Accusoft Corporation

Pegasus Imaging Corporation

Front Porch Digital, Inc.

Tamiras Per Pte. Ltd., LLC

Murdock Fund 8 Limited Liability Company

Stephen A Martucci

John H Elton

Jay Yogeshwar

Frederick M Venzie

Bobby R Gupta

Melanie R Fendt

William Douglas Withers

Melanie R Reeder

Image binarization methods and apparatus are described. A set of input image pixel values, e.g., a set of grayscale values corresponding to an input image, is processed to determine whether to recommend to use local binarization thresholds or a global binarization threshold. Edges including edge pixels are identified. A first histogram corresponding to edge pixel values and a second histogram corresponding to image pixel values are generated, subjected to one or more smoothing operations, and truncated, based on information derived from the edge histogram. Characteristics of the histograms including, e.g., minima, maxima, points of inflection, and hidden peaks, are determined, evaluated, and used to decide between local binarization thresholds and a global threshold. Based on the recommendation, a global threshold is used or local thresholds are used to process the set of input image pixel values and generate a corresponding set of bi-level values.

Methods and apparatus relating to image binarization

Methods and apparatus for: identifying perimeter lines in an image, e.g., document border lines forming a non-rectangular quadrilateral corresponding to a scanned document, determining document corner points, and correcting the input image based on determined corner points are described. Lines are identified in the input image and a line weight is generated for each identified line. The identified lines are classified into two different groups based on direction, e.g., predominately vertical or predominately horizontal. For each group at least two, and sometimes more, candidate perimeter lines are determined to be kept, based on line weight and line length, and other lines in the group are eliminated. Two best candidate perimeter lines are identified from each group, e.g., based on distance between the remaining lines in the group. Four document corner points are determined based on the remaining lines in the two groups.

Methods and apparatus for identifying lines in an image and using identified lines

Methods and apparatus for generating a binarization threshold are described. A set of input image pixels is processed. Edges including edge pixels are identified. In various embodiments histograms of pixel values and edge pixel values are generated and jointly used in determining an appropriate binarization threshold. In some embodiments a first histogram of edge pixel values is used to determine an interval of pixel values of interest to limit the set of pixel values used for determining a binarization threshold statistically. In some embodiments a first histogram corresponding to edge pixel values and a second histogram corresponding to image pixel values are generated, subjected to one or more smoothing operations, and truncated, based on information derived from the edge histogram. Characteristics of the histograms including, e.g., minima, maxima, are determined, evaluated, and used to generate a best global threshold.

Method and apparatus for image binarization

Archival storage and retrieval of audio/video information is described. Audio and/or video information is digitized, compressed and stored in an intermediate archive format (IAF), which preserves the content at a high-enough quality for subsequent retrieval and conversion into various formats required at the time of use or distribution. A single capture operation is performed with ancillary metadata being added to facilitate subsequent searching, indexing and format conversion. Captured data content is catalogued and indexed at or subsequent to the creation of an IAF file that includes the archived information. The IAF includes a family of audio-video digital encoding formats based on public standards. The encoding format used in any particular application is determined at encoding time from information provided by the archive system user. At encoding, the particular encoding scheme is selected to optimize a tradeoff between storage constraints and end use quality requirements.

Methods and apparatus for indexing and archiving encoded audio/video data

Methods and apparatus for identifying lines in an image are described. An image to be processed is divided into a plurality of tiles, and processing is performed on a per tile basis. Lines are identified in tiles and a weight is assigned to each line based on among other things, the length of the line. Quantized first and second parameter values, e.g., values defining where lines enters and leave an area, are used in defining the identified lines. A set of lines is selected based on the weight information and output or used in image processing the image including the lines.

Methods and apparatus for locating lines in images and using located lines to make image adjustments

Bi-level pixel values are generated from a set of input pixel values corresponding to an image. Various described methods and apparatus are well suited for applications with limited computational capability and/or limited available resources to be used for performing image processing. Corresponding to an individual input pixel being processed, a plurality of windows including the pixel are evaluated to determine statistics including a variance for each window. Based upon the determined variances, one of a plurality of binarization threshold generation functions is selected. A binarization threshold for the input pixel is determined using the selected binarization threshold generation function. A bi-level pixel value is generated based on a comparison of the input pixel value to the generated binarization threshold. In various embodiments, the binarization threshold determination functions use non-zero integer powers of one or more variances, and intentionally avoid performing a square root operation, thus limiting computational complexity.

Methods and apparatus for adaptive auto image binarization

Block-based image processing methods and apparatus that provide a reduction in block-transform image coding artifacts are described. In various embodiments, the invention is directly incorporated into a decoding process. In such embodiments, transform coefficients are modified in simple but particularly effective ways that reduce or eliminate many of the artifacts that were caused by the quantization of the transform coefficients during encoding and/or by independent block processing during encoding. In other embodiments, the invention is used on an image that has already been decoded. In such embodiments image data values are directly modified in a block-based fashion or a forward block transform is applied and then the methods of the invention for processing transform coefficient blocks are used, followed by an inverse transform operation to generate pixel values from the resulting processed transform coefficient blocks.

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Kendall Park, NJ, United States of America

Stephen A Martucci