No abstract

Abstract:Measurement of the appearance of an object consists of a group of measurements to characterize the color and surface finish of the object. This group of measurements involves the spectral energy distribution of propagated light measured in terms of reflectance and transmittance, and the spatial energy distribution of that light measured in terms of the bidirectional reflectance distribution function (BRDF). In this article we present the virtual gonio-spectrophotometer, a device that measures flux (power) as a function of illumination and observation. Virtual gonio-spectrophotometer measurements allow the determination of the scattering profile of specimens that can be used to verify the physical characteristics of the computer model used to simulate the scattering profile. Among the characteristics that we verify is the energy conservation of the computer model. A virtual gonio-spectrophotometer is utilized to find the correspondence between industrial measurements obtained from gloss meters and the parameters of a computer reflectance model.

Nowadays digital cameras with both high resolution and the high dynamic range (HDR) can be considered as parallel multiple sensors producing multiple measurements at once. In this paper we describe a technique for processing the captured HDR data and than fit them to theoretical surface reflection models in the form of bidirectional reflectance distribution function (BRDF). Finally, the tabular BRDF can be used to calculate the gloss reflection of the surface. We compare the captured glossiness by digital camera with gloss measured with the industry device and conclude that the results fit well in our experiments.

In photo-realistic image synthesis the incoming light from the environment is particularly important. In this work we focus on capturing the incoming light in the form of the radiance map using a common mobile device. This involves the reconstruction of the spherical panorama sky-dome in high dynamic range (HDR) quality and save it to a usable data format. Our setup requires a common smartphone devices with an additional fish-eye lens attached to the camera. In this paper we discuss the calibration of our setup and the implementation of selected tone mapping operator (TMO) allowing satisfactory display of HDR images on the mobile device screen. Built-in cameras on mobile devices do not generally capture the HDR image. In this work, we describe an algorithm for capturing an HDR image on the Android platform. Using an optimization method we are able to acquire the camera response curve needed in the reconstruction of the HDR image from multiple snapshots. Subsequent HDR panoramas represent radiance sphere-maps of the incoming light from an environment. These radiance sphere-maps are useful in realistic image synthesis to illuminate the objects in the 3D scenes.

Accurate and fast identification of a person from a security point of view is a key procedure. The most common technique of person identification uses identity cards. In contrary to the common approach we focus our research on identification based on the body movement such as the gait in this paper. The gait and the posture belong to the unique characteristics of the person that helps us to facilitate the identification. The proposed methodology allows us to incorporate personal characteristics into the access control systems using the color depth camera (RGBD). For the sake of gait analysis, the important task is to recognize the figure and extract the skeleton data from a video recording. Besides the usage of the mathematical statistics methods, we are opting to use computer animation and computer vision methods, which makes the research interdisciplinary. The main novelty of the paper is the definition and extraction of the feature vector from motion capture data, the analysis methodology and finally the selection of few statistically dominant motion attributes for the identification purposes. Besides the development of new approaches in this field, we validate proposed approaches from the perspective of accuracy.