Depth Super-Resolution with Hybrid Camera System

An important field of research in computer vision is the 3D analysis and reconstruction of objects and scenes. Currently, among all the the techniques for 3D acquisition, stereo vision systems are the most common. More recently, Time-of-Flight (ToF) range cameras have been introduced. The focus of this thesis is to combine the information from the ToF with one or two standard cameras, in order to obtain a high- resolution depth imageopenEmbargo per motivi di segretezza e/o di proprietà dei risultati e informazioni di enti esterni o aziende private che hanno partecipato alla realizzazione del lavoro di ricerca relativo alla tes

Acquisition and Processing of ToF and Stereo data

Providing a computer the capability to estimate the three-dimensional geometry of a scene is a fundamental problem in computer vision. A classical systems that has been adopted for solving this problem is the so-called stereo vision system (stereo system). Such a system is constituted by a couple of cameras and it exploits the principle of triangulation in order to provide an estimate of the framed scene. In the last ten years, new devices based on the time-of-flight principle have been proposed in order to solve the same problem, i.e., matricial Time-of-Flight range cameras (ToF cameras). This thesis focuses on the analysis of the two systems (ToF and stereo cam- eras) from a theoretical and an experimental point of view. ToF cameras are introduced in Chapter 2 and stereo systems in Chapter 3. In particular, for the case of the ToF cameras, a new formal model that describes the acquisition process is derived and presented. In order to understand strengths and weaknesses of such different systems, a comparison methodology is introduced and explained in Chapter 4. From the analysis of ToF cameras and stereo systems it is possible to understand the complementarity of the two systems and it is intuitive to figure that a synergic fusion of their data might provide an improvement in the quality of the measurements preformed by the two devices. In Chapter 5 a method for fusing ToF and stereo data based on a probability approach is presented. In Chapter 6 a method that exploits color and three-dimensional geometry information for solving the classical problem of scene segmentation is explaine

System for measuring steel scrap volume using depth imaging

Abstract. Sustainability and green values are major themes in the world today. Companies across all fields are constantly implementing new technologies to reduce emissions and to limit the magnitude of global warming. The steel industry in general is one of the major producers of carbon dioxide emissions. The objective of this thesis was to develop a system to measure the volume of scrap metal being charged to an electric arc furnace. Obtaining the scrap volume would help the furnace operators in timing the charging of scrap baskets, thus avoiding the adverse effects resulting from early and late charging. The intention is to increase the energy efficiency of the process. The theory section of the thesis provides a short overview of the electric arc furnace process and a more detailed description of the charging process. Depth imaging technologies are then explored from a theoretical standpoint to provide the background for the selection and usage of imaging hardware. In this thesis, design science research methodology was utilized to develop the scrap volume measurement system, which consists of imaging hardware and developed software. The actual contribution of this thesis is the algorithm to extract the height of the scrap surface level from a 3-dimensional image of scrap baskets. The development process was iteratively carried out in a steel factory. The system performance was evaluated in a real-world scenario. It was established that the system was able to capture 3-dimensional data from scrap baskets and determine the scrap surface level height according to the algorithm. However, for some cases the image capturing did not perform as expected. These failure cases were a result of either steel dust obstructing the scene or the inability of the camera to capture data from unreflective material. Further research prospects were identified during conducting of the thesis. The failure cases could be addressed either programmatically, with new hardware technology, or a combination of both. Also, research could be conducted on the usage of the information provided by the system in actual charging events with the goal of optimizing charging timing

Automotive Three-Dimensional Vision Through a Single-Photon Counting SPAD Camera

We present an optical 3-D ranging camera for automotive applications that is able to provide a centimeter depth resolution over a mbox{40}^{\circ} \times mbox{20}^{\circ} field of view up to 45 m with just 1.5 W of active illumination at 808 nm. The enabling technology we developed is based on a CMOS imager chip of 64 \times 32 pixels, each with a single-photon avalanche diode (SPAD) and three 9-bit digital counters, able to perform lock-in time-of-flight calculation of individual photons emitted by a laser illuminator, reflected by the objects in the scene, and eventually detected by the camera. Due to the SPAD single-photon sensitivity and the smart in-pixel processing, the camera provides state-of-the-art performance at both high frame rates and very low light levels without the need for scanning and with global shutter benefits. Furthermore, the CMOS process is automotive certified