JPH0450738A - Infrared measuring instrument - Google Patents

Abstract

PURPOSE:To stably take a measurement without giving the sense of incongruity at the time of display screen switching by providing a means which detects a change in measurement condition, and detects the blanking period of the change when the change is detected and then rewriting a conversion table into new measurement conditions. CONSTITUTION:When the change of one of the measurement conditions such as measurement center temperature, a set range, a temperature table, room temperature, and a conversion table saturated part is detected, specific arithmetic for rewriting the conversion table is carried out. Then when a blanking period is judged, the conversion table is rewritten. Consequently, the stable measurement is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an infrared measuring device that measures the level of infrared rays emitted from an object.

[Prior Art] It is known that any object with a temperature above absolute zero emits infrared rays from its surface, and there is a relationship between the amount of radiated infrared rays (amount of energy) and the surface temperature of the object. There is a certain relationship called Blank's radiation formula9. Therefore, the surface temperature of an object can be determined by measuring the amount of infrared radiation. This amount of infrared rays is detected by an infrared detector, but one infrared detector can only detect infrared rays coming from a certain fixed direction. However, if a mechanism for bending the path of light, that is, a scanning mechanism is provided in front of the infrared detector, infrared radiation coming from various directions can be detected.

FIG. 4 is a diagram showing an example of this method, in which 1 is a rotating mirror configured in an annular manner with 10 plane mirrors having slightly different vertical angles, 2 is a silicon window, 3 is a folding mirror, and 4 is a condensing lens; 5 is a positioning motor; 6 is 10 infrared detection elements arranged vertically;
Reference numeral 7 denotes an amplifier provided for each infrared detection element, and is configured to send out independent output signals for 10 channels.

In the device configured in this manner, only infrared rays pass through the silicon window 2 and reach the rotating mirror 1. As described above, the rotating mirror 1 is provided with plane mirrors that are slightly shifted in the vertical direction, so each plane mirror scans a portion of the subject that is slightly shifted in the vertical direction in the lateral direction. One rotation of the rotating mirror 1 scans a range of 10 degrees in the vertical direction. On the other hand, ten elements of the infrared detector 6 are arranged in the vertical direction, and rWI19iI corresponds to an angle of 1.0 degrees in the vertical direction.

Therefore, one plane mirror has 10 elements of infrared detector 6.
, thermal image signals at intervals of 0 degrees are simultaneously received, and the next plane mirror simultaneously receives thermal image signals at a position shifted by 1.0 degrees from the previous position. In this way, one rotation of the rotating mirror 1 scans 10 degrees in the vertical direction of the subject. Also,
In the horizontal direction, the horizontal viewing angle (approximately 18 degrees) of each plane mirror of the rotating mirror is scanned.

The thermal image signals thus obtained are each amplified by ten amplifiers 7 and output. Reference numeral 8 denotes a temperature table, in which data such as the one shown in Table 1, which has been temperature-corrected in a blackbody furnace, is stored. If, for example, a temperature range from 14 degrees to 23 degrees is required among the temperature ranges in Table 1, the temperature range indicated by symbol A is selected using the switch 9, and the data for that range is written in the conversion table 10.

Table 1 As shown in FIG. 5, the voltage corresponding to the energy of infrared rays, that is, the Kugata voltage value in Table 1 is written on the horizontal axis, and the temperature at that time is written on the vertical axis. Table 1 is written using an analog signal, but since writing is performed using an 8-bit digital signal, the values range from 0 to 255. For this purpose, data is created by interpolating the missing portions from the values in Table 1.

In this case, the lowest value is set to zero and the highest value is set to 255.

However, the linearity of infrared detectors is guaranteed only within a certain range. For this reason, if the signal falls outside of the linearity range, the Kugata signal is attenuated by a filter or the like so that it falls within the linearity range.

[Problems to be Solved by the Invention] The temperature of the object measured in this manner is colored in accordance with the temperature and displayed on a cathode ray tube. It is necessary to write data to the conversion table every time the measurement conditions change, such as when changing the setting range. However, if the setting range is automatically determined, if the measurement conditions change while the display screen is being scanned, the data will be written in the middle of the screen. Since the conversion table is rewritten from the beginning, the displayed screen loses continuity, which creates a sense of discomfort for the person taking the measurement. Additionally, if the measurement target is subject to rapid temperature changes, if the setting range is set to automatic, the conversion table will be rewritten each time a temperature change occurs, resulting in a screen that is very difficult to read.

[Means for Solving the Problems] In order to solve such problems, a first invention is such that data is rewritten to a conversion table during a display blanking period.

In the second aspect of the invention, the conversion table is rewritten when the temperature at a specific point of the object to be measured exceeds a predetermined limit set in a set range.

[Operation] In the first invention, data in the conversion table is rewritten when measurement conditions change, and the rewriting is performed during the blanking period of the display.

The second invention is that when the temperature of the measurement object changes and the setting range is automatically set, if the temperature at a specific point of the measurement object is within the predetermined limit of the setting range, the data is not rewritten to the conversion table. , data is rewritten when a predetermined limit is exceeded.

[Example] Assuming that the setting range is determined according to FIG. 1, in the first invention, when the setting range is shifted within the determined setting range, the conversion table is rewritten. As shown in FIG. 2, this is performed during the blanking period of the display. As shown in step 200 in FIG. 2, a change in measurement conditions is first detected.

There are various changes in this measurement condition, such as when changing the measurement center temperature, changing the setting range, changing the temperature resolution), changing the temperature table, changing the room temperature, and saturation of the conversion table. Sometimes parts change.

In this way, each time the measurement conditions change, step 200
If the answer is YES, a predetermined calculation such as an interpolation calculation for rewriting the conversion table is performed in step 201. When it is determined in step 202 that the display is in a blanking period, processing for rewriting the conversion table is performed as shown in step 203. Note that step 20
If it is 0 and the measurement conditions do not change, the conversion table is not rewritten.

FIG. 3 is a flowchart showing the second invention, and is an example of changing the setting range. In this case, when a change in the temperature of the measurement target is detected in step 300, it is determined in step 301 whether the temperature at a specific point of the measurement target has changed to less than 25% of the set range. When it is determined that it is less than 25%, step 30
The conversion table is rewritten as shown in 3. If not less than 25% in step 301, step 30
In step 2, it is determined whether the temperature at the specific point has reached 75% or more of the set range. If this determination is rNOJ, the process ends. In other words, leave the current setting range as is,
Do not perform extra rewrite processing. However, step 30
If it is determined that 2 is 75% or more, step 30
The conversion table is rewritten as shown in 3.

Although the operation shown in FIG. 2 is not explained in FIG. 3 to avoid redundant explanation, it is better to rewrite the conversion table during the blanking period in order to avoid a strange feeling in the display.

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

Pax = Maximum input in Figure 5 (digital amount from 0 to 255, equivalent to infrared energy) Pain: Minimum input in Figure 5 (digital amount from 0 to 255, equivalent to infrared energy) TL: Measurement range Minimum temperature set value (analog amount) TIl
: Maximum temperature setting value of measurement range (analog amount) To) 1:
Maximum temperature of the measurement target [Tot+=f (Pmax), which is an analog quantity] TOL: Minimum temperature of the measurement target [Tot= f (Pai
n ), which is an analog quantity] In Fig. 1, the case where P wax and P in are equal is explained. In this case, both the minimum value and the maximum value are outside the setting range (including the case where they are exactly on the boundary). or, within the setting range, the maximum and minimum values of the setting values are equal.

In step 100, it is determined that the minimum input value P win and the maximum input value P ax are equal, and as shown in step 101, the input data P is not 255.
If it is determined that the value is not 0 as shown in 3, this means that the maximum and minimum values of the current set values are too close to each other. In this case, as shown in step 105, the minimum temperature setting value TL of the measurement range is lowered by 10% of the current setting range, and the maximum temperature setting value Tll of the measurement range is increased by 10% of the current setting range. Then, as shown in step 106, it is determined whether the temperature difference of the object to be measured has reached 60% of the set range, and the set range is changed until the condition is satisfied.

If it is determined in step 101 that the input data P=255, the maximum value of the setting range is too low, so the maximum value is moved to the higher side by the temperature difference of the current setting range amount as shown in step 102. The processing after step 11 is performed. If it is determined in step 103 that the input data is P-0, the minimum value of the set range is too high, so as shown in step 104, the minimum value is moved to the lower side by the temperature difference in the current set range. Step 1
02. No matter which process is performed in step 104, it is determined whether or not there is a measurement target within the measurement range as shown in step 117. If there is no measurement target within the measurement range, as 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 currently set range each time until the measurement target is within the measurement range. The object to be measured will eventually come within the measurement range, but the expansion of the measurement range continues until both the minimum and maximum values of the object to be measured fall within the set range, as shown in step 118.

When it is determined in step 118 that both the minimum value and maximum value of the measurement target are within the set range, as shown in step 112, it is determined whether the temperature difference of the measurement target is 60% or less of the set range. is judged.

If the temperature difference of the object to be measured is greater than 60% of the set range, the set range is too narrow, so step 115,1
As shown in 16, the minimum setting value is lowered by 10% of the current setting range and the maximum setting value is increased by 10% of the current setting value until it reaches 60%. If the temperature difference of the object to be measured is less than 60% of the set range in step 712, the reverse operation is performed as shown in steps 113 and 114.

In Ste Tsubu 100, P wax = P win
It is determined that the data P is not the same in step 107.
When it is determined that wax is 255 and P win is 0, the setting range is too narrow compared to the temperature difference of the measurement target. Therefore, as described above in steps 105 and 106, the set range is expanded until the temperature difference of the object to be measured becomes 60% of the set range. However, if it is determined in step 108 that only the maximum value Pg*ax of the input data is 255 and the minimum value Pwin is not 0, then only the maximum value of the measurement target is outside the measurement range.
After increasing the maximum setting value by 10% of the current setting range as shown in step 109, it is determined in step 112 whether the temperature difference of the object to be measured is larger or smaller than 60% of the setting range. Thereby, as described above, the process of steps 113, 114 or 115 and 116 is performed to widen or shorten the set range until the temperature difference of the object to be measured becomes 60% of the set range. Also, the input data minimum value Pwin is 0 and the maximum value P wax is 255.
If not, the minimum setting value is too high, so as shown in step 111, lower the minimum setting value by 10% of the current setting range, and adjust the temperature difference of the measurement target to 60% of the setting range. , the setting range is automatically adjusted in the same manner as described above.

"Effects of the Invention" As explained above, in the first invention, data is written to the conversion table during the blanking period of the display, so the measurement results under new conditions are displayed after the display screen is switched. This has the effect of not giving a sense of discomfort to the person taking the measurement.In the second invention, the conversion table is not rewritten while the temperature change is small, so even if the temperature of the measurement object frequently changes, it can be stably measured. This has the effect of allowing measurements to be made.

[Brief explanation of drawings]

FIG. 1 is a flowchart for explaining the automatic setting of the setting range, FIG. 2 is a flowchart for explaining the first invention, FIG. 3 is a flowchart for explaining the second invention, FIG. 4 is a diagram showing the configuration of the infrared detection section, and FIG. 5 is a graph showing the characteristics of the conversion table. 1... Rotating mirror, 2... Silicon window,
6... Infrared detection element, 7... Amplifier, 8...
...Temperature table.

Claims (2)

[Claims] (1) In an infrared measurement device that measures the temperature of the object to be measured using a conversion table that outputs temperature data according to the value of infrared energy and displays it on the display screen, a data change detection signal is generated when a change in measurement conditions is detected. a blanking period detection signal that detects a blanking period of the display and generates a blanking period detection signal when the data change detection signal is supplied; An infrared measuring device comprising: rewriting means for rewriting a time conversion table to match new measurement conditions. (2) The infrared measurement device according to claim 1, wherein the change in measurement conditions is detected when the temperature of a specific location on the measurement target exceeds a predetermined limit set in a set range.