JPH01260329A - Infrared imaging apparatus - Google Patents

Abstract

PURPOSE:To easily and inexpensively perform DC reproduction, by setting the average radiation quantity from an objective space as a reference standard. CONSTITUTION:Afocal optical systems 1, 2 have a function of condensing the infrared rays from an object as luminous flux. A mechano-optical scanner 4 has a function of scanning the incident luminous flux all over in a two-dimensional space. An image forming lens 5 has a function of forming the luminous flux into an image on an infrared ray detector 6 and the infrared ray detector 6 has a function of outputting an electric signal corresponding to the intensity of the incident infrared rays. The radiation from an objective space is condensed by a condenser 71 and transmitted to a focal plane 3 by a non-imaging type optical fiber 7 to obtain a reference standard level and the signal corresponding to said reference level is clamped to reproduce a DC component.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an infrared imaging device, and more particularly to an infrared imaging device that is improved in regenerating a DC component lost in an AC coupling method.

[Conventional technology]

The parallel light flux in the objective space formed by the afocal optical system is scanned by a two-dimensional mechanical-optical scanner, and the output consonant light is imaged and detected by an infrared detector. AC-coupled infrared imaging devices, which amplify and process the image in a device and display it on a display, are well known these days. In this case, the output obtained by the infrared detector is obtained in the form of a weak AC component superimposed on a large DC component, and this AC component has a level corresponding to the incident light from the object space. For this reason, the output amplification of the infrared detector is performed by AC coupled amplification that cuts the DC component, and in the final level display, the level of the incident light is determined by taking into account a reference level that uses the average value of the DC component, etc. A so-called electrical clamping process is required.

Conventionally, regeneration of the DC component lost in the AC coupling method requires 2
The signal level during the period when the dimensional mechanical-optical scanner is scanning the inner surface of the infrared imager is a reference standard level,
The output voltage can be reproduced by electrically clamping it to this reference level potential, or as shown in FIG. DC regeneration was performed by placing a reference heat source 8 and electrically clamping the signal while the light beam was scanning the reference heat source 8 using the same mechanical-optical scanner 4 as a reference level.

Fig. 3 shows that a mechanical optical scanner 4 captures the parallel light obtained by the afocal optical system 1.2 at the so-called pupil position, which is detected by an infrared detector 6 using an imaging lens 5, and then transferred to an AC coupled amplifier. This shows the contents of the amplification and processing 1 displayed on the signal processing 9 display and the like.

[Problem to be solved by the invention]

In the conventional DC regeneration described above, if the signal corresponding to the inner surface of the infrared imaging device is to be set at a reference standard level, the temperature inside the device is usually quite high and varies depending on the location, so DC regeneration cannot be performed reliably. The disadvantage is that it is difficult to

Furthermore, when the reference heat source is built into the device, there is a drawback that the device becomes larger and more expensive because the heat reference member, its power source, etc. must be incorporated.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an inexpensive infrared imaging device that can perform DC regeneration easily and reliably.

[Means to solve the problem]

The device of the present invention scans the light beam in the objective space obtained through the optical system with a two-dimensional optical scanning mechanism, and displays the output detected by the infrared detector after performing AC coupling amplification and predetermined signal processing. In an infrared imaging device, the reference standard level when regenerating the DC component lost due to AC coupling amplification is defined as the average radiation amount of light in the objective space that enters the infrared imaging device and is focused on the focal plane in the optical system. It is equipped with the means to guide the image.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

1 and 2 are the first and second embodiments of the present invention, respectively.
It is a block diagram of an Example.

1 and 2, the afocal optical system 1,
2 has a function of condensing infrared rays from an object as a luminous flux, a mechanical optical scanner 4 has a function of scanning the incident luminous flux in a two-dimensional space without corners, and an imaging lens 5 condenses the luminous flux. It has a function of forming an image on an infrared detector 6, and the infrared detector 6 has a function of outputting an electric signal according to the intensity of incident infrared light.

The light beam scanned by the mechanical-optical scanner 4 is focused on the focal plane 3 within the afocal optical system, so by arranging the reference standard level within this focal plane, a signal corresponding to this reference standard level is extracted. This signal can be clamped to reproduce the DC component.

As a reference standard level, in the embodiment of FIG. I'm taking it.

In addition, in the second embodiment shown in FIG. 2, the radiation from the objective space is focused by a condenser 91, and the radiation from the objective space is imaged by a reference light waveguide 9 whose interior is mirror-finished. This is done by transmitting it to the focal plane 3 and using it as a reference standard.

〔Effect of the invention〕

As explained above, the present invention enables infrared imaging to easily and inexpensively perform DC reproduction by using the average radiation amount from the objective space as a reference standard, and to provide higher quality infrared images. This has the effect of allowing the construction of devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment of the present invention, and FIG. 3 is a block diagram showing an example of a conventional infrared imaging device. 1.2... Afocal optical system, 3... Focal plane, 4
...Mechano-optical scanner, 5...Imaging lens, 6
... Infrared detector, 7, 9 ... Reference light waveguide, 8
...Reference heat source.

Claims (1)

[Claims] In an infrared imaging device that scans the light flux in the objective space obtained through an optical system with a two-dimensional optical scanning mechanism and displays the output detected by an infrared detector after performing AC coupling amplification and predetermined signal processing, DC lost due to combined amplification
It is characterized by comprising a means for guiding the average radiation amount of light in the object space incident on the infrared imaging device as a reference standard level when reproducing the component, and forming an image on a focal plane in the optical system. Infrared imaging device.