Computer-generated holography(CGH) is a technique for converting a three-dimensional(3D) object scene into a two-dimensional(2D), complex-valued hologram. One of the major bottlenecks of CGH is the intensive computati...Computer-generated holography(CGH) is a technique for converting a three-dimensional(3D) object scene into a two-dimensional(2D), complex-valued hologram. One of the major bottlenecks of CGH is the intensive computation that is involved in the hologram generation process. To overcome this problem, numerous research works have been conducted with the aim of reducing arithmetic operations involved in CGH. In this paper,we shall review a number of fast CGH methods that have been developed in the past decade. These methods,which are commonly referred to as point-based CGH, are applied to compute digital Fresnel holograms for an object space that is represented in a point cloud model. While each method has its own strength and weakness,trading off conflicting issues, such as computation efficiency and memory requirement, they also exhibit potential grounds of synergy. We hope that this paper will bring out the essence of each method and provide some insight on how different methods may crossover into better ones.展开更多
Past research has demonstrated that if the intensity image of an object is uniformly down-sampled and converted into a Fresnel hologram, the phase component alone will be sufficient to reconstruct the source image. Ho...Past research has demonstrated that if the intensity image of an object is uniformly down-sampled and converted into a Fresnel hologram, the phase component alone will be sufficient to reconstruct the source image. However, due to down-sampling, the edge and line patterns are degraded heavily. In this Letter, we propose an enhance- ment on the parent method by incorporating an adaptive down-sampling lattice. A hologram generated with our proposed method, which is referred to as the edge-enhanced sampled phase-only hologram, preserves favorable visual quality on both the shaded regions as well as the edge patterns of the object image.展开更多
Past research has demonstrated that a static, three-dimensional （3D） object scene can be directly recorded as a complex digital hologram. However, numerical reconstruction of the object scene, which may comprise mul...Past research has demonstrated that a static, three-dimensional （3D） object scene can be directly recorded as a complex digital hologram. However, numerical reconstruction of the object scene, which may comprise multiple sections located at unknown distances from the hologram, is a complicated and computation-intensive process. To the best of our knowledge, we propose, for the first time, a low complexity method that is capable of recon- structing a complex hologram, such that sections at different depths in the 3D object scene can be automatically reconstructed at the correct focal distances and merged into a single image for an extended depth of field. We demonstrate an order of magnitude increase of the depth of field for binary objects. With the use of a graphical processing unit, the reconstruction of a 512 × 512 complex hologram can be accomplished in about 100 ms, equivalent to around 10 frames per second.展开更多
A method for fast and low bit-rate compression of digital holograms based on a new vector quantization （VQ） method known as the skip-dimension VQ （SDVQ） is proposed. Briefly, a complex hologram is converted into a...A method for fast and low bit-rate compression of digital holograms based on a new vector quantization （VQ） method known as the skip-dimension VQ （SDVQ） is proposed. Briefly, a complex hologram is converted into a real off-axis hologram, and partitioned into a set of image vectors. The image vectors are passed into a graphic processing unit （GPU）, and compressed through SDVQ into a set of code indices considerably smaller in data size than the source hologram. Experimental evaluation reveals that our scheme is capable of compressing a digital hologram to a compression ratio of over 500 times, in approximately 20-22 ms.展开更多
文摘Computer-generated holography(CGH) is a technique for converting a three-dimensional(3D) object scene into a two-dimensional(2D), complex-valued hologram. One of the major bottlenecks of CGH is the intensive computation that is involved in the hologram generation process. To overcome this problem, numerous research works have been conducted with the aim of reducing arithmetic operations involved in CGH. In this paper,we shall review a number of fast CGH methods that have been developed in the past decade. These methods,which are commonly referred to as point-based CGH, are applied to compute digital Fresnel holograms for an object space that is represented in a point cloud model. While each method has its own strength and weakness,trading off conflicting issues, such as computation efficiency and memory requirement, they also exhibit potential grounds of synergy. We hope that this paper will bring out the essence of each method and provide some insight on how different methods may crossover into better ones.
文摘Past research has demonstrated that if the intensity image of an object is uniformly down-sampled and converted into a Fresnel hologram, the phase component alone will be sufficient to reconstruct the source image. However, due to down-sampling, the edge and line patterns are degraded heavily. In this Letter, we propose an enhance- ment on the parent method by incorporating an adaptive down-sampling lattice. A hologram generated with our proposed method, which is referred to as the edge-enhanced sampled phase-only hologram, preserves favorable visual quality on both the shaded regions as well as the edge patterns of the object image.
基金partially support by the MSIP(Ministry of Science,ICT and Future Planning),Korea,under the ITRC(Information Technology Research Center)support program(IITP-2015-R0992-15-1008)supervised by the IITP(Institute for Information&communications Technology Promotion)
文摘Past research has demonstrated that a static, three-dimensional （3D） object scene can be directly recorded as a complex digital hologram. However, numerical reconstruction of the object scene, which may comprise multiple sections located at unknown distances from the hologram, is a complicated and computation-intensive process. To the best of our knowledge, we propose, for the first time, a low complexity method that is capable of recon- structing a complex hologram, such that sections at different depths in the 3D object scene can be automatically reconstructed at the correct focal distances and merged into a single image for an extended depth of field. We demonstrate an order of magnitude increase of the depth of field for binary objects. With the use of a graphical processing unit, the reconstruction of a 512 × 512 complex hologram can be accomplished in about 100 ms, equivalent to around 10 frames per second.
文摘A method for fast and low bit-rate compression of digital holograms based on a new vector quantization （VQ） method known as the skip-dimension VQ （SDVQ） is proposed. Briefly, a complex hologram is converted into a real off-axis hologram, and partitioned into a set of image vectors. The image vectors are passed into a graphic processing unit （GPU）, and compressed through SDVQ into a set of code indices considerably smaller in data size than the source hologram. Experimental evaluation reveals that our scheme is capable of compressing a digital hologram to a compression ratio of over 500 times, in approximately 20-22 ms.
