Laser Speckle Contrast Imaging Based on a Mobile Phone Camera

• Published in: IEEE access Vol. 9; pp. 76730 - 76737
• Main Authors: Kong, Ping, Xu, Hao, Li, Ran, Huang, Gang, Liu, Wei
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Blood flow; Cameras; Cellular telephones; Discrete Wavelet Transform; Image contrast; image enhancement; Image processing; Image resolution; Interpolation; Laser speckle contrast imaging; Lasers; Mobile handsets; mobile phone camera; Smartphones; Speckle; Wavelet transforms
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2021.3076799

Laser speckle contrast imaging (LSCI) technology, a type of blood flow monitoring technology, has broad application prospects and has become an attractive subject of research. In recent years, with the popularization of smart phones, mobile healthcare has gradually entered the lives of the general public. In this paper, a camera system used on smart phones was employed to replace the industrial camera on the traditional laser speckle perfusion imager, and the quality of blood flow imaging was improved. Since the difference between the static and dynamic region of the raw speckle image can be reflected in the subbands of wavelet decomposition, the image processing can be performed while retaining the velocity information. Further, a speckle contrast analysis method based on mobile phone cameras is proposed; the method first processes the raw speckle images with a two-dimensional discrete wavelet transform and image interpolation and then performs a morphological operation. This method improved the speckle image contrast resolution and improved the visualization of images. The results showed that the contrast-to-noise ratio (CNR) of the blood perfusion image processed by the new method can be increased by up to 128%.