Matthieu Rossé

HDR-ARtiSt: High dynamic range advanced real-time imaging system

This paper describes the HDR-ARtiSt hardware platform, a FPGA-based architecture that can produce a real-time high dynamic range video from successive image acquisition. The hardware platform is built around a standard low dynamic range (LDR) CMOS sensor and a Virtex 5 FPGA board. The CMOS sensor is a EV76C560 provided by e2v. This 1.3 Megapixel device offers novel pixel integration/readout modes and embedded image pre-processing capabilities including multiframe acquisition with various exposure times. Our approach consists of a hardware architecture with different algorithms: double exposure control during image capture, building of an HDR image by combining the multiple frames, and final tone mapping for viewing on a LCD display. Our video camera system is able to achieve a real-time video rate of 30 frames per second for a full sensor resolution of 1,280 × 1,024 pixels.

Smart camera design for realtime high dynamic range imaging

Many camera sensors suffer from limited dynamic range. The result is that there is a lack of clear details in displayed images and videos. This paper describes our approach to generate high dynamic range (HDR) from an image sequence while modifying exposure times for each new frame. For this purpose, we propose an FPGA-based architecture that can produce a real-time high dynamic range video from successive image acquisition. Our hardware platform is build around a standard low dynamic range CMOS sensor and a Virtex 5 FPGA board. The CMOS sensor is a EV76C560 provided by e2v. This 1.3 Megapixel device offers novel pixel integration/readout modes and embedded image pre-processing capabilities including multiframe acquisition with various exposure times, approach consists of a pipeline of different algorithmic phases: automatic exposure control during image capture, alignment of successive images in order to minimize camera and objects movements, building of an HDR image by combining the multiple frames, and final tonemapping for viewing on a LCD display. Our aim is to achieve a realtime video rate of 25 frames per second for a full sensor resolution of 1, 280 × 1, 024 pixels.

A 1.3 megapixel FPGA-based smart camera for high dynamic range real time video

A camera is able to capture only a part of a high dynamic range scene information. The same scene can be fully perceived by the human visual system. This is true especially for real scenes where the difference in light intensity between the dark areas and bright areas is high. The imaging technique which can overcome this problem is called HDR (High Dynamic Range). It produces images from a set of multiple LDR images (Low Dynamic Range), captured with different exposure times. This technique appears as one of the most appropriate and a cheap solution to enhance the dynamic range of captured environments. We developed an FPGA-based smart camera that produces a HDR live video colour stream from three successive acquisitions. Our hardware platform is build around a standard LDR CMOS sensor and a Virtex 6 FPGA board. The hardware architecture embeds a multiple exposure control, a memory management unit, the HDR creating, and the tone mapping. Our video camera enables a real-time video at 60 frames per second for a full sensor resolution of 1, 280 × 1, 024 pixels.

Multisite field potential recordings and analysis of the impulse propagation pattern in cardiac cells culture

To provide further insights into the impulse propagation between cardiac myocytes, we performed multiparametric studies of excitation spread with cellular resolution in confluent monolayers of cultured cardiomyocytes (CM). Simultaneous paired intracellular recordings of action potentials in two individual CM revealed slight periodic spontaneous advances/delays in the interspike time lag. Multisite field potential recordings performed with microelectrode arrays (MEA) confirmed random and iterative cycle-to-cycle changes in the direction of excitation spread. These local spontaneous variations in the cardiac impulse propagation pathways may be a safety process protecting against microscopically discontinuous conduction, and abnormality of this natural process could contribute to the genesis of some heart arrhythmias.