Phase Quantization in Holograms–Depth Effects

Dallas, William J.; Lohmann, Adolf W.

doi:10.1364/ao.11.000192

Cited by 45 publications

(24 citation statements)

References 11 publications

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“…In the 1960-70s, various authors studied the influence of quantization arising from the finite printer resolution in computer generated holograms and their efficiency [24][25][26]. In [27], Powers and Goodman derive the probability of error in holographic memory employing computer-generated holograms when there is a quantization error in the hologram plane.…”

Section: Introductionmentioning

confidence: 99%

Quantization noise and its reduction in lensless Fourier digital holography

Pandey

Hennelly

2011

Appl. Opt.

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Digital holography is an imaging technique that enables recovery of topographic 3D information about an object under investigation. In digital holography, an interference pattern is recorded on a digital camera. Therefore, quantization of the recorded hologram is an integral part of the imaging process. We study the influence of quantization error in the recorded holograms on the fidelity of both the intensity and phase of the reconstructed image. We limit our analysis to the case of lensless Fourier off-axis digital holograms. We derive a theoretical model to predict the effect of quantization noise and we validate this model using experimental results. Based on this, we also show how the resultant noise in the reconstructed image, as well as the speckle that is inherent in digital holography, can be conveniently suppressed by standard speckle reduction techniques. We show that high-quality images can be obtained from binary holograms when speckle reduction is performed.

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Section: Introductionmentioning

confidence: 99%

Quantization noise and its reduction in lensless Fourier digital holography

Pandey

Hennelly

2011

Appl. Opt.

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“…For a double random phase encoding system, 10 Javidi et al 24 and Goudail et al 25 have studied how encrypted image perturbations affect the decrypted image. Treatments of quantisation in holograms can be found in the literature, 26,27 and quantisation of real-valued 28 and complex-valued 29-32 digital holograms, including encrypted digital holograms, has been studied in the context of data compression. A desirable feature when using a SLM for encryption and pattern recognition applications is a large space-bandwidth product (number of pixels in the SLM).…”

Section: 17mentioning

confidence: 99%

<title>Capture, encryption, compression, and display of digital holograms of three-dimensional objects</title>

et al. 2006

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Digital holography can be used to capture the whole Fresnel field from a reflective or transmissive object. Applications include imaging and display of three-dimensional (3D) objects, and encryption and pattern recognition of two-dimensional (2D) and 3D objects. Often, these optical systems employ discrete spatial light modulators (SLMs) such as liquid-crystal displays. In the 2D case, SLMs can encode the inputs and keys during encryption and decryption. For 3D processing, the SLM can be used as part of an optical reconstruction technique for 3D objects, and can also represent the key during encryption and decryption. However, discrete SLMs can represent only discrete levels of data necessitating a quantisation of continuous valued analog information. To date, many such optical systems have been proposed in the literature, yet there has been relatively little experimental evaluation of the practical performance of discrete SLMs in these systems. In this paper, we characterise conventional phase-modulating liquid-crystal devices and examine their limitations (in terms of phase quantisation, alignment tolerances, and nonlinear response) for the encryption of 2D and 3D data. Finally, we highlight the practical importance of a highly controlled discretisation (optimal quantisation) for compression of digital holograms.

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“…Quantization and phase quantization have been applied successfully to Fourier and holographic data in the past [14,13,15,16,12,17,18,19,20,21]. In this paper, we apply quantization directly to the complex-valued holographic pixels.…”

Section: Introductionmentioning

confidence: 99%

A companding approach for nonuniform quantization of digital holograms of three-dimensional objects

2006

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Abstract:We apply two novel nonuniform quantization techniques to digital holograms of three-dimensional real-world objects. Our companding approach, combines the efficiency of uniform quantization with the improved performance of nonuniform quantization. We show that the performance of companding techniques can be comparable with k-means clustering and a competitive neural network, while only requiring a single-pass processing step. The quantized holographic pixels are coded using lossless techniques for the calculation of compression ratio.

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Phase Quantization in Holograms–Depth Effects

Cited by 45 publications

References 11 publications

Quantization noise and its reduction in lensless Fourier digital holography

Quantization noise and its reduction in lensless Fourier digital holography

<title>Capture, encryption, compression, and display of digital holograms of three-dimensional objects</title>

A companding approach for nonuniform quantization of digital holograms of three-dimensional objects

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