Speckle reduction in optical coherence tomography images based on wave atoms.
Optical coherence tomography (OCT) is an emerging noninvasive imaging technique, which is based on low-coherence interferometry. OCT images suffer from speckle noise, which reduces image contrast. A shrinkage filter based on wave atoms transform is proposed for speckle reduction in OCT images. Wave atoms transform is a new multiscale geometric analysis tool that offers sparser expansion and better representation for images containing oscillatory patterns and textures than other traditional transforms, such as wavelet and curvelet transforms. Cycle spinning-based technology is introduced to avoid visual artifacts, such as Gibbs-like phenomenon, and to develop a translation invariant wave atoms denoising scheme. The speckle suppression degree in the denoised images is controlled by an adjustable parameter that determines the threshold in the wave atoms domain. The experimental results show that the proposed method can effectively remove the speckle noise and improve the OCT image quality. The signal-to-noise ratio, contrast-to-noise ratio, average equivalent number of looks, and cross-correlation (XCOR) values are obtained, and the results are also compared with the wavelet and curvelet thresholding techniques.
University of California, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612bSichuan University, Department of Opto-Electronics, No.24 South Section 1st, Yihuan Road, Chengdu 610065, China.
Yongzhao
Y
Du
University of California, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612cUniversity of California, Department of Biomedical Engineering, 3120 Natural Sciences II, Irvine, California 92697-2715.
Gangjun
G
Liu
Sichuan University, Department of Opto-Electronics, No.24 South Section 1st, Yihuan Road, Chengdu 610065, China.
Guoying
G
Feng
University of California, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612cUniversity of California, Department of Biomedical Engineering, 3120 Natural Sciences II, Irvine, California 92697-2715.
Zhongping
Z
Chen
D000465:Algorithms; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D012160:Retina / Q000033:anatomy & histology; D059629:Signal-To-Noise Ratio; D041623:Tomography, Optical Coherence / Q000379:methods*