1. Lock-in camera based heterodyne holography for ultrasound-modulated optical tomography inside dynamic scattering media.
- Author
-
Yan Liu, Yuecheng Shen, Cheng Ma, Junhui Shi, and Wang, Lihong V.
- Subjects
OPTICAL tomography ,OPTICAL images ,HETERODYNE detection ,DATA acquisition systems ,DIGITAL image correlation - Abstract
Ultrasound-modulated optical tomography (UOT) images optical contrast deep inside scattering media. Heterodyne holography based UOT is a promising technique that uses a camera for parallel speckle detection. In previous works, the speed of data acquisition was limited by the low frame rates of conventional cameras. In addition, when the signal-to-background ratio was low, these cameras wasted most of their bits representing an informationless background, resulting in extremely low efficiencies in the use of bits. Here, using a lock-in camera, we increase the bit efficiency and reduce the data transfer load by digitizing only the signal after rejecting the background. Moreover, compared with the conventional four-frame based amplitude measurement method, our single-frame method is more immune to speckle decorrelation. Using lock-in camera based UOT with an integration time of 286 μs, we imaged an absorptive object buried inside a dynamic scattering medium exhibiting a speckle correlation time (τ
c ) as short as 26 μs. Since our method can tolerate speckle decorrelation faster than that found in living biological tissue (τc ℓ100-1000 μs), it is promising for in vivo deep tissue non-invasive imaging. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF