Showing papers on "Edge enhancement published in 1986"

Optical Hough transform.

Abstract: An optical technique is presented for achieving the Hough transform at video rates. Both coherent and incoherent approaches are discussed and analyzed. An incoherent system which combines edge enhancement with the Hough transform is also considered. Use of the optical Hough transform for the location of the bridges and roadways in outdoor scenes and for the locations of parts, as used in automated manufacturing, is demonstrated.

The effect of varying high pass filter parameters on the detectability of isolated pulmonary nodules in digitized chest images.

Abstract: The effect of image processing of digital radiographic data on lesion detectability in clinical images has not been systematically studied. In this experiment, we evaluated a low frequency suppression filter program applied to CT digital radiographic localization images (General Electric Scoutview). Three different filter parameters affecting edge enhancement and local image contrast were applied to a set of digital chest images. A standard observer detection experiment comparing the variously filtered digital images and standard chest radiographs in the detection of lung nodules (11 peripheral lung fields, one superimposed on aortic arch) was performed. Standard chest radiography was more sensitive than the digital chest images, although some improvement was noted with increase in local image contrast and edge enhancement. Both image formats were equally specific. Image processing would be better evaluated using a digital imaging system with better performance parameters.

A method for reconstructing patterns of somatosensory cerebral cortical activity.

Abstract: An interactive graphics package was developed in order to acquire, display, and manipulate images of cerebral cortical autoradiographic data. The primary purpose for development of the system was to reconstruct accurate 2-dimensional maps of the functional activity within the somatosensory cerebral cortex. A Datacube Q-bus graphics module (QVG/QAF-123) was interfaced with the Micro PDP-11/23 to accept a standard RS170 video input signal, and autoradiographs of serial sections (each 20 microns thick) of a cerebral cortex were digitized individually to 768 X 512 X 8 bit resolution. Input look-up tables were used to standardize the autoradiographic data. Boundaries of the somatosensory cortex were entered (with a Summagraphics MM 1201 digitizer), and the image data was stored on disk file (a method of data compression was devised). A method for segmenting the image data for many (sequential) sections was developed that provided arrays from which the maps were generated. Thresholding, histogram equalization, edge detection and edge enhancement, and filters in both the spatial and frequency domains were employed to process the images of the maps. Plots of optical density values along any axis of the maps and gray level histograms of any map region could also be generated. Maps made by the described method are much higher in resolution than those produced by traditional (manual) methods, and permit analysis of the reconstructions in both the frequency and spatial domains.

Circuit arrangement for increasing the definition of color contours of a color television signal using selective edge enhancement

Abstract: The invention relates to a circuit arrangement for increasing the resolution of color contours. A slope detector detects the slope of the luminance signal and, when a predetermined slope value is exceeded, produces a detection signal for energizing a counter. The counter controls an edge enhancement circuit for a color difference signal, in which, as soon as the counter is energizing, the value of the color difference signal is stored and is available as an output signal. After a predetermined number of equidistant clock pulses has been counted, the edge enhancement circuit (7, 16) supplies the actual color difference signal value. If before the end of the counting operation, a new detection signal is produced, then the edge enhancement circuit briefly receives and stores the actual color difference signal value, and the counter starts a new counting cycle.

Electronic image generation

Abstract: A method of generating an electronic representation of an original image (2) is described. The method comprises illuminating the image (2) with a scanning beam; causing relative movement between the scanning beam impinging on the image and the image (2) whereby the original image (2) is scanned in a series of overlapping scan lines. The scanning beam is caused to impinge on one or more arrays of radiation sensitive elements (14-16), each array having dimensions smaller than the dimensions of the image (2), and the elements being sensitive to the intensity of respective portions of the incident beam received from corresponding pixels of the original image within a scan line at least some of which extends transversely to the scanning direction. The sensed intensities are regularly monitored and data related to the intensities monitored in a predetermined number n of the montioring steps is stored in a memory (20). A predetermined algorithm, such as an edge enhancement, is applied to the stored data to generate enhanced image data and part of the stored data is replaced with the enhanced image data.

Derivative Method for Edge Enhancement in Radiographic Testing

Abstract: The definition of edge is essential for dimension extraction from radiographic testing. One of the straightforward techniques for edge enhancement is the use of the derivative operator. This techni...

Edge enhancement of coherent magnetooptic images.

Abstract: The Litton magnetooptic spatial light modulator has a periodic structure which produces a replicated Fourier transform under coherent illumination. As a result, this modulator is not responsive to edge enhancement by the conventional means of a centered dc blocking spot in the transform plane of a coherent optical processor. Alternative spatial filtering masks for edge enhancement are described, which produce output images having dark edges on a light background as well as masks which produce bright edges on a dark background. Adjustable edge widths can be achieved. Both bright and dark edges can be produced in the same output image. One edge enhancement method requires no spatial filter mask.

Method and system for edge enhancement in reproducing multi-level digital images on a bi-level printer of fixed dot size

Abstract: A system for producing improved halftone images from continuous tone input images,the pixels of which have been digitized as gray scale values, using a printer having the capability to print a set of output pel patterns producing a respective set of discrete gray scale values, is disclosed. For edge enhancement the brightness gradient surrounding each input pixel is determined and a threshold value is set below which said gradient is classified as small and above which it is classified as large. When said gradient is small, the selected discrete pattern is printed for the pixel , and when said gradient is large, the pel pattern is altered and the block representing the pixel is printed biasing the pels therein toward the darker input pixels.

Special Information Processing Capabilities Of The Photoemitter Membrane Light Modulator (PEMLM)

Abstract: The PEMLM has been used to demonstrate several real-time image-processing operations: contrast reversal, edge enhancement, image addition/subtraction, and synchronous detection of time-modulated light in a scene. Experimental results will be presented, and the relationship between the device physical parameters and performance characteristics will be discussed. Future developments to improve the PEMLM performance will also be described. Demonstration of quantum-limited sensitivity, millions of resolution elements, and frame rates greater than a kilohertz is expected in the near future.© (1986) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

AN Edge Enhancement Algorithm Using a Polynomial Transformation

Abstract: The paper describes a new algorithm proposed for improving the subjective quality of picture by means of contour enhancement The method applies on digitalized pictures The algorithm is based on a transient detection scheme followed by a polunomial transformation The possibility of choosing a specific polynomial makes this new method useful for various applications, such as chrominance contour improvement on television pictures or edge enhancement for picture coding

A multi-resolution representation of 3D imagery for efficient image enhancement and processing

Abstract: The representation and processing of images at multiple levels of resolution is primarily used as a computational tool in image processing. Multi-resolution techniques have been used successfully for edge enhancement, data compression and transmission, and for planning, that is, images processed at a low resolution are used as a guide for processing and detecting features at a higher resolution. In this paper we generalize the methodology of 2D multi-resolution techniques to 3D, and then show some of the applications of the multiresolution technique for band-pass filtering, feature detection, and image enhancement.

Real time image enhancement by simple video systems

Abstract: In image processing, digital systems give the highest flexibility in the sense that they allow in general to solve many problems by only changing software.

A Portable Image Workstation/Transmission System

Abstract: This paper describes a PC-based workstation for the acquisition, enhancement, transmission and reception of image and text data. The system was designed to provide both ease of use and reasonable performance using IBM PC technology with a 512 X 512 monochrome frame grabber board (PCVISION). The system allows the user to annotate an image with text legends and graphics. The system utilizes some unique methods for achieving eye pleasing two pixel graphics. An image may also be enhanced in two ways: globally with look up table alterations and locally with contrast and edge enhancing operations. Performance enhancement is achieved by implementing primarily integer operations, thereby elimating floating point operations, and radically increasing the apparent processor speed. We show that designing a system for ease of use may also significantly enhance its responsiveness and speed. For example, the edge enhancement technique only allows selection of low, medium, and high levels of enhancement, simplifying user choices and speeding up process operations. In addition, all look up table enhancements are precalculated and stored, allowing the user to alter the contrast with keystroke rapidity without being concerned about the applicability of the algorithm to a particular image.© (1986) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An Experimental Digital Image Processor

Abstract: A prototype digital image processor for enhancing photographic images has been built in the Research Laboratories at Kodak. This image processor implements a particular version of each of the following algorithms: photographic grain and noise removal, edge sharpening, multidimensional image-segmentation, image-tone reproduction adjustment, and image-color saturation adjustment. All processing, except for segmentation and analysis, is performed by massively parallel and pipelined special-purpose hardware. This hardware runs at 10 MHz and can be adjusted to handle any size digital image. The segmentation circuits run at 30 MHz. The segmentation data are used by three single-board computers for calculating the tonescale adjustment curves. The system, as a whole, has the capability of completely processing 10 million three-color pixels per second. The grain removal and edge enhancement algorithms represent the largest part of the pipelined hardware, operating at over 8 billion integer operations per second. The edge enhancement is performed by unsharp masking, and the grain removal is done using a collapsed Walsh-hadamard transform filtering technique (U.S. Patent No. 4549212). These two algo-rithms can be realized using four basic processing elements, some of which have been imple-mented as VLSI semicustom integrated circuits. These circuits implement the algorithms with a high degree of efficiency, modularity, and testability. The digital processor is controlled by a Digital Equipment Corporation (DEC) PDP 11 minicomputer and can be interfaced to electronic printing and/or electronic scanning de-vices. The processor has been used to process over a thousand diagnostic images.

Edge enhancement via phase contrast filtering: A new technique.

Abstract: Edge enhancement is encountered in a number of applications of digital'image processing. Edges characterize the boundaries of objects and are useful for segmentation, registration and object identification in images. Numerous enhancement techniques are in existence and various classes of these shall be briefly reviewed here. An alternate technique has been proposed by Soltis [1] which he termed 'phase contrast filtering' (PCF). It is the intent of the thesis to examine this new technique on the basis of its edge enhancement capabilities and to develop a method for the design of two-dimensional (2-D) recursive digital filters to meet the specifications of the PCF method. An examination of the PCF's applicability to enhancement of various images such as medical Xrays, metal surfaces, etc., is also given. Finally, a comparison between selected edge enhancement techniques and the PCF technique is presented.

Image enhancement via transform amplitude sharpening

Abstract: A new frequency-domain based image edge enhancement technique is described. In the proposed method, the magnitude of the transform of an image is modified using a novel amplitude change function with the phase kept invariant, which is followed by an inverse transform resulting in the crispening of the edge. The new method is somewhat similar to the alpha-rooting method but does not suffer from certain objectionable artifacts associated with the latter, and also exhibits less degradation due to noise. A post-processing of the enhanced image generated using the proposed transform amplitude sharpening method via histogram modification has been found to improve the image quality. Images enhanced with the proposed method are included to illustrate the method.

Suitability and Applications of Liquid Crystal Televisions in Optical Pre-Processors.

Abstract: : The suitability of a low-cost liquid crystal television to function as a spatial light modulator for lasers is investigated along with an application of using such a modulator in an optical pre-processor for an electronic pattern recognition system. The particular pre-processor application investigated is that of optically enhancing the edges of an image. It was determined that the liquid crystal television could perform reasonably well as a spatial light modulator for applications where very high image quality was not required. Three different methods were found to produce recognizable edges of a given image: spatial filtering in the Fourier plane, image cancellation, and phase cancellation. The phase cancellation method was discovered during the course of the research. These methods were able to perform the edge enhancement task whether the image was binary as in a computer generated image, or was continuous as from a television camera. (Thesis).