长波红外与可见光图像的自然感彩色融合有助于观察者快速感知环境和发现目标, 而共光轴结构对于提高融合图像质量和简化配准算法具有独特的优势。为满足战场侦查、监视等需求, 设计了一种基于TMS320DM642数字信号处理器和ATmega32单片机的共光轴实时彩色融合系统。融合系统的长波红外和可见光成像系统平行放置, 利用分光镜和反射镜实现光路分离, 通过视场匹配和光轴校准实现双波段视频图像完全配准。图像处理程序基于DSP/BIOS嵌入式操作系统开发, 根据视频图像的特点, 采用基于CbCr查找表的自然感彩色融合算法。针对硬件特点, 对融合算法进行优化, 使720 pixel×576 pixel的单帧图像融合时间为9.18 ms, 满足25 frame/s的实时融合要求; 融合图像呈现自然色彩, 场景中的热目标易于辨识。文中对共光轴融合系统设计、实现过程中相关问题的研究具有参考借鉴价值。

Natural color fusion of long-wave infrared and visible images is helpful to observers for quick perception of the environment and discovery of targets. The coaxial optical structure enjoys the unique advantages in terms of improving the quality of the fused image and simplifying the registration algorithm. According to the requirements in battlefield detection, surveillance, and so on, a real-time coaxial color fusion system based on TMS320DM642 DSP and ATmega32 MCU was designed in the present work. In the fusion system, the long-wave infrared imaging system is combined in parallel with the visible imaging system. The optical path was separated by a beam splitter and a mirror. The dual-band images were absolutely registered using field-of-view matching and optical-axis calibration. The image processing program was developed based on a DSP/BIOS embedded operating system. A natural color fusion algorithm based on a CbCr look-up table was adopted according to the features of the video image. The fusion algorithm was optimized according to the hardware features. The fusion time of a single-frame image with resolution of 720 pixel×576 pixel is 9.18 ms, which satisfies the real-time fusion requirements of 25 frames per second. The fusion image exhibits a natural color, and the hot targets in the scene can be readily identified. The research on related problems presented in this paper can provide references to the design and implementation of a coaxial image fusion system.