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Contrast enhancement and speckle suppression in OCT images based on a selective weighted variational enhancement model and an SP-FOOPDE algorithm
- Source :
- Journal of the Optical Society of America. A, Optics, image science, and vision. 38(7)
- Publication Year :
- 2021
-
Abstract
- Simultaneous contrast enhancement and speckle suppression in optical coherence tomography (OCT) are of great significance to medical diagnosis. In this paper, we propose a selective weighted variational enhancement (SWVE) model to enhance the structural parts of OCT images, and then present a shape-preserving fourth-order-oriented partial differential equations (SP-FOOPDE) algorithm to suppress speckle noise. To be specific, in the SWVE model, we first introduce the fast and robust fuzzy c-means clustering (FRFCM) algorithm to generate masks based on the gray-level histograms of the reconstructed OCT images and utilize the masks to distinguish the structural parts from the background. Then the retinex-based weighted variational model, combined with gamma correction, is adopted to enhance the structural parts by multiplying the estimated reflectance with the adjusted illumination. In the despeckling process, we present an SP-FOOPDE algorithm with the fidelity term modified by the shearlet transform to strike a splendid balance between noise suppression and structural preservation. Experimental results show that the proposed method performs well in contrast enhancement and speckle suppression, with better quality metrics of the MSE, PSNR, CNR, ENL, EKI, and ν and better noise immunity than the related method. Moreover, the application to the segmentation preprocessing exhibits that the retinal structure of the OCT images processed by the proposed method can be completely segmented.
- Subjects :
- medicine.diagnostic_test
Color constancy
Computer science
Image registration
Speckle noise
Image processing
01 natural sciences
Atomic and Molecular Physics, and Optics
Retina
Electronic, Optical and Magnetic Materials
010309 optics
Speckle pattern
Optical coherence tomography
Gamma correction
Histogram
0103 physical sciences
medicine
Image Processing, Computer-Assisted
Humans
Computer Vision and Pattern Recognition
Algorithm
Algorithms
Tomography, Optical Coherence
Subjects
Details
- ISSN :
- 15208532
- Volume :
- 38
- Issue :
- 7
- Database :
- OpenAIRE
- Journal :
- Journal of the Optical Society of America. A, Optics, image science, and vision
- Accession number :
- edsair.doi.dedup.....4bbd93bd6798bc4e71562ef01dec0b3c