The Specific Aim of this application is to develop a device-independent measurement system to measure the color and translucency of human dentition. Accurate measurement of tooth color and translucency is essential for tooth matching in the restorative procedures. Such an accurate and device-independent technique also can be used in assessing the effectiveness of bleaching procedures. In this project, a spectroradiometer along with the standard color test targets will be used to determine the spectral characteristics of the illumination source and the CCD sensor of a digital camera. The calibration will be achieved in two steps: 1) measuring the spectral characteristics of the light sources (a viewing booth and an electronic flash); 2) obtaining a transformation from camera red-green-blue (RGB) to a device-independent color set. To obtain the color transformation for the camera, a set of test targets of known color components will be used. Each test target is measured twice: 1) using the digital camera to be calibrated; and 2) using a highly accurate spectroradiometer. The spectroradiometer serves as the reference standard. The steps involved in the calibration procedure will be encapsulated in a computer program, which automatically computes the final transformation matrix. This approach will be used to measure color and translucency of 150 extracted teeth and compare them with the spectroradiometric measurements. A GUI will be designed which can be used to measure color of spots/regions/area and obtain the best shade match. Success in this step will allow not only the testing of the technique, clinically in Phase 2, wherein there are also plans to assess capability of the system in measuring other aspects of tooth appearance, such as fluorescence, but also the evaluation of a digital intraoral camera for this task
