Abstract: A system and method for tone mapping on a high dynamic range (HDR) image of a scene are disclosed. In one embodiment, tone mapping on the HDR image is performed using a set of bit-depths, that corresponds to a plurality of images of the scene, obtained at each unit of an irradiance range of the scene.

Abstract: A method for generating a high dynamic range (HDR) image from images of a scene obtained at one or more exposure values is disclosed. In this embodiment, one of the obtained images is selected as a reference image. Further, mapped images are obtained by mapping pixel intensity values to corresponding irradiance values in each image. Furthermore, a pixel intensity value dependent weighting factor is determined. Moreover, a set of images is identified from the mapped images for pixels in the reference image. Also, a set of corresponding mapped pixels is established for the mapped pixels in reference image in the set of images. Further, a similarity measure is computed for the mapped pixels of reference image and corresponding mapped pixels in the set of images. Furthermore, each mapped pixel of the reference image is combined with a subset of its established corresponding mapped pixels in the set of images.

Abstract: A system and method for determining rotation invariant feature descriptors for points of interest in digital images for image matching are disclosed. In one embodiment, a point of interest in each of two or more digital images is identified. Further, the digital images are transformed to change location of the point of interest in each of the digital images to a principal point. Furthermore, a rotation invariant feature descriptor is determined for the point of interest in each of the transformed digital images for image matching.

Abstract: A system and method for determining rotation invariant feature descriptors for points of interest in digital images for image matching are disclosed. In one embodiment, a point of interest in each of two or more digital images is identified. Further, the digital images are transformed to change location of the point of interest in each of the digital images to a principal point. Furthermore, a rotation invariant feature descriptor is determined for the point of interest in each of the transformed digital images for image matching.

Abstract: A system and method for tone mapping on a high dynamic range (HDR) image of a scene are disclosed. In one embodiment, tone mapping on the HDR image is performed using a set of bit-depths, that corresponds to a plurality of images of the scene, obtained at each unit of an irradiance range of the scene.

Abstract: A method for generating a high dynamic range (HDR) image from images of a scene obtained at one or more exposure values is disclosed. In this embodiment, one of the obtained images is selected as a reference image. Further, mapped images are obtained by mapping pixel intensity values to corresponding irradiance values in each image. Furthermore, a pixel intensity value dependent weighting factor is determined. Moreover, a set of images is identified from the mapped images for pixels in the reference image. Also, a set of corresponding mapped pixels is established for the mapped pixels in reference image in the set of images. Further, a similarity measure is computed for the mapped pixels of reference image and corresponding mapped pixels in the set of images. Furthermore, each mapped pixel of the reference image is combined with a subset of its established corresponding mapped pixels in the set of images.

Abstract: A technique for computing perceptual noise in an audio signal that is computationally efficient. In one example embodiment, the technique includes computing perceptual noise in an input audio signal. The steps involve pre-computing NER (noise-to-excitation ratio) values associated with critical bands within a frame by zeroing out associated spectral coefficient values before the quantization loop, and also assuming bands with lower spectral energy than the band under consideration are zeroed out during quantization. When a critical band is zeroed out during quantization, the associated NER values which have been pre-computed are used in computing an overall perceptual distortion of the frame.

Abstract: An improved decoding process as applied to MPEG AAC decoders of the type that use codebooks, reduces redundant traversing steps while finding the location of a specific binary stream codeword in the codebook. To this end, the codebooks are divided into a plurality of node-tables, each table corresponding to a node. From the number of bits “k” in a given node-table, the decimal value of the first “k” bits in a binary stream to be decoded is ascertained and compared with the decimal value of the maximum code word in the given node-table. The comparison is used for the identification of the location of the codeword in the node-tables to assist in decoding without unnecessary traversing of all the nodes in the codebook.

Abstract: A non-iterative and computationally efficient bit allocation technique for perceptual audio coders employing uniform quantization schemes. This is achieved by computing a target MNR for all critical bands in a frame using a target bit rate and associated SMRs. Associated SNRs are then computed for the critical bands using the computed target MNR and the associated SMRs. Bits are then allocated to the critical bands based on the computed associated SNRs.

Abstract: A technique to enhance audio quality of a quantized audio signal when a perceptual audio coder is operating at low bit rates. The perceptual audio coder uses a modified two-loop quantization technique that maintains audio quality at medium to high bit rates while eliminating artifacts at low bit rates. The perceptual audio coder saves vanishing bands by stealing bits from surviving bands to reduce artifacts at low bit rates.

Abstract: A technique for computing perceptual noise in an audio signal that is computationally efficient. In one example embodiment, the technique includes computing perceptual noise in an input audio signal. The steps involve pre-computing NER (noise-to-excitation ratio) values associated with critical bands within a frame by zeroing out associated spectral coefficient values before the quantization loop, and also assuming bands with lower spectral energy than the band under consideration are zeroed out during quantization. When a critical band is zeroed out during qunatization, the associated NER values which have been pre-computed are used in computing an overall perceptual distortion of the frame.

Abstract: A non-iterative and computationally efficient bit allocation technique for perceptual audio coders employing uniform quantization schemes. This is achieved by computing a target MNR for all critical bands in a frame using a target bit rate and associated SMRs. Associated SNRs are then computed for the critical bands using the computed target MNR and the associated SMRs. Bits are then allocated to the critical bands based on the computed associated SNRs.

Abstract: An improved decoding process as applied to MPEG AAC decoders of the type that use codebooks, reduces redundant traversing steps while finding the location of a specific binary stream codeword in the codebook. To this end, the codebooks are divided into a plurality of node-tables, each table corresponding to a node. From the number of bits “k” in a given node-table, the decimal value of the first “k” bits in a binary stream to be decoded is ascertained and compared with the decimal value of the maximum code word in the given node-table. The comparison is used for the identification of the location of the codeword in the node-tables to assist in decoding without unnecessary traversing of all the nodes in the codebook.

Abstract: A technique to enhance audio quality of a quantized audio signal when a perceptual audio coder is operating at low bit rates. The perceptual audio coder uses a modified two-loop quantization technique that maintains audio quality at medium to high bit rates while eliminating artifacts at low bit rates. The perceptual audio coder saves vanishing bands by stealing bits from surviving bands to reduce artifacts at low bit rates.