Research On Fault Detection Method Of Circuit Board Based On Infrared Thermal Imaging Technology

The deficiency of the traditional circuit board fault detection method is gradually outstanding,which can not meet the requirements of the circuit board testing and maintenance.Infrared thermal imaging technology as a new method, will gradually be applied in the field of PCB fault detection.In this paper, the development status at home and abroad of infrared thermal imaging technology and fault detection is analyzed,and the related theory of infrared detection technology is discussed in detail.On this basis,it was elaborated circuit board fault detection of infrared thermal imaging technology-based process,the necessary technical measures and means of infrared image processing.In this paper,the infrared imaging technology is used to study the faulty circuit board to be tested and the normal operation of standard circuit board.Under the same conditions,due to the regional board fault element temperature distribution and temperature distribution standard plate in the same region there are differences,it will produce different infrared images as a basis for fault detection,and detection and differential thermal sequence detection method combined with each other fault detection circuit board.Differential detection method requires the use of an infrared image of the board, but in the use of infrared camera to obtain infrared images, because the infrared camera resolution, camera angles will differ captured infrared image errors,and therefore it is need to be necessary image pre-processing, registration, etc.Image registration is designed to eliminate differences in the position of the space, the premise is the image pre-processing,pre-processing in this paper includes an infrared image enhancement, de-noising.In order to achieve infrared image enhancement, this paper proposes a weighted average of the enhanced processing method histogram equalization and high pass filter enhancement, based on the enhancement effect is more obvious than a single method.In addition,the noise is enhanced by image enhancement,so we need to make the infrared image de-noising.In this paper,different de-noising methods are analyzed and compared,and the median filtering method is improved,the experimental results show that the proposed algorithm has a significant effect on the removal of noise.By design fault judging process and build a platform for experiments, experiments show that the circuit board by fault detection method designed in this paper is feasible, with high fault detection rate.