Future multispectral and hyperspectral remote sensing systems and image archives will benefit from effective, high-fidelity image compression techniques. in evaluating the effects of compression upon the data, one mus...
详细信息
ISBN:
(纸本)0819423645
Future multispectral and hyperspectral remote sensing systems and image archives will benefit from effective, high-fidelity image compression techniques. in evaluating the effects of compression upon the data, one must not only consider the qualitative and quantitative effects upon the images themselves, but also upon the end user products that are derived from the imagery through the application of environmental retrieval algorithms. At The Aerospace Corporation, we have developed a fast algorithm for image compression techniques known as the Modulated Lapped Transform (MLT). This compression algorithm obviates many of the artifacts that are introduced by some of the standard compression techniques. One example of compression artifacting is the blocking errors from Discrete Cosine Transformation (DCT) based algorithms, which include the JPEG compression scheme. The Aerospace MLT technique is a hybrid of the wavelet and DCT techniques. It employs our patented split-radix approach, which is the fastest DCT algorithm known today. In this paper, we compare Aerospace MLT to JPEG, using cloud imagery and Earth surface scene classification, We also discuss the availability of a cost-effective VLSI hardware implementation of the Aerospace compression algorithm. The Modulated Lapped Transform employs a peano scan with a split-radix approach to avoid blockiness artifacts. It has excellent resistance to errors, and it is amenable to fast processing using a 1-D hardware architecture to process a 2-D image. This technique encapsulates the favorable aspects of the wavelet transforms and produces images which, when compressed 10:1 and decompressed, compare very favorably (using error statistics, classification accuracy and visual quality metrics) to the original uncompressed image.
This paper proposes a new technique based on vector quantization (VQ) for very low bit-rate encoding of multispectral images. The new algorithm relies on the observation that in high spectral-resolution imagery the sh...
详细信息
This paper proposes a new technique based on vector quantization (VQ) for very low bit-rate encoding of multispectral images. The new algorithm relies on the observation that in high spectral-resolution imagery the shape of a generic spatial block does not change significantly from band to band. Therefore, it is reasonable to represent each 3-D spatial/spectral block as the Kronecker product of a spatial-shape vector and a spectral-gain vector, and to jointly quantize only these representative vectors in place of the original block. Even though such an encoding strategy is suboptimal with respect to full-search VQ, the huge complexity reduction allows one to use much larger blocks and to better exploit the redundancy among close pixels of the image. Numerical experiments carried out on high spectral-resolution images show fully satisfactory results, with compression ratios exceeding 100:1, good image quality and very low encoding complexity.
As a precursor to hardware implementation, we have performed mine detection functions in simulation on a polarimetric hyperspectral imaging (PHI) dataset collected by using a technique of acousto-optic tunable filter ...
详细信息
ISBN:
(纸本)0819418528
As a precursor to hardware implementation, we have performed mine detection functions in simulation on a polarimetric hyperspectral imaging (PHI) dataset collected by using a technique of acousto-optic tunable filter (AOTF) camera. In principle, PHI data of an image containing objects of interest in a cluttered background provide significant information about the objects, including their relative sizes, shapes, orientation, and other characteristics such as light reflectance and polarization signatures based on their material properties. The present study was, however, limited only to the direct spectral data for the object of interest. A feedforward artifical neural network (ANN) architecture was programmed to recognize predefined spectral 'templates' by using a well-known, hardware implementable inner-product matching scheme. This scheme is particulartly suited to the problem of spectral discrimination where the spectra to be examined or the objects to be discriminated are uncorrelated, as in the present case. In this paper, we describe the ANN architecture and discuss its hardware implementation issues. In addition, we provide the results of our simulation study performed along with suitable preprocessing steps with various window sizes from 1 X 1 to 50 X 50 pixels, leading to an unambiguous detection of the position of mines in test runs without false alarms.
Image analysis is especially laborintensive in the multispectral domain due to the non-intuitive nature of the data. The data is frequently separated by frequency range into a set of image planes. For image analysts (...
详细信息
This paper reports results from an analysis of polarimetric hyperspectralimagery collected using a prototype acousto-optic tunable filter (AOTF) instrument in an outdoor environment. Spectra, derivative spectra, and ...
详细信息
In this paper we present a new method for the extraction of information about Lines of Communication (LOC) from Landsat Thematic Mapper (TM) imagery. While other techniques have demonstrated some success in the extrac...
详细信息
A combination of towed and stationary shipboard measurements, bio-optical mooring data, and a series of AVIRIS images were acquired near an offshore sewage outfall which services the Los Angeles metropolitan area. The...
详细信息
ISBN:
(纸本)0819415359
A combination of towed and stationary shipboard measurements, bio-optical mooring data, and a series of AVIRIS images were acquired near an offshore sewage outfall which services the Los Angeles metropolitan area. The image containing the outfalls and in-situ measurements was examined using statistical techniques to derive the spectral components responsible for salient variations. These computed components agree quite well with spectra which were hand selected to qualitatively represent the scene. Suspended sediment and aquatic vegetation detection were investigated using spectral derivative techniques, which were quite successful in showing the extent of offshore kelp forests and storm-induced resuspension of previously deposited outfall effluent, or the effluent itself. The in-situ and remote sensing measurements were used to constrain a numerical model of the underwater light field, and the scattering properties along a surface transect were investigated using two phase functions. Using a one-term Henyey-Greenstein function with a backscattering ratio of nearly 30%, we were able to reproduce the remotely- sensed radiance, suggesting that the particulates had a size distribution skewed toward small. These investigations show the utility of high spectral resolution in determining the extent and character of several important natural and anthropogenic components of coastal areas, as well as parameterizing models of the inherent optical properties of the underwater light field.
暂无评论