An Aproach To Obtain 3D Shape And BSSRDF Reflectance From Translucent Objects

The jade digitization problem in museum can be attributed to the 3D shape scanning of translucent objects and realistic rendering issues,and the latter one needs to sample real surface's optical characteristics.But it is a complex task to acquire the shape and surface reflectance properties of translucent objects.On the one hand,the surface scattering would interfere with the measurement of surface points' spatial position by photometric stereo method;on the other hand,the geometry of the object makes that the scattering profile of the illuminated point is not on the same plane in space through this point,and therefore scattering reflectance properties' collection of translucent objects are harder than flat samples.Existing 3D shape and surface scattering integrated collection method often indirectly scan the 3D shape,such as using lime-coated object or the contour shape matting to obtain shape,then densely sampling object surface points,such kind of approaches do not apply relics with higher heritage conservation value,and they require complex algorithms for interpolation or matching features to the models.This paper therefore designed a method to directly obtain the shape of the translucent objects and simultaneously sample their surface material.This paper discussed the latest developments in translucent object shape and material modeling technology,and built a shape and material model of translucent artifacts,then based on translucent object 3D scanning and heterogeneous isotropic scattering reflectance sampling techniques,an acquisition method was proposed by integrating phase-shifting structure light 3D scanning and scatter diagram reflection sampling,and finally obtained 3D shape and BSSRDF model parameters from a number of samples by this method at the same time.In this paper,polarized images and phase-shifting structured light technology are used to directly capture 3D shapes of translucent objects;After the calculation of the normal of the surface points,a continuous surface area is chosen from a single view's projection as the scattering reflection sampling surface;a single point scattering profile mapping method is proposed so that it could use spatial distance to calculate diffuse BSSRDF.The models and BSSRDF of portion of the surface areas are captured from several artifacts,the rendered images using acquired data show that the method in this paper can effectively realize the digitization of translucent objects' shape and material.