Hardware Implemented On Laser Beam Divergence Angle Measurement Based On Image Fusion

In recent years, the laser-based laser photonics technology has been widely used with the development of laser technology.So the quality of the laser has been higher requirements.However, The divergence angle of the laser beam can be more accurate evaluation of the pros and cons for the laser. The method is time-consuming and laborious through the instruments, it has some limitations for applications in laser weapon system. So the new method that basing on image fusion should be used to monitored laser quality in real-time. Through the simulation and objective evaluation of the parameters knows the feasibility of this approach. Meanwhile, the new way been implemented on the hardware platform. The main work of this paper are as follows:First of all, the traditional ways measuring the beam divergence angle were analyzed and compared and their deficiencies were pointed out. Then the characteristics of the laser were analyzed and the basic principles of the CCD were studied, at the same time the basic principle of image fusion were analyzed and the method been used in the paper that measuring laser beam divergence angle。The circuit has been completed according to the design requirements,.Then, according to the particularity of the laser spot, the image from CCD should be preprocessed. Through comparison of image preprocessing methods and the evaluation of extraction knowing the pros and cons of different approaches. Then a suitable methods is presented for the paper---- circle approximation.Finally, through the analysis of the linear of CCD, the best threshold is found out that suitable for image fusion. Image pre-processing studied within the DSP module, at the same time, the integration algorithm has been studied; After the fused image data is obtained, it was sent into the FPGA module to completing the beam divergence angle calculation process. Uncertainty beam divergence angle was analyzed.Through the above research, The method in the paper can measure the high-energy pulsed laser in real-time, and the energy range could be extended to thousands of Joule, Meanwhile, the measurement accuracy can achieve the requirements of the objective. The entire process can be realized on the design of the hardware platform, meet the real-time, means that the per laser beam divergence angle can be detected within 100 ms. Through the method of image fusion oversaturated and undersaturated image fusion, the dynamic range of the image is increased and the range of the laser energy is extended, at the same time the measurement accuracy of the beam divergence angle is improved.