Research On Image Feedback Control In Measurement Of Spatial Melt Wettability

The key technology of high-precision on-line real-time measurement of melt wettability under microgravity is to meet the application requirements of future on-orbit connection and on-orbit repair of space station key components and space 3D printing of equipment parts,providing ground and space wettability comparison,offering accurate parameter input for material simulation calculation,giving technical support to future space station and space material science research.At the same time,the experimental results will promote the improvement of ground material technology.Under the space environment,the software is designed to achieve the purpose of saving storage resources,reducing the amount of information transmission,and achieving unattended functions.The spatial intelligent image feedback control software proposed in this paper is to carry out the wettability verification experiment of high temperature key materials in space station,and provide technical support for the space station and future microgravity material science experiments in China.The hardware devices in the experiment include a laser light source,a heating furnace,a high-resolution camera,and a PC end.The laser source externally supplies illumination to the melt sample in the furnace;the furnace is a fusion heating device with a built-in temperature sensor and can set the heating rate from the outside and display the temperature;the high resolution camera is fixed to the other side of the bracket On the top,the real-time image acquisition of the melt under the laser light source is performed,and the image is transmitted to the PC end;the spatial intelligent image feedback control software loaded on the PC side is used for feedback adjustment of the camera acquisition frame rate.In the process of melt heating and melting,the first step of real-time monitoring and intelligent image acquisition by spatial intelligent image feedback control software is to achieve real-time monitoring and intelligent image acquisition is to develop the CCD interface twice.On this basis,the target image is detected,the edge detection and the Hu moment similarity matching algorithm are used to automatically identify the metal begins melting.The target detection algorithm is realized by image preprocessing,including binarization,image filtering and morphological processing,and then contour searching and target positioning;edge detection can accurately detects the edge contour information of the sample,using the classic Canny operator;finally,based on the Hu moment,judging whether the contour shape of the image changes.Once changing,the effective images of the sample during the melting process is collected in real time,and the frame rate is controlled according to the feedback information,so as to save the storage space;and the droplet can be processed in real time.The thermal property parameters are stored in a CSV file.Experiments show that when the initial frame rate of the camera is set to 100 ms,compared with the traditional static frame rate method,in this experiment,the maximum memory usage obtained by the image feedback control algorithm is only 85.9% of the memory occupied by the static frame rate method,which effectively achieving savings and optimization of total storage space.