An optical CT device (10) chiefly comprises a container (12) filled with optical interface material (20), a projector including a light source (22) and an optical switch (24) to project light into the container (12), a photodetector including a photodetector element (30) and a shutter (32) to detect the light through the container (12), and a processor/controller (14) for computing the spatial distribution of an absorption coefficient. The processor/controller (14) determines the spatial distribution of the quantity of feature concerning an optical characteristic of an object (200) for measurement based on the comparison between the light intensity signal from the detector (30) with the container (10) filled with the optical interface material (20) and such a signal from the detector (30) with the optical interface material (20) replaced in part by the object (200) for measurement.
