Infrared Image System Based On FPGA

Any object with temperature above-273°, spontaneously emits outwardly infrared radiation energy, which varies according to the object's temperature. Based on that, infrared thermal image technology was developed to sample the invisible infrared energy in passive way and convert it into the visible thermal image. Because the infrared thermal image technology is only related to the object's temperature, it will not be limited by the bad weather or night, which is quite different with the other image technology.Due to the continuous development and the lowcost feature, the infrared thermal image technology was broaden its application range from the military field to the civilian field, such as security, forest fire prevention, power monitoring and physical examination and so on. Due to the diversity of applications, the portability of infrared image system becomes significant.This paper introduces the principle of infrared imaging technology, applications and development status. Comparing with the features of different infrared thermal image system, the infrared thermal image system based on the FPGA system was adopted, which make the infrared camera is very user-friendly and easy to operate. The 293×392 microbolometer was used as the infrared detector and the FPGA EP2C35F484C8 N chip was adopted as the core processor. This structure of infrared thermal image system includes drive circuit module, the FPGA image data signal processing circuit module and display circuit module.The drive circuit module contained the precision bias voltage source, the analog-to-digital conversion circuit, and clock driving signal from FPGA. First the analog-to-digital conversion circuit used the AD9240 chips to convert the analog signal from the infrared detector into the 14 bits digital signal. Then the FPGA processed the digital signal, strengthen the image comparison and remove the noise contained in the signal. Meanwhile, the SDRAM was designed to storage data. Due to the difference in data transmission between the FPGA and SDRAM, the FIFO way was designed as the data transmission way. Finally, the processed digital signal was converted by the ADV7123 chip into the analog signal to drive the screen display.Moreover, the hardware platform was designed based on FPGA. The Altiume Designer was used to draw circuit and 4 layers PCB. In addition, the software system of the infrared image system was built by using the Verilog language to program the IP core of different modules which mainly contains FPGA_driver, Image_processing, Sdram_driver and Display_driver.Finally, to ensure the stability of the system, the power testing, the simulation based on the PCB board and the anti-interference feature of the infrared image system were carried out. Finally, the paper shows the structure of the system, as well as infrared imaging parameters.