S. L. Zhuang

Real-time white light spatial frequency and density pseudocolor encoder

A real-time white light pseudocolor encoding technique for spatial frequency and density encodings is presented. In spatial frequency color coding, the encoding is accomplished by spatial filtering of the color signal spectra, while in density pseudocoloring, the encoding consists of contrast reversal of a color object image. The technique is simple, versatile, and economical to operate, which may offer some practical applications. Because the encoding colors are primarily derived from a white light source, the annoying coherent artifact noise can be substantially reduced. Since the encoding is obtained with a broad spatial band of the signal spectra, this technique offers no apparent resolution loss. We stress that this real-time white light pseudocolor encoding technique may offer several major advantages that previous techniques have offered. Experimental demonstrations of this pseudocolor encoding technique are also provided.

Smeared-photographic-image deblurring utilizing white-light-processing technique.

A white-light-processing technique for smeared-photographic-image restoration is described. A simple technique of synthesizing a complex deblurring spatial filter is also given. Experimental demonstrations of smeared-image deblurring with a white-light-processing technique are provided. Compared with the coherent-processing technique, the white-light technique offers artifact-noise suppression, and the processing system is simple, versatile, and economicaL. We note that the white-light-processing technique is suitable for smeared-color-image restoration.

Resolution and color blur of the one-step rainbow hologram

From the point spread function and wavelength spread, the hologram image resolution and color blur for a one-step rainbow holographic process are analyzed. To achieve a higher image resolution and smaller degree of color blur, we proposed the insertion of a cylindrical lens in a one-step rainbow holographic process. We have shown that higher image resolution and a smaller degree of color blur can be obtained by the cylindrical lens technique. Experimental confirmations of the calculated results are also demonstrated. There is another advantage of the cylindrical lens technique, that is, a higher object beam irradiance, for which it relaxes the power requirement of the coherent source.

Coherence requirements for partially coherent optical processing

The mutual intensity function for a partially coherent light is used to develop an expression for the output intensity distribution for a broadband optical information processor. The coherence requirement for smeared image deblurring and image subtraction is then determined using the intensity distribution. We also quantitatively show the dependence of coherence criteria on the spectral bandwidth, the source size, deblurring width, spatial frequency, and the separation of input object transparencies.

Broad spectral band color image deblurring.

A broadband white-light processing technique for smeared color photographic image deblurring is described. The technique utilizes a diffraction grating method to disperse the smeared image spectra in the Fourier plane so that the entire spectral band of the white-light source can be utilized for the deblurring. In this paper the technique of synthesizing a fan-shape type complex deblurring filter to accommodate wavelength variation is presented. Experimental results showed that this broad spectral band processing technique offers an excellent coherent artifact noise suppression, and the technique is particularly suitable for color image deblurring. Experimental demonstrations and comparisons with the narrowband and coherent deblurring are also provided.

Progress report on archival storage of color films utilizing a white-light processing technique

The authors report a spatial encoding technique such that the moire fringe pattern inherently existing with the retrieved image can be avoided. To improve the diffraction efficiency of the film, they have introduced a bleaching process so that the step of obtaining a positive encoded transparency can be eliminated. Instead of restricting the encoding processing to the linear region of the T-E curve, they allow encoding in the linear region of the D-E curve, so that a broader range of encoding exposure can be utilized. Experimental results indicate that excellent color fidelity, high signal to noise ratio, and good resolution of the reproduced color images can be obtained.

Multi-image regeneration by white light processing

Abstract A technique of multi-image regeneration by white light processing is described. This white light method is very simple, versatile and economical, and it offers the advantages of multi-image regeneration and the elimination of coherent artifact noise that plagues coherent optical systems. Although this method is effective only in 1-D processing, nonetheless it also works very well for the 2-D multi-image deconvolution operation. A simple experimental demonstration of multi-image regeneration by this technique is also presented.

Coherence requirement for partially coherent correlation detection

The coherence requirement for correlation detection is determined using the theory of partially coherent light. It is shown that the requirement for temporal coherence strongly dependes on the spatial frequency and the spatial extension of the target (i.e., space bandwidth product). However, the spatial coherence requirement depends only on the extension of the target. Some numerical results are also presented.

Color photographic-image deblurring utilizing white-light processing technique

A white-light processing technique for smeared color photographic image deblurring is described. A simple technique of synthesizing complex spatial filters for color image deblurring is also given. An experimental demonstration of smeared color image deblurring with white-light processing technique is provided. Since the white-light source contains all the visible wavelength of the electromagnetic wave, it is particularly suitable for color image processing. The authors also note that the white-light processing technique is simple and economical to operate and it offers the advantage of artifact noise suppression.

Progress report on archival storage of color films by a one-step rainbow holographic process

Abstract The application of a one-step rainbow holographic process, utilizing a cylindrical lens technique, to the archival storage of color films is described. Although this technique improves the hologram image resolution, color blur, and speckle noise, it still suffers the same drawbacks. First, the coherent artifact noise and color blur still can not be totally eliminated. Secondly, the technique is still elaborate and expensive, which limits its practical application to the archival storage of color films.