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Strategies for cloud top phase determination - Differentiation between thin cirrus clouds and snow in manual (ground truth) analyses

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Conference on Satellite Remote Sensing and Modeling of Clouds and the Atmosphere

作者： Hutchison, KD Etherton, BJ Topping, PC Lockheed Martin Missiles & Space Co. Inc. (United States)

ISBN: (纸本)0819423653

Quantitative assessments on the performance of automated cloud analysis algorithms require the creation of highly accurate, manual cloud,no cloud (CNC) images from multispectral meteorological satellite data. In general, the methodology to create ground truth analyses for the evaluation of cloud detection algorithms is relatively straightforward. However, when focus shifts toward quantifying the performance of automated cloud classification algorithms, the task of creating ground truth images becomes much more complicated since these CNC analyses must differentiate between water and ice cloud tops while ensuring that inaccuracies in automated cloud detection are not propagated into the results of the cloud classification algorithm, The process of creating these ground truth CNC analyses may become particularly difficult when little or no spectral signature is evident between a cloud and its background, as appears to be the case when thin cirrus is present over snow-covered surfaces. In this paper, procedures are described that enhance the researcher's ability to manually interpret and differentiate between thin cirrus clouds and snow-covered surfaces in daytime AVHRR imagery. The methodology uses data in up to six AVHRR spectral bands, including an additional band derived from the daytime 3.7 micron channel, which has proven invaluable for the manual discrimination between thin cirrus clouds and snow. It is concluded that while the 1.6 micron band is needed to distinguish between snow and water clouds in daytime data, the 3.7 micron channel remains essential to differentiate between thin ice clouds and snow. However, this capability that may be lost if the 3.7 micron data switches to a nighttime-only transmission with the launch of future NOAA satellites.

关键词： Clouds detection and tracking algorithms Solar energy Analytical research Atmospheric optics Channel projecting optics Image classification Meteorological satellites Multispectral imaging Satellites

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Real-time processing of Mid-wave infrared imaging spectrometer data 2

Real-time processing of Mid-wave infrared imaging spectromet...

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Conference on algorithms for Multispectral and Hyperspectral Imagery II

作者： Norton, M SCITEC INC PRINCETONNJ 08540

ISBN: (纸本)0819421391

A custom six channel digital processing card has been built for the mid-wave infrared spectral imager (MIRSI) for spectrally classifying objects in the 2.9 - 4.9 micron spectral region. The card, called the real time processor, fits in a standard ISA PC slot and operates on the 12 bit data from the MIRSI InSb camera, performing six spectrally weighted sums on each focal plane array row (i.e., spectrum of a spatial pixel). Objects in the scene are classified according to the amplitudes of the weighted sums, where the weighting functions are obtained using a least squares technique. An optional analog interface has been added to the real time processor to allow RS-170 input of HSI data from a video tape or standard video camera output. A preprocessing card is being designed to provide bad pixel substitution and to apply gains and offsets independent to each pixel prior to the spectral classification to provide calibrated data to the real time processor.

关键词： Calibration Imaging systems Black bodies Image processing Spectroscopy Staring arrays detection and tracking algorithms Infrared imaging Thermography Sensors

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Real-time automatic target location by template matching on blurred images

Real-time automatic target location by template matching on ...

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Conference on Nondestructive Evaluation for Process Control in Manufacturing

作者： Kumar, R Downs, J Peterson, ML Colorado State Univ. (United States)

ISBN: (纸本)0819423521

High precision manufacturing is dependent on the accurate positioning of the part prior to each processing step. The part is typically held in a transfer fixture which many be used either simply as a part holder or as an alignment reference. A typical application is explored in this work, grinding of slots in a thick ceramic wafer mounted on a part fixture. A 1 micron slot is located with a position tolerance of 10 microns in the nickel-zinc-ferrite wafer. Part location is determined by means of a 50.8 by 1 micron target deposited onto the ceramic during an earlier process. In the current process, the target is magnified by a 250X vision system and the machine operator manually aligns the part using a set of cross hairs overlaid on the image. A high precision x-y stage is used to adjust the part location. However, the use of a fixed focal distance camera combined with part mounting variation results in an unfocused image for the operator. Manual alignment of the unfocused image leads to target location error during centering of the target in the cross hairs. The misalignment, in turn, results in process variation. The location of the slots varies based on alignment and reduces the process capability. To reduce process variation, an automated target location algorithm has been applied. The algorithm uses template matching to detect the target. This simple algorithm has been shown to locate the target within the required tolerance in spite of image blur. Using low cost processing, the system is able to determine the target location in real-time. For real-time control, the algorithm must determine the x-y coordinate of the target in 10 seconds or less. This effort shows the potential for a simple location algorithm to be implemented in a manner which can significantly decrease process variation in a precision fabrication process.

关键词： detection and tracking algorithms Image processing Convolution Edge detection Target detection Binary data Tolerancing CCD cameras Manufacturing Semiconducting wafers

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Stereo Matching by optimization using weak environmental constraints

Stereo Matching by optimization using weak environmental con...

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Conference on Intelligent Robots and Computer Vision XV: algorithms, Techniques, Active Vision, and Materials Handling

作者： Branca, A Stella, E Attolico, G Distante, A Istituto Elaborazione Segnali ed Immagini/CNR (Italy)

ISBN: (纸本)0819423068

Oue goal is to mar ch primitives of a pair of images, thereby solving the correspondence problem, in order to estimate depths of 3D scene points from the relative distance (disparity) between matched features. We propose a feature-based approach to solve the correspondence problem by minimizing an appropriate energy function where constraints on radiometric similarity and projective geometric invariance of coplanar points are defined. The method can be seen as a correlation based approach which take into account the projective invariance of coplanar points in computing the optimal matches.

关键词： detection and tracking algorithms Feature extraction 3D image processing Error analysis Direct methods Image segmentation Object recognition Optimization (mathematics) 3D vision Machine vision

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FAST ANALOG ARCHITECTURE FOR HIGH-ORDER CURVE RECOGNITION

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JOURNAL OF ELECTRONIC IMAGING 1995年第2期4卷 114-122页

作者： INIGO, RM ARRUE, BC UNIV SEVILLA ESCUELA SUPER INGNDEPT INGN SIST & AUTOMATE-41012 SEVILLESPAIN

An original method of higher order curve detection using the straight-line Hough transform (HT) is presented. This scheme is possible because curves in an image can be approximated by small straight-line segments. By combining the straight-line HT mapping scheme with an associative memory (AM), the method can discriminate and identify between different curves. Curves such as circles, ellipses, and parabolas have been studied. This method is computationally very efficient and may yield to hardware implementation, thus making it possible to use the HT in last real-time applications. The system consists of a parallel analog mapping from image plane to parameter plane and an AM pattern classifier.

关键词： Analog electronics Image segmentation Content addressable memory Neural networks Image processing Quantization detection and tracking algorithms Hough transforms Image resolution Pattern recognition

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FEATURE-PRESERVING THINNING ALGORITHM FOR OPTICAL CHARACTER-RECOGNITION

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JOURNAL OF ELECTRONIC IMAGING 1995年第3期4卷 298-304页

作者： FU, HC CHENG, TS CHIANG, CC ROAN, SM National Chiao Tung Univ. (Taiwan)

We propose an improved thinning algorithm. Basically, the algorithm uses a 3 x 3 window to accommodate an eight-neighbor skeleton in each thinning iteration. This algorithm overcomes many thinning problems, such as Y-shaped distortions, spiky skeletons and skeleton shortening, and thus preserves precise features of digital character patterns. By using this thinning algorithm, better structural features of a character pattern can be provided to an optical character recognition system, such that accurate recognition results can be achieved.

关键词： detection and tracking algorithms Optical character recognition Computer architecture Computer science Computing systems Electronic imaging Information science Picosecond phenomena

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RECOGNITION OF A LOW-RESOLUTION DOCUMENT CONSISTING OF KOREAN AND ENGLISH CHARACTERS

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JOURNAL OF ELECTRONIC IMAGING 1995年第2期4卷 161-171页

作者： HAM, YK DOH, SY CHUNG, HK KIM, WS PARK, RH Sogang Univ. (South Korea)

We propose an efficient algorithm that recognizes handwritten Korean and English characters in a low-resolution document. For a user-friendly input system for low-resolution documents consisting of two different sets of characters obtained by a facsimile or scanner, we propose a document-recognition algorithm utilizing several effective features (partial projection, the number of cross points, and distance features) and the membership function of the fuzzy set theory. Via computer simulation with several test documents, we show the effectiveness of the proposed recognition algorithm for both printed and handwritten and Korean and English characters in a low-resolution document.

关键词： detection and tracking algorithms Optical character recognition Fuzzy logic Visualization Scanners Evolutionary algorithms Binary data Algorithm development Distortion Head

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DESIGN OF IMAGE-ADAPTIVE QUANTIZATION TABLES FOR JPEG

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JOURNAL OF ELECTRONIC IMAGING 1995年第2期4卷 144-150页

作者： FUNG, HT PARKER, KJ Univ. of Rochester (United States)

The rate-distortion trade-off in the discrete cosine transform-based coding scheme in ISO/JPEG is determined by the quantization table. To permit a different quality to be selected by a user, a common practice is to scale the standard quantization tables that have been empirically determined from psychovisual experiments. In this paper, an algorithm is presented to generate a quantization table that is optimized for a given image and for a given distortion. The computational complexity of this algorithm is reduced compared to other techniques. The optimized, image-adaptive quantization table typically yields an improvement of 15% to 20% in bit rate compared to the use of standard, scaled quantization tables. Once an optimized quantization table has been generated for a specific image, it can also be applied to other images with similar content with a small sacrifice in bit rate.

关键词： Quantization Distortion detection and tracking algorithms Image compression Computer programming Image enhancement Image quality Error analysis Signal to noise ratio Yield improvement

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ANALYSIS OF COLOR IMAGES OF NATURAL SCENES

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JOURNAL OF ELECTRONIC IMAGING 1995年第4期4卷 382-396页

作者： CELENK, M Ohio Univ. (USA)

A clustering algorithm for analyzing and partitioning the color images of natural scenes is described. The proposed method operates in the 1976 CIE (L*,a*,b*)-uniform color coordinate system. It detects image clusters in some circular-cylindrical decision elements of the color space. This estimates the clusters' color distributions without imposing any constraints on their forms. Surfaces of the decision elements are formed with constant lightness and constant chromaticity loci. Each surface is obtained using only 1-D histograms of the L*,H-o,C* cylindrical coordinates of the image data or the extracted feature vector. The Fisher linear discriminant method is then used to project simultaneously the detected color clusters onto a line for 1-D thresholding. This permits utilization of all the color properties for segmentation, and inherently recognizes their respective cross correlation. in this respect, the proposed algorithm also differs from the multiple histogram-based thresholding schemes in that it generates more reliable gross segmentation results.

关键词： Image analysis Image segmentation detection and tracking algorithms Feature extraction Image processing algorithms and systems

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NEW EDGE-ENHANCED ERROR DIFFUSION ALGORITHM-BASED ON THE ERROR SUM CRITERION

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JOURNAL OF ELECTRONIC IMAGING 1995年第2期4卷 172-178页

作者： KIM, JH CHUNG, TI KIM, HS SON, KS KIM, YS SAMSUNG ELECTR CO LTD VISUAL COMMUN LABSUWON 440600SOUTH KOREA PUSAN NATL UNIV INFORMAT & COMMUN RES INSTPUSAN 609735SOUTH KOREA

A new edge-enhanced error diffusion algorithm, based on Eschbach's algorithm, is proposed. Thick-edged artifacts as well as small edge-enhancement effects for the bright or dark pixel values are observed in the previous algorithm. By analyzing the phenomena, a new improved algorithm is proposed by using the diffused error sum and input pixel value. An input pixel is classified into a normal- or edge-region pixel based on the error sum criterion. A new error calculation is then employed for the edge-region pixel, while conventional error calculation is used for the normal-region pixel. The proposed method requires only a few additional calculations and provides edge-enhanced binary output images. The edges are influenced less by the brightness offset, and thick-edged artifacts are reduced.

关键词： Diffusion Binary data Error analysis Image quality Electronics Image filtering detection and tracking algorithms Optical filters Linear filtering Scanners

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