Pembangunan sistem perolehan imej fotogrametri digital jarak dekat bagi pengukuran craniofacial

Abstract

In recent years, measurement of the human face has gained importance both for medical, computer animation purposes and other applications. The former approach is usually used for medical purposes such as measurement for craniofacial surgery. Several methods are currently employed to produce 3D craniofacial landmarks of the human face. The first most commonly used methods include laser scanning, coded light based triangulation approaches and digital photogrammetry. In Malaysia, the data for craniofacial surgery is commonly obtained by using contact physical measurement of the facial features using calipers. This conventional contact method is not practical and time-consuming. Alternatively, non-contact methods such as close-range digital photogrammetry offer a new approach for such measurement. This research focuses on the design and calibration of a prototype stereo-image acquisition system for imaging and recording of human faces via digital photogrammetry. The system configuration comprises of three pairs of digital cameras (to provide a stereo image of a face), object space control (control frame, camera platform and special chair) and two projectors. The projector is used to project a precise grid onto the patients face and in the measurement stage. To date, a digital stereo-workstation known as Digital Video Plotter (DVP) was used to observe the stereo-images in 3D mode to acquire specific 3D spatial data of the face. The DVP has the ability to measure craniofacial landmarks perfectly if three aspects of control points can be fullfiled, i.e. (i) control points is 2.0 mm in size, (ii) number of control points is eight and (iii) the control points are located in front (parallel) of camera station. The measurements are very stable and the result given is consistent comparing with laser scanner and caliper.