关键词: 光电子学与激光技术, 激光束散角, 二阶矩, 临界饱和, 图像融合

Abstract: Laser beam divergence angle measurement by spot image is often restricted by the camera dynamic range. Adding attenuators will affect the distributed characteristics of the spot, thus influence the measurement accuracy. Making use of the camera linear dynamic range, a practicable image measurement method for the divergence angle is presented in this paper. After using the mean filter on the critical saturated spot images, the divergence angle measurement uncertainty can be increased to 0.02 mrad. Simultaneously, a method for image fusing is proposed, which fuses the under-exposure and over-exposure spot images, to expand the camera dynamic range, then, the overall distribution characteristics of laser spot can be obtained. The experiment results verify the efficiency and divergence angle measurement accuracy of the proposed method.

Key words: optoelectronics and laser, laser beam divergence angle, second-order moment, critical saturation, image fusing