In this paper, we report a method for color image reconstruction by recording only one single multi-wavelength
hologram. In the recording process, three lasers of different wavelengths emitting in the red, green and blue regions are
used for illuminating on the object and the object diffraction fields will arrive at the hologram plane simultaneously.
Three reference beams with different spatial angles will interfere with the corresponding object diffraction fields on the
hologram plane, respectively. Finally, a series of sub-holograms incoherently overlapped on the CCD to be recorded as a
multi-wavelength hologram. Angular division multiplexing is employed to reference beams so that the spatial spectra of
the multiple recordings will be separated in the Fourier plane. In the reconstruction process, the multi-wavelength
hologram will be Fourier transformed into its Fourier plane, where the spatial spectra of different wavelengths are
separated and can be easily extracted by employing frequency filtering. The extracted spectra are used to reconstruct the
corresponding monochromatic complex amplitudes, which will be synthesized to reconstruct the color image. For singleexposure
recording technique, it is convenient for applications on the real-time image processing fields. However, the
quality of the reconstructed images is affected by speckle noise. How to improve the quality of the images needs for
A novel algorithm of multi-image hiding method is presented based on polarization multiplexing digital holography
(PMDH). In our single wavelength PMDH scheme, four beams, two p-polarized beams and two s-polarized beams, are
formed by two Polarization Beam Splitters (PBS) in the Mach-Zehnder interferometer. Then two different object waves
with mutually orthogonal polarization states interfere corresponding reference waves respectively. Therefore two objects
can be acquired from the compound holography recorded by CCD with proper incident angle between two reference
beams simultaneously. The hologram storing multi-image is then superposed on the discrete-cosine-transform (DCT)
domain of the content image, and the extraction process only requires the watermarked image without content image.
Simulation results also demonstrate that the embedded multi-image can be successfully extracted under different kinds of
Proc. SPIE. 7850, Optoelectronic Imaging and Multimedia Technology
KEYWORDS: Wavelet transforms, Principal component analysis, Digital holography, Data hiding, Wavelets, Digital watermarking, Discrete wavelet transforms, Image analysis, Image storage, Information security
In this paper, a hiding method is proposed to store vast quantities of image information based on PCA. A sequence
eigenimages of objects are obtained by using PCA method. Then, wavelet coefficients of eigenimages are embedded into
the wavelet domain of the carrying image. When the hiding information is extracted, we can take advantage of the
decomposition coefficients to reconstruct the objects. The proposed method does not store the object images directly, but
store the eigenimages which contain information of the objects. The experimental results show that the features of object
are effectively embedded into the carrying image, and the proposed algorithm has a high capacity.
Region logical operation is proposed for segmenting the object from the background or noise. Region logical operation is quite different from ordinary pixel logical operation. The entire object is processed region-by-region rather than pixel-by-pixel when regional logical algorithm is used for pattern recognition. The experimental results show object pre-processing based on region logical operation is simple and effective, it can be widely used in optical pattern recognition and image processing.
A novel algorithm, which is based on creating the variance image of original image, for infrared image enhancement is proposed. Ordinary spatial filtering is powerful of reducing the noise of image, but it also reduces the contrast of image. Compared with spatial filtering, variance image not only reduces the noise but also enhances the image. In this paper, we combine the variance image and histogram equalization to enhance the infrared image blurred by random noise. The experimental results show the algorithm based on creating variance image is simple and effective, it can be widely used in infrared image enhancement.
In this paper, aspheric surface testing technique with radial shearing interferometer has been developed. Zone plates are proposed to construct radial shearing interferometer because of its stability and simplicity. Zone plates were designed and fabricated by photographic processing, which is used as radial shearing devices. Radial shearing interferogram are detected by a CCD camera and processed by a PC computer. Fringe phase of shearing interferogram is evaluated by Fast Fourier transform (FFT) algorithm. Wave aberration estimation method of aspheric surface is also presented, which is depended on polynomial expansion fitting. Some errors of interferometer are discussed. Finally, theoretical analysis and experimental results are compared, which shows its accuracy is less than λ/20.
The importance of phase and amplitude in the field of image processing is compared by using the method of Fourier transform. The digital image is encoded with only-phase encode and the computer simulation results are given. The research shows that phase is more important than the amplitude, and phase-only code of image is effective for image encryption and we should make full use ofthe phase of the image.
A simple and effective error detection and error concealment based on the H.263 video decoder has been described in this paper. The H.263 syntax structure and semantics, VLC code word and continuity property of video signal at the video decoder are employed to process the error detection. The spatial and temporal correction is made full of use for error concealment. It has been found that this method can greatly improve the quality of the reconstruction images without decreasing the coding efficiency.
We describe a method for the ultrasonic displacement measurement in a small volume based on self-mixing effect in a laser diode. The interference signal (mode-hop signal) is modulated with injection variation and demodulated by signal analysis. The interference signal due to the vibration of a testing example under the ultrasonic excitation is used for a determination of the sound displacement. Self-mixing interferometer is used, because it is much simper than the conventional interferometers. Many optical elements like the beamsplitter, reference mirror, and external photodetector are not required. Theoretical analysis and experimental method are presented. The vibration of a PZT transducer-driven sample was measured with resolution of sub-micron.
The design of optical array generator is based on the scalar diffraction theory. Optical array diffraction intensity is the same for all diffraction levels. Optical array generator can be modulated by either the amplitude or phase profile, however, phase array generator is done through ion etching. The design and fabrication of highly efficient optical array generator is studied, one and two dimensional optical array generator is designed, which generate 16, 32,64, 256, 1024, 4096 uniform optical arrays separately. The optical array generator has been used in optical pattern recognition and multi-channel imaging, and the experimental results are presented.
Many optical sensors for the displacement measurement in sub-micron have been developed. In this paper, we propose a new type of self-mixing interferometry (SMI) to measure microscopic displacement in microelectromechanical systems(MEMS). The phase of SMI signal is modulated with external cavity length and demodulated by signal analysis technique. The experimental system was developed to have a sensitivity of several nanometers for displacement sensing.
Optical coherence microcopy (OCM) is a new method for optical and near-infrared imaging of biological tissues. This method is based on the detection of least-back-scattering light that maintain coherence and has thus spend shortest time that its path-length difference (Delta) L falling within the coherence length Lc of the low-coherence source. This paper points out that there are also a special part of multiple scattering light which has the sufficient small part length differences (Delta) L falling within the coherence Lc. The effects of this part of multiple scattering light can be divided into two categories. One is nonlinear effects and the other is speckle effects.
At the optical processing domain, the three-dimension reconstruction of information is an important problem of research. At the last few years, the laser confocal scanning microscope (LCSM) system was researched and has been used successfully as advanced optical instrument in the biological and medical research range. This paper primarily research the 3-D image reconstruction of the cell using its 2-D section image formed by the laser confocal scanning microscopy. First, the paper rests on the LCSM system characteristic of forming image to analyze the image noise and remove it. Then we extract the information of 2-D section image edge, and we use these informations to reconstruct the 3-D image of cell surface by method of B-Spline.
Presented is the analyses of influence of Hadamard coding system on imaging error in laser coding Synthetic Aperture Radar. The result shows that using Hadamard coding can increase the amplitude of echo signal and reduce noise. Coding and sampling circuit possess good linearly respond property.
This paper describes the application of parallel processing technique in optical pattern recognition. We present a multiplexing parallel processing system. A plane optical lenslet array is used to produce multiple paralled beam, which read out multiimage of object from LCLV. The parallel iterative algorithm is adopted to design the bank of eigenfunction filters. Multiplexing correlation results are processed and determined synthetically. At last the recognition results are provided.
In this paper, a principle of synthetic aperture microscope based on the synthetic aperture principle and inverse scattering imaging is described. The algorithm of inverse problem is introduced and the results of computer simulation are given.
In this paper, computer simulation of 3D object parallel correlation pattern recognition has been done by using a bank of filters, the results show that a bank of filters is essential to pattern recognition. The reason that the experimental results are not satisfactory is analyzed.
A procedure is presented for extracting eigen information from a large number of perspective views of an object. Eigenfunction filters are designed to realize perspective invariant pattern recognition in optical correlation system. Each filter contains complete information about the object, its dimension is 2 X 2 mm2, resolution is 1.5 micrometers .
Based on the Gaussian cross-sections of laser beam, real-time weighting of Gaussian beam on synthetic aperture radar (SAR) range signals has performed. Sidelobe height of range point spread function of SAR processor is decreased efficiently and imaging quality is improved.
A new design of the correlation filter is proposed. The spectral iterative technique and the Fourier-Mellin descriptor are used in the filter design. Targets are detected by rotating this filter in the Fourier plane to determine points of constant intensity. The results of computer simulation show that distortion (translation, rotation, scale, and intensity) invariant pattern recognition can be achieved.