Interlace motion artifact detection using vertical frequency detection and analysis

A method for the detection of interlaced motion artifacts comprising:

• a) obtaining eight vertically aligned luma data samples;
• b) calculating a partial discrete fourier transform for fmax value;
• c) calculating a partial discrete fourier transform for a fmax/2 value;
• and
• d) calculating a partial discrete fourier transform for a fmax/4 value.

A method for boosting frequency detection values in areas of low brightness and contrast comprising:

• a) obtaining a plurality of input pixel data values;
• b) determining a maximum value;
• c) determining a range value;
• and
• d) selectively boosting a frequency detection value based upon the maximum value, the range value and a plurality of filtered frequency detection values.

A method for the prevention of false detection of interlace motion artifacts comprising:

• a) obtaining a plurality of fmax frequency detection values;
• b) comparing the plurality of fmax frequency detection values to a threshold;
• and
• c) adjusting the plurality of fmax frequency detection values based upon the comparison.

A system for the reduction of interlace motion artifacts by vertical frequency analysis comprising:

• a) a four-point partial discrete fourier transform module responsive to a set of four vertically aligned luma data sample inputs selected from and approximately centered about a set of eight vertically aligned luma data sample inputs and operative to develop a first frequency detection value;
• b) an eight-point partial discrete fourier transform module responsive to the set of eight vertically aligned luma data sample inputs and operative to develop a second, third and fourth frequency detection value;
• c) a dynamic range/maximum detection module responsive to the set of eight vertically aligned luma data sample inputs in conjunction with pixel data from a two-dimensional array surrounding a current input pixel and operative to develop a maximum data value and a range value;
• d) a horizontal lowpass filter module responsive to the first, second, third and fourth frequency detection values and operative to develop filtered first, second, third and fourth frequency detection values;
• e) a detection value boost module responsive to the filtered first, second, third and fourth frequency detection values, the maximum data value and the range value, operative to develop a level boosted four-point fmax frequency detection value, a level boosted eight-point fmax frequency detection value, a level boosted fmax/2 frequency detection value and a level boosted fmax/4 frequency detection value;
• f) an averaging module responsive to the level boosted four-point frequency detection value and the level boosted eight-point frequency detection value, operative to develop a numeric average;
• g) a threshold comparison/level correction module responsive to the numeric average, the level boosted fmax/2 frequency detection value and the level boosted fmax/4 frequency detection value, operative to develop a level-corrected fmax frequency detection value;
• h) a horizontal weighted average module responsive to the level-corrected fmax frequency detection value and operative to develop a center-weighted horizontal frequency detection value;
• and
• i) a threshold adjust module responsive to the center-weighted horizontal frequency detection value and operative to develop a final frequency detection value.