32×32 winner-take-all matrix with single winner selection

A 32 × 32 winner-take-all (WTA) matrix with single winner selection is introduced. A high-resolution gain-boosted regulated-cascode WTA circuit is used in a first competition stage. Because of the large number of competing cells the possibility of a multiple winners situation arises. A single winner is obtained by means of a digital inhibitory circuit following each WTA analogue amplifier. Simulations show that this mixed analogue-digital circuit achieves its objective with a current resolution of approximately 10 nA (0.8% of the maximum input current in the simulated case). A time response of ?s can be achieved.

Selective Change Driven Imaging: A Biomimetic Visual Sensing Strategy

Selective Change Driven (SCD) Vision is a biologically inspired strategy for acquiring, transmitting and processing images that significantly speeds up image sensing. SCD vision is based on a new CMOS image sensor which delivers, ordered by the absolute magnitude of its change, the pixels that have changed after the last time they were read out. Moreover, the traditional full frame processing hardware and programming methodology has to be changed, as a part of this biomimetic approach, to a new processing paradigm based on pixel processing in a data flow manner, instead of full frame image processing.

High-speed motion detection using event-based sensing

Speeding-Up Differential Motion Detection Algorithms Using a Change-Driven Data Flow Processing Strategy

A constraint of real-time implementation of differential motion detection algorithms is the large amount of data to be processed. Full image processing is usually the classical approach for these algorithms: spatial and temporal derivatives are calculated for all pixels in the image despite the fact that the majority of image pixels may not have changed from one frame to the next. By contrast, the data flow model works in a totally different way as instructions are only fired when the data needed for these instructions are available. Here we present a method to speed-up low level motion detection algorithms. This method is based on pixel change instead of full image processing and good spee…

Address Event Representation (AER) approach to resistive sensor arrays

Address event representation (AER) has become an excellent strategy when approaching traditional frame based applications, mainly vision sensors. In this paper, and Within this scope, the potential of the AER paradigm is demonstrated when considering resistive (non-vision) sensor arrays. For showing quantitative evidences, MOS AMS 0.35 μm versions of some of the circuit cells typically used in AER systems, such as Winner-Take-All (WTA) circuits, have been implemented and analyzed. In these unit-cells, basic resistance-controlled sources are considered as per sensing devices. Preliminary simulation results demonstrate that this approach is valid for a wide range of resistive sensors.

On the Advantages of Asynchronous Pixel Reading and Processing for High-Speed Motion Estimation

Biological visual systems are becoming an interesting source for the improvement of artificial visual systems. A biologically inspired read-out and pixel processing strategy is presented. This read-out mechanism is based on Selective pixel Change-Driven (SCD) processing. Pixels are individually processed and read-out instead of the classical approach where the read-out and processing is based on complete frames. Changing pixels are read-out and processed at short time intervals. The simulated experiments show that the response delay using this strategy is several orders of magnitude lower than current cameras while still keeping the same, or even tighter, bandwidth requirements.

A reconfigurable architecture for autonomous visual-navigation

This paper describes the design of a reconfigurable architecture for implementing image processing algorithms. This architecture is a pipeline of small identical processing elements that contain a programmable logic device (FPGA) and double port memories. This processing system has been adapted to accelerate the computation of differential algorithms. The log-polar vision selectively reduces the amount of data to be processed and simplifies several vision algorithms, making possible their implementation using few hard-ware resources. The reconfigurable architecture design has been devoted to implementation, and has been employed in an autonomous platform, which has power consumption, size a…

A Selective Change Driven System for High-Speed Motion Analysis.

Vision-based sensing algorithms are computationally-demanding tasks due to the large amount of data acquired and processed. Visual sensors deliver much information, even if data are redundant, and do not give any additional information. A Selective Change Driven (SCD) sensing system is based on a sensor that delivers, ordered by the magnitude of its change, only those pixels that have changed most since the last read-out. This allows the information stream to be adjusted to the computation capabilities. Following this strategy, a new SCD processing architecture for high-speed motion analysis, based on processing pixels instead of full frames, has been developed and implemented into a Field …

Selective Change Driven Vision Sensor With Continuous-Time Logarithmic Photoreceptor and Winner-Take-All Circuit for Pixel Selection

The objective of Selective Change Driven (SCD) Vision is to capture and process those scene pixels that have the greatest impact in the motion estimation task. The implemented SCD Vision sensor delivers the pixels ordered according to the illumination change undergone by each pixel, from the last time each pixel was read-out. This ordering strategy is especially interesting for motion detection algorithms, since it allows for a reduction in data bandwidth requirements without decreasing accuracy. The speed of the obtained pixel flow allows movement detection and tracking at a speed several orders of magnitude higher than conventional vision systems. To accomplish these objectives, the senso…

Space variant vision and pipelined architecture for time to impact computation

Image analysis is one of the most interesting ways for a mobile vehicle to understand its environment. One of the tasks of an autonomous vehicle is to get accurate information of what it has in front, to avoid collision or find a way to a target. This task requires real-time restrictions depending on the vehicle speed and external object movement. The use of normal cameras, with homogeneous (squared) pixel distribution, for real-time image processing, usually requires high performance computing and high image rates. A different approach makes use of a CMOS space-variant camera that yields a high frame rate with low data bandwidth. The camera also performs the log-polar transform, simplifyin…

Taking Advantage of Selective Change Driven Processing for 3D Scanning

This article deals with the application of the principles of SCD (Selective Change Driven) vision to 3D laser scanning. Two experimental sets have been implemented: one with a classical CMOS (Complementary Metal-Oxide Semiconductor) sensor, and the other one with a recently developed CMOS SCD sensor for comparative purposes, both using the technique known as Active Triangulation. An SCD sensor only delivers the pixels that have changed most, ordered by the magnitude of their change since their last readout. The 3D scanning method is based on the systematic search through the entire image to detect pixels that exceed a certain threshold, showing the SCD approach to be ideal for this applicat…

REsect: Blinded assessment of amenability to potentially curative treatment of previously unresectable colorectal cancer liver metastases (CRC LM) after chemotherapy ± RadioEmbolization (SIRT) in the randomized SIRFLOX trial.

3532 Background: Secondary resection and radiofrequency ablation (RFA) of primarily unresectable LM from CRC can prolong survival and cure some patients (pts). Effective downsizing treatments are needed but their impact on secondary amenability to surgery/RFA is difficult to evaluate objectively. The added value of SIRT is not well established. Methods: Baseline (BL) and follow-up (FU) imaging at best response for CRC pts treated with FOLFOX chemotherapy±bevacizumab (bev) (CT) vs. CT+SIRT in the phase III SIRFLOX RCT were reviewed by 3−5 expert HPB surgeons (from a panel of 15) for resectability of LM. Reviewers were blinded to each other and to all clinical information incl. time of imagi…

Preoperative hepatic artery embolization before distal pancreatectomy plus celiac axis resection does not improve surgical results: A Spanish multicentre study

Distal pancreatectomy with celiac axis resection (DP-CAR) is a surgical procedure with high morbidity and mortality performed in patients with locally advanced pancreatic cancer. Preoperative embolization of hepatic artery (PHAE) has been postulated as a technical option to increase resection rate.comparison of morbidity and mortality at 90 days, operative time, hospital stay and survival between patients that performed DP-CAR with and without PHAE.Observational retrospective multicentre study.patient operated in Spanish centers with DP-CAR for pancreatic cancer from April 2004 until 23 June 2018. Preoperative (PHAE, neodjuvant treatment), intraoperative (operative time and blood loss) and …

Feature extraction and correlation for time-to-impact segmentation using log-polar images

In this article we present a technique that allows high-speed movement analysis using the accurate displacement measurement given by the feature extraction and correlation method. Specially, we demonstrate that it is possible to use the time to impact computation for object segmentation. This segmentation allows the detection of objects at different distances.

Advanced Giant Magnetoresistance (GMR) sensors for Selective-Change Driven (SCD) circuits

Nowadays, bio-inspiration is driving novel sensors designs, beyond vision sensors. By taking advantage of their compatibility with standard CMOS technologies, the integration of giant magneto-resistance (GMR) based magnetic sensors within such event-driven approaches is proposed. With this aim, several topologies of such GMR sensors have been designed, fabricated and characterized. In addition, integrated circuit interfaces of a standard CMOS technology are also proposed. Their suitability for this approach is then demonstrated by means of Cadence IC simulations.

Change-driven Image Architecture on FPGA with adaptive threshold for Optical-Flow Computation

Optical flow computation has been extensively used for object motion estimation in image sequences. However, the results obtained by most optical flow techniques are as accurate as computationally intensive due to the large amount of data involved. A new strategy for image sequence processing has been developed; pixels of the image sequence that significantly change fire the execution of the operations related to the image processing algorithm. The data reduction achieved with this strategy allows a significant optical flow computation speed-up. Furthermore, FPGAs allow the implementation of a custom data-flow architecture specially suited for this strategy. The foundations of the change-dr…

SimuRed: A flit-level event-driven simulator for multicomputer network performance evaluation

The interconnection network is one of the most important multicomputer components, since it has a great impact on global system performance. Many models and simulators have been proposed to evaluate network performance. This paper presents SimuRed, an event-driven flit-level, cycle-accurate simulator to evaluate different orthogonal network configurations. The core of the simulator has been designed to be expandable and portable to different situations. Some of the advantages of this simulator over other similar tools are its visual interface, its fast execution and its simplicity. Moreover, it is multiplatform and its source code versions (C++ and Java) are freely available under GNU open-…

Random telegraph signal transients in active logarithmic continuous-time vision sensors

Abstract Random Telegraph Signal (RTS) is a well-known source of noise in current submicron circuits. Its static effects have been widely studied and its noise levels are in the order of other noise sources, especially for moderate submicron transistors. Nevertheless, RTS events may produce transients many times larger than the RTS itself, and this problem seems to have not yet been addressed. In this article we present results on the transients produced by RTS events in a smart vision sensor. RTS transients in closed-loop amplifiers can be many times greater than static RTS. The duration of the RTS transient may last for several milliseconds, and can be considered almost stationary for som…

Detecting motion independent of the camera movement through a log-polar differential approach

This paper is concerned with a differential motion detection technique in log-polar coordinates which allows object motion tracking independently of the camera ego-motion when camera focus is along the movement direction. The method does not use any explicit estimation of the motion field, which can be calculated afterwards at the moving points. The method, previously formulated in Cartesian coordinates, uses the log-polar coordinates, which allows the isolation of the object movement from the image displacement due to certain camera motions. Experimental results on a sequence of real images are included, in which a moving object is detected and optical flow is calculated in log-polar coord…

Secondary technical resectability of colorectal cancer liver metastases after chemotherapy with or without selective internal radiotherapy in the randomized SIRFLOX trial

Background: Secondary resection of initially unresectable colorectal cancer liver metastases (CRLM) can prolong survival. The added value of selective internal radiotherapy (SIRT) to downsize lesions for resection is not known. This study evaluated the change in technical resectability of CRLM with the addition of SIRT to FOLFOX-based chemotherapy. Methods: Baseline and follow-up hepatic imaging of patients who received modified FOLFOX (mFOLFOX6: fluorouracil, leucovorin, oxaliplatin) chemotherapy with or without bevacizumab (control arm) versus mFOLFOX6 (with or without bevacizumab) plus SIRT using yttrium-90 resin microspheres (SIRT arm) in the phase III SIRFLOX trial were reviewed by thr…

A 4K-Input High-Speed Winner-Take-All (WTA) Circuit with Single-Winner Selection for Change-Driven Vision Sensors

Winner-Take-All (WTA) circuits play an important role in applications where a single element must be selected according to its relevance. They have been successfully applied in neural networks and vision sensors. These applications usually require a large number of inputs for the WTA circuit, especially for vision applications where thousands to millions of pixels may compete to be selected. WTA circuits usually exhibit poor response-time scaling with the number of competitors, and most of the current WTA implementations are designed to work with less than 100 inputs. Another problem related to the large number of inputs is the difficulty to select just one winner, since many competitors ma…

Synthesizing on a reconfigurable chip an autonomous robot image processing system

This paper deals with the implementation, in a high density reconfigurable device, of an entire log-polar image processing system. The log-polar vision reduces the amount of data to be stored and processed, simplifying several vision algorithms and making it possible the implementation of a complete processing system on a single chip. This image processing system is specially appropriated for autonomous robotic navigation, since these platforms have typically power consumption, size and weight restrictions. Furthermore, the image processing algorithms involved are time consuming and many times they have also real-time restrictions. A reconfigurable approach on a single chip combines hardwar…

Selective Change-Driven Image Processing: A Speeding-Up Strategy

Biologically inspired schemes are a source for the improvement of visual systems. Real-time implementation of image processing algorithms is constrained by the large amount of data to be processed. Full image processing is many times unnecessary since there are many pixels that suffer a small change or not suffer any change at all. A strategy based on delivering and processing pixels, instead of processing the complete frame, is presented. The pixels that have suffered higher changes in each frame, ordered by the absolute value of its change, are read-out and processed. Two examples are shown: a morphological motion detection algorithm and the Horn and Schunck optical flow algorithm. Result…