Noise Reduction Method for Image Signal Processor Based on Unified Image Sensor Noise Model

Yeul-Min BAEK  Whoi-Yul KIM  

IEICE TRANSACTIONS on Information and Systems   Vol.E96-D   No.5   pp.1152-1161
Publication Date: 2013/05/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.E96.D.1152
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Image Processing and Video Processing
image signal processor,  noise modeling,  denoising,  image sensor,  SUSAN filtering,  

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The noise in digital images acquired by image sensors has complex characteristics due to the variety of noise sources. However, most noise reduction methods assume that an image has additive white Gaussian noise (AWGN) with a constant standard deviation, and thus such methods are not effective for use with image signal processors (ISPs). To efficiently reduce the noise in an ISP, we estimate a unified noise model for an image sensor that can handle shot noise, dark-current noise, and fixed-pattern noise (FPN) together, and then we adaptively reduce the image noise using an adaptive Smallest Univalue Segment Assimilating Nucleus ( SUSAN ) filter based on the unified noise model. Since our noise model is affected only by image sensor gain, the parameters for our noise model do not need to be re-configured depending on the contents of image. Therefore, the proposed noise model is suitable for use in an ISP. Our experimental results indicate that the proposed method reduces image sensor noise efficiently.