Showing papers on "Image scaling published in 1984"

Shaded Display of Digital Maps

Abstract: Improved techniques of surface interpolation, clipping, and hidden-surface elimination help solve some problems in generating perspective views of digital terrain data.

Image Decimation and Interpolation Techniques Based on Frequency Domain Analysis

Abstract: A scheme for a spatial domain image data preprocessing decimation and postprocessing interpolation is presented. The scheme is implemented by appropriate FIR digital filters. Frequency and patial domain specifications are discussed in the design of the corresponding digital filters. Fast approximation techniques in the spatial domain are presented.

Approximation Quality Improvement Techniques in Progressive Image Transmission

Abstract: Progressive transmission of images has proved to be an efficient way of reaching effective bit rate reductions in highly interactive contexts such as telebrowsing systems, or low bandwidth communication channels. However, the lack of quality of the intermediate approximations has so far limited the obtained effective compression to a small factor. Three different and compatible techniques are presented to improve this quality: use of smoother interpolation schemes in its generation, a nonuniform decomposition procedure to favor the early refinement of relevant areas of the image, and an extension of the transmission hierarchy to pixel quantization producing successive refinement of the grey level resolution of the approximations. Combined use of these approaches yields effective bit rate reductions of up to 12.5:1, considerably extending the range and power of progressive transmission methods.

Halftone image scaling

Abstract: A method of enlarging or reducing the size of a halftone one bit per pixel raster image without changing the screen pitch is disclosed. First, there is a determination of whether the current byte is on an image edge using any edge detection means. If the current byte is on an edge, the nearest neighbor algorithm is applied to the original image on a bit by bit basis to prevent edge jaggedness. If the current byte is not on an edge, the nearest neighbor algorithm is applied on a byte by byte basis to prevent Moire patterns in the solid areas of the image.

High-speed image scaling for integrated document management

Abstract: Document information often includes image data (eg handwritten annotations, signatures, maps, sketches and photos) as well as alphanumeric and other coded data Thus, the capability of handling these image data plays an important role in reforming current office-work activitiesThis paper presents a high-speed scaling method to enlarge or reduce digital images defined as two-dimensional pixel arrays Scale factors are assumed to be rational numbers R/r and S/s for the vertical and horizontal directions, respectively, where R, S, r, s denote positive integers Under this assumption, coordinate determination for image scaling is performed by simple table look-up and shift operations This method excludes time-consuming arithmetic operations for coordinate determination Thus, high-speed scaling is realized Experiments showed that the execution time per output pixel is about 150 ns when the shift clock frequency is 8 MHzThe proposed algorithm has been successfully applied to a multi-functional office workstation featuring integrated functions of data processing, document processing and image processing

High-fidelity Image Resampling For Remote Sensing

Abstract: Investigation of the image resampling requirements of remote sensing has indicated a need for improved resampling convolution kernel design. Areas in which progress has been made include a recognition of the improved phase linearity of longer kernels and the need for similarity of the modulation transfer function (MTF) across all filters. The computational capability required for the longer kernels is achieved with a dedicated signal processor.

Image interpolation apparatus

Abstract: PURPOSE:To prevent deterioration in the quality of picture by performing interpolation at the writing into or reading from a digital scan converter. CONSTITUTION:In a sector scan ultrasonic diagnosing equipment having a digital scan converter, an ultrasound echo signal returned from a body is inputted into an A/D converter 1 after amplifier and detected to make a digital sample data. The data is written into a frame memory 3 through a lateral direction writing interpolation device 2. The lateral direction writing interpolation device 2 is a circuit which is adapted to perform a writing on real time into a frame memory 3 interolating several subscan lines between original scan lines and a data to be interpolated is done so from those at the same depth of the original scan line. This interpolation may be performed at the reading from or writing into the frame memory and at the time of both writing into the reading from the frame memory.

Simulation of electronic registration of multispectral remote sensing images to 0.1 pixel accuracy

Abstract: Band-to-band coregistration of multispectral remote sensing images can be achieved by electronic signal processing techniques rather than by costly and difficult mechanical alignment. This paper describes the results of a study of the end-to-end performance of electronic registration. The software simulation includes steps which model the performance of the geometric calibration process, the instrument image quality, detector performance and the effects of achieving coregistration through image resampling. The image resampling step emulates the Pipelined Resampling Processor, a real-time image resampler. The study demonstrates that the electronic alignment technique produces multispectral images which are superior to those produced by an imager whose pixel geometry is accurate to 0.1 pixel rms. The implications of this approach for future earth observation programs are discussed.

An optimized cubic interpolator for image resampling

Abstract: It is noted that the cubic resampling function is only one member of a family of functions, defined by the single parameter of the slope of the cubic function at its first zero crossing, whose other members are in some cases superior to the standard cubic. This superiority is especially noteworthy with respect to the extent of gray level overshoot induced by the resampling process at high contrast edges. It is shown that there is an optimum member of this 'parametric cubic convolution' family which minimizes the mean-squared radiometric error arising from interpolation. This interpolator requires no additional computation time over the conventional cubic one. These conclusions are supported and illustrated by resampling simulations with both a high resolution digitized aerial image and a Landsat Multispectral Scanner image.

Image Interpolation for Real-Time Compound Dual Sector Scans

Abstract: Many technical advantages and clinically valuable evaluations have been reported since simultaneous multifrequency ultrasonography was introduced1–2 This newly devised technique enables dual ultrasonic images to be simultaneously obtained One application of this technique—real-time compound dual sector scanning—offers more valuable information than conventional ultrasonography

A Practical Architecture For A Real-Time Image Resampling Processor

Abstract: A hardware architecture for real-time image resampling has been developed which will support a wide range of image resampling tasks arising in remote sensing applications. In particular, local spatial sampling errors caused by misalignment of sensor arrays and optical defects, plus global spatial sampling errors caused by platform pointing errors, can be simultaneously rectified. This is achieved by referring all sample errors to the same fixed ideal sampling coordinate frame This has the added advantage of providing automatic co-registration of images obtained in several spectral bands with separate sensor arrays. The resulting architecture is modular and flexible due to a decomposition into independent parallel structures. The use of very large scale integrated circuits for memories and mul-tiplier/accumulators results in a design with a processing speed/power ratio in excess of 10° pixels per second per Watt and providing 1/16 pixel resampling accuracy.© (1984) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.