U.S. Philips Corporation

Martinus B Van Der Mark

Coen T Liedenbaum

Sel Brian Colak

Dimitrios Papaioannou

Henri M Boots

Jeroen J Vleggaar

Gert W T Hooft

Jeroen J Horikx

Wilhelmus M Walraven

Adrianus J Berntsen

Nicolaas A A J Van Asten

The light to be generated by a light source in a device for localizing an object in a turbid medium is successively coupled into the turbid medium from different directions by use of an optical detection unit. The light coupled in is transported in different directions through the turbid medium. A part of the light emanating from the turbid medium is measured by use of photodetectors. An image of the interior of the turbid medium is reconstructed by optical tomography on the basis of the measured intensities. The device includes structure which reduces variations in the intensity of the light coupled into the turbid medium from the same direction in order to reduce errors occurring on repeated executions of the measurements for successively localizing the object.

Device for localizing an object in a turbid medium

The illumination system (1) has a substrate (2) and an active layer (3) comprising an electroluminescent material, in which the active layer (3) is present between a first, optically transparent electrode layer (5) and a second electrode layer (7). The illumination system (1) is characterized in that a light-scattering layer (28) comprising a medium having light-scattering properties is present in a forward direction (29) with respect to the active layer (3), in which the non-scattered fraction of a (collimated) light beam, when passed through the light-scattering layer (8) in the forward direction (29), is in the range between 0.05 and 0.8, preferably in the range between 0.1 and 0.5. The light-scattering properties of the medium are preferably stronger as the light is more obliquely incident, as is achieved by using birefringent particles and/or media. A very suitable light-scattering layer (28) is a (half) monolayer of TiO.sub.2 particles provided on the substrate (2), with an average size of the (spherical) particles of 0.1-1 .mu.m. The light output of the illumination system (1) is further improved by providing the edges of the substrate (2) with a reflective coating (26).

Electroluminescent illumination system with an active layer of a medium

A device for imaging a turbid medium, for example a breast of a female, includes a holder for receiving the turbid medium, a light source, a photodetector and a processing unit for deriving the image from the intensities measured. The holder is adapted to receive besides the turbid medium also an adaptation medium having substantial identical optical parameters as the optical parameters of the turbid medium. In this way artefacts in the reconstructed image due to the boundary effect between the turbid medium and the holder can be reduced. When a liquid is used as the adaptation medium a perfect match between the holder and the shape of the turbid medium can be obtained. Further, also intensity differences in the image due to different path lengths between light source and photodetector can be equalized.

Device for and method of forming an image of a turbid medium

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Eindhoven, Netherlands

Martinus B Van Der Mark