JPH06303502A - Image pickup device - Google Patents

Abstract

PURPOSE:To improve S/N of an infrared image pickup device to obtain a satisfactory picture quality and a high temperature measurement precision. CONSTITUTION:An infrared detector 1 which detects infrared rays to convert them to an electric signal, an A/D converter 3 which converts the electric signal to a digital signal, a memory operation part 4 where the digital signal is stored, an address generating part 7 which sends an address code expressed with plural bits to the memory operation part 4, and a code conversion part 9 which converts the address code from the address generating part 7 to a code by reduction of the number of simultaneously changed bits and sends this code to the memory operation part 4 are provided. By this constitution, the number of input terminals whose logics are simultaneously inverted among input terminals of a memory IC of the memory operation part 4 is reduced, and the supply current change in the address generating part 7 and the code conversion part 9 is suppressed, and the unnecessary electromagnetic radiation due to impedance mismatching of an address code transmission line is reduced to improve S/N of a video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device, and more particularly to a digital infrared image pickup device.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a conventional digital type infrared image pickup device.

Infrared rays radiated from a subject become an electric signal at the infrared ray detector 101, and the signal is preamplifier 10
The signal is amplified by 2 and is converted into a digital signal by the A / D converter 103 according to the control signal from the timing control unit 108. Thereafter, the memory calculation unit 104 performs image processing such as frame addition and storage, sensitivity correction calculation of the infrared detector 101, and the like, and the D / A converter 105 uses the control signal from the timing control unit 108 to convert the analog video signal ( It is converted into a video signal and output, and displayed on the display unit 106. In the memory operation unit 104, the timing control unit 1
Address synchronized with control signal from 08, that is, AD
The position in the screen of each pixel of the converted digital signal is received from the address generation unit 107, and stored in the memory and calculated.

A plurality of memory ICs corresponding to the number of pixels are used as a storage device in the memory operation unit 104, and a memory IC having the number of screens must be used to enable storage of multiple screens. Each of these memory ICs has a plurality of memory ICs depending on the position on the screen from the address generator 107.
A binary address code represented by a plurality of bits is output. The memory IC sequentially writes and reads based on this address code.

[0005]

Since the address input section of the memory IC of the memory operation section 104 has an input capacity,
A charging / discharging current must be passed when inverting the input logic. When a subject is sequentially scanned, for example, when a binary address code is output from the address generation unit 107, a large number of inputs of the address input units of many memory ICs may be logically inverted at the same time. A very large current change occurs in the power supply line of the address input section of the memory IC, fluctuation of the power supply voltage of other electric circuits due to the common impedance of the power supply line, and generation of unnecessary radiation due to impedance mismatch of the input / output circuits. However, there is a problem that noise is superposed on the video signal as a result, which adversely affects the image quality. Particularly, in the infrared imaging device, since the voltage value of the video signal is converted into the temperature to measure the temperature, noise in the video signal deteriorates the accuracy of the temperature measurement of the imaging target.

The present invention has been made in view of such circumstances, and an object thereof is to provide an image pickup apparatus capable of suppressing generation of noise and obtaining good image quality and high temperature measurement accuracy.

[0007]

In order to solve the above-mentioned problems, an image pickup apparatus according to the present invention comprises a detector for detecting light and converting it into an electric signal, and an analog-digital conversion for converting the electric signal into a digital signal. An image pickup apparatus comprising means, storage means for storing the digital signal, and address generation means for sending an address code represented by a plurality of bits to the storage means, the address code from the address generation means being simultaneously It is provided with a code converting means for converting into a code in which the number of changing bits is reduced and sending it to the storage means.

[0008]

As described above, since the address code from the address generating means is converted by the code converting means into a code in which the number of simultaneously changing bits is reduced and sent to the storing means, the change of the power supply current in the address generating means is suppressed. At the same time, unnecessary electromagnetic radiation due to impedance mismatch of the address code transmission path is reduced, and the S / N ratio of the video signal is improved.

[0009]

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

FIG. 1 is a block diagram showing a digital infrared image pickup device according to an embodiment of the present invention. The output side of the infrared detector 1 which detects infrared rays and converts it into an electric signal is connected to the A / D converter 3 via the preamplifier 2,
The output side of the / D converter 3 is connected to the memory operation unit 4. The memory calculation unit 4 is composed of a calculation unit (not shown) and a plurality of memory ICs, and performs image processing such as frame addition and storage, and sensitivity correction calculation of the infrared detector. The output side of the memory operation unit 4 is connected to the D / A converter 5,
The output side of the A converter 5 is connected to the display 6.

An address generator 7 for outputting an address code A represented by a plurality of bits is connected to the input side of the memory IC of the memory operation unit 4 via a code converter 9. A timing controller 8 is connected to the address generator 7, the A / D converter 3 and the D / A converter 5 to control the timing of each.

The code conversion unit 9 includes an address generation unit 7
The binary address code A from is converted into the address code B in which the number of bits that change simultaneously is reduced, and the address code B is sent to the input side of the memory IC of the memory operation unit 4.

Next, the operation of the infrared image pickup device of this embodiment will be described.

Infrared rays from the subject are converted into electric signals by the infrared detector 1, the signals are amplified by the preamplifier 2, and converted into digital signals by the A / D converter 3 by the control signal from the timing control section 8. It is input to the memory IC of the memory calculation unit 4.

Further, the address generator 7 receiving the control signal from the timing controller 8 outputs the address code A, and the code converter 9 converts the address code A into the address code B in which the number of simultaneously changing bits is reduced. Then, the data is sent to the input side of the memory IC of the memory calculation unit 4. To give a typical example of code conversion (conversion from binary code to Gray code), A has k + 1 digits,

[Equation 1] And when

[Equation 2] And

[Equation 3] Convert to.

When sequentially scanning from A = 0 to A = 2 ^{k + 1} -1, the address code A is maximum when changing to A = 2 ^k -1 and A = 2 ^k , and the lower k digits are from 1 to 1 at the same time. Although it is inverted to 0, the above conversion does not cause a simultaneous change of two digits or more over the entire scanning area.

Numerical values of a model having a current change depending on the input capacity of the memory IC of the memory operation unit 4 are shown below. Memory i
C input capacitance 10 [pF], simultaneous change address code 10
Digit, address code change time 10 [ns], signal potential difference 4 [V] for logic inversion, and 10 memory ICs, current change per unit time is about 4 × 10 ⁷ [A / s] Becomes the value of. This causes a large variation due to the inductance component of the common impedance of the power supply line with the other electric circuit section, but since the code conversion section 9 causes the simultaneous change of the address code to one digit at the maximum, it adversely affects the image quality and the like. It is possible to suppress the noise that causes the noise to 1/10. Therefore, it is possible to reduce the noise that is superimposed on the video signal, and obtain good image quality and high accuracy of temperature measurement.

The memory operation unit 4 which has received the address code B
Then, storage and calculation in the memory IC are performed. D / A
The converter 5 converts the digital signal from the memory operation unit 4 into an analog video signal (video signal) by the control signal from the timing control unit 8, and the analog video signal is displayed by the display unit 6.
Is displayed in.

In the above embodiment, the case where the present invention is applied to the infrared image pickup device has been described, but the present invention may be applied to other image pickup devices other than the infrared image pickup device.

Further, in the above-mentioned embodiment, the example in which the binary code from the address generator 7 is converted into the Gray code has been shown, but it goes without saying that the present invention is not limited to this.

[0021]

As described above, according to the image pickup device of the present invention, the change in the power supply current in the address generating means is suppressed, and the unnecessary electromagnetic radiation due to the impedance mismatch of the address code transmission line is reduced. The noise superimposed on the video signal is reduced, and good image quality and high accuracy of temperature measurement can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a digital infrared image pickup device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional digital infrared image pickup device.

[Explanation of symbols]

 1 infrared detector 3 A / D converter 4 memory calculator 7 address generator 9 code converter

Claims (1)

[Claims] 1. A detector for detecting light and converting it into an electric signal, an analog-digital conversion means for converting the electric signal into a digital signal, a storage means for storing the digital signal, and a plurality of storage means. In the image pickup apparatus having an address generating means for transmitting an address code represented by the bit, a code to be transmitted to the storage means by converting the address code from the address generating means into a code in which the number of simultaneously changing bits is reduced. An image pickup apparatus comprising a conversion unit.