Abstract

Imaging of a turbid object utilizes interference among the modulation wavefronts of a plurality of modulated light rays propagating through the object by diffusion and having predetermined phases relative to one another. A computer controlled phase and amplitude selecting device, such as a zone plate, is used to modulate light rays at appropriate phases in order to obtain constructive interference only at a predetermined portion of the object, including one or more preselected voxels. The rays reflected from (or diffusively transmitted through) the predetermined portion are received simultaneously at a detector, thus providing simultaneously all the data necessary to describe or image the portion. A single detector element may be used to detect the scattered reflected or transmitted light from the portion and to generate a signal representing the amplitude and phase characteristics for the modulation wavefront, thereby to provide absorption (and other) characteristics descriptive of the portion. An array of detectors may be used to detect the light from a plurality of individual voxels simultaneously and to provide such characteristics for each of the voxels. By dynamically controlling the phase and amplitude selecting device, the voxels selected for imaging are changed without mechanical scanning. Light rays having different frequencies may be modulated to provide complete absorption spectra for an arbitrarily selected portion of the object.

Other References

• Fishkin et al., "Diffusion of Intensity Modulated Near-Infrared Light in Turbid Media", Tissues, SPIE, Los Angeles, California, Jan. 1991
• E. Gratton et al., "A Continuously Variable Frequency Cross-Correlation Phase fluorometer with Picosecond Resolution", vol. 44 Biophys. J., 315-324, Dec. 198