Machine vision systems are often confronted with images of great complexity. Preprocessing, region growing, and edge extraction algorithms must rely on their underlying image models in order to make effective use of t...
详细信息
Machine vision systems are often confronted with images of great complexity. Preprocessing, region growing, and edge extraction algorithms must rely on their underlying image models in order to make effective use of the data. This study presents an alternate approach to the definition of an image model. It also discusses an algorithm, based on this model, which reduces noise in a digitized image without destroying the information contained within the image. This algorithm is based upon a neighbor-weighting function which incorporates spatial separation as well as intensity difference and is modulated by the variance in the local neighborhood.
Segmentation of monochrome images to obtain boundaries of the object is an important problem in scene analysis. An algorithm is described for locating object boundaries from an image of objects. The algorithm, called ...
详细信息
Segmentation of monochrome images to obtain boundaries of the object is an important problem in scene analysis. An algorithm is described for locating object boundaries from an image of objects. The algorithm, called Global-Local-Edge-Coincidence (GLEC) uses both local and global edge information to select a stable set of object boundaries. Significantly improved results are shown in several examples including blocks, building and aerial photograph. The significance of this algorithm is that the boundaries of objects can often be located from a single image.
An analysis is given of the Moire pattern formation in scanning and reproducing halftone pictures. The analysis includes the effects of the aperture size and shape of the reproduction printing process. Also the effect...
详细信息
An analysis is given of the Moire pattern formation in scanning and reproducing halftone pictures. The analysis includes the effects of the aperture size and shape of the reproduction printing process. Also the effects of parallelogram grid sampling as well as square grid sampling have been taken into consideration. A simulation program has been written to synthesize the Moire patterns based upon the Fourier transform of the output picture. Several observations will be discussed and among two of the more important ones are: (a) Moire fringes can result from beating together of clusters of Fourier spatial frequencies and (b) fixed value thresholding intensifies Moire patterns.
A method is described that generates 3D descriptions of arbitrarily-curved surfaces of physical objects by imageprocessing and photogrammetric techniques. A surface that is to be described is illuminated by a pattern...
详细信息
A method is described that generates 3D descriptions of arbitrarily-curved surfaces of physical objects by imageprocessing and photogrammetric techniques. A surface that is to be described is illuminated by a pattern of lines. The 3D shape of the surface causes the pattern to be distorted. The illuminated parts of the surface are photographed from two or more vantage points and the resulting images are digitized. The 2D perspective projection of the surface-distorted line pattern is extracted from each digitized image. Camera calibration marks are also extracted and the position of the camera is determined for each image. Two or more projections of the line pattern are then matched and the line pattern projected on the surface is reconstructed into 3D.
A simple image smoothing scheme for improving the quality of noisy pictures is proposed. This scheme employs a 3 by 3 mask in which the weighting coefficients re the normalized gradient inverses. The smoothing operati...
详细信息
A simple image smoothing scheme for improving the quality of noisy pictures is proposed. This scheme employs a 3 by 3 mask in which the weighting coefficients re the normalized gradient inverses. The smoothing operation will clean out noises inside a region without blurring its boundary. Simulation studies show that this method tends to reduce the gray level variance within a region, and keep its mean relatively unchanged. Results of applications to several real world images are presented.
A description is provided of some novel algorithms for patternrecognition research and a framework for efficient development, maintenance, and sharing of interactive software among several users and diverse applicati...
详细信息
A description is provided of some novel algorithms for patternrecognition research and a framework for efficient development, maintenance, and sharing of interactive software among several users and diverse application areas. This modular interactive software system (MISS) forms the basis of a general purpose image analysis and patternrecognition research system (IPS). The algorithms and some preliminary results are discussed first. Then, the MISS and IPS software systems are described.
A method for optimizing the performance of the line detector described by Duda and Hart is presented. Comparisons are made of the error probabilities for the optimal and previous schemes. A method for approximating th...
详细信息
A method for optimizing the performance of the line detector described by Duda and Hart is presented. Comparisons are made of the error probabilities for the optimal and previous schemes. A method for approximating the optimal scheme is also presented.
The potential uses of Charge Transfer Devices (CTDs) in pattern classification operations are explored. The needs for a hardware-based pattern classifier are established, and a matrix multiplication subsystem based up...
详细信息
The potential uses of Charge Transfer Devices (CTDs) in pattern classification operations are explored. The needs for a hardware-based pattern classifier are established, and a matrix multiplication subsystem based upon a sum-of-products CTD is presented. Applications of the subsystem to the classification of multi-modal Gaussian distributions in general and to LANDSAT data processing in particular are discussed. The potential impact of this technology on satellite data processing methodologies is discussed.
A map-guided approach to interpretation of remotely sensed imagery is described, with emphasis on applications involving continuous monitoring of predetermined ground sites. Geometric correspondence between a sensed i...
详细信息
A map-guided approach to interpretation of remotely sensed imagery is described, with emphasis on applications involving continuous monitoring of predetermined ground sites. Geometric correspondence between a sensed image and a symbolic reference map is established in an initial stage of processing by adjusting parameters of a sensor model so that image features predicted from the map optimally match corresponding features extracted from the sensed image. Information in the map is then used to constrain where to look in an image and what to look for. With such constraints, previously intractable remote sensing tasks can become feasible, even easy, to automate.
The problem of estimating the error probability of a given classification system is considered. Statistical properties of the empirical error count (C) and the average conditional error (R) estimators are studied. It ...
详细信息
The problem of estimating the error probability of a given classification system is considered. Statistical properties of the empirical error count (C) and the average conditional error (R) estimators are studied. It is shown that in the large sample case the R estimator is unbiased and its variance is less than that of the C estimator. In contrast to conventional methods of Bayes error estimation the unbiasedness of the R estimator for a given classifier can be obtained only at the price of an additional set of classified samples. On small test sets the R estimator may be subject to a pessimistic bias caused by the averaging phenomenon characterising the functioning of conditional error estimators.
暂无评论