Noise filtering method and apparatus considering noise variance and motion detection
AssigneeSamsung Electronics Co., Ltd.
InventorsSanghoon Lee, Sungcheol Park
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Abstract
Provided herein are an apparatus and a method of performing image noise filtering with respect to an image obtained from an image sensor, the method including: applying a noise deviation with respect to a temporal difference between a previous pixel value and a current pixel value when obtaining a temporal weight value to be used in temporal filtering. The noise deviation is obtained according to an intensity level of the current pixel value. Temporal filtering and spatial filtering may be performed, and blending filtering may be selectively performed by blending an output value of the temporal filtering and an output value of the spatial filtering.
Claims11
An image noise filtering method comprising:
- obtaining a temporal weight based on an adaptive noise deviation value obtained with respect to a temporal difference between a current pixel and a previous pixel;
- refining the obtained temporal weight based on a peripheral pixel of the current pixel and other channel pixels;
- and
- performing temporal filtering on the current pixel based on the refined temporal weight,
- wherein an output value of the temporal filtering is blended with an output value of spatial filtering, to obtain a result of spatio-temporal filtering as a sum of the output value of the temporal filtering and a weighted difference between the output value of the spatial filtering and the output value of the temporal filtering, and
- the output value of the spatial filtering is obtained by blending a value of the current pixel and a mean value of peripheral pixels in a spatial domain using the temporal weight.
An image noise filtering method comprising:
- obtaining a noise deviation according to an intensity level of a current pixel value;
- obtaining a temporal weight by applying the noise deviation with respect to a temporal difference between a previous pixel value and the current pixel value;
- performing temporal filtering by blending the current pixel value and the previous pixel value using the temporal weight;
- performing spatial filtering by blending the current pixel value and a mean value of peripheral pixels in a spatial domain using the temporal weight;
- performing blending filtering by blending an output value of the temporal filtering and an output value of the spatial filtering;
- and
- selecting one of an output of the blending filtering and an output of the spatial filtering in response to a selection control signal,
- wherein the performing blending filtering comprises:
- calculating a result of blending as a sum of the output value of the temporal filtering and a weighted difference between the output values of the spatial filtering and the temporal filtering.
An image noise filtering device comprising:
- an intensity level calculating part which calculates an intensity level of a current pixel value;
- a noise standard deviation calculating part which calculates a noise deviation according to the intensity level;
- a temporal weight value generating part which generates a temporal weight by applying the noise deviation with respect to a temporal difference between a previous pixel value and the current pixel value;
- a temporal blending part which blends the current pixel value and the previous pixel value using the temporal weight;
- a spatial filtering part which blends a mean value of peripheral pixels and the current pixel value in a spatial domain using the temporal weight;
- and
- a spatio-temporal blending part configured to blend an output value of the temporal blending part and an output value of the spatial filtering part and calculate a result as a sum of the output value of the temporal filtering and a weighted difference between the output values of the spatial filtering and the temporal filtering.
Dependencies are inferred from the claim text.