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 proce...

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Detalles Bibliográficos
Autores: Fernández Berni, Jorge, Carmona Galán, Ricardo, Río Fernández, Rocío del, Leñero Bardallo, Juan Antonio, Suárez Cambre, Manuel, Rodríguez Vázquez, Ángel Benito
Tipo de recurso: artículo
Estado:Versión enviada para evaluación y publicación
Fecha de publicación:2014
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/74780
Acceso en línea:https://hdl.handle.net/11441/74780
https://doi.org/10.1117/12.2042384
Access Level:acceso abierto
Palabra clave:Viola-Jones algorithm
Smart imaging
Sensing-processing arrays
Mixed-signal circuitry
Haar-like features
OpenCV library
Integral images
Descripción
Sumario: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.