Gradient response maps for real-time detection of textureless objects.

We present a method for real-time 3D object instance detection that does not require a time-consuming training stage, and can handle untextured objects. At its core, our approach is a novel image representation for template matching designed to be robust to small image transformations. This robustness is based on spread image gradient orientations and allows us to test only a small subset of all possible pixel locations when parsing the image, and to represent a 3D object with a limited set of templates. In addition, we demonstrate that if a dense depth sensor is available we can extend our approach for an even better performance also taking 3D surface normal orientations into account. We show how to take advantage of the architecture of modern computers to build an efficient but very discriminant representation of the input images that can be used to consider thousands of templates in real time. We demonstrate in many experiments on real data that our method is much faster and more robust with respect to background clutter than current state-of-the-art methods.

Estimating radiation exposure in interventional environments.

In the last decade the use of interventional X-ray imaging, especially for fluoroscopy-guided procedures, has increased dramatically. Due to this the radiation exposure of the medical staff has also increased. Although radiation protection measures such as lead vests are used there are still unprotected regions, most notably the hands and the head. Over time these regions can receive significant amounts of radiation. In this paper we propose a system for approximating the radiation exposure of a physician during surgery. The goal is to sensibilize physicians to their radiation exposure and to give them a tool to quickly check it. To this end we use a real-time 3D reconstruction system which builds a 3D-representation of all the objects in the room. The reconstructed 3D-representation of the physician is then tracked over time and at each time step in which the X-Ray source is used the radiation received by each body part is accumulated. To simulate the radiation we use a physics-based simulation package. The physician can review his radiation exposure after the intervention and use the collected radiation information over a longer time period in order to minimize his radiation exposure by adjusting his positioning relative to the X-ray source. The system can also be used as an awareness tool for less experienced physicians.