Showing papers by "Javier Garcia published in 1997"
TL;DR: The wavelet transform, which has had a growing importance in signal and image processing, has been generalized by association with both the wavelettransform and the fractional Fourier transform.
Abstract: The wavelet transform, which has had a growing importance in signal and image processing, has been generalized by association with both the wavelet transform and the fractional Fourier transform. Possible implementations of the new transformation are in image compression, image transmission, transient signal processing, etc. Computer simulations demonstrate the abilities of the novel transform. Optical implementation of this transform is briefly discussed.
128 citations
TL;DR: An optical encoding and decoding system is suggested for transmitting one- or two-dimensional images by means of a single-mode fiber based on wavelength multiplexing of the input spatial information, which is achieved with diffractive optical elements.
Abstract: The expanding use of optical communication by means of optical fibers and the situation of drastically increasing amounts of data to be transmitted urge the exploration of novel systems permitting the transmission of large amounts of spatial information by fiber with smaller spatial resolution. An optical encoding and decoding system is suggested for transmitting one- or two-dimensional images by means of a single-mode fiber. The superresolving system is based on wavelength multiplexing of the input spatial information, which is achieved with diffractive optical elements. Preliminary experimental results demonstrate the capabilities of the suggested method for the one- and two-dimensional cases.
36 citations
TL;DR: Both computer simulations and optical experiments are presented, showing the discrimination capability for this implementation of a bank of wavelets used for pattern recognition by means of sequential filtering.
20 citations
TL;DR: In this article, the scaling factor between the input pattern and the filter can be adjusted at will with the help of converging beam illumination and using an adjusting device consisting of a combination of Fresnel zone plates.
12 citations
TL;DR: Rotation-invariant pattern recognition can be achieved with circular-harmonic decomposition by use of wavelength multiplexing, where different harmonic terms are encoded by different wavelengths, and then they all are added incoherently in the output correlation plane.
Abstract: Rotation-invariant pattern recognition can be achieved with circular-harmonic decomposition. A common problem with such a filter is that, because it is only a single term out of the circular decomposition, it does not contain much of the reference object's energy. Thus, the obtained correlation selectivity is low. This problem is solved by use of wavelength multiplexing. First, different harmonic terms are encoded by different wavelengths, and then they all are added incoherently in the output correlation plane. This process leads to rotation-invariant pattern recognition with a higher discrimination ability.
8 citations
22 Sep 1997
TL;DR: In this article, the authors proposed a super resolving system based on wavelength multiplexing of the input spatial information that is achieved with diffractive optical elements for transmitting 1D or 2D images via a single mode fiber.
Abstract: The expanding usage of optical communication via optical fibers and the situation of drastic increasing of the data required to be transmitted, urge the exploration of novel systems allowing to transmit high amount of spatial information by fiber with smaller spatial resolution. In this paper, optical encoding and decoding system is suggested for transmitting 1D or 2D images via a single mode fiber. The super resolving system is based on wavelength multiplexing of the input spatial information that is achieved with diffractive optical elements. Preliminary experimental results demonstrate the capabilities of the suggested method for the 1D case.
8 citations
TL;DR: The formed filter is actually a real function, hence, it is theoretically possible to be implemented under both spatially coherent and spatially incoherent illuminations, and the obtained output is shown to be invariant to 2-D scaling even when different scaling factors are applied on the different axes.
3 citations
TL;DR: In this article, a color image pattern recognition method using a fractional correlator (FC) is proposed, where the input plane is illuminated with three different coherent sources of wavelengths corre- sponding to RGB (red, green, and blue) colors.
Abstract: A novel method for performing color image pattern recogni- tion using a fractional correlator (FC) is proposed. The input plane is illuminated with three different coherent sources of wavelengths corre- sponding to RGB (red, green, and blue) colors. The output plane pro- vides a single output peak, which is a result of an incoherent addition between the three correlations obtained per each color. By using the fractional correlator, which is a partially space variant correlator, we achieve space-variance-controlled color pattern recognition. The use of the three-color illumination can drastically increase the discrimination ability of the suggested correlator. © 1997 Society of Photo-Optical Instrumenta- tion Engineers. (S0091-3286(97)02808-0)
3 citations