Tissue perfusion measurements: multiple-exposure laser speckle analysis generates laser Doppler-like spectra.

Variations in skin perfusion are easily detected by laser speckle contrast maps, but a robust interpretation of the information has been lacking. We show that multiple-exposure laser speckle methods produce the same spectral information as laser Doppler methods when applied to targets with embedded moving scatterers. This enables laser speckle measurements to be interpreted more quantitatively.

Noncontact, high-resolution ultrasonic imaging of wood samples using coded chirp waveforms.

A noncontact ultrasonic inspection technique has been developed to study the properties of wood samples in air. The system makes use of two broad bandwidth capacitive transducers, combined with signal processing techniques. A coded chirp signal was used in the current application to provide a waveform that could be postprocessed to provide sufficient sensitivity for transmission across samples of wood.