Fringe projection phase shift variance effects on breast height imaging

Abstract

Fringe projection has been garnering tremendous interest in the field of optical imaging. A wide range of surface measurement application including the medical application utilizes the fringe projection as means of surface metrology due to its non-invasive imaging modality. Although fringe projection has been applied in the medical field, minimal work has been conducted in the field of breast height imaging. In this work, a digital fringe projection system based on the phase shifting fringe projection is applied on a prosthetic tear drop breast. The fringe projection system consists of a digital projector, CCD camera and a computer. A phase shift variance of π/4, π/2 and 2π/3 from the fringe patterns are projected onto the breast sample using the three step phase shift fringe projection. The phase shift is varied to determine a suitable phase shift for the tear drop breast height imaging obtained from the phase map followed by the phase unwrapping process. The surface height profile obtained from the varied phase shift of the fringe projection system was compared to the height profile of the tear drop breast obtained from a direct method using the electronic digital vernier caliper. The results demonstrate that the fringe patterns phase shifted by 2π/3 produce a smooth phase map and unwrapped phase map which resulted in a clear and visible height profile of the tear drop breast with an almost identical height profile with the direct measurement method. The preliminary results from this study can be further extended to breast imaging with the presence of cancerous breast tumors.