Offset-compensated comparator with full-input range in 150nm FDSOI CMOS-3d technology

This paper addresses an offset-compensated comparator with full-input range in the 150nm FDSOI CMOS- 3D technology from MIT- Lincoln Laboratory. The comparator discussed here makes part of a vision system. Its architecture is that of a self-biased inverter with dynamic offset correction. At simulation level, the comparator can reach a resolution of 0.1mV in an area of approximately 220μm2 with a time response of less than 40ns and a static power dissipation of 1.125μW

In-pixel generation of gaussian pyramid images by block reusing in 3D-CMOS

This paper introduces an architecture of a switched-capacitor network for Gaussian pyramid generation. Gaussian pyramids are used in modern scale- and rotation-invariant feature detectors or in visual attention. Our switched-capacitor architecture is conceived within the framework of a CMOS-3D-based vision system. As such, it is also used during the acquisition phase to perform analog storage and Correlated Double Sampling (CDS). The paper addresses mismatch, and switching errors like feedthrough and charge injection. The paper also gives an estimate of the area occupied by each pixel on the 130nm CMOS-3D technology by Tezzaron. The validity of our proposal is assessed through object detection in a scale- and rotation-invariant feature detector.Xunta de Galicia 10PXIB206037PRMinisterio de Ciencia e Innovación TEC2009-12686Office of Naval Research (USA) N00014111031

Form Factor Improvement of Smart-Pixels for Vision Sensors through 3-D Vertically- Integrated Technologies

While conventional CMOS active pixel sensors embed only the circuitry required for photo-detection, pixel addressing and voltage buffering, smart pixels incorporate also circuitry for data processing, data storage and control of data interchange. This additional circuitry enables data processing be realized concurrently with the acquisition of images which is instrumental to reduce the number of data needed to carry to information contained into images. This way, more efficient vision systems can be built at the cost of larger pixel pitch. Vertically-integrated 3D technologies enable to keep the advnatges of smart pixels while improving the form factor of smart pixels.Office of Naval Research N000141110312Ministerio de Ciencia e Innovación IPT-2011-1625-43000

Gaussian Pyramid Extraction with a CMOS Vision Sensor

Comunicación presentada en 2014 14th International Workshop on Cellular Nanoscale Networks and Their Applications, CNNA 2014; University of Notre Dame; United States; 29 July 2014 through 31 July 2014This paper addresses a CMOS vision sensor with 176 × 120 pixels in standard 0.18 μm CMOS technology that computes the Gaussian pyramid. The Gaussian pyramid is extracted with a double-Euler switched-capacitor network, giving RMSE errors below 1.2% of full-scale value. The chip provides a Gaussian pyramid of 3 octaves with 6 scales each with an energy cost of 26.5 nJ at 2.64 Mpx/s.Gobierno de España ONR N000141410355 TEC2009-12686 MICINNMINECO TEC2012- 38921-C02 (FEDER)MINECO IPT-2011-1625-430000 IPC-20111009Junta de Andalucía TIC 2338-2013Xunta de Galicia EM2013 / 038 (FEDER)FEDER CN2012/151 GPC2013 / 04

Switched-capacitor networks for scale-space generation

In scale-space filtering signals are represented at several scales, each conveying different details of the original signal. Every new scale is the result of a smoothing operator on a former scale. In image processing, scale-space filtering is widely used in feature extractors as the Scale-Invariant Feature Transform (SIFT) algorithm. RC networks are posed as valid scale-space generators in focal-plane processing. Switched-capacitor networks are another alternative, as different topologies and switching rate offer a great flexibility. This work examines the parallel and the bilinear implementations as two different switched-capacitor network topologies for scale-space filtering. The paper assesses the validity of both topologies as scale-space generators in focal-plane processing through object detection with the SIFT algorithm.Xunta de Galicia 10PXI206037PRMinisterio de Ciencia e Innovación TEC2009- 12686, TEC2009-11812Office of Naval Research (USA) N00014111031

Low-Power CMOS Vision Sensor for Gaussian Pyramid Extraction

This paper introduces a CMOS vision sensor chip in a standard 0.18 μm CMOS technology for Gaussian pyramid extraction. The Gaussian pyramid provides computer vision algorithms with scale invariance, which permits having the same response regardless of the distance of the scene to the camera. The chip comprises 176×120 photosensors arranged into 88×60 processing elements (PEs). The Gaussian pyramid is generated with a double-Euler switched capacitor (SC) network. Every PE comprises four photodiodes, one 8 b single-slope analog-to-digital converter, one correlated double sampling circuit, and four state capacitors with their corresponding switches to implement the double-Euler SC network. Every PE occupies 44×44 μm2 . Measurements from the chip are presented to assess the accuracy of the generated Gaussian pyramid for visual tracking applications. Error levels are below 2% full-scale output, thus making the chip feasible for these applications. Also, energy cost is 26.5 nJ/px at 2.64 Mpx/s, thus outperforming conventional solutions of imager plus microprocessor unit.Office of Naval Research, USA N00014-14-1-0355Ministerio de Economía y Competitividad TEC2015-66878- C3-1-R, TEC2015-66878-C3-3-RJunta de Andalucía TIC 2338, EM2013/038, EM2014/01

Smart imaging for power-efficient extraction of Viola-Jones local descriptors

In computer vision, local descriptors permit to summarize relevant visual cues through feature vectors. These vectors constitute inputs for trained classifiers which in turn enable different high-level vision tasks. While local descriptors certainly alleviate the computation load of subsequent processing stages by preventing them from handling raw images, they still have to deal with individual pixels. Feature vector extraction can thus become a major limitation for conventional embedded vision hardware. In this paper, we present a power-efficient sensing processing array conceived to provide the computation of integral images at different scales. These images are intermediate representations that speed up feature extraction. In particular, the mixed-signal array operation is tailored for extraction of Haar-like features. These features feed the cascade of classifiers at the core of the Viola-Jones framework. The processing lattice has been designed for the standard UMC 0.18μm 1P6M CMOS process. In addition to integral image computation, the array can be reprogrammed to deliver other early vision tasks: concurrent rectangular area sum, block-wise HDR imaging, Gaussian pyramids and image pre-warping for subsequent reduced kernel filtering.Ministerio de Economía y Competitividad TEC2012-38921-C02-01, IPT-2011-1625-430000, IPC-20111009Naval Research (USA) N00014111031

Placa en flor para artrodesis escafo-trapecio-trapezoide como tratamiento quirúrgico de la pseudoartrosis del polo distal del escafoides: caso clínico

La osteonecrosis postraumática del polo distal del escafoides es una complicación rara, ya que hasta donde hemos podido conocer solo se encuentran recogidos 3 casos en la literatura mundial. Presentamos un paciente con fractura de polo distal de escafoides que evolucionó a osteonecrosis y el tratamiento quirúrgico realizado con artrodesis escafo-trapecio-trapezoide con placa en flor. A los 6 meses de postoperatorio el paciente presenta mejoría del dolor y rango adecuado de movilidad de muñeca y pulgar, realizando pinza sin dificultad y con buen agarre. Obtuvimos por tanto un buen resultado en la mejoría del dolor y en la funcionalidad de la mano. Entre los casos reportados en la literatura no hemos encontrados tratamientos similares al que presentamos

Flexor tendon pulley reconstruction using a flexor digitorum superficialis slip in an animal model

Comparar la biomecánica en la reconstrucción de la polea flexora en un vector oblicuo con una bandeleta de flexor digitorum superficialis vs la reconstrucción con vector trasversal en un modelo animal. Diseño: Estudio experimental en que se utiliza una técnica de reconstrucción de poleas con un vector oblicuo en una pata de una gallina y se comprara con una técnica de reconstrucción con vector transversal realizada en la pata contraria, en 18 gallinas (32 patas). Además se realiza en 10 patas de gallina un análisis del efecto de la sección de la polea. Se utilizó un dispositivo diseñado y construido para este proyecto con el que se mide los grados de flexión y la fuerza de flexión del dedo de una pata de gallina con la polea intacta, lesionada y reconstruida. Los resultados se recopilan en el software diseñado y adaptado al dispositivo de medición, y se analizarán utilizando el programa estadístico SPSS. Se realizó análisis con prueba t de Student Resultados: En las 10 patas en las que se realizaron las mediciones con la polea intacta se encontró que en promedio ejercían una fuerza de 8,16 psi, al seccionar la polea se encontró una disminución de la fuerza en promedio de 15,2% (p<0,001). En cuanto a los ángulos de flexión se encontró que las patas con la polea intacta lograron un ángulo en la articulación interfalángica distal de 96,5° en promedio, al seccionar la polea se produjo un incremento en el ángulo de 19,8 % en promedio (p<0,001). En las 16 gallinas, se encontró una diferencia en la fuerza de flexión de 0,026 psi (p=0,634) y una diferencia en los ángulos de flexión de 1,23° (p=0,0291). Conclusiones: Al igual que en los humanos, en las gallinas las poleas son importantes para la biomecánica de la flexión de los dedos. El comportamiento biomecánico de una reconstrucción de la polea del sistema flexor con vector oblicuo es igual al que se obtiene con una reconstrucción con vector transversal.ColcienciasTo compare flexor tendon pulley reconstruction biomechanics with an oblique vector using a flexor digitorum superficialis slip vs. reconstruction with a transverse vector, in an animal model. Materials and Methods: 32 long toe´s flexor pulley of 16 chickens were reconstructed using either the oblique technique (in one of the feet) or the transverse technique (in the other foot). Ten additional feet were analyzed before and after flexor pulley section, to determine section effect in flexion biomechanics. A specially designed and constructed device was used for the study, which measured toe´s flexion degree and strength with the intact, sectioned and reconstructed pulley. Data was collected with a specially designed software, adapted to the device, and analyzed with the SPSS statistics program, Student´s t-test. Results: In 10 chicken feet with an intact pulley, flexion strength was found to be 8.16 psi; after flexor pulley tendon a mean flexor strength decrease of 15.2% was found (p<0.001). Intact pulley feet were found to achieve a mean flexion of 96.5° at the DIP joint, which after tendon pulley section decreased an average of 19.8% (p<0.001). In the other 32 chicken feet analyzed, differences in flexion strength of 0,026 psi (p=0.634) and flexion angle of 1.23° (p=0.0291) were found. Conclusions: As in human fingers, flexor pulley are essential to flexion biomechanics in chicken toes. Biomechanical behavior of flexor pulley reconstruction with an oblique vector is equal to that obtained with a transverse vector