Showing papers on "Channel (digital image) published in 1973"
01 Jan 1973
TL;DR: A new algorithm based on a nonlinear programming technique to correct the geometrical distortions of one digital image with respect to another is discussed, capable of treating localized differential scaling, translational and rotations over the whole image plane.
Abstract: A new algorithm based on a nonlinear programming technique to correct the geometrical distortions of one digital image with respect to another is discussed. This algorithm promises to be superior to existing ones in that it is capable of treating localized differential scaling, translational and rotational errors over the whole image plane. A series of piece-wise 'rubber-sheet' approximations are used, constrained in such a manner that a smooth approximation over the entire image can be obtained. The theoretical derivation is included. The result of using the algorithm to register four channel S065 Apollo IX digitized photography over Imperial Valley, California, is discussed in detail.
9 citations
TL;DR: In this paper, an ideal ultrasonic imaging system for undersea applications is described that would provide diffraction-limited performance at high resolutions (500 2000) over a field of view of at least ±10°.
Abstract: An ideal ultrasonic imaging system for undersea applications is described that would provide diffraction‐limited performance at high resolutions (500 2000) over a field of view of at least ±10°. The image surface of the ideal system would be an array of closely spaced sensors with the size of each sensor being determined by the image spot size. Each sensor would be connected via a discrete processing channel to an element in an electro‐optical display. Each processing channel would provide either linear or exponential amplification in specified temporal frequency bands and signal integration with controllable or automatic selection of the integration time. The merits of dividing the passband into three overlapping bands to provide a color display will be explored. The need for broad spatial and temporal frequency bandwidths will be shown. Since an ideal system cannot be built at this time, an examination of the parameters and performance which must be compromised to obtain practical ultrasonic imaging systems will be made. A number of systems that have been developed for undersea applications will be reviewed.
2 citations