JPH0518826A - Measuring apparatus for temperature distribution - Google Patents

Abstract

PURPOSE:To obtain a measuring apparatus of temperature distribution which is of low cost and has high space resolution and temperature resolution. CONSTITUTION:A measuring apparatus of temperature distribution is equipped with an infrared sensor 11 detecting infrared rays, a chopping means 19 for intercepting intermittently the infrared rays entering the infrared sensor 11 and a sampling means 14 for sampling an output signal of the infrared sensor 11 at a prescribed period at each chopping. A measured temperature is calculated by using a sampling value obtained by this means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation temperature distribution measuring apparatus using a pyroelectric infrared sensor.

[0002]

2. Description of the Related Art In recent years, in security and air conditioning control, there is an increasing demand for measuring the temperature distribution in a room in order to detect the presence or absence of a person in the room and the amount of activity.

Conventionally, there is a method for obtaining a temperature distribution by using a two-dimensional quantum type solid-state imaging infrared sensor as an apparatus for measuring a temperature distribution in space using infrared rays.

On the other hand, methods for obtaining a spatial temperature distribution using a pyroelectric sensor are disclosed in JP-A-64-88391 and JP-A-5-39391.
7-185695, Japanese Patent Laid-Open Nos. 2-183752, 2
As disclosed in the publication such as -196932, there is a method of using a single pyroelectric sensor to mechanically scan the vertical and horizontal directions to detect the input energy in each direction and obtain the temperature distribution. .

[0005]

However, in the case of the quantum type sensor, the measurement temperature accuracy and resolution are high, but since the sensor part needs to be cooled, it becomes expensive and is not suitable for use in household appliances. Is.

On the other hand, the latter one using the pyroelectric sensor is
Due to the problem of low sensor sensitivity, the complexity of the mechanism, and the complexity of signal processing, there were problems to be solved such as low spatial resolution and temperature resolution.

In view of the above problems of the conventional temperature distribution measuring method, the present invention provides a temperature distribution measuring device using an infrared array sensor such as a pyroelectric sensor at low cost and having high spatial resolution and high temperature resolution. The purpose is to do.

[0008]

SUMMARY OF THE INVENTION According to the present invention, an infrared sensor for detecting infrared rays, chopping means for intermittently blocking the infrared rays incident on the infrared sensor, and a constant output signal of the infrared sensor for each chopping. A temperature distribution measuring device comprising: a sampling means for sampling in a cycle; and using the sampled value to calculate a measured temperature.

[0009]

According to the present invention, the infrared rays incident on the infrared sensor are interrupted intermittently by the chopping means, the output signal of the infrared sensor is sampled at a constant period for each chopping, and the measured value is used to measure the measured temperature. calculate.

[0010]

【Example】

Example 1 FIG. 1 shows a schematic diagram of a measuring circuit which is an example of a temperature distribution measuring apparatus according to the present invention. The output signal from the sensor 11 having a plurality of elements is filtered by the filter circuit 12 to remove noise, and then amplified by the amplifier circuit 13. The signal after being amplified by the amplifier circuit 13 is the multiplexer 1
At 4, the signal of each sensor is A /
It is sent to the D converter 15 and subjected to A / D conversion. The resulting digitized signal is a CPU 1 having a memory section for recording data, an arithmetic section, and a clock generating section.
6 is input. Further, the CPU 16 drives the multiplexer 14 and the chopper 19. 17 is a chopper 1
9 is an I / O board for controlling 9.

The timing of the drive signal of the chopper 19 and the output signal of one sensor element is shown in FIG.
As shown in the figure, the output of the sensor element changes according to the opening / closing of the chopper 19.

Next, a method of calculating the maximum value of the output of the sensor element will be described in more detail with reference to FIGS. 3 and 4.

FIG. 3 is a flow chart of the signal processing of the present invention, and FIG. 4 is a diagram for explaining the signal processing contents when the chopper is in an open state, where (a) is an analog of a channel (CH) having a sensor. Signal waveform, (b) is A / of (a)
The digital output value after D conversion, (c) shows the output maximum value change value after the comparison process. Here, the maximum output value when the chopper is in the open state accurately corresponds to the incident infrared light amount and accurately corresponds to the temperature of the measurement object. Therefore, it suffices to detect this maximum output value.

First, the memory data after A / D conversion of all sensor elements (here, it is assumed that there are channels 1 to (CH) to n channels) is cleared (S1). Next, when the input voltage of the chopper 19 corresponding to the sensor input state becomes HIGH (the chopper is open) (S
2) The multiplexer 14 sequentially takes in from the 1st CH to the nCH at a constant sampling speed, and A / D
Conversion is performed (S3, S4, S5, S6). For each channel, the converted value (for example, the i-th data Si) is compared with the maximum value (Smax) in the converted values up to the previous one (S7), and when Si> Smax, the maximum is obtained. The value is updated to set Smax = Si (S8), and in other cases, updating is avoided. After the above comparison calculation processing,
While the input voltage of the chopper is in the HIGH state (S9),
The above operation is repeated to find the maximum value of each CH in the opened state of one chopper.

The data processing time is about 100 μsec for one sensor element, and the sampling cycle f is f when the number of elements is 10 (that is, 10 CH).
= 1 kHz, the chopping frequency during measurement is 10
In the case of Hz, sampling can be performed 50 times for each open state of the chopper. As described above, the one-dimensional temperature distribution can be accurately evaluated by obtaining the calibration curve of the temperature of the measurement object having the known temperature and the maximum output value in advance.

Example 2 Next, another embodiment will be described.

The temperature of the object to be measured corresponds to the maximum output value when the chopper is in the open state as shown in the first embodiment, and the integrated value of the output within a certain period of time when the chopper is in the open state is used.
Can be adapted.

Now, in the same measurement system as in Example 1,
Another method for calculating the measured temperature using the A / D converted digital signal will be described.

FIG. 5 is a diagram for explaining the signal processing contents when the chopper is in the open state. (A) is an analog signal waveform of a channel (CH) with a sensor, (b) is A of (a).
The digital output value after the / D conversion, (c) shows the output value after the integration processing until a certain fixed time. FIG. 6 shows a flowchart of signal processing.

First, the memory data after A / D conversion of all sensor elements (here, there are channels 1 to (CH) to n channels) is cleared (S1). Next, the input voltage of the chopper corresponding to the sensor input state is H
When IGH (the chopper is in the open state) (S2), the multiplexer 14 sets the sampling rate to 1 at a constant rate.
The CHth to nCH are sequentially taken in and A / D converted (S3, S4, S5, S6). For each channel, the converted value (for example, the i-th data Si) is added to the previous integrated value to obtain the value of [Stotal = Stotal + Si] (S7). Next, the above operation is repeated up to the preset number of sampling times (that is, set time) Ko (S8), and the value of each CH in the open state of one chopper is obtained. The one-dimensional temperature distribution could be accurately evaluated by previously obtaining a calibration curve of the temperature of the measurement object having a known temperature and the integrated value at the set time.

The feature of the present embodiment is effective when a lot of noise is included in the sensor output signal, and the first embodiment is likely to be erroneously evaluated by the maximum value of the noise, while in the case of high frequency noise, it is almost left and right. It is something that is not done.

In the above embodiment, after the A / D conversion and before the next data sampling, the integral calculation processing is executed. In that case, however, the sampling cycle may be delayed, so that it is necessary. By taking in all the data within the time period, temporarily storing it in the memory unit, and finally collectively performing the arithmetic processing, higher-speed sampling can be achieved.

Embodiment 3 FIG. 7 shows a schematic structure for explaining an embodiment of the present invention. A pyroelectric infrared array in which a plurality of light receiving portions are provided in a line on the rotating portion 4 is shown. A sensor 1 and a silicon infrared lens 2 for condensing infrared rays on the pyroelectric sensor array are provided on the front surface of the array sensor 1, and the infrared rays incident on the lens 2 are intermittently provided on the front surface of the lens 2. A chopper 3 for shutting off is provided. The rotating unit 4 is mechanically connected to the stepping motor 5.

Now, when the long axis direction of the array sensor 1 is set in the vertical direction and the chopper 3 is driven at 10 Hz, 1/1
The distribution of the amount of radiant heat in the column in the direction in which the sensor 1 and the lens 2 face each other, that is, the temperature distribution can be measured every 0 sec.

FIG. 8 shows a schematic diagram of the measuring circuit. The output signal from the sensor 11 having a plurality of elements is filtered by a filter circuit 12 to remove noise, and then an amplifier circuit 13
Is amplified by. The signal after amplification is sequentially sent to the A / D converter 15 by the multiplexer 14 at a constant sampling period to perform A / D conversion. Reference numeral 16 is a CPU having a memory unit for recording data, a calculation unit, and a clock generation unit, and 17 is an I / O board for controlling the chopper 19 and the stepping motor 18. FIG. 9 shows the timing of the drive signal of the stepping motor, the drive signal of the chopper, and the output signal of the sensor.

Using the above-mentioned measuring system, in the case of measuring the two-dimensional temperature distribution by changing the measuring direction by the rotating mechanism, the same experiment as in Examples 1 and 2 was carried out for each facing direction. The two-dimensional temperature distribution could be measured accurately.

[0027]

As is apparent from the above description, the present invention provides a temperature distribution measuring device using an infrared array sensor such as a pyroelectric sensor, which is low in cost and high in spatial resolution and temperature resolution. Can be done.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of a temperature distribution measuring device according to the present invention.

FIG. 2 is a timing diagram of electric signals of the embodiment.

FIG. 3 is a flowchart of the signal processing of the same embodiment.

FIG. 4 is a diagram for explaining the signal processing of the same embodiment.

FIG. 5 is a diagram for explaining signal processing of another embodiment of the present invention.

FIG. 6 is a flowchart of the signal processing of the same embodiment.

FIG. 7 is a schematic perspective view of another embodiment of the present invention.

FIG. 8 is a schematic view of a measuring circuit of the present invention in the same example.

FIG. 9 is a timing diagram of electric signals of the embodiment.

[Explanation of symbols]

1 Infrared array sensor 2 infrared lens 3 chopper 4 rotating parts 5 Stepping motor 11 sensors 12 Filter circuit 13 Amplifier circuit 14 Multiplexer 15 A / D converter 16 CPU 17 I / O board 18 stepping motor 19 chopper

Claims (4)

[Claims] 1. An infrared sensor for detecting infrared rays, a chopping means for intermittently blocking the infrared rays incident on the infrared sensor, and a sampling means for sampling the output signal of the infrared sensor at a constant cycle for each chopping. A temperature distribution measuring device, comprising: the temperature distribution measuring device; 2. The temperature according to claim 1, wherein the maximum value of the infrared sensor output is updated by sequentially comparing the sampling values for each chopping, and the measured temperature is obtained from the obtained maximum value. Distribution measuring device. 3. The temperature distribution measuring device according to claim 1, wherein the sampling values are sequentially added for each chopping, and the measured temperature is obtained from the added integrated value. 4. An infrared array sensor having a plurality of light receiving portions for detecting infrared rays arranged in an array, a chopping means for intermittently blocking infrared rays incident on the light receiving portions, and a facing direction of the infrared array sensor. A driving means for rotating in a stepwise manner, performing chopping one or more times in each facing direction, sampling the output signal of each of the light receiving sections at a constant cycle for each chopping, and using the sampling value to measure the temperature. A temperature distribution measuring device, characterized in that