Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Jorge Caviedes

Carolina Miro Sorolla

Yingwei Chen

Hugo Strubbe

Max Wu

Arnaud Gesnot

Eric Cohen-Solal

Mohamed S Abdel-Mottaleb

Arnaud Bourge

Hugo J Strubbe

Deepak S Turaga

Estelle Lesellier

Joel Jung

Ahmed Elgammal

Nermeen Ismail

Soumitra Sengupta

Adrian Martel

Sabri Gurbuz

Nermeen M Ismail

The invention relates to a method of measuring blocking artefacts on the basis of video data encoded in accordance with a block encoding technique. This method comprises a step of computing a monodimensional inverse discrete transform () of a first row of a first block of encoded video data, suitable for supplying a value of a first virtual border pixel (vep). It also comprises a step of computing a monodimensional inverse discrete transform () of a first row of a second block of encoded video data, the second block being adjacent to the first block, suitable for supplying a value of a second virtual border pixel (vep). Finally, the method comprises a step of computing () a blocking artefact level (VEP-L) on the basis of an absolute value of the difference between the values of the first and second virtual pixels. This method finds its application, for example, in video encoders, decoders and transcoders.

Method of measuring blocking artefacts

A method and an arrangement for processing data in a digital input image include a decoder configured to decode encoded data. A detector is configured to detect the decoded data and a correction device is configured to correct the detected data. A predicted maximum frequency is calculated based on first and second data sets transformed by first and second transform, respectively. A real maximum frequency is calculated based on data transformed by an overall transform of a data set corresponding to the concatenation of the first and second data sets. A grid is determined by comparing the real and predicted maximum frequencies for a portion of the digital input image.

Video data processing method by calculating a DCT of the concatenated data set

A method of post-processing digital images frequency transforming a set of the pixels to a set of transformed coefficients; extracting original low-frequency coefficients and original high-frequency coefficients from the set of transformed coefficients; correcting the original low-frequency coefficients and the original high-frequency coefficients for delivering a set of corrected transformed coefficients including corrected low-frequency coefficients and corrected high-frequency coefficients; and combining the set of corrected transformed coefficients and the original high-frequency coefficients for delivering a set of combined transformed coefficients. The set of combined transformed coefficients are inverse frequency transformed for delivering a processed set of pixels that are ready for display on a screen.

Method and device for post-processing digital images

The present invention relates to a method and system for estimating the quality of encoded video data without gaining access to the source data. The system is configured to decode compressed video data using an MPEG/H.263 decoder to produce decompressed video data. The decoded data is subject to a discrete cosine transform (DCT) to produce a set of DCT coefficients of the decompressed video data is determined to be intra-coded. Meanwhile, the quantization matrix including a quantizier step size for each block of the decompressed video data are extracted. Following this, statistical properties of the DCT coefficients are extracted from the decoded video. Then, an average quantization error for both AC and DC coefficients is determined using information regarding the quantization and the statistical properties. Finally, this estimated quantization error is used for in computing a peak signal to noise ratio (PSNR).

Method and system for estimating no-reference objective quality of video data

A method and system for estimating the quality of video data without gaining access to the source data, are configured to perform a Fast Fourier Transform (FFT) from at least some of the pixel values of the image in at least the horizontal direction, and at most, in the horizontal and vertical directions for the luminance and chrominance components. An average FFT is used to calculate kurtosis and skewness, then an image-quality metric is determined by calculating an offset from the kurtosis and skewness outputs.

Objective method and system for estimating perceived image and video sharpness

A video conferencing system and method which automatically determines the appropriate preset camera parameters corresponding to participants participating in the video conference. A camera zooms out or pans the video conference space and looks for participants based on their faces. When a participant is detected, the preset camera parameters for that participant are calculated for when the center of the participant is in the center of the camera's view. This is continued for all the participants in the room. The optimal position for each participant and corresponding camera parameters are determined based on cultural preferences. Updates in the presets can be made periodically by the camera zooming out or panning the room. Multiple cameras can be used to continually update the presets.

Conferencing system and method for the automatic determination of preset positions corresponding to participants in video-mediated communications

The present invention relates to a method and system for controlling the quality of video data by selecting the optimal quantization parameter during encoding. The system is configured to perform quantization for one or more macroblocks using a different range of step sizes, then the kurtosis for the respective quantized data is performed to determine the macroblock and the corresponding quantization step size that yields the highest kurtosis value. The quantization step size that generates the highest kurtosis value is selected to the blocks of input-video data during encoding.

Method and system for optimizing image sharpness during coding and image enhancement

The present invention relates to a method and apparatus for generating a model used to estimate the quality of input-video data. The apparatus is configured to obtain a plurality of average subjective scores from a plurality of sample video data, and a plurality of image metrics for each of the plurality of said average subjective scores is calculated. Some of the plurality of said image metrics is converted into corresponding, perceived quality metrics, then an image-quality metric is predicted based on the calculated quality metrics and the perceived quality metrics.

Method and apparatus for measuring the quality of video data

The present invention relates to a device for processing blocks of coded data included in a sequence of coded digital images (ES) according to a block-based coding technique, said device comprising a post-processing circuit DFD (). Such a device effectively corrects the blocking artifacts while minimizing the bandwidth used, the decoder directly transmitting decoded data blocks (B) to the post-processing circuit. In addition, such a device introduces no or little drift during the decoding since the decoder continues to use reference images (RB) during a motion compensation step. This is because the reference images are no longer the decoded images but the completely processed images as the post-processing circuit is situated in the decoding loop.

Device jointly implementing a post-processing and a decoding of data

The present invention relates to a method and system for evaluating the quality of video data without gaining access to the source data. The system is configured to estimate sharpness metrics by detecting edge pixels and enclosing them with 8&#xd7;8 pixel blocks. For each block, the sharpness according to the Kurtosis of the DCT is computed. The final metric is the average sharpness of the blocks in the edge profile and includes a robust combination of spatial and frequency domain information.

Method and system for estimating sharpness metrics based on local edge kurtosis

The present invention relates to a method of measuring video quality. Said method comprises a step of determining ( ) at least one reference level (JND) above which visual artifacts become noticeable to a group of subjects, with a corresponding predetermined artifact metric (M), from a set of reference sequences (RS) of digital pictures only comprising a corresponding artifact. The method of measuring video quality also comprises a step of measuring ( ) at least one artifact level (L) of the input sequence (IS) with the corresponding predetermined artifact metric (M). It further comprises a step of computing ( ) a video quality metric (OQM) of the input sequence from at least one ratio of the artifact level (L) to the reference level (JND) corresponding to a same predetermined artifact metric. Such a method of measuring video quality provides an objective quality metric.

Method of measuring digital video quality

The present invention relates to a method and system for evaluating the quality of encoded video data without gaining access to the source data or the compressed video bitstream. The system is configured to decode compressed video data using an MPEG decoder to produce decompressed video data. The decoded data is analyzed to determine whether the decompressed video data is intra-coded. If so, a discrete cosine transform (DCT) is performed to produce a set of DCT coefficients for at least one AC frequency band in the decompressed video data. At the same time, quantization matrix data of a frame of the decompressed video data as well as a quantizer scale for each block of the decompressed video data are extracted. Thereafter, the variance of the converted DCT coefficients is obtained, and then an average quantization error for each set of said DCT coefficients is determined based on the variance, the quantization matrix, and the quantizer scale. Lastly, a peak signal to noise ratio (PSNR) is calculated based on the resultant average quantization error.

Method and system for estimating objective quality of compressed video data

The invention relates to a communication method and a terminal ( ) for use with such a method. The method uses at least two interconnected terminals ( ), at which input data from associated participants is captured. The input data comprises at least video and/or audio data. A monitoring unit ( ) derives activity information about the participants from the input data. The monitoring unit ( ) is either located in one terminal ( ) for centrally deriving the activity information, or present in all terminals ( ) for, at least partly, deriving the activity information locally. The activity information is subsequently visualized in the form of tables and/or diagrams or by manipulating the windows in which the participants are displayed. Also this visualization step can be performed only at a central terminal ( ) or at the terminal of each participant ( ). The activity information comprises for instance talking time and a number of key strokes of the participant.

Communication method and terminal

A method by which video compression parameters of different video streams are changed to optimize overall bandwidth utilization according to rules related to the varying interactions among group members. Different video streams are allocated different portions of the overall bandwidth based on a priority scheme. The priority scheme is based upon group dynamics. A controller (central or distributed) receives a group dynamics monitoring signal which monitors the various activities of group members. The controller (central or distributed) uses the network congestion control feedback signal and the priorities assigned to the different video streams to send feedback signals to the different video transmitters requesting the transmitters to adhere to, increase, or decrease their video data rates by changing parameters controlling the video encoding process.

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Yorktown Heights, NY, United States of America

Jorge Caviedes