A New Idea of Fast Three-Dimensional Median Filtering for Despeckling of Optical Coherence Tomography Images

Abstract

Median filtering has been widely used in image processing for noise removal because it can significantly reduce the power of noise while limiting edge blurring. This filtering is still a challenging task in the case of threedimensional images containing up to a billion of voxels, especially for large size filtering windows. The authors encountered the problem when applying median filter to speckle noise reduction in optical coherence tomography images acquired by the Spark OCT systems. In the paper a new approach to the GPU (Graphics Processing Unit) based median smoothing has been proposed, which uses two-step evaluation of local intensity histograms stored in the shared memory of a graphic device. The solution is able to output about 50 million voxels per second while processing the neighbourhood of 125 voxels by Quadro K6000 graphic card configured on the Kepler architecture.

Extraction of the Polyurethane Layer in Textile Composites for Textronics Applications Using Optical Coherence Tomography

“…OCT images are usually distorted by the strong speckle noise that always occurs during infrared short coherence laser scanning [38]. Typically, diffusion or median filters are used to enhance OCT images with a minimal loss of image detail [39,40]. F1(·) and F2(·) are the cascades of a local mean filter followed by a Laplacian of Gaussian (LoG) filter in the image space.…”

Surface Morphology Analysis of Metallic Structures Formed on Flexible Textile Composite Substrates

“…Speckle noise, induced by the laser beam scanning the tested material, appears as a strong and frequent variation in image pixel intensity. Such noise is an integral part of every OCT image [52]. The speckles are generated by random interference between mutually coherent waves of infrared light, which are reflected from material inhomogeneities.…”