Spectral attenuation pathway length

The fundamental link between experimental and theoretical research is complementarity. The importance of attenuation models resides in the fact that most locations will not be able to measure their own spectral solar outputs. Attenuation models based on a dynamic database produced from a number of climate profiles, on the contrary, can fit all those climates and almost any other. No attenuation coefficient can dispense with a pathway length estimated using the most accurate methodology available. The author proposes a purely geometric calculation of the pathway length of a monochromatic bundle of collimated rays from the periphery of the atmosphere to the Earth's surface, through layers of different density having different attenuation coefficients. A simplification is offered to the user, who may choose to consider a homogeneous atmosphere with a single layer. The method is supposed to be accurate for any zenith angle. The author expects feedback.     

Robust feature extraction algorithm suitable for real-time embedded applications

Smart cameras integrate processing close to the image sensor, so they can deliver high-level information to a host computer or high-level decision process. One of the most common processing is the visual features extraction since many vision-based use-cases are based on such algorithm. Unfortunately, in most of cases, features detection algorithms are not robust or do not reach real-time processing. Based on these limitations, a feature detection algorithm that is robust enough to deliver robust features under any type of indoor/outdoor scenarios is proposed. This was achieved by applying a non-textured corner filter combined to a subpixel refinement. Furthermore, an FPGA architecture is proposed. This architecture allows compact system design, real-time processing for Full HD images (it can process up to 44 frames/91.238.400 pixels per second for Full HD images), and high efficiency for smart camera implementations (similar hardware resources than previous formulations without subpixel refinement and without non-textured corner filter). For accuracy/robustness, experimental results for several real-world scenes are encouraging and show the feasibility of our algorithmic approach.