JPH0452532A - Measuring apparatus of distribution of stress of infrared rays - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an infrared stress distribution measuring device for measuring stress distributed in a measurement object.

(Prior art) Traditional methods for measuring the stress distribution of a measurement object include the strain gauge method and the stress paint method, but the former is a point measurement method that does not give a complete stress distribution image, and the latter There is a limit to the stress that can be detected.

For this reason, in recent years, infrared stress distribution measurement methods have come into use that allow observation of a two-dimensional stress distribution image without contacting an object to be measured by using an infrared camera.

One of the devices that makes such an infrared stress distribution measurement method possible is a stress distribution measurement device disclosed in Japanese Patent Publication No. 1204/1983. This device holds an object to be measured in a stress device, sequentially applies two different loads such as compression and tensile loads to the object, and responds to the switching of each load for a period of time during which the load is applied. Frame scanning with an infrared camera is performed during the process, and the temperature distribution image of the measurement target obtained when the first load is applied and the temperature distribution image of the measurement target obtained when the second load is applied. By calculating the difference between and displaying this difference signal on a television monitor, a stress distribution image of the object to be measured is obtained.

(Problem to be Solved by the Invention) However, this stress distribution measuring device sequentially applies two different types of loads to the object to be measured, and scans the frames of the infrared camera in synchronization with each load application period. Therefore, the infrared camera intermittently photographs one screen at a time based on the synchronization signal generated from the stress device.

Therefore, during the load application period, the infrared camera must be moved to perform frame scanning, and during the period when the load is changing, the infrared camera must be controlled so as not to perform frame scanning by stopping the operation of the infrared camera. When changes occur quickly, it is difficult to follow, and control is also complicated.

In particular, when the infrared camera uses a mechanical raster scanning mechanism using a mirror, it is difficult to finely intermittent frame scanning.

(Means for Solving the Problems) In order to solve such problems, the present invention applies a varying load to the measurement object using a stress device, and images the measurement object with an infrared camera. An infrared stress distribution measuring device that measures the stress distribution of an object includes an infrared camera that two-dimensionally photographs the object to be measured, and a first t5 and a second t5 that store temperature distribution images of the object to be measured that are output from the infrared camera. a frame memory; a trigger signal generator that detects different load states of the stress device and separately outputs write trigger signals in each load state to the first and second frame memories; and the trigger signal generator. an arithmetic unit that calculates a difference between a temperature distribution image stored in the first frame memory and a temperature distribution image stored in the second frame memory stored in response to a trigger signal output from the arithmetic unit; and a difference signal from the arithmetic unit. It is equipped with a display device that is supplied with the following information.

(Function) Detects each load state from two different loads applied by the stress device, and separately outputs write trigger signals for each load state to the first and second frame memories, and performs continuous operation. A temperature distribution image for one frame of the object to be measured corresponding to the load condition is written from the infrared camera into the first and second frame memories, respectively, and the difference between the temperature distribution images in both memories is determined to obtain a stress distribution image. displayed on a TV monitor.

(Example) Hereinafter, details of the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the infrared stress distribution measuring device according to the present invention, and FIG. 2 shows various timing charts in FIG. 1.

In FIG. 1, numeral 1 is a stress device that holds an object to be measured 2 and applies a periodically changing load to the object 2, and numeral 3 is a stress device that applies infrared rays generated from the object to be measured 2 mechanically or electronically. This is an infrared camera that scans the temperature distribution of the object 2 to be measured. Measurement object 2 under periodically changing load conditions detected by infrared camera 3
The analog temperature distribution signal is converted into a digital temperature distribution signal by an A/D converter 4, and a pair of frame memories 5 are allocated to store the temperature distribution image at maximum or minimum load.
, 6 are sequentially output. The frame memories 5 and 6 take in the digital temperature distribution signal from the A/D converter 4 at timings to be described later.
, 6, respectively. The digital temperature distribution images stored in the frame memories 5 and 6 are simultaneously read out, subtracted by a calculator 7, and then supplied to a monitor television 9 via an image processing device 8 and displayed as a stress distribution image.

To explain with reference to the timing diagram of FIG. 2, A/D
The digital temperature distribution signal from the infrared camera 3 outputted via the transducer 4 determines the voltage value E that the stress device WL1 generates in proportion to its load state, depending on the maximum and minimum loads applied to the stress device 1. The maximum load voltage value e1 and the minimum load voltage value e preset in the trigger signal generator 10 are
Compare with 2. When the voltage value E proportional to the load exceeds the reference voltage value e, a trigger signal al is output to the image sampling circuit 11, and when the load proportional voltage value E falls below the reference voltage value e2, image sampling is performed. A trigger signal a2 is output to the circuit 11. Image sampling circuit 11
In addition to the trigger signal at+a2, the infrared camera 3
A vertical synchronization signal Pv is supplied every time a frame is scanned, and a digital temperature distribution signal for one frame synchronized with the trigger signal a or a2 and this vertical synchronization signal Pv is stored in a frame memory 5 or 6. In order to incorporate it into
A write signal W1 or W2 is output to the frame memory 5 or 6.

The frame memory 5 stores the digital temperature distribution signal supplied from the A/D converter 4 while the write signal W is supplied, and the frame memory 6 stores the digital temperature distribution signal supplied from the A/D converter 4 while the write signal W2 is supplied. The digital temperature distribution signal supplied from the converter 4 is stored.

Both the maximum load temperature distribution image and the minimum load temperature distribution image stored in the frame memory 5.6 are read out, and the arithmetic unit 10
The difference image between both temperature distribution images is output. The image subtracted by the arithmetic unit 10 is supplied to the image processing device 8,
The signal is A/D converted and supplied to the monitor television 9 as a luminance signal for display. Therefore, a stress distribution image of the measurement object is obtained on the monitor television 9 with brightness depending on the stress.

In the above embodiment, a case was described in which the maximum and minimum load points are detected as different load states of the stress device, but since any change in the applied load will cause a temperature change in the object to be measured, the maximum and minimum load points are detected as different load states of the stress device. Detection is not limited to the detection of any different load conditions. In this case, the reference voltage of the trigger signal generator should be set to a value corresponding to the arbitrary load, or the trigger signal should be set using a delay circuit, etc. The output point can be adjusted to any load condition.

Note that storage to frame memory 5 is performed when the load is maximum, and storage to frame memory 6 is performed when the load is minimum, but these are reversed, and storage to frame memory 5 is performed when the load is minimum, and storage to frame memory 8 is performed when the load is minimum. The maximum load may be the memory of .

(Effects of the Invention) As explained above, the present invention detects the maximum load and the minimum load from the periodically changing loads caused by the stress device.
A write trigger signal is separately output to the second frame memory, and the temperature distribution image for one frame of the measurement target corresponding to the load is output from the continuously operating infrared camera to the first frame memory.
The difference between the temperature distribution images stored in both memories is calculated and displayed on the monitor TV as a stress distribution image. Since it is not necessary to perform scanning and capture images only during the load application period, it is possible to provide an infrared stress distribution measuring device that can sufficiently follow changes in the load cycle even if the load cycle changes quickly.

In particular, when using an infrared camera that uses a mechanical Lascou scanning mechanism using mirrors, etc., there is no need to finely intermittent frame scanning, which simplifies the configuration of the device and makes it easy to obtain accurate temperature distribution images. be able to.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an infrared stress distribution measuring device according to an embodiment of the present invention, and FIG. 2 is a timing chart of various signals in the present invention. 1... Stress device, 2... Measurement object,
3... Infrared camera, 4... A/D converter, 5, 6... Frame memory, 7...
...Arithmetic unit, 8...Image processing device, 9...
...Monitor TV, 10...Trigger signal generator, 11...Sampling circuit, 11...
・Subtractor 2...Image processor, 13...
...Monitor TV.

Claims (1)

[Claims] In an infrared stress distribution measurement device that measures the stress distribution of a measurement target by photographing the measurement target with an infrared camera while applying a varying load to the measurement target using a stress device,
an infrared camera that two-dimensionally photographs the measurement target;
first and second frame memories for storing temperature distribution images of the measurement object outputted from the infrared camera; and detecting different load states of the stress device and storing the images in the first and second frame memories, respectively. a trigger signal generator that separately outputs a write trigger signal in a loaded state; a storage temperature distribution image of the first frame memory stored in accordance with the trigger signal output from the trigger signal generator; and a temperature distribution image of the first frame memory and the second frame memory; 1. An infrared stress distribution measuring device comprising: a computing unit for determining a difference between a temperature distribution image stored in a frame memory; and a display unit to which a difference signal from the computing unit is supplied.