Abstract: A method of optical imaging through a scattering medium is provided in which a fit is made to an inhomogeneous diffusion model. The method facilitates good differentiation between scattering and absorption. The variation of the diffusion curve associated with the presence of an inclusion is considered rather than the diffusion curve itself. An empirical model is provided which describes the variation of the diffusion curve. A linear curve fitting process is performed to provide two parameters, one parameter associated with the scattering property of the inclusion and the other parameter associated with the absorption property of the inclusion.

Abstract: In general, the spatial resolution and repeatability of results using infrared detectors for examining printed circuit cards has been so poor that the devices have failed to achieve commercial success. These problems are overcome by a system including an isothermal enclosure for receiving a card to be tested, an infrared camera in the chamber defined by the enclosure, sensors for monitoring the temperature of the card and ambient temperature conditions in the chamber to derive signals indicative of the temperatures, and a computer connected to the camera and to the sensors for examining all signals to produce a three dimensional image of the sample, variations in the image from sample to sample being indicative of an anomaly in a sample.

Abstract: The most common method of determining whether a breast contains cancerous tissue utilizes ionizing radiation, i.e. x-rays, which possible have tissue damaging properties. It has been found that lasers can be used as a light source in a breast tissue transillumination process. However, due to the high scattering coefficient (or diffusing properties) of breast tissue, it is not possible to obtain images having good resolution using classical transillumination techniques, even when a laser is used as the light source. When passing through a diffusing medium, a laser pulse decomposes into three classes of photons, namely ballistic, snake-like and diffuse photons. In most practical situations, the ballistic photon portion of a laser pulse, which travels in a straight line, does not pass through the tissue, i.e. only snake-like and diffuse photons pass through the tissue.