Tektronix, Inc.

Ca, Inc.

Secureworks, Inc.

Steven Douglas Maurer

Bozidar Janko

Robert W Parish

John W Edwards

A method for task access behavior based site security includes recording file accesses by an application and user during operation; automatically generating a permissions record indicating allowable access to files by the application and user based on the recorded file accesses; intercepting a file access request; comparing the file access request to a permissions record; and blocking access to the file when the file access is not included in the permissions record.

Systems and methods for task access behavior based site security

A method is disclosed for encoding and decoding integer values ranging over a known gamut of values used by a data system. By noting that a data system may store and/or transmit integer values over a predefined gamut having a minimum and a maximum limit, integer values at or near the maximum may be compressed to a greater degree than in conventional systems without any loss of data resolution.

System for storing and transmitting compressed integer data

A method of detecting content based defects in previously compressed video streams decodes a video channel from the compressed video streams and performs a match on a frame/field basis between each frame/field of the video channel and a black frame/field and/or a previous frame/field to detect missing frames/fields and/or duplicate frames/fields. The number of consecutive missing and/or duplicate frames/fields are counted and an alarm signal is generated when the count exceeds a specified value. A beat pattern detector may be used to differentiate between 3/2 pulldown and other duplicate frame/field content errors, and a graphics detector may be used to differentiate between lettering/graphics stills and other duplicate frame/field content errors.

Detecting content based defects in a video stream

A picture quality measurement technique using blockiness provides realtime analysis without the use of a reference signal. A field/frame of an image represented by a processed video signal is captured in a bit-map for analysis. The image is filtered to enhance edges and then correlated with a kernel having a size corresponding to the block size of the compression algorithm used in compressing and decompressing the video signal to produce the processed video signal. The correlation results are processed by comparing an average value with the maximum value to produce a picture quality rating for the processed video signal.

Picture quality measurement using blockiness

A method of determining the blockiness period in DCT-based codecs determines the blockiness period having the maximum measurement value for each image of an input video signal. The blockiness periods having the maximum measurement values for each image are accumulated in a histogram representing the number of images at each different blockiness period. The maximum peak of the histogram represents the blockiness period induced by DCT-based codecs.

Blockiness period detection of DCT-based codecs

A method of detecting frozen fields in a video signal that has undergone analog encoding at some point along a transmission path acquires the video signal as a digital video signal. Every field of the digital video signal and its nth subsequent field are selected as a pair, where n is an integer multiple of the number of fields required for one cycle of color phasing in the analog encoding. The pairs of the selected fields are compared and, if the difference is essentially zero, a frozen field error is indicated.

Frozen field detection of formerly encoded video

A method of efficient and reliable detection of error blocks in a DCT-based compressed video sequence extracts edges from an image that correspond to the DCT blocks. These edges are processed to determine an edge energy value. The edge energy value is compared with a threshold to provide an alarm for an error block when the threshold is exceeded. The edge energies for each block may be summed and compared with an overall threshold value to generate the alarm, or the edge energy for each edge may be compared with an edge threshold value to determine which are good and which are suspect, with the alarm being set when at least three of the edges are suspect (two edges for corner blocks).

Efficient detection of error blocks in a DCT-based compressed video sequence

A picture quality assessment method based upon spatial location with or without subsampling within the picture divides the video picture into a plurality of arbitrarily sized, geometric segments. A segment weighting map is generated that provides one value for &ldquo;safe picture&rdquo; segments of the video picture and another value for the other segments. Optionally one or more of the segments may be subsampled to reduce processing time for realtime applications. The video picture on a segment basis is compared with a corresponding test video picture using a picture quality assessment algorithm to generate a quality error value for each segment. The quality error values are weighted according to the segment weighting map, and on an error display the weighted quality error values are displayed.

Picture quality assessment using spatial location with or without subsampling

A serial digital video data analyzer combines a co-processor capable of handling the serial digital video data stream bit rate with a microprocessor operating at a slower bit rate. The co-processor includes a video feature detection/decision module that identifies specified errors or features from the serial digital video data stream and freezes the portion of the serial digital video data stream around such feature/error in a video data store. The co-processor may also insert a cursor into the serial digital video data stream prior to display on a monitor to indicate the position of indicated errors. The acquired serial digital video data is transferred to the microprocessor for an initial determination as to whether further processing is required. If further processing is required, the results are displayed as a report and the microprocessor interacts with the co-processor to acquire additional data needed for processing or to indicate that the processing is completed and the co-processor should continue its feature detection/decision process. In this way any desired analysis of the serial digital video data stream may be performed.

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Aloha, OR, United States of America

Steven Douglas Maurer