Many clinically important applications require measurements on a large portion of the human body surface that may not be visible from a single view. For example, a single view may be insufficient for the measurement of a complete facial surface for facial plastic surgery. And observing breast surfaces from multiple views is needed in accurate breast volume measurement. On the other hand most 3D vision systems only recover 3D data from a single viewpoint and the recovered 3D data are often incomplete due to the occlusion problem and thus cannot uniquely define the surface. A unique and more complete description of the surface is necessary for most applications such as measuring area or volume and finding the best 3D registration between corresponding surfaces. This thesis describes a structured light based system for fast and noncontact 3D measurement of the human body from multiple views. A particular application of our system is the study of human lactation through measuring the breast surface and volume. Fast, accurate, non-contact, and biologically safe measurement is the key requirement in our application. We use structured light to fulfill the requirement. Based on the SHAPE system [4,3], a single view structured light system developed at Monash University, our system for breast volume measurement generates more complete 3D information on object surfaces by observing the object from more than one viewpoint. The breast volume is computed using the integrated data from all views. We present a simple method that performs 3D measurement from multiple views simultaneously. Combined with a camera and a projector, a mirror is used in the method to create an additional viewpoint to recover the occluded regions that are illuminated by the light source but were previously invisible to the camera. Images from the two views one directly seen by the camera and the other seen via the mirror are taken simultaneously. We develop the method for the purpose of achieving more complete measurements without increasing image capture time, which is very useful in situations where both speed and accuracy are important. The complete 3D description of the surface of objects requires the acquisition of several images from different vantage viewpoints. Each image contains information on the part of the object that is visible from its viewpoint. A very important task consists in the integration of the information present in each view. We have developed a two view system to achieve a more complete breast volume measurement. The system uses a stationary sensor at each view. Our system can largely eliminate the occlusion regions produced by a single view system and all data from different views are integrated into an object centered coordinate system and resampled by a single parametric grid. The system has been used to accurately measure short term changes in breast volume for lactating mothers. Currently, the system is also used to observe the breast volume change of pregnant women over many weeks' time.
|Publication status||Unpublished - 1994|