A multi-layer coding algorithm is proposed for grey image lossless compression. We transform the original image by a set of bases (e.g., wavelets, DCT, and gradient spaces). Then, the transformed image is split into a sub-image set with a binary tree. The set include two parts: major sub-images and minor sub-images, which are coded separately. Experimental results over a common dataset show that the proposed algorithm performs close to JPEG-LS in terms of bitrate. However, we can get a scalable image quality, which is similar to JPEG2000. A suboptimal compressed image can be obtained when the bitstream is truncated by unexpected factors. Our algorithm is quit suitable for image transmission, on internet or on satellites.
A remote sensing image classification algorithm based on image activity measure is proposed, which is used for adaptive image compression applications. The image activity measure has been studied and the support vector machine(SVM) is introduced. Then, the relationship between the image activity measure and the distortion caused by quantization is discussed in our image compression experiments (JPEG2000, CCSDS and SPIHT). Another two image activity measures are proposed as well. Then a feature vector is constructed by image activity measures in order to describe the image compression features of different images. The test images are classified by support vector machine classifier. The effectiveness of the proposed algorithm has been tested using an image data set, which demonstrates the advantage of the proposed algorithm.
Classical compression methods of remote sensing (RS) panchromatic images are much the same as the traditional compression ones, in which distributions of different surface features are not taken into account. Instead, RS panchromatic images are divided into blocks in our method and those blocks can be classified into several categories by analyzing their intensity distributions. Afterwards, each category is compressed separately. According to Shannon’s theorem 3, a source with given distribution and distortion has a unique theoretical minimum bitrate. Hence, under a given compression quality, the theoretical minimum bitrate of each category can be calculated using rate-distortion theory. Meanwhile, each category may have its own distortion due to the user’s different quality requirements. Our method performs well in reducing the redundancy of surface features which users do not care about so that more “valid data” would be obtained from the compressed images. Furthermore, it also provides flexibility between fixed compression ratio and quality-based compression.
This paper presents an effective method to detect small and dim infrared image target under complex background, which is performed in spatial domain. Roughly speaking, the new method contains two steps. The first step is further divided into two steps (called difference between maximum and minimum filters, DMMFs): firstly, an original image is filtered by maximum (max) and minimum (min) filters based on the considering max filter can enhance the target and preserve the background while min filter can eliminate the target and also preserve the background; and then the difference between these two results is obtained, therefore the target is enhanced and its background is suppressed at the same time. To obtain an accurate location of the target, the second step called post processing involves local feature mapping and projecting techniques. This DMMF method focuses on reducing the cost of computation, tracking the target in real-time, enhancing the SNR, and suppressing its background clutter. The simulation results show that the proposed algorithm is effective and practical.