Research On Mobile Display Technology Based On BOS

Background oriented schlieren(BOS)is a novel flow visualization technique,which has the advantages of simple in structure,low cost,quantitative measurement,transient measurement,suitable for large field of view measurement,suitable for measurement in complex environment,etc.It is one of the hottest techniques in the field of flow visualization.In this paper,a BOS technique based on FFT phase extraction is proposed and used for flow visualization of flow field.The LED array background plane and the multi-scale wavelet noise background image are also designed.According to the characteristics of the two background images,point recognition algorithm and optical flow algorithm are used respectively to process the two background images to extract the image displacement.The data of the image displacement obtained from the measurement of the flow field by the BOS device proposed in this paper can be used to reconstruct the three-dimensional density field of the flow field.This paper mainly focuses on the following aspects:Firstly,to improve the current BOS device,the background plane is replaced by the LED array background plane,and the background image of the LED array background plane is processed by the point recognition algorithm to extract the image displacement.The influence of multiple parameters on the sensitivity of the BOS device is theoretically analyzed and verified by experiments.Secondly,a multi-scale wavelet noise background image is designed.The pyramid L-K optical flow algorithm principle is introduced.The pyramid L-K optical flow algorithm is used to process the multi-scale wavelet noise background image to extract the image displacement.The BOS device based on the pyramid L-K optical flow algorithm used for flow visualization of flow field generated by the heat gun.Thirdly,the BOS technique based on FFT phase extraction is proposed and verified by numerical simulation experiments.The BOS device based on FFT phase extraction is used for flow visualization of flow field generated by the heat gun.