Studies On Methods To Monitor Clouds Next To The Sun For Heliostats Field

It is a key technology to study on methods to monitor clouds next to the sun for heliostats field to ensure the safe operation of solar thermal tower power system. However, the current methods cost a lot and only have some simple functions, therefore, to reduce the cost and improve the efficiency, this research conducted cloud monitoring by the using of industrial cameras and image processing technology, while monitoring the trends of the clouds of the heliostats field effectively and give appropriate warnings.This article is based on three-dimensional image processing and computer vision theory, give a new way to monitoring the clouds above the heliostat field(height, the moving speed of the clouds, relative relationship with the sun). Firstly, Wiener filtering method is used in the wavelet domain to reduce the noise of the sky image, then, in order to study the way of controlling the camera tracking device to track the sun, this work achieves the the position of the sun in the imaging plane and the trajectory model respectively. At the same time, give the analysis of the sun spot luminance distribution and the solar flare fitting method, then complete the detection and removal of the sun. After that, using gradient edge detection method based on Lab space color difference to detect the clouds of the sky, and with the feature points of the clouds, this work can calculate the clouds moving speed. Then, study the projection relationship between the heliostats field and the camera imaging plane, at the same time, this work also achieves the method of measuring the height of the clouds with dual camera ranging, dual camera ranging has a low-cost and gives follow-up related research some reference. By the projected of the heliostats field on the imaging plane and the clouds state of motion, the impact of the clouds to the heliostats field can be calculated visually by using clouds monitoring software, include when the clouds obscured the heliostat field and when the clouds leave the heliostat field.The study on methods for monitoring of heliostats field is feasible through the experiments, and it is expected to be able to complete the objectives, and shows the accuracy and real-time through calculation results.The conclusions of this thesis lay a foundation to achieve the high-efficiency control of the heliostats for the solar Power tower technology.