Research On Terahertz Fast Imaging Detection And Image Processing

As an emerging imaging technology,terahertz imaging technology has important application research value and technology development prospects in the fields of safety detection,non-destructive testing and biomedicine.Since the X-ray electron energy is high,it is easy to cause ionizing damage to the detected substance.Therefore,the mainstream X-ray security scanner on the market cannot perform non-destructive testing and can not directly perform safe scanning on the human body.As a powerful spectral detection technology,terahertz imaging can detect dangerous goods,and improve detection efficiency,and avoid privacy violations caused by search and inspection.In the treatment of medical fractures,X-ray monitoring is required for the fixation and reduction of bones.Due to the damage of X-ray radiation to the human body,monitoring methods cannot be performed during surgery.If the reset fails,secondary radiation is required to determine the position of the metal bracket fixing holes.It caused inconvenience to the surgery and caused secondary injuries to doctors and patients.If terahertz imaging technology is used as an auxiliary medical device for fracture surgery,it will improve the safety and efficiency of the operation.In this paper,we will use the built-in terahertz fast imaging system to detect the metal objects hidden under different thickness and different material objects,judging the detection ability of the hidden metal,analyzing the influence of different materials on the quality of terahertz imaging and the problem with the terahertz image.The detection target is 1.metal pendant built in uniform material and thinner clothes;2.metal scissors built under thick PVC material with thicker thickness(PVC thickness is about 3 times that of clothing);3.Metal bracket fixing holes built into the bone(the bone thickness is about 3 times that of PVC).It is verified whether the terahertz fast imaging system can detect the built-in metal smoothly.We need record the experimental methods and effects,and analyze the problems of the experimental results and the reasons that affect the imaging quality,and use the algorithm to further highlight and extract the image details and enhance the image quality.The main contents and innovations are as follows:1.Firstly,the experiment verified the penetration of the terahertz wave on the clothing fabric,and used the BWO-based terahertz fast scanning imaging system to detect small metal heart pendants and metal arrows hidden in the clothes.The experimental results show that the system can detect metal substances under thinner materials.The material of the clothing is thinner and more uniform,and the background noise of the obtained terahertz image is relatively simple and uniform.The characteristics of the image are analyzed,and the image quality is improved by combining the existing image preprocessing methods at home and abroad.Aiming at the shortcomings of traditional denoising and target detection algorithms for terahertz image processing,the second chapter proposes a terahertz image target detection method based on double threshold canny equalization algorithm,and compares and analyzes the experimental results obtained by different methods.,proved the validity of the experiment.2.Using the Tera Sense terahertz detector builds a terahertz fast imaging system,the terahertz imaging target detection of the metal scissors hidden in the PVC material,and exploring the feasibility of the system in the non-destructive testing application based on the conveyor device.The experiment can detect the metal scissors under the PVC,indicating that the system can effectively pass the conveyor belt and let the detector receive the signal.The device can be applied to the conveyor-based non-destructive testing.However,due to the thick PVC material and many impurities,the metal scissor terahertz image obtained by the experiment has a lower background gray level,interference fringes around the target,uniform noise with lower gray level,and non-uniform interference information close to gray level of the sample boundary,local information is more complex and diverse.Aiming at the local characteristics of the terahertz images obtained from experiments,the method of enhancing and extracting the local features of terahertz images is proposed and paved for the subsequent experiments.A method for fast imaging of terahertz in the direction of non-contact detection provides a method for improving the quality of terahertz images.3.At present,there are few studies on the detection of bone-incorporated metal by using terahertz imaging technology.In order to explore the application prospect of terahertz wave in the treatment of medical femur fracture,this chapter will refer to the experimental method of the built-in metal equipment construction in the first two chapters.The terahertz transmission imaging system and the terahertz reflection imaging system were built,and the terahertz wave imaging test was performed on the fixed hole of the built-in metal bracket of the pig bone.The experimental results show that the device can detect the position of the fixed hole of the metal bracket in the bone,which proves that the terahertz wave has the ability to penetrate the dense bone.The fixing hole is small.The fixing hole is small.In order to better determine the imaging position of the metal stent fixing hole in the bone tissue,the paper introduces a morphological operation to preserve the visual effect based on the original information of the terahertz image.This experiment promotes the development and research of terahertz rapid imaging in the medical field.