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Author

Hongzhen Jin

Bio: Hongzhen Jin is an academic researcher from Zhejiang Normal University. The author has contributed to research in topics: Holography & Digital holography. The author has an hindex of 9, co-authored 27 publications receiving 308 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a new technique for 3D shape measurement by recovering the 3D numerical reconstruction image of a digital hologram is presented. But this method requires the reconstruction of the digital holograms from the reconstructed field of the hologram and the depth information of each small image patch.
Abstract: In this paper, we present a new technique for 3D shape measurement by recovering the 3D numerical reconstruction image of a digital hologram. Firstly, we fabricate a Fresnel digital hologram. Then, a number of 2D light field intensity distributions, which are in the reconstructed field of the digital hologram, are computed on the different depth planes. Finally, the focus measure evaluation of the grey level variance is applied. By finding the maximum focus measure, we decide on the depth information of each small image patch. The experiment confirms that the technique can materialize the 3D rebuilding of the reconstruction image and obtain 3D profile information on the object recorded. So digital holography can be a very promising technology for non-destructive 3D shape measurement.

117 citations

Journal ArticleDOI
Yong Li1, Cuifang Zhao1, Yixian Qian1, Hui Wang1, Hongzhen Jin1 
TL;DR: This paper presents a method for measuring spatially isolated objects using defocused binary patterns and a measurement system with a modified DLP projector and a high-speed camera, suited for defocused optical system.
Abstract: The three-dimensional (3-D) shape measurement using defocused Ronchi grating is advantageous for the high contrast of fringe. This paper presents a method for measuring spatially isolated objects using defocused binary patterns. Two Ronchi grating with horizontal position difference of one-third of a period and an encoded pattern are adopted. The phase distribution of fringe pattern is obtained by Fourier analysis method. The measurement depth and range is enlarged because the third harmonic component and background illumination is eliminated with proposed method. The fringe order is identified by the encoded pattern. Three gray levels are used and the pattern is converted to binary image with error diffusion algorithm. The tolerance of encoded pattern is large. It is suited for defocused optical system. We also present a measurement system with a modified DLP projector and a high-speed camera. The 3-D surface acquisition speed of 60 frames per second (fps), with resolution of 640 × 480 points and that of 120 fps, with resolution of 320 × 240 points are archived. If the control logic of DMD was modified and a camera with higher speed was employed, the measurement speed would reach thousands fps. This makes it possible to analyze dynamic objects.

40 citations

Journal ArticleDOI
Jian Liu1, Hongzhen Jin1, Lihong Ma1, Yong Li1, Weimin Jin1 
TL;DR: A novel technique of optical color image encryption and decryption based on computer generated hologram (CGH) and chaotic theory is proposed, which has the feasibility and its robustness against occlusion and noise attacks.

38 citations

Journal ArticleDOI
Yile Shi1, Hui Wang1, Yong Li1, Hongzhen Jin1, Lihong Ma1 
TL;DR: A novel method for computer-generated rainbow holograms (CGRHs) of full-color objects of real-existing objects is proposed based on the interrelationship between coding of a CGRH and reconstruction of the hologram.
Abstract: A novel method for computer-generated rainbow holograms (CGRHs) of full-color objects is proposed. First, a new algorithm for fabricating full-color CGRHs of real-existing objects is proposed based on the interrelationship between coding of a CGRH and reconstruction of the hologram. Second, a color rainbow hologram for a real-existing object is generated by combining the proposed algorithm and computer-generated hologram generating system. Finally, the hologram is outputted by an auto-microfilming system. The principle of the algorithm, the process of hologram calculation, and the hologram generating system for real-existing objects and experimental results are presented. The experimental results demonstrate that the new method is feasible.

26 citations

Journal ArticleDOI
TL;DR: A fast reliability-guided phase unwrapping algorithm, using an optimized quality map and combining it with look-up table operation, is proposed for digital holographic microscopy, demonstrating that not only does the proposed algorithm perform well, but also the speed is significantly faster than that of the conventional flood fill algorithm using insert sorting.
Abstract: A fast reliability-guided phase unwrapping algorithm, using an optimized quality map and combining it with look-up table operation, is proposed for digital holographic microscopy. First, by detecting the residues in the wrapped phase map, an intensity threshold is calculated in the normalized intensity image and the measured region is distinguished into the reliable region and the doubtful region. An optimized quality map is derived by the method in which the intensity values in the reliable region are set to 1 and those in the doubtful region remain unchanged. Then the flood fill algorithm by look-up table is implemented with the optimized quality map to retrieve true phase map. The experimental results demonstrate that not only does the proposed algorithm perform well, but also the speed is significantly faster than that of the conventional flood fill algorithm using insert sorting.

21 citations


Cited by
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Journal ArticleDOI
TL;DR: A focus plane determination method that computes the digital refocus distance of an object investigated by digital holographic microscopy working in transmission and it is shown that when the focus distance is reached, the integrated amplitude is minimum for pure amplitude object and maximum for pure phase object.
Abstract: We propose and test a focus plane determination method that computes the digital refocus distance of an object investigated by digital holographic microscopy working in transmission. For this purpose we analyze the integrated amplitude modulus as a function of the digital holographic reconstruction distance. It is shown that when the focus distance is reached, the integrated amplitude is minimum for pure amplitude object and maximum for pure phase object. After a theoretical analysis, the method is demonstrated on actual digital holograms for the refocusing of pure amplitude and of pure phase microscopic samples.

327 citations

Journal ArticleDOI
Song Zhang1
TL;DR: Two conventional absolute phase unwrapping methods are presented: multi-frequency or -wavelength phase-shifting methods, and hybrid binary coding and phase-Shifting methods; and some non-conventional methods that are specific for DFP systems are introduced.

262 citations

Journal ArticleDOI
Joowon Lim1, KyeoReh Lee1, Kyong Hwan Jin1, Seungwoo Shin1, SeoEun Lee1, YongKeun Park1, Jong Chul Ye1 
TL;DR: Various existing iterative reconstruction algorithms are systematically compared for mitigating the missing cone problem in optical diffraction tomography and three representative regularization schemes, edge preserving, total variation regularization, and the Gerchberg-Papoulis algorithm were evaluated.
Abstract: In optical tomography, there exist certain spatial frequency components that cannot be measured due to the limited projection angles imposed by the numerical aperture of objective lenses. This limitation, often called as the missing cone problem, causes the under-estimation of refractive index (RI) values in tomograms and results in severe elongations of RI distributions along the optical axis. To address this missing cone problem, several iterative reconstruction algorithms have been introduced exploiting prior knowledge such as positivity in RI differences or edges of samples. In this paper, various existing iterative reconstruction algorithms are systematically compared for mitigating the missing cone problem in optical diffraction tomography. In particular, three representative regularization schemes, edge preserving, total variation regularization, and the Gerchberg-Papoulis algorithm, were numerically and experimentally evaluated using spherical beads as well as real biological samples; human red blood cells and hepatocyte cells. Our work will provide important guidelines for choosing the appropriate regularization in ODT.

237 citations

Journal ArticleDOI
TL;DR: An easy-to-implement three-dimensional (3-D) real-time shape measurement technique using the authors' newly developed high-speed 3-D vision system that employs only four projection fringes to realize full-field phase unwrapping in the presence of discontinuous or isolated objects.
Abstract: This paper describes an easy-to-implement three-dimensional (3-D) real-time shape measurement technique using our newly developed high-speed 3-D vision system. It employs only four projection fringes to realize full-field phase unwrapping in the presence of discontinuous or isolated objects. With our self-designed pattern generation hardware and a modified low-cost DLP projector, the four designed patterns can be generated and projected at a switching speed of 360 Hz. Using a properly synchronized high-speed camera, the high-speed fringe patterns distorted by measured objects can be acquired and processed in real-time. The resulting system can capture and display high-quality textured 3-D data at a speed of 120 frames per second, with the resolution of 640 × 480 points. The speed can be trebled if a camera with a higher frame rate is employed. We detail our shape measurement technique, including the four-pattern decoding algorithm as well as the hardware design. Some evaluation experiments have been carried out to demonstrate the validity and practicability of the proposed technique.

194 citations

Journal ArticleDOI
TL;DR: This paper presents a method to unwrap phase pixel by pixel by solely using geometric constraints of the structured light system without requiring additional image acquisition or another camera to demonstrate the success of this proposed novel absolute phase unwrapping method.
Abstract: This paper presents a method to unwrap phase pixel by pixel by solely using geometric constraints of the structured light system without requiring additional image acquisition or another camera. Specifically, an artificial absolute phase map, Φmin, at a given virtual depth plane z = zmin, is created from geometric constraints of the calibrated structured light system; the wrapped phase is pixel-by-pixel unwrapped by referring to Φmin. Since Φmin is defined in the projector space, the unwrapped phase obtained from this method is absolute for each pixel. Experimental results demonstrate the success of this proposed novel absolute phase unwrapping method.

160 citations