High-Contrast Optical Coherence Tomography Angiography Based on Normalized Complex Decorrelation

In this letter, a Sigmoid-shaped curve is proposed to enhance the contrast between blood vessels and static tissue in optical coherence tomography angiography. Different from the conventional parabolic curve, the Sigmoid-shaped function biases the decorrelation histogram towards both ends, which suppresses the static tissue background as well as enhances the flow signal in the blood vessels region. An intensity mask is generated to remove the decorrelation signal at the noise level and then the filtering method is used to improve the image quality. A white diffuse plate has been used and verified to remove the static background deeper when our method is applied, and the z-axis range of static signal increases from
$27.3~\mu $
m to
$31.9~\mu $
m, indicating the extent of decorrelation has been improved by 17%. We demonstrate that the contrast of vascular image of the mouse ear has been improved from 32.6 to 43.1, compared with the conventional decorrelation method.