three-dimensional (3D) shape data sizes can be substantially reduced using the Holoimage technique which converts the 3D shape data into regular 24-bit 2D images. However, the Holoimage technique generally takes up al...
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three-dimensional (3D) shape data sizes can be substantially reduced using the Holoimage technique which converts the 3D shape data into regular 24-bit 2D images. However, the Holoimage technique generally takes up all the three standard image channels (RGB) and leave no room in an image to store other information, such as a texture or a normal map. Meanwhile, the recovered 3D accuracy is not very high due to the rounding process of image storage. To overcome these problems, this paper first proposes a two-channel Holoimage technique to compress 3D data and thus leave one more channel for storing other information. In addition, a novel phase-error compensation approach is also presented to enhance the recovered accuracy for Holoimage techniques. Without adding anymore bits, the error compensation approach can greatly improve the 3D recovered accuracy. Experimental results are presented to verify the performance of the proposed methods. (C) 2016 Elsevier Ltd. All rights reserved.
Digital holography is a technique that permits digital capture of holograms and subsequent processing on a digital computer. This paper reviews various applications of this technique. The presented applications cover ...
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Digital holography is a technique that permits digital capture of holograms and subsequent processing on a digital computer. This paper reviews various applications of this technique. The presented applications cover three-dimensional (3-D) imaging as well as several associated problems. For the case of 3-D imaging, optical and digital methods to reconstruct and visualize the recorded objects are described. In addition, techniques to compress and encrypt 3-D information in the form of digital holograms are presented. Lastly, 3-D pattern recognition applications of digital holography are discussed. The described techniques constitute a comprehensive approach to 3-D imaging and processing.
We describe the wavelets around land masses (WAVAL) system for the embedded coding of three-dimensional (3-D) oceanographic images. These images differ from those arising in other applications in that valid data exist...
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We describe the wavelets around land masses (WAVAL) system for the embedded coding of three-dimensional (3-D) oceanographic images. These images differ from those arising in other applications in that valid data exists only at grid points corresponding to sea. Grid points that cover land or lie beyond the bathymetry have no associated data, For these images, the WAVAL system employs a 3-D lifting wavelet transform tailored specifically to the potentially sparse nature of the data by processing only the valid sea data points between land masses. We introduce successive-approximation runlength (SARL) coding, an embedded-coding procedure that adds successive-approximation properties to the well known stack-run (SR) algorithm. SARL is employed to code wavelet coefficients resulting from the 3-D transform in the WAVAL system. However, it is a general technique applicable to other coding tasks in which embedded coding is desired but for which zerotree techniques are impractical. Experimental results show that the WAVAL system achieves substantial improvement in rate-distortion performance over the technique currently used by the U,S. Navy for compression of oceanographic imagery.
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