Due to the improvement of image rendering processes, and the increasing importance of quantitative comparisons among synthetic color images, it is essential to define perceptually based metrics which enable to objectively assess the visual quality of digital simulations. In response to this need, this paper proposes a new methodology for the determination of an objective image quality metric, and gives an answer to this problem through three metrics. This methodology is based on the LLAB color space for perception of color in complex images, a modification of the CIELab1976 color space. The first metric proposed is a pixel by pixel metric which introduces a local distance map between two images. The second metric associates, to a pair of images, a global value. Finally, the third metric uses a recursive subdivision of the images to obtain an adaptative distance map, rougher but less expensive to compute than the first method.

Automotive lighting systems are constituted of light sources and projection lens system. Thermal effects may induce hot spots on the reflectors and screens. It is essential that temperature of these hot spots doesn't exceed the degradation temperature level of materials. The crucial issue of our work is to model properly the interaction between the radiation emitted by several lamps and the enclosed chamber. In order to develop a reliable numerical model, pertinent input data are required such as filament and glass bulb temperatures. In this study, we focus on the infrared heating modelling of a specific incandescent lamp. As the filament is the main source of heat transfers, an approach is presented for its temperature determination: the "resistivity" method coupled with an optical method.