Speckle Denoise In Optical Coherence Tomography

Optical coherence tomography(OCT)is a noninvasive high-resolution optical interferometry imaging tool,widely used in the field of dermatology and ophthalmology.Over the past two decades,OCT technologies have been improved to produce images with so clear and such high resolution that sub-micrometer axial-resolution scanning is now possible.However,the image inevitably suffers from speckle noise because OCT acquires images from optical interference caused by backscattered light from the sample.Speckle noise limits some information that can be obtained from an image,leading to interpretational difficulties in histological examinations and diagnoses.Many previous studies have suggested various methods for the efficient and effective removal of speckle noise from OCT images,and these methods can generally be divided into two categories: hardware and software.The software methods include digital signal processing;Hardware methods include space synthesis,polarization synthesis,etc.In this paper,we adopted the hardware method,based on the previous angular compounding method we improve the hardware system to reduce speckle noise.The method based on swept-source OCT system,used dual-beam method to obtain four reflect paths beam in sample arm.There are three same images with different speckle noise displayed on the image window while the four reflect paths light interference with reference arm light,and then we averaged the three image to reduce the speckle.Due to the images are real-time to obtain,we used dual-beam method in vivo,in late study we add the method in human-eye system,realized the real-time speckle reduction.