A method for digital meter display value recognition from a video with MATLAB and its application

Objective:To recognize the digital temperature monitor meter display value from a multiple-channel video in order to determine the thermal effect of electromagnetic irradiation.Methods:MATLAB,especially its video image toolbox,was used to a chieve the interactive location and segmentation of the digit image in video signals,image preprocessing with morphology operation,digit recognition with seven segment display rules,the value determination and plotting.Results:The method was able to recognize the value in the video signals with nearly 100% correctness in multiple sampling tests.However,there were also some abnormal data caused by LED light retention in the dynamic display process and recorded by high frame rate video.The problem was solved by replacing the points outside the range(neighborhood average±standard deviation) with neighborhood median.Conclusion:This method is simple,highly adaptable and reliable,facilitating the research on biological effects of high power millimeter wave and providing a set of reference solution for this kind of research.