海天类红外图像的增强要求去除风浪等的环境影响,同时增强目标区域的对比度。通过探索几种典型的图像增强算法,结合红外图像梯度幅值直方图特点,提出基于梯度域的海面红外场景增强算法,将低梯度值置零去除海浪干扰,调整梯度范围对结果控制亮度,利用有效梯度范围均衡化增强目标区域的细节。实验结果表明,该算法可以明显降低图像的干扰信息,同时提高目标区域的对比度和信息熵。

The enhancement of infrared images containing sea and sky requires not only to remove effects by heavy wind and waves, but also to enhance target region’s contrast. Exploring several typical image enhancing algorithms, and combining the characteristics of infrared image’s histogram of gradient magnitude, an algorithm based on the infrared image’s gradient domain is proposed. Low magnitude is set to zero to reduce wave disturbance, gradient magnitude range is adjusted to control brightness, and valid gradient magnitude range is equalized to enhance target region’s details. Experimental results show that the proposed algorithm can obviously reduce the interference information of the image and improve the contrast and information entropy of target region.