A new segmentation method for very high resolution imagery using spectral and morphological information

Image segmentation is a key and prerequisite step for object-based analysis of very high resolution (VHR) imagery. Most existing image segmentation methods use either spectral or spatial information of an image alone. A novel image segmentation method for VHR multispectral images using combined spectral and morphological information is proposed in this paper. The method can be summarized as follows. First, a morphological derivative profile is calculated from an original multispectral image and combined with the spectral bands to quantify spectral-morphological characteristics of a pixel, which are considered as a criterion of homogeneity of neighboring pixels. Image segmentation is then conducted using a seeded region-growing procedure, which is based on the seed points automatically generated from the gradient image and dynamically added and the similarity between a seed pixel and its neighboring pixels in terms of spectral-morphological characteristics. The obtained segmentation result is further refined by a region merging procedure to generate a final segmentation result. The proposed method is evaluated using three VHR images of urban and suburban areas and compared with two existing segmentation methods, in terms of visual inspection, quantitative evaluation and indirect evaluation. Experimental results demonstrate that the joint use of spectral and morphological information outperformed the use of morphological information alone. Furthermore, the proposed image segmentation method performed better than existing methods. The proposed image segmentation method is well applicable to the segmentation of VHR imagery over urban and suburban areas.