JPH0676925B2 - Temperature measurement method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an infrared measuring method for measuring an infrared level emitted from an object.

[Prior Art] It is known that all objects having a temperature of absolute zero or more radiate infrared rays from the surface thereof, and between the radiated infrared ray amount (energy amount) and the surface temperature of the object, There is a certain relationship called Planck's radiation formula. Therefore, the surface temperature of the object can be known by measuring the amount of infrared radiation. This infrared amount is detected by the infrared detector, but one infrared detector can only detect infrared rays coming from a certain direction. However, if a mechanism for bending the light path, that is, a scanning mechanism is provided in front of the infrared detector, it is possible to detect infrared radiation coming from various directions.

FIG. 4 is a view showing an example of this method, in which 1 is a rotary mirror which is formed in an annular shape with 10 plane mirrors having slightly different vertical angles, 2 is a silicon window, 3 is a folding mirror, and 4 is a mirror. Is a condenser lens, 5 is a positioning motor, 6 is an infrared detection element arranged in a vertical direction, and 7 are
Is an amplifier provided for each infrared detection element, and is designed to send independent output signals for 10 channels.

In the device thus configured, only infrared rays pass through the silicon window 2 and reach the rotating mirror 1. As described above, since the plane mirrors of the rotary mirror 1 are provided so as to be slightly displaced in the vertical direction, each plane mirror laterally scans a portion of the subject that is slightly displaced in the vertical direction. One rotation of the rotary mirror 1 scans a range of 10 degrees in the vertical direction. On the other hand, ten infrared detectors 6 are arranged in the vertical direction, and the distance between them corresponds to an angle of 1.0 degree in the vertical direction. For this reason, the infrared detector 6 of 10 elements receives the thermal image signal at every 1.0 degree at the same time by the plane mirror of one surface, and the infrared image signal at the position shifted by 1.0 degree from the previous position at the same time at the next plane mirror. . In this way, one rotation of the rotating mirror 1 scans the subject 10 degrees in the vertical direction. In the horizontal direction, the horizontal viewing angle (about 18 degrees) of each plane mirror of the rotating mirror is scanned.

The thermal image signal thus obtained is amplified by each of the ten amplifiers 7 and output. Reference numeral 8 is a temperature table in which data such as that shown in Table 1 whose temperature is corrected by the black body furnace is stored. If a temperature range of, for example, 14 degrees to 23 degrees is required among the temperature ranges shown in Table 1, the temperature range indicated by the symbol a is selected by the switch 9, and the data of the range is written in the conversion table 10.

In this writing, as shown in FIG. 5, the voltage corresponding to the energy of infrared rays, that is, the input voltage value in Table 1 is written on the horizontal axis. Write the temperature at that time on the vertical axis. Although Table 1 is described with an analog signal, since writing is performed with an 8-bit digital signal, it takes a value of 0 to 255. Therefore, the first
Interpolate the missing parts from the values in the table to create data.

In this case, set the lowest value to zero and the highest value to 255. However, the linearity of the infrared detector is guaranteed only in a certain range. Therefore, when the linearity is out of the linear range, the input signal is attenuated by a filter or the like so that the input signal falls within the linearity range.

[Problems to be Solved by the Invention] The temperature of the measurement target thus measured is colored according to the temperature and displayed on a cathode ray tube. It is necessary to write the data to the conversion table each time the measurement condition changes, such as changing the setting range.However, if the setting range is automatically determined, the measurement condition may change during the scanning of the display screen. Since the conversion table is rewritten from the above, there is a problem in that the displayed screen loses continuity and gives a sense of discomfort to the measurer. Further, if the temperature of the measurement target is drastically changed, the conversion table is rewritten every time the temperature change occurs when the setting range is automatically set, and the screen becomes very difficult to see.

[Means for Solving the Problem] In order to solve such a problem, when a change in the measurement condition is detected, a data change detection signal is generated (step 200),
When the change of the measurement condition exceeds the predetermined limit set in the setting range of the temperature of the specific point in the measurement object (step
301, 302) Detect the blanking period of the display (step
202), and rewrite the conversion table during the blanking period so as to meet the new measurement conditions (step 203).
It is a thing.

[Operation] When the measurement condition changes, the conversion table data is rewritten, but the rewriting is performed during the blanking period. In addition, when the temperature of the measurement target changes and the setting range is automatically set, if the temperature of the specific point of the measurement target is within the required limit of the setting range, the data is not rewritten in the conversion table and the predetermined limit Data is rewritten when the value exceeds the limit.

[Embodiment] It is assumed that the setting range is determined according to FIG. 1, and the conversion table is rewritten when the setting range is shifted within the determined setting range. The rewriting is shown in FIG. As such, the display is done during the blanking period. As shown in step 200 in FIG. 2, a change in the measurement condition is first detected. There are various changes in this measurement condition. For example, when the measurement center temperature is changed, when the setting range is changed (when the temperature resolution is changed), when the temperature table is changed, when the room temperature changes, and when the conversion table changes. There are times when the saturated part changes.

Each time the measurement conditions change in this way, step 200
S ”is determined, and in step 201, a predetermined calculation such as interpolation calculation for rewriting the conversion table is performed. When it is determined in step 202 that the blanking period is the display period, the conversion table is rewritten as shown in step 203. If the measurement condition does not change in step 200, the conversion table is not rewritten.

FIG. 3 is a flow chart showing a specific example of changing the setting range. In this case, when the temperature change of the measurement target is detected in step 300, it is determined in step 301 whether the temperature of the specific point of the measurement target has changed to less than 25% of the set range. If it is determined that the value is less than 25%, the conversion table is rewritten as shown in step 303. If it is not less than 25% in step 301, it is determined in step 302 whether or not the temperature of the specific point is 75% or more of the set range. If this determination is "NO", the process is terminated. That is, the current setting range is left as it is and no extra rewriting processing is performed. However, when it is determined that the step 302 is 75% or more, the conversion table is rewritten as shown in step 303.

Next, the operation of automatic setting of the setting range shown in FIG. 1 will be described. In FIG. 1, each symbol is defined as follows.

Pmax: Maximum input in Fig. 5 (digital amount from 0 to 255 corresponding to infrared energy) Pmin: Minimum input in Fig. 5 (digital amount from 0 to 255 corresponding to infrared energy) T _L : Measuring range Minimum temperature set value (analog amount) _TH : Maximum temperature set value in measurement range (analog amount) T _OH : Maximum temperature of measurement target [T _OH = (Pmax), analog amount] T _OL : Measurement target The minimum temperature of [T _OL = (Pmin),
It is an analog quantity] Explaining the case where Pmax and Pmin are the same in FIG. 1, in this case, both the minimum value and the maximum value are outside the setting range (including the case where they are exactly at the boundary) or within the setting range. Is the case where the maximum and minimum set values are equal.

Minimum input value Pmin and maximum input value Pmax in step 100
If it is determined that the input data P is not 255 as shown in step 101 and is not 0 as shown in step 103, the maximum and minimum values of the present set values are too close to each other. If there is. At this time, as shown in step 105, the minimum temperature set value T _L of the measurement range is lowered by 10% of the current set range and the maximum temperature set value T _L of the measurement range is set.
Increase _H by 10% of the current setting range. And step 106
As shown in, it is determined whether or not the temperature difference of the measurement target is 60% of the set range, and the set range is changed until the condition is satisfied.

If the input data P = 255 is determined in step 101, the maximum value of the setting range is too low. Therefore, as shown in step 102, the maximum value is moved to the side higher by the temperature difference of the current setting range amount, and will be described later. The processing after step 117 is performed. If it is determined in step 103 that the input data P = 0, the setting range minimum value is too high, so the minimum value is moved to the lower side by the temperature difference of the current setting range as shown in step 104. Then, whichever of the processing of steps 102 and 104 is performed, it is determined whether or not there is a measurement target in the measurement range as shown in step 117, and when there is no measurement target in the measurement range, the processing is shown in step 119. The measurement range is set to double. If there is still no measurement target within the measurement range, the measurement range is changed to twice the current set range each time until the measurement target falls within the measurement range. Then, the measurement target comes to fall within the measurement range, but as shown in step 118, the measurement range is continuously expanded until both the minimum value and the maximum value of the measurement target fall within the set range.

When it is determined in step 118 that both the minimum and maximum values of the measurement target are within the setting range, as shown in step 112, whether the temperature difference of the measurement target is 60% or less of the setting range. Is judged. The temperature difference of the measurement target is 60% of the setting range
If it is larger, the setting range is too narrow, so as shown in steps 115 and 116, until it reaches 60%,
The minimum setting value is lowered by 10% of the current setting range, and the maximum setting value is raised by 10% of the current setting value. When the temperature difference of the measurement target is 60% or less of the set range in step 112, the reverse operation is performed as shown in steps 113 and 114.

In step 100, it is determined that Pmax = Pmin is not satisfied,
When it is determined in step 107 that the data Pmax is 255 and Pmin is 0, the setting range is too narrow compared to the temperature difference of the measurement target. Therefore, step 105,
As described above in 106, the setting range is expanded until the temperature difference of the measurement target reaches 60% of the setting range. However, if it is determined in step 108 that only the maximum value Pmax of the input data is 255 and the minimum value Pmin is not 0, only the maximum value of the measurement target is outside the measurement range, so as shown in step 109, the set value maximum After increasing the value by 10% of the current setting range, it is determined in step 112 whether the temperature difference of the measurement target is larger or smaller than 60% of the setting range. Thereby, as described above, steps 113, 114 or 115, 116
By the process of, the setting range is expanded or contracted until the temperature difference of the measurement target becomes 60% of the set range. If the minimum value Pmin of input data is 0 and the maximum value Pmax is not 255, the minimum set value is too high.
As shown in 1, lower the minimum setting value by 10% of the current setting range and automatically adjust the setting range in the same manner as above so that the temperature difference of the measurement target is 60% of the setting range. To do.

[Effect of the Invention] As described above, according to the present invention, since the data writing to the conversion table is performed during the display blanking period,
After the display screen is switched, the measurement result of the new condition is displayed, which has the effect of not giving the operator a feeling of strangeness. Since the conversion table is not rewritten while the temperature change is small, there is an effect that stable measurement can be performed even if the temperature change of the measurement target frequently occurs.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining a state in which a setting range is automatically set, FIG. 2 is a flow chart for explaining the first invention, FIG. 3 is a flow chart for explaining the second invention, and FIG. 4 is a diagram showing the configuration of the infrared detecting section, and FIG. 5 is a graph showing the characteristics of the conversion table. 1 ... Rotating mirror, 2 ... Silicon window, 6 ... Infrared detecting element, 7 ... Amplifier, 8 ... Temperature table.

Claims (1)

[Claims] 1. A temperature measuring method for measuring a temperature of a measuring object by a conversion table for outputting temperature data according to an infrared energy value and displaying the temperature on a display screen, wherein a temperature of a specific portion of the measuring object exceeds a set range. The temperature measuring method is characterized in that the temperature is detected, the blanking period of the display is detected at that time, and the conversion table is rewritten during the detected blanking period so as to meet new measurement conditions.