滤光片阵列多光谱图像拼接与灰度调整算法

Filter Array Multi-spectral Image Stitching and Grayscale Adjustment Algorithm

针对滤光片阵列多光谱图像拼接后单波段图像中地物灰度不一致的问题,提出各波段重叠区域灰度均值比的均值统调算法。首先,根据各条带有效区域构建多光谱图像模板,利用平台姿态信息对多光谱图像及图像模板进行投影变换,再利用加速稳健特征算法提取图像匹配点并计算相邻图像间单应性转换矩阵,选择中间序列图像为参考图像,对投影后的图像及其模板进行配准;其次,计算投影后各单波段图像重叠区域灰度平均值比的均值作为图像灰度调整系数,并以参考图像为基准,依次调整配准后图像灰度;最后,利用灰度调整后多光谱图像和配准后图像模板得到各单波段序列图像,通过图像拼接得到灰度一致的大区域单波段图像。结果表明:该方法不仅可以有效解决图像地物灰度不一致的问题,而且能够最大限度保持地物在不同波段下的光谱信息特征。

Aiming at the problem of inconsistent grayscale in single-band image after stitching of multispectral images of filter array,a new method of the mean tuning algorithm for mean ratio of grayscale in overlapping regions of each band was proposed.Firstly,multispectral image template was constructed based on the effective region of each band,the projection transformation of multispectral image and image template was carried out using the platform posture information,speeded up robust features(SURF)algorithm was used to extract image matching points and calculate homography matrix between adjacent images,intermediate sequence image was selected as reference image to register projected image and image template.Secondly,the mean gray mean ratio of each single-band image overlapping region after projection was calculated as the gray adjustment coefficient of image,and reference image was used as a reference to adjust the grayscale of the aligned image.Finally,each single-band sequence image was obtained by using the grayscale adjusted multi-spectral image and the aligned image template,the large area single-band image with consistent grayscale was obtained by image stitching.Experimental results show that this method can effectively solve the problem of image grayscale inconsistency,and then maintain the spectral information characteristics of the features in different wavelength bands to the maximum extent.