JPH053534B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an infrared imaging device that detects infrared rays emitted from various parts of an object and displays the temperature distribution of the object as a visible image.

[Prior art]

Generally, the display section of an infrared imaging device displays the appearance of an object in several to more than ten colors according to temperature (however, in the case of a monochrome display, it is color-coded according to brightness).

The temperature range corresponding to one color at this time is called temperature resolution, and once this temperature resolution is determined, the temperature range of the temperature range that can be observed simultaneously (observation temperature range) is also determined. For example, when displaying in 16 colors, if the temperature resolution is 1°C, the temperature width of the observed temperature range is 1°C x 16 = 16°C.

On the other hand, the temperature range (detected temperature range) that can be detected by the detection unit (infrared camera) is much wider than the temperature width of the observed temperature range. Therefore, normal infrared imaging devices have a function that allows the observer to set the optimal temperature resolution and observation temperature range depending on the object. The optimal observation temperature range can be set manually while viewing the thermal image.

However, with such conventional infrared imaging devices, when the temperature of an object changes rapidly, it is not possible to take enough time to set the optimal observation temperature range, and as a result, the temperature of the object is not observed properly. It is not possible to observe the temperature distribution of the object when the temperature is below the lower limit or above the upper limit of the temperature range.

[Summary of the invention]

The present invention has been made in view of the above problems, and its purpose is to constantly observe the temperature of an object without changing its temperature resolution, even if the temperature of the object changes rapidly. It is an object of the present invention to provide an infrared imaging device having a function of automatically shifting the observation temperature range so that the observed temperature range falls within the temperature range.

In order to achieve such an object, the present invention converts an analog thermal image signal output from a camera section into a digital thermal image signal using an A/D converter based on an appropriate reference voltage, and temporarily stores this signal in a frame memory. In an infrared imaging device that stores and then reads out again to display a thermal image on a display, the highest temperature of all pixels or the temperature of a predetermined pixel is determined based on the temperature data of each pixel read out from the frame memory. A temperature detection circuit that generates a predetermined command signal when the temperature falls outside the currently observed temperature range; and a storage means that stores in advance the relationship between the temperature of the object and the voltage amount of the electric signal output by the camera unit. When a command signal from the temperature detection circuit is input, the reference voltage value of the A/D converter is set in the storage means so that the highest temperature of all pixels or the temperature of a predetermined pixel falls within the observed temperature range. and a means for changing the information based on the content.

Hereinafter, the present invention will be explained in detail together with examples.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of the present invention.

The camera unit 11 consists of an optical scanning mechanism, a condensing lens, an infrared detector, and a synchronization signal generator, and scans each part of the object, converts the amount of infrared rays emitted from the surface into an electrical signal, and converts the signal into an analog It is output to the A/D converter 12 as a thermal image signal. At the same time, a synchronization signal S is output.

The A/D converter 12 converts the analog thermal image signal from the camera section 11 into a digital quantity with a predetermined number of bits in synchronization with the synchronization signal S also from the camera section 11. Note that a reference voltage for digital conversion is provided from a microprocessor 18, which will be described later.

The frame memory 13 stores the thermal image signal converted into a digital quantity by the A/D converter 12 at a predetermined address based on the synchronization signal from the camera section 11.

The display processor 14 reads out the digital thermal image signal stored in the frame memory 13 at a scanning rate suitable for the display 15, and also performs coloring processing on the thermal image on the display 15 and additional information such as a temperature scale and a color scale, which will be described later. Perform display processing.

The display 15 consists of a color monitor television, and a specific example of its display is shown in FIG. At the top of the screen, a temperature scale 1 numerically displaying observed temperatures and temperature ranges, and a color scale 2 arranged corresponding to this temperature scale 1 are displayed. In this embodiment, the color scale 2 is displayed in 16 divisions, and one color out of the 16 divisions represents the temperature resolution.

A thermal image 3 of the object is displayed in the center of the screen,
In this display example, area T4, area T11, area T1
Color coded into 6. This area T4, area T1
1. Since the region T16 matches the color of the color scale 2 corresponding to the temperatures T4, T11, and T16 that are numerically displayed on the temperature scale 1, the observer can understand the temperature of each region of the thermal image 3, that is, the temperature of the object. You can know the temperature distribution.

Note that the cursor 4 can be moved so that the cross point 5 can be brought to any position on the screen.

The temperature detection circuit 17 reads the temperature data of each pixel read out from the frame memory 13, compares it with the maximum value of the reference voltage value given from the microprocessor 18, which will be described later, and determines the maximum value within the screen or the temperature data of the temperature data. When the cross point falls outside the observed temperature range, a command signal to that effect and the corresponding temperature value are generated. Note that whether to issue a command signal for the highest value on the screen or for the cross point value is determined by the instruction from the operation panel 21; in the former case, switch 17a; in the latter case, switch 17.
b will be closed.

The microprocessor 18 executes an automatic temperature tracking program stored in the ROM 19 according to the command signal and temperature value from the temperature detection circuit 17.
A predetermined process is performed based on the temperature table stored in the ROM 20 to generate a digital conversion reference voltage for the A/D converter 12. Here, the automatic temperature tracking program is a program that automatically changes the observed temperature range so that the actual observed temperature falls within the observed temperature range. Furthermore, the temperature table is a table obtained by converting the relationship between the amount of infrared rays emitted from the object, that is, the temperature, and the amount of voltage converted by the detector built into the camera section 11 into a digital value.

FIG. 3 shows an example of the relationship between the temperature of the object and the amount of voltage converted by the detector built into the camera unit 11. A solid line 30 shows the relationship between the temperature of the object (blackbody reference) and the output voltage from the detector of the camera section 11, and as is clear from the figure, this relationship is not linear. The maximum output voltage Vz is determined by the characteristics of the voltage amplifier added after the detector. The ROM 20 stores voltage values Va, Vb, Vc, which are obtained by dividing this maximum voltage Vz by a predetermined number of bits.
..., the digitally converted value of Vz and the voltage value Va,
Temperatures Ta, Tb, Tc, corresponding to Vb, Vc, …, Vz,
..., the digitally converted values of Tz are stored in table format.

Next, the operation of this embodiment will be explained.

FIG. 4, like FIG. 3, is a graph showing the relationship between the temperature of the object and the amount of voltage converted by the detector built into the camera unit 11.

Now, when the lower limit of the observation temperature range is specified as T0 and the temperature resolution as S1 on the operation panel 21, this command is input to the microprocessor 18, and the value is compared and referenced with the value in the temperature table in the ROM 20. Digital voltage value V0~V corresponding to temperature
16 is calculated and sent to the A/D converter 12.

In the A/D converter 12, this voltage value V0 to V16
The analog thermal image signal from the camera unit 11 is converted into digital based on the reference value. That is, the observed temperature range is digitally converted in 16 steps (4 bits) from T0 to T16. At this time, the thermal image signal is
It is digitized at a frequency that determines the number of horizontal pixels in one scanning line based on the scanning synchronization signal from 1.

Note that if the lower limit value of the observed temperature range and temperature resolution designated from the operation panel 21 do not match the temperature value in the temperature table stored in the ROM 20, the reference voltage is determined by interpolation and output.

Next, the operation of the screen maximum temperature tracking function will be explained.

When a command is issued on the operation panel 21 to activate the maximum temperature tracking function within the screen, the switch 17a closes. The temperature data for each pixel sequentially read out from the frame memory 13 is output to the display processor 14 and input to the temperature detection circuit 17, so the temperature detection circuit 17 converts the input temperature data of all pixels into the current Observation temperature range (Fig. 4 T0 to T16)
If it is detected that even one pixel is higher than the maximum value (T16) of the observed temperature range, a command is sent to the microprocessor 18 via the switch 17a.

The microprocessor 18 operates the automatic temperature tracking program stored in the ROM 19 based on this command, and specifies the lower limit value of the reference voltage (V0 in FIG. 4) for digital conversion to the A/D converter 12. The temperature resolution is increased in increments of the specified temperature resolution, and changes are made continuously until the maximum temperature within the screen is equal to or less than the maximum value of the observed temperature range. At this time, the level within the observed temperature range at which the maximum temperature within the screen should be settled can be specified in the automatic temperature tracking program.

In Figure 4, the temperature TX is within the observed temperature range T.
When it is 0 to T16, it is indicated by the value of T16, but
If the observed temperature range is T0 to T16 as a result of the main tracking, it is indicated as a value (T10) that matches the actual temperature.

Next, the operation of the cross-point temperature tracking function will be explained. Here, the cross point refers to a point that can be placed at any position on the screen of the display 15 as the intersection point of the cursor 4 (see Figure 2), and the cross point temperature tracking function is the cross point. A function that operates so that the temperature of the point indicated by the point automatically falls within the observed temperature range.

When the operation panel 21 commands to operate the cross-point temperature tracking function, the switch 17b closes, and the temperature detection circuit 17 focuses on the pixel at the cross-point address and checks whether the temperature of this pixel is within the observed temperature range. Check the
When detecting that the temperature is outside the observed temperature range, a command is sent to the microprocessor 18 via the switch 17b.

The subsequent operation is the same as that for tracking the maximum temperature within the screen described above, and will therefore be omitted.

In this embodiment, a color monitor television is used as the display, but a monochrome monitor television may also be used.

Also, although it is a 16-part display, it goes without saying that it is not necessarily limited to this number.

〔Effect of the invention〕

As explained above, when the present invention detects that the highest temperature of all pixels or the temperature of a predetermined pixel is outside the currently observed temperature range, it is possible to Since the reference voltage value of the A/D converter is changed so that the temperature of the object falls within the observed temperature range, the observed temperature range can be automatically shifted with the same temperature resolution even for objects whose temperature changes rapidly. This ensures that the temperature of the object is always within the observation temperature range, allowing for accurate and optimal observation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Figure 2 is a plan view showing an example of the display screen;
Both the figure and FIG. 4 are graphs showing the relationship between the temperature of the object and the voltage amount of the electric signal output by the camera section. 11...Camera section, 12...A/D converter, 13...
Frame memory, 14...Display processor, 15...Display device, 17...Temperature detection circuit, 18...Microprocessor, 19, 20...ROM.

Claims (1)

[Scope of Claims] 1. A camera section that scans an object, converts the amount of infrared rays emitted from the surface of the object into an electrical signal, and outputs it as an analog thermal image signal, and a camera section that converts the analog thermal image signal to an appropriate standard. an A/D converter that converts into a digital thermal image signal based on voltage; a frame memory that stores the digital thermal image signal as temperature data for each pixel; and temperature data for each pixel stored in the frame memory. In an infrared imaging device consisting of a display processor that reads out the thermal image at an appropriate scanning rate and a display that displays a thermal image based on the signal from the display processor, a standard is used to determine the desired observation temperature range. a setting means for setting a temperature and a temperature resolution, and a setting means for setting a maximum temperature of all pixels or a temperature of a predetermined pixel based on temperature data for each pixel read from the frame memory; A temperature detection circuit that generates a predetermined command signal when the current observed temperature falls outside the set range, and a memory that stores in advance the relationship between the temperature of the object and the voltage amount of the electrical signal output by the camera unit. a reference voltage of the A/D converter such that when a command signal from the temperature detection circuit is input, the highest temperature of all pixels or the temperature of a predetermined pixel falls within the observed temperature range; An infrared imaging device comprising: means for changing the value in units of temperature resolution set by the setting means based on the contents of the storage means.