Research And Implementation Of Imaging Technology Of Terahertz Array Detector

Terahertz wave is a kind of electromagnetic radiation between microwave and infrared wave and its frequency is between 0.1THz-10 THz.The subject areas of this band include both electronics and optics. It has many characteristics like low energy, transient property, high permeability, water absorption, coherence and broadband, which have research and application value in fields of nondestructive testing, biological and medical treatment, terahertz communication and military radar detection and so on.Terahertz imaging technology is divided into two classes: pulsed terahertz imaging and continuous terahertz imaging. Till the beginning of this century, both the domestic and foreign team of researching terahertz have made a certain development. However, due to the technical limitations of terahertz wave generation and detection, the factors such as water, temperature, signal to noise ratio of the system, power of the terahertz source and the optical path will greatly reduce the quality of terahertz imaging.Under this background, this paper analyzed the preprocessing steps and the main algorithms of terahertz image and finally presented a scheme of imaging system of terahertz array detector by studying the transmission imaging theory of continuous terahertz wave and the characteristics of the terahertz image. Specific contents include:According to the basic characteristics of terahertz image, there are three steps in processing the terahertz image. They are non uniformity correction, blind pixel compensation and image enhancement. According to the characteristics of the blind element in pyroelectric detector, a new blind element compensation method based on Newton interpolation method is proposed. A new image enhancement method based on weight distribution is proposed by comparing the advantages and disadvantages of the traditional image enhancement algorithms.An implementation scheme of the imaging system of terahertz array detector is proposed. The scheme mainly includes two aspects, hardware circuit design and embedded system. Hardware circuit design mainly involves driving circuit, digital analog conversion circuit, bias voltage modulation circuit, FPGA module, serial port module, storage module and video output module, etc. And by designing the program of the core control circuit, the imaging system achieved a set of functions including terahertz detection, data acquisition, data correction, image enhancement and real-time display.The ultimate goal of this terahertz array detector imaging system is to make the sample detected by terahertz wave can be imaging in real-time and in a higher quality.The image processing method presented in this paper has many advantages like simple mathematical model, small amount of computation and portability, which has been applied to the imaging system mentioned in this paper. The system is stable, low power consumption and high image quality by tested.