Depth estimation of absorbing object in turbid medium using two wavelengths – For high resolution in transillumination imaging of biological body –

To attain high spatial-resolution in transillumination imaging with near-infrared light, a new technique was developed to estimate the depth of the absorber in turbid medium by convolution operation with a point spread function (PSF). We choose two wavelength at which the scattering property of the medium is different. The transillumination image at one of the wavelength is convolved with the PSF of another wavelength. Two images of alternative wavelengths are compared while changing the depth of the PSF. We can obtain the correct depth that gives minimum difference between the two convoluted images. This technique does not require the repetition of the unstable deconvolution operation. The effectiveness of the proposed technique was verified in experiments.