by controlling a variable opening mechanism 6, and conducts signal processing according to the value of (a) or the value of space resolution. The space resolution is regulated by moment visual field and the distance from a radiometer to a material subjected to image pickup, and the moment visual field is the ratio a/f of the focus distance (f) of an optical system 3 and the size (a) of the opening 5. The maximum value of (a) is limited by the diameter (d), but the value of (a) is conformed to the value of the space resolution in 1:1. Thus, the processing part 7 minimizes the opening 5 and the extends the signal band, when the space resolution is enhanced to shorten sampling period. When the space resolution is lowered, the processing part 7 receives a set program or external command and executes signal processing according to the resolution as to control conversely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning radiometer for optically scanning an object to be imaged.

[0002]

2. Description of the Related Art As is well known, a scanning radiometer scans an object to be imaged with a scanning mirror, obtains image pickup light, collects the image pickup light with an optical system, and forms a diaphragm aperture at a focal position of the optical system. A device that obtains an image of the object to be imaged by subjecting the detector to an appropriate amount of light to form an image on the detector and subjecting the output signal of the detector to signal processing. It may be mounted on.

Here, the spatial resolution of the scanning radiometer is the instantaneous field of view (ratio between the focal length of the optical system and the aperture of the detector (that is, the size of the diaphragm aperture)) and the radiometer from the radiometer to the object to be imaged. It is defined by the distance and it has been fixed in the past.

[0004]

As described above, since the conventional scanning radiometer has a fixed spatial resolution, it hardly causes any trouble when it is installed on the ground, but it does not interfere with an artificial satellite or the like. When installed and used for observing the ground surface, if the spatial resolution is fixed, it is not possible to make observations according to the conditions of the ground surface, such as making coarse observations to some extent and making detailed observations in the event of a disaster, for example. There is.

An object of the present invention is to provide a variable resolution scanning radiometer capable of automatically variably setting the spatial resolution.

[0006]

In order to achieve the above object, the scanning radiometer of the present invention has the following constitution. That is, the scanning radiometer of the present invention includes a scanning mirror that scans an object to be imaged; an optical system that collects the imaging light from the scanning mirror; and an electrical conversion that receives the imaging light from the optical system through a diaphragm aperture. A detector for controlling the output signal of the detector; in a scanning radiometer; the aperture of the diaphragm aperture is variable, and a variable aperture mechanism capable of varying the size of the aperture. And a means for controlling the variable aperture mechanism is provided in the signal processing section.

[0007]

Next, the operation of the scanning radiometer of the present invention constructed as described above will be described. The spatial resolution of a scanning radiometer is defined by the instantaneous field of view and the distance from the radiometer to the imaged object, which is determined by the ratio of the focal length of the optical system to the size of the aperture. Therefore, in the present invention, the diaphragm aperture is of variable aperture type, the size of the aperture is changed by a variable aperture mechanism that operates under the control of the signal processing unit, the instantaneous visual field is changed, and the spatial resolution is automatically changed. ..

As a result, when the scanning radiometer of the present invention is mounted on an artificial satellite or the like and used for observing the ground surface, it is usually observed with a coarse resolution, and when a disaster such as a fire or earthquake occurs, it is observed with a fine resolution. Observations can be performed according to the conditions of the ground surface, such as

[0009]

1 shows a scanning radiometer according to an embodiment of the present invention. In FIG. 1, a scanning mirror 1 scans an object to be imaged (not shown). The imaging light 2 acquired by the scanning mirror 1 is condensed by the optical system 3 and forms an image on the detector 4 arranged at the focal position.

At this time, a diaphragm aperture 5 is provided on the front surface of the detector 4, that is, at the focal position so that an appropriate amount of light is incident on the detector 4, but in the present invention, this diaphragm is used. The size of the opening 5 is variable, and a variable opening mechanism 6 for changing the size of the opening is provided.

The signal processing unit 7 performs signal processing on the output signal of the detector 4 and outputs a video signal of the object to be imaged. In the present invention, the variable aperture mechanism 6 is controlled to control the aperture opening 5.
A means for setting the aperture size a of a to an appropriate value between a = 0 and a = d (d is the diameter of the light receiving surface of the detector 4 in the illustrated example) is provided, and the value of a, that is, the value of the spatial resolution. Signal processing according to the above.

That is, the spatial resolution of the scanning radiometer is defined by the instantaneous field of view and the distance from the radiometer to the object to be imaged. The instantaneous field of view is the focal length f of the optical system 3 and the aperture size of the diaphragm aperture 5. It is a ratio (a / f) with a. Therefore, in the illustrated example, since the aperture opening 5 is provided on the front surface of the detector 4,
As shown in FIG. 2A, the maximum value of the aperture size a of the diaphragm aperture 5 is restricted by the diameter d of the light receiving surface of the detector 4, and the value of the aperture size a is paired with the spatial resolution value. Corresponds to 1.

Therefore, the signal processing unit 7 reduces the aperture opening 5 when increasing the spatial resolution, widens the signal band and shortens the sampling period, and reduces the aperture resolution 5 when decreasing the spatial resolution. As well as
A preset program that performs signal processing according to the resolution, such as narrowing the signal band and lengthening the sampling cycle, or performing the extraction (average) processing using the short sampling cycle similar to the case of high resolution. According to
Alternatively, it is executed by receiving a command from the outside.

As shown in FIG. 3, when the optical system 3 is composed of the condensing system 3a and the relay system 3b, the focal point is located between the condensing system 3a and the relay system 3b. Therefore, the diaphragm aperture 5 and the variable aperture mechanism 6 are arranged in the optical system 3 as shown in FIG.
However, the operation is the same as that described above.

[0015]

As described above, according to the scanning radiometer of the present invention, the diaphragm aperture is of the variable aperture type, and the size of the aperture is changed by the variable aperture mechanism operating under the control of the signal processing unit. Since the instantaneous visual field is changed and the spatial resolution can be automatically changed, when the scanning radiometer of the present invention is mounted on an artificial satellite or the like and used for observing the ground surface, it is usually observed with a coarse resolution to some extent. For example, when a disaster such as a fire or an earthquake occurs, there is an effect that observation can be performed with a fine resolution according to the condition of the ground surface.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a scanning radiometer according to an embodiment of the present invention.

FIG. 2 is a relationship diagram between a detector and a diaphragm aperture in the scanning radiometer shown in FIG. 1, where (a) shows a case where the aperture size is the same as the light receiving surface of the detector, and (b) shows The case where the aperture size is smaller than the size of the light receiving surface of the detector is shown.

FIG. 3 is a configuration diagram of a scanning radiometer according to another embodiment of the present invention.

[Explanation of symbols]

 1 Scanning Mirror 2 Imaging Light 3 Optical System 3a Condensing System 3b Relay System 4 Detector 5 Aperture Aperture 6 Variable Aperture Mechanism 7 Signal Processor

Claims (1)

[Claims] 1. A scanning mirror for scanning an object to be imaged;
An optical system that collects the imaged light from the scanning mirror; a detector that receives the imaged light from the optical system through a diaphragm aperture and electrically converts it; a signal processing unit that processes the output signal of the detector;
A scanning radiometer including: a diaphragm aperture having a variable aperture size, and a variable aperture mechanism for changing the aperture size; and means for controlling the variable aperture mechanism in the signal processing unit; And a scanning radiometer.