PTMs developments for the appearance control on high-added value surfaces
Résumé
In many areas of activity, the value of a product depends greatly on the perceived quality, including visual one. This work aims to better control sensory perception of products with high added value, especially on the first step of the visual control: the detection, or localization of anomalies in appearance to the surfaces. Companies have controllers, specially trained to locate and evaluate anomalies. These specialists have a higher sensitivity for the detection and evaluation of defects as a potential buyer for example, and this higher acuity is generally completed by a weighting of the intensity of defects according to their location. However, there is still great variability on the results of the visual inspection. To overcome the disadvantages of human subjectivity, and also handling parts, we present a new device of analysis of surfaces, specifically focused on the step of detection of appearance anomalies, based on a technique called Polynomial Texture Mapping. By varying the direction of the light source, it makes possible to figure out the anomalies present on the surface. The device was developed and built entirely in the Symme laboratory (Université de Savoie, France, Annecy). We are working on developments of the method: - To improve the quality of the "PTM": a new approximation method of reflective surfaces ("Modal Mapping") of each pixel has been done, using the Modal Discrete Decomposition - To estimate the fields of surface normals (slopes). - To integrate normal fields, in order to do 3D reconstruction of the surface - To implement the methodology related to the sensory "human" control of appearance, like simulating the path of the controller eyes, or simulating the lights effects. The results obtained show that the control aspect is greatly facilitated by the device, and that the PTM method is relevant for the appearance control in an industrial environment. Improved estimation of the surface reflectance of each pixel increase greatly the quality of texture mapping, and makes possible current developments (Curvature Mappings, Slope mappings, 3D mappings). It opens new possibilities of augmented reality in the control of surface appearance.