Patent ID: 8804046
Filing Date: 2014-08-12
Classification: H04N

Abstract:
1. A method for detecting one or more chroma dropout errors in a current field, the current field associated with a video frame, the method comprising: grouping a first plurality of pixels associated with the current field into a first set of pixel pairs; calculating a first co-occurrence matrix corresponding to a second set of pixel pairs associated with a previous field, wherein each pixel pair of the second set of pixel pairs corresponds in location to each pixel pair of the first set of pixel pairs, wherein the previous field is a field processed previously having a polarity similar to that of the current field, wherein the second set pixel pairs includes a second plurality of pixels; selecting a first pixel pair associated with the first set of pixel pairs, wherein the first pixel pair includes first and second pixels of the first plurality of pixels, wherein the first and second pixels include first and second chroma values, respectively, and wherein the first and second pixels include first and second luma values, respectively; selecting a first set of entries of the first co-occurrence matrix based on the first and second chroma values; determining a presence of the first pixel pair in the first co-occurrence matrix by analyzing the first set of entries of the first co-occurrence matrix; calculating a first absolute difference between the first and second chroma values; comparing the first absolute difference with a first predetermined threshold; populating a first table that includes one or more chroma values associated with the second plurality of pixels and a count of pixels corresponding to each of the one or more chroma values; sorting the first table in an ascending order based on the one or more chroma values; selecting a first minimum chroma value from the first table that is a smallest chroma value having a corresponding count of pixels at least one of greater than and equal to a predetermined value; selecting a first maximum chroma value from the first table that is a largest chroma value having a corresponding count of pixels at least one of greater than and equal to the predetermined value; comparing the first and second chroma values with the first minimum and maximum chroma values; calculating a second absolute difference between the first and second luma values; comparing the second absolute difference with a second predetermined threshold; marking a first template block of a predefined size and having a centre within a first predetermined distance from first and second pixels; obtaining a first motion compensated template block in the previous field corresponding to the first template block; calculating a first matching metric corresponding to a first plurality of luma values associated with corresponding pixels of the first template block and the first motion compensated template block; marking the first pixel pair as erroneous when the first matching metric is less than a third predetermined threshold; increasing an error count corresponding to the current field when the first matching metric is less than the third predetermined threshold; and marking the current field as erroneous when the error count is greater than a fourth predetermined threshold.