Adaptive non-linear noise reduction techniques
AssigneeBroadcom Corporation
InventorJosé Roberto Alvarez
Life of this patent
Estimating the term…
Abstract
An impulse-reducing module (200) reduces random noise in video pixels by providing an impulse detector (244) and an impulse reducer, such as a median filter (250). The impulse detector (244) generates filter control signals in response to detection of impulses, and the median filter (250) generates filtered pixel values in response to the filter control signals. The control signals set the median filter to a plurality of filter operating modes.
Claims22
Apparatus for reducing random noise in video pixels having digital pixel values by processing the pixel values, said apparatus comprising:
- an impulse detector arranged to perform a step impulse detecting process and to generate control signals is in response detection of step impulses represented by the pixel values;
- and
- an impulse reducer responsive to the pixel values and the control signals to generate filtered pixel values with reduced impulses,
- wherein the step impulse detecting process comprises:
- generating a first signal if the absolute difference between the pixel value being processed and an adjacent pixel value is less than a difference threshold value;
- generating a second signal if the value of the pixel being processed is greater than a high level value or less than a low level value and the first signal is generated;
- counting the number of consecutive pixels for which the second signal is generated;
- and
- generating a third signal indicating a step impulse if the counting results in a number greater than a predetermined minimum number.
A method of reducing random noise in video pixels having digital pixel value by processing the pixel value, said method comprising:
- performing a step impulse detecting process to generate control signals in response detection of step impulses represented by the pixel values;
- and
- generating impulse-reduced pixel values in response to the pixel values and the control signals;
- wherein the step impulse detecting process comprises:
- generating a first signal if the absolute difference between the pixel value being processed and an adjacent pixel value is less than a difference threshold value;
- generating a second signal if the value of the pixel being processed is greater than a high level value or less than a low level value and the first signal is generated;
- counting the number of consecutive pixels for which the second signal is generated;
- and
- generating a third signal indicating a step impulse if the counting results in a number greater than a predetermined minimum number.
Dependencies are inferred from the claim text.