JPS6333630A - Signal processing for 2-d infrared sensor - Google Patents

Abstract

PURPOSE:To enable signal processing accurately regardless of the mixing of positive and negative signals, by storing a signal into separate memories corresponding to positive or negative or a modulation mode as obtained by the modulation of infrared rays incident into a 2-D infrared sensor at a fixed cycle. CONSTITUTION:An infrared sensor 19 is made up of N lines of infrared detectors arranged (n) per line and detects infrared rays incident through a light modulator 20'. The light modulator 20' modulates an incident light by vibrating slits formed per line of infrared sensors 19 to make outputs of the infrared sensors 19 a positive or negative signal at each line. This signal is converted into a digital signal with an A/D modulator 21 and determined to be positive or negative with a positive/negative decision circuit 22. Then, the signal is stored into a positive memory 27 or a negative memory 28. Outputs of both of the memories 27 and 28 undergo a subtraction processing with a subtractor 25 and the results are converted with a D/A converter 26 into an analog signal to be outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a No. 18 processing method for a two-dimensional infrared sensor that converts the temperature distribution of an object into a two-dimensional signal.

2. Description of the Related Art Two-dimensional infrared sensors in which a plurality of infrared detectors are two-dimensionally arranged have recently come to be used in fields such as heat management processes for products. FIG. 5 shows an example of a two-dimensional infrared sensor.

The infrared detection 118 is set to n([1 in the horizontal direction, Nl1 in the vertical direction)
A two-dimensional infrared sensor 19 is formed by arranging them two-dimensionally.

In the figure, one row in the horizontal direction is indicated by L, and one row in the horizontal direction is indicated by C. Since this two-dimensional infrared sensor uses a pyroelectric element in the infrared detector 1B, it is necessary to use an optical chopper or the like to modulate the incident infrared rays when imaging an object that does not change in temperature. . That is, as shown in FIG.
9. In this case, the light is intermittent over the entire light-receiving surface of the two-dimensional infrared sensor f19 in a field-sequential manner. therefore,
The output signal from the infrared sensor 19 has a waveform (bl) shown in FIG.

1 is a chopper opening/closing signal. When the chipper opening/closing signal 41 is ON, the output signal 42 becomes a positive two-dimensional signal for each line Ll to LN.

On the other hand, when the chopper opening/closing signal 41 is OFF, the output signal 42 becomes a negative two-dimensional signal for each line Ll to LN.

The output signal 42 of the infrared sensor 19 is converted to A by the A/D converter 21.
After being D-converted, a positive signal (hereinafter referred to as P signal) is sequentially stored in the positive memory section 27 and a negative signal (hereinafter referred to as N signal) is sequentially stored in the negative memory section 28 according to the cycle of the chopper opening/closing signal 41. The P signal and N signal stored in the positive memory section 27 and the negative memory section 28 are subjected to a subtraction operation of (P signal) - (N signal) by a subtracter 25, and converted into an analog signal by an OA converter.

Problems to be Solved by the Invention However, this method is effective when there are continuous P signals or N signals on one screen, that is, when one screen is all P signals or N signals. If the P signal and N signal are mixed in the signal, it is impossible to distinguish between the P signal and the N signal, so signal processing cannot be performed.

The object of the present invention is to solve the above problems and provide a signal processing method that can reliably process signals even when P signals (!:N signals) are mixed on one screen.

Means for Solving the Problems In order to achieve the above goals, the present invention has a two-dimensional field sensor in which infrared detectors are two-dimensionally arranged in N lines each line nfrIA, and the infrared light incident on each line of the sensor is arranged at a constant period. The infrared signals obtained by modulation are stored in separate memories depending on whether the signal is negative or the modulation mode, and the output from each memory is subtracted.

Effect In the above configuration, if the infrared signal obtained by modulation is stored in separate memories depending on the positive or negative, by subtracting the entire output of each memory, or by storing in separate memories depending on the modulation mode of the infrared signal. If the memory outputs are stored in , each memory output is subtracted, the polarity of the negative component of the obtained signal is inverted, and it is taken out as a serial signal together with the positive component.

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment showing a circuit configuration for implementing the signal processing method according to the present invention. The same parts in the figure as in FIG. 6 are given the same reference numerals. For example, when the P signal and the N signal are mixed on one screen, the optical modulator 20' has a configuration as shown in FIG. The optical modulator 20' includes a modulation plate 51 in which a plurality of horizontally long slits 52 are formed, and this modulation plate 6.
1 is composed of a bimorph limiter 53 that vibrates in the vertical direction. The slit 52 is located at the side 1 of the two-dimensional infrared sensor 19.
The two-dimensional infrared sensor 19 is formed so as to correspond to every other line, and is vibrated by the bimorph vibrator 53 by the line pitch A, so that infrared light is incident on the two-dimensional infrared sensor 19 alternately every other horizontal line.

FIG. 3 shows the output signal waveform from the infrared sensor 19 obtained in this manner. In the figure, 11 and 12 are output signals of one screen each, which are two-dimensional infrared signals in which positive and negative signs are mixed. Now, Ll, L3 of the two-dimensional infrared sensor 19...
When the slit 52 corresponds to the output signal 11, the output signal 11 is obtained.
This output signal 11 is converted into a digital signal by an AD converter 21, and a positive/negative determining circuit 22 determines whether the signal is positive or negative.If the signal is positive, a positive address switching unit 23 converts the signal into a positive memory 2.
7 is designated and stored in the primary memory 27.

- In the case of a negative signal, the negative address switching unit 24 selects the negative memory 2.
8 and stores it in the negative memory 28.

When the modulation plate 51 vibrates and the opening/closing relationship of the slits 52 is reversed, an output signal 12 is obtained and stored in the positive memory 27 and negative memory 28 in exactly the same manner. In this way, positive and negative two-dimensional infrared signals are stored in the positive memory 27 and the negative memory 28.

The P signal and N signal stored in the positive memory 27 and the negative memory 28 are subjected to a subtraction operation of (P signal) - (N signal) in a subtracter 25, and are converted to an analog signal in an OA converter 26, and are converted into 2x A two-dimensional infrared signal of (lpl + INI) is obtained.

FIG. 4 shows another embodiment of the invention. Optical modulator 20' and infrared sensor 19 are similar to the embodiment of FIG. The output of the infrared sensor 19 is AD converted by an AD converter 21 and applied to a memory selection section 31.

The memory selection unit 31 is configured such that the slit 52 is located at the position 27 of the optical modulator 20', that is, the line L1. of the infrared sensor 19. L3
．． . L4. (The state at this time is called a secondary state, and the output signal 42 obtained is called a secondary signal.)
Select one of 35 and 36 and store the output signal. Now, the memory 35 is used to store the primary signal, and the memory 36 is used to store the primary signal.
It shall be used to store all secondary signals. The subtracter 33 performs a subtraction operation of (-secondary signal)-(secondary signal) between the primary signal read out from the memory 35 and the secondary signal read out from the memory 36. At this time, line signals that become P signal-N signal, ie, Ll, L3 . L5.・・・・・・
・Then, 2 x (lpl + INI) is obtained, and N
The line signal that becomes the signal-P signal, that is, L2. L4.
L6. ...In a song, an output of -2X (IPI + INI) can be obtained. When the polarity of only the line signal for which the N signal - P signal is calculated is inverted by the polarity inverting section 34, 2 X (lpl + INI
)tonashi, convert it into an analog signal with the DA converter 26, and
A two-dimensional infrared signal of X(lpl+IN!) is obtained.

The inversion timing of the polarity inversion section 34 may be synchronized with the modulation period of the optical modulator 20'.

As described above, according to the present invention, a two-dimensional infrared signal in which positive and negative line signals are mixed for each line on one screen can be converted into a two-dimensional serial infrared signal with a simple circuit configuration.

Effects of the Invention As described above, the present invention has four infrared detection lines and n infrared detection lines.
The mixed positive and negative infrared signals obtained by effectively modulating the infrared light incident on each line of a two-dimensional infrared sensor arranged in N lines two-dimensionally are stored in separate memories according to the sign of the signal or the modulation mode. This is a signal processing method that converts a two-dimensional serial infrared signal into a two-dimensional serial infrared signal by subtracting the output from each memory.With a simple circuit configuration, a two-dimensional infrared signal containing both positive and negative signals can be converted into a two-dimensional serial infrared signal. be able to.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram for carrying out a signal processing method of an embodiment of a two-dimensional infrared sensor according to the present invention, FIG. 2 is a perspective view showing the main parts of FIG. 1, and FIG. 3 is a circuit block diagram according to the present invention. An infrared signal waveform diagram in the signal processing method, FIG. 4 is a circuit block diagram for implementing the signal processing method of another embodiment of the signal processing method according to the present invention, and FIG. 5 is a diagram of a conventional two-dimensional infrared sensor. FIG. 6 is a perspective view showing an example; FIG. 6 is a circuit block diagram for implementing the entire signal processing method of a conventional two-dimensional infrared sensor;
The figure is an infrared signal waveform diagram in a conventional signal processing method. 1B... Infrared detector, 19... Two-dimensional infrared sensor, 20'... Light modulator, 25.33... Subtractor, 27.28.35.36... ...Memory, 51
...Modulation plate, 52...Slit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 5

Claims (3)

[Claims] (1) The infrared light incident on each line of the two-dimensional infrared sensor is arranged in N lines with n infrared detectors arranged in each line, and the infrared light incident on each line is modulated at a constant cycle, and the obtained signals are divided separately depending on the positive/negative or modulation mode. A signal processing method for a two-dimensional infrared sensor, characterized in that the signals are stored in a memory, and the outputs of each memory are subtracted. (2) A two-dimensional infrared sensor according to claim 1, which determines whether the infrared signal obtained by modulation is positive or negative, and stores the positive signal in a positive signal memory and the negative signal in a negative signal memory. Signal processing method. (3) The first infrared signal obtained by modulation is
2. A signal processing method for a two-dimensional infrared sensor according to claim 1, wherein the signal is stored in a memory and a second memory, and after subtracting the output of each memory, the polarity of the signal of one polarity is inverted.