External field infrared measurement is often affected by environmental radiation, scattering, atmospheric transmission, and other factors, which cause the poor spatial correlation, low signal-to-noise ratio of the infrared images, and it is difficult to segment the target and background for quantitative calculation. Therefore, in this paper, a method of infrared image enhancement and segmentation for external field measurement is described; based on Butterworth high pass filter, an enhancement factor is proposed to improve the transfer function. An infrared image of a cargo ship on the sea is processed by this method. The results indicated that, this method can effectively segment the target and background, and provide support for the quantitative calculation of infrared characteristics.
In this paper, the influences for one LWIR thermal camera in different integrate time are studied by using surrounding temperature simulator and blackbody of independent research and development, which compared to theoretical results. In experiment, the image of camera is obtained by using different integrate time and same temperature of blackbody at surrounding temperature of-30°C, 0°C and 20°C, the result show that the output voltage is linearly proportion to integrate time in those surrounding temperature. The experiment is studied for different blackbody temperature at surrounding temperature of-30°C, the result shows that: the slope of “integrate time vs. DL value” is increased with the target temperature. The noise of output image is increased with the increasing of integrate time. Whose agree with theoretical result. According to the conclusion, the DL value of random integrate time can be derived by known two integrate time DL for one blackbody temperature. And the calibration in random integrate time between two integrate time whose calibration curve are known, which is verified in experiment: the blackbody brightness deviation between test and derivation is less than 1%, which corresponds to blackbody temperature deviation between test and derivation is less than 1°C. The experiment results show that the measurement efficiency can be improved by using appropriate integrate time.
Based on the characteristics of infrared imaging, the algorithm of pseudo-color processing for infrared images is studied on the basis of independent research and development of infrared imaging system. A real-time pseudo-color processing algorithm based on FPGA is designed, software module by Verilog and the hardware platform are also introduced. In this method, three kinds of RGB color components are obtained by three kinds of independent transform, finally, the color images are synthesized. The algorithm has been applied to our self-designed infrared imaging system, results show that it is easy to implement and image enhancement effect is good.
An array extended blackbody is designed to quantitatively measure and evaluate the performance of infrared imaging systems. The theory, structure, control software and application of blackbody are introduced. The parameters of infrared imaging systems such as the maximum detectable range, detection sensitivity, spatial resolution and temperature resolution can be measured.
This paper, we introduced the system structure and operation principle of the device, and discussed our solutions for image data acquisition and storage, operating states and modes control and power management in detail. Besides, we proposed a algorithm of pseudo color for thermal image and applied it to the image processing module of the device. The thermal images can be real time displayed in a 1.8 inches TFT-LCD. The device has a compacted structure and can be held easily by one hand. It also has a good imaging performance with low power consumption, thermal sensitivity is less than 150mK. At last, we introduced one of its applications for fault diagnosis in electronic circuits, the test shows that: it’s a good solution for fast fault detection.
Calibration is important to the application of infrared camera. For improving low temperature infrared
measurement accuracy. A small extend blackbody is specially designed to meeting the requirement of
low temperature calibration. The temperature range of blackbody is 5℃~90℃ with effective radiation
area 150mm×150mm.The design adopts thermoelectric cooler as driver and chooses the PID
temperature control algorithm. By testing the stability, emissivity and uniformity of blackbody, the
design is proved quiet practical, which meets the needs of infrared camera, spectrometer and other
measuring equipment in low temperature calibration.
For performing infrared accurate measurement, It is necessary to calibrate infrared camera and spectrometer equipment field. Nowadays people generally use extend blackbody as standard radiation source. Since the outer environment of low temperature and wind field, blackbody general laboratory used is difficult to meet the requirement of field calibration. Therefore a portable field blackbody is specially developed. The temperature range of blackbody is 50 °C ~200 °C with effective radiation area 200mm×200mm. Using the effective insulation and windproof techniques, the blackbody can work at -20 °C to 40 °C environment. Basically meet the needs of infrared camera, spectrometer and other measuring equipment field calibration.
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