JPS61146077A - Infrared image projection device - Google Patents

Abstract

PURPOSE:To eliminate a narcissus signal in an infrared image pickup device to obtain a good quality image by extracting and storing a narcissus signal element from an infrared video signal, and applying compensation depending on the memory contents of the objective infrared image. CONSTITUTION:The objective infrared image obtained by scanning a scanning mirror 3 is photoelectrically converted by an infrared detector 4 to form image signal including narssicus signal elements. This signal is successively converted to digital signal by an A/D converter 10 and stored in the first memory 11a. On the other hand, in the initial stage of image pickup, the infrared rays from the objective is shielded by a knife edge 14 and under uniform background light only the narcissus signal is extracted and stored in the second memory 11b. Then the output of the second memory 11b is subtracted from the output of the first memory 11a and by the elimination circuit 12 the narcissus signal is eliminated, thus, only the signal of the objective body is extracted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an infrared imaging device, and more particularly to an infrared imaging device using a digital image processing method to remove the Narcissus spot.

Infrared imaging equipment uses a scanner to capture infrared rays emitted from a target object, focuses the captured infrared rays on an infrared detector installed on the optical path via an infrared optical system, and converts them into video signals by the infrared detector. Then, the video signal is image-processed and the temperature pattern of the target object is displayed as an image on the display unit.

The optical system of this infrared imaging device uses a refractive receiving optical system, and the optical lens that targets infrared light with a wavelength of around 10 μm is made of germanium material due to its cost and durability. . The refractive index of this germanium is about 4
If the fabric is left alone, the surface reflection is extremely large. Therefore, they are usually used with an anti-reflection coating applied to their surfaces, but at present the reflection of infrared rays from the lens surface is much greater than that of visible light optical systems. Therefore, the infrared rays emitted from the infrared imaging device are reflected by the lens surface and are incident on the infrared detector. This incident light is converted by an infrared detector into a Narcissus signal, which is image-processed together with the video signal, and a Narcissus spot is displayed superimposed on the video pattern near the center position of the display section.

Therefore, in an infrared imaging device using a refractive light receiving optical system, an infrared imaging device that removes the Narcissus spot that does not correspond to the target object and displays only the temperature pattern of the target object is required.

In particular, in recent years, in order to improve display image quality, a method has been adopted in which video signals are converted into digital signals and displayed, and it has become necessary to remove Narcissus spots in this method.

[Conventional technology]

FIG. 4 shows a diagram of the principle of generation of the Narcissus signal.

In FIG. 4, infrared rays A emitted from a target object 1 are captured and refracted by an optical system 2 consisting of an ahocus lens 21, a refractive lens 22, etc., and are incident on an infrared detector 4 via a scanning mirror 3. .

On the other hand, infrared rays B generated by the temperature of the infrared imaging device (hereinafter referred to as the device) are focused near the center of the refracting lens 22 by the scanning mirror 3, reflected by the refracting lens 22, and incident on the infrared detector 4. be done.

FIG. 5 is an image display example of a Narcissus spot. Narcissus spot D is displayed near the center of the display section 5, and its brightness is proportional to the difference in temperature between the device temperature and the target object. That is, since the low-temperature infrared detector 3 is inside the device, the device temperature is lower than the target object temperature, and the Narcissus spot is displayed with lower brightness than the target object.

FIG. 2 is a block diagram of a conventional infrared imaging device. In the figure, a position detection circuit 6 inputs the scanning signal output from the scanning mirror 3, detects a position near the center of scanning, and outputs a detected position signal to a correction voltage generation circuit 7. The correction voltage generating circuit 7 inputs a positive potential correction signal E having a maximum voltage at the center position to one end of the adding circuit 8, as shown in E in FIG. 3, in synchronization with the timing of the input position signal.

On the other hand, the negative potential Narcissus signal (FIG. 3F) output from the infrared detector 4 is input to the other input terminal of the adder circuit 8. After the addition circuit 8 adds the re-input signals and removes the Narcissus signal, the image processing section 9 performs image processing, and displays an image of only the target object on the display section 5.

[Problem that the invention seeks to solve]

The above-mentioned infrared imaging device uses an analog image processing method that performs analog image processing on the output video signal of the infrared detector. In recent years, in order to improve image display quality, a digital image processing method has been adopted in which the output video signal of an infrared detector is converted into a digital signal, and the digital signal is processed and displayed. needed to be removed.

[Means for solving problems]

The present invention provides an infrared imaging device that removes the Narcissus spot of the digital image processing method described above. It has an extraction means for extracting a Narcissus signal component due to reflection of the target object, and a storage section for storing the extracted Narcissus signal component, and further includes a video signal corresponding to an infrared image of the target object according to the storage contents of the storage section. This is done by an infrared imaging device that includes a removal circuit that corrects and removes the Narcissus signal component from the video signal.

[Effect]

The infrared radiation of the target object and the device captured by the scanning of the scanning mirror is photoelectrically converted by an infrared detector to become a video signal containing a Narcissus signal component. This signal is A/
The signals are sequentially converted into digital signals by a D converter and stored in a first memory provided in the storage section.

On the other hand, at the initial stage of imaging the target object, the light path from the target object is shielded with a low-temperature knife to block infrared rays from the target object to the scanning mirror, and the Narcissus signal component is transmitted under uniform background light. Only the corrected signal is extracted and stored as a correction signal in a second memory provided in the storage section.

Next, the video signal containing the Narcissus signal component outputted from the first memory and the Narcissus signal component stored in the second memory section are sequentially input to the removal circuit for each corresponding position (for each pixel), and the first 2nd than the memory signal level of
The Narcissus signal is removed by subtracting the memory signal level of , and only the signal from the target object is extracted. As a result, only the video signal dependent on the temperature pattern of the target object is output, and a clear image without narcissism can be obtained.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of an infrared imaging device according to an embodiment of the present invention, and the same parts as in FIGS. 2 and 4 are denoted by the same reference numerals. In the figure, the infrared imaging device of one embodiment captures infrared rays emitted by scanning a target object,
An optical system 2 consisting of an ahocus lens 21 and a refractive lens 22 that condense light onto an infrared detector 4, a scanning mirror 3, an infrared detector 4 that photoelectrically converts the captured infrared rays into an analog signal, and an infrared detector 4 that converts the captured infrared rays into an analog signal. A/D converter 10 that converts the analog signal converted by the converter 4 into a digital signal.
, a first memory Ila provided in the storage unit 11 and storing a video signal of a target object containing a Narcissus signal component converted by the A/D converter 10; a first memory Ila and a second memory Ilb. a changeover switch 13 for switching the input of
b, a removal circuit 12 which inputs the output signals of the first memory lla and the second memo 1b, performs subtraction processing to remove the Narcissus signal component, and extracts the signal of only the target object; An image processing unit 9 that processes and displays an output signal; a display unit 5; a knife edge 14 that is provided on the condensing optical path and functions to block infrared rays from the target object and provide a uniform background; It is composed of a changeover switch 13 and a control section 15 that controls the operation of the storage section 11.

In its operation, infrared rays emitted from a target object are collected and captured by the optical system 2 and scanning by the scanning & 113, reach the infrared detector 4, and are converted into a video signal. Further, the infrared rays emitted from the device are reflected by the lens of the optical system 2, focused at the scanning center position of the scanning mirror 3, and reach the infrared detector 4, where they are mixed into the video signal as a Narcissus signal component. The analog video signal thus converted is converted into a digital signal by the A/D converter 0 and is input to the first memory lla of the storage section 11.

The storage unit 11 includes a first storage area lla and a second storage area llb. In the first storage area lla, a video signal in the form of a Narcissus signal superimposed on an external video signal is stored for one screen.

On the other hand, at the initial stage of the imaging operation, the controller 7 is operated to insert the low-temperature knife 14 into the condensing optical path C, and the changeover switch 13 is switched to change the output of the A/D converter 10 and the second memory. Connect the inputs. As a result, infrared rays from the direction of the target object 1 are blocked, and only the Narcissus signal component is stored as a correction signal for one screen in the second memory. Note that the correction signal in this case is actually stored in a form obtained by subtracting the uniform background pattern component from the imaged Narcillus pattern signal, and such arithmetic processing is performed by the control unit 15.

Both signals for one screen stored in the first and second memories are controlled by a control circuit 15 and are sequentially read out pixel by pixel. These two systems of signals are then sequentially input to the removal circuit 12, which subtracts the Narcissus signal component from the video signal. By the subtraction processing by the removal circuit 12, the Narcissus signal is removed, and a signal of only the target object is obtained for one screen. The output signal of the removal circuit 12 is subjected to image processing in the image processing section 9 and displayed as an image on the display section 5.

In this way, by using the Narcissus signal component stored in the second memory 11b and performing subtraction processing to remove the Narcissus signal each time the target object is imaged for one screen, all captured video images are created using the Narcissus spot. The result is a clear image with no blemishes.

Note that if the loading and updating of the Narcissus signal component to the second memory llb is done automatically each time the device is started or at a predetermined time interval, it will be possible to always accurately image images by following changes in the environmental temperature. can be displayed.

〔Effect of the invention〕

As described above, according to the present invention, the Narcissus signal in an infrared imaging device using a digital image processing method is removed, and a high-quality image display can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an infrared imaging device according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional infrared imaging device, and FIG. 3 is a block diagram of a conventional infrared imaging device.
FIG. 4 is a signal waveform diagram for explaining the operation of removing the Narcissus signal of a conventional infrared imaging device, FIG. 4 is a diagram of the principle of generation of the Narcissus signal, and FIG. 5 is an example of an image display of a Narcissus spot. In the figure, 1 is a target object, 2 is an optical system, 21 is an ahocus lens, 22 is a refractive lens, 3 is a scanning mirror, 4 is an infrared detector, 5 is a display unit, 6 is a position detection circuit, and 7 is a correction voltage 8 is an adder circuit, 9 is a video processing section, 10 is A
/D converter, 11 is a storage section, lla is a first memory, l
lb is a second memory, 12 is an elimination circuit, I3 is an on/off switch, I4 is a knife, and I5 is a control section.

Claims (1)

[Claims] An infrared imaging device that converts infrared rays emitted from a target object into a video signal and displays an image, comprising an extraction means for extracting a Narcissus signal component due to reflection from the device itself, and a storage section for storing the extracted Narcissus signal component. , further comprising a removal circuit for removing the Narcissus signal component from the video signal by correcting the video signal corresponding to the infrared image of the target object according to the content stored in the storage unit. Video equipment.