Digital speckle photography (DSP) is used for velocity field measurements inside a fiber network. The width of the channels in which the flow is measured is typically less than 1 mm. Therefore a microscope is used to image the fiber network. When we sample 30 images/s and separate the moving parts of the images from the stationary parts, the velocity field can be deduced with DSP.
© 2002 Optical Society of America
Per Synnergren, Linda Larsson, and T. Staffan Lundström, "Digital Speckle Photography: Visualization of Mesoflow through Clustered Fiber Networks," Appl. Opt. 41, 1368-1373 (2002)