We propose a wavelet domain diversity combining method to combat errors during image transmission on wireless channels. For images represented in the wavelet domain, diversity is used to obtain multiple data streams corresponding to the transmitted image at the receiver. These individual image data streams are combined to form a composite image with higher perceptual quality. Both uncompressed and compressed images are considered. The SPIHT algorithm is used for image compression. Diversity combining methods for both uncompressed and compressed images exploit the characteristics of the wavelet transform. For compressed images, unequal error protection is employed in conjunction with diversity combining. Simulation results demonstrate that the quality of the received image can be significantly improved.

We present an approach to automatically register and fuse IR and MMW images for concealed weapon detection. The distortion between the two images is assumed to be a rigid body transformation without rotation and we assume that the scale factor can be found from both the sensor parameters and the distance ratio of the object to the two sensors. Our registration procedure involves image segmentation, binary correlation and other image processing algorithms. Our fusion method involves a pyramidal image decomposition scheme based on the wavelet transform. Performance of the image registration and image fusion algorithm is illustrated through an example.

A relative entropy based approach to image thresholding was proposed recently. It was demonstrated that this method was successful for image thresholding. Relative entropy is a member of the class of Ali-Silvey distance measures. In this paper we generalize the relative entropy based approach and present image thresholding algorithms based on the class of Ali-Silvey distance measures. A number of members of this class are selected and used for implementation in image thresholding algorithms. Performance is evaluated by applying these algorithms to several images and comparing them to a few histogram based thresholding methods.