Attempt to estimate absorber depth in two-dimensional near-infrared transillumination image

抄録

Near-infrared light has relatively high transmission through mammalian tissue. With this light transillumination imaging is possible, if we can get transmitted light. In contrast to X-ray, the image of internal light-absorbing structure is blurred by the strong light-scattering in animal tissue. The degree of the blur is dependent on the depth of the absorber as well as other optical parameters. Therefore, we can expect to estimate the absorber depth from the blur by appropriate data processing. To realize this principle, we theoretically derived the point spread function for a turbid medium, and calculated the blur in various physical conditions to make a large database of the blur. We analyzed the database and extracted two parameters which are useful to estimate the absorber depth. They were the spread and the contrast of the light intensity (brightness) profile of the absorber image. The effectiveness of the depth estimation using these parameters were confirmed in simulation.