Comparison of an auto-stereoscopic display and polarized stereoscopic projection for macroscopic pathology.

We investigated stereoscopic imaging for gross examination in telepathology. A conventional macroscopic station was equipped with two cameras mounted 6.5 cm apart and images were produced of 30 different routine pathology specimens. Still images were displayed on a three-dimensional auto-stereoscopic display with a lenticular plate (which did not require the viewer to wear special glasses) and as a three-dimensional projection that required the viewer to wear glasses with polarized lenses. Nine observers (pathologists, laboratory technicians and engineers) viewed the three-dimensional images first on the auto-stereoscopic display and then with polarized projection. The observers scored the images for spatial reproduction, surface structure, proportions, colour and sharpness (10 indices in total, each rated on a five-point Likert scale of 1-5, with lower scores indicating better quality). Results were compared with those from five observers who had previously viewed the corresponding two-dimensional images on a conventional (two-dimensional) display. The mean scores across each of the 10 indices were 2.9 (two-dimensional display), 2.1 (auto-stereoscopic display) and 1.6 (polarized projection). All observers stated that the polarized projection had superior image quality with regard to resolution, colour and surface structures. The results obtained in the present study with still images have encouraged us to integrate stereoscopy into a dynamic telepathology system.