Active Aperture Control and Sensor Modulation for Flexible Imaging

Gao, Chunyu; Ahuja, Narendra; Hua, Hong

doi:10.1109/cvpr.2007.383219

Cited by 7 publications

(11 citation statements)

References 18 publications

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“…The two imagers, sharing the same entrance pupil, are optically coupled together through a two-axis microelectro-mechanical systems (MEMS) scanner, which is driven by fovea tracking algorithms. Depending on the light levels of the entire scene, and local features of interest, the imagers may be adaptively modulated to acquire HDR images by implementing the pixel-by-pixel modulation approach described in [27]. The ability to dynamically steer the fovea region toward a detected stimulus via instantaneous eye movements is referred to as adaptive foveation; the ability to adapt the pupil opening in response to a large magnitude of illumination level variations is referred to as adaptive illumination sensing.…”

Section: Design Of a Dual-sensor Fovated Imaging Systemmentioning

confidence: 99%

“…It dynamically adjusts the active aperture of the imaging system based on the overall light levels detected from the peripheral and foveated imagers. The second modulator is to enhance the dynamic range of the imaging system by using a method by Gao et al [27], in which the image exposure of a scene is controlled on a pixel-by-pixel basis to deal with scenes with a wide dynamic range locally [27]. Fovea tracking algorithms can be implemented to dynamically detect the salient region of interest and stimulus events from the peripheral image.…”

Section: A Conceptual Designmentioning

confidence: 99%

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Dual-sensor foveated imaging system

Hua

Liu

2008

Appl. Opt.

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Conventional imaging techniques adopt a rectilinear sampling approach, where a finite number of pixels are spread evenly across an entire field of view (FOV). Consequently, their imaging capabilities are limited by an inherent trade-off between the FOV and the resolving power. In contrast, a foveation technique allocates the limited resources (e.g., a finite number of pixels or transmission bandwidth) as a function of foveal eccentricities, which can significantly simplify the optical and electronic designs and reduce the data throughput, while the observer's ability to see fine details is maintained over the whole FOV. We explore an approach to a foveated imaging system design. Our approach approximates the spatially variant properties (i.e., resolution, contrast, and color sensitivities) of the human visual system with multiple low-cost off-the-shelf imaging sensors and maximizes the information throughput and bandwidth savings of the foveated system. We further validate our approach with the design of a compact dual-sensor foveated imaging system. A proof-of-concept bench prototype and experimental results are demonstrated.

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Section: Design Of a Dual-sensor Fovated Imaging Systemmentioning

confidence: 99%

Section: A Conceptual Designmentioning

confidence: 99%

Dual-sensor foveated imaging system

Hua

Liu

2008

Appl. Opt.

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“…Novel approaches to solve these problems have also been proposed in [2][9] [10], where the exposure of each pixel is adaptively controlled. These methods use a camera combined with a device that enables the attenuation of the pixels to be independently controlled.…”

Section: Introductionmentioning

confidence: 99%

“…As a device to control radiance, a transmissive liquid crystal is used in [2] [9], and a Digital Micro-mirror Device(DMD) is used in [10]. However, each device has limitations.…”

Section: Introductionmentioning

confidence: 99%

High Dynamic Range Camera using Reflective Liquid Crystal

Mannami

Sagawa

Mukaigawa

et al. 2007

2007 IEEE 11th International Conference on Computer Vision

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High Dynamic Range Images (HDRIs) are needed for capturing scenes that include drastic lighting changes. This paper presents a method to improve the dynamic range of a camera by using a reflective liquid crystal. The system consists of a camera and a reflective liquid crystal placed in front of the camera. By controlling the attenuation rate of the liquid crystal, the scene radiance for each pixel is adaptively controlled. After the control, the original scene radiance is derived from the attenuation rate of the liquid crystal and the radiance obtained by the camera. A prototype system has been developed and tested for a scene that includes drastic lighting changes. The radiance of each pixel was independently controlled and the HDRIs were obtained by calculating the original scene radiance from these results.

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“…5) Intensity modulator is an optical device that attenuates the intensity of the incoming rays [see Fig. 5(e)] and can be made of many materials [e.g., photomasks [33]- [36], liquid crystal display (LCD) [37], liquid crystal on silicon (LCoS) [38] and digital micromirror device (DMD) [39]- [42]]. The color filter is also a type of intensity modulator whose attenuation is wavelength dependent [43]- [45].…”

Section: A Optical Element Formulationmentioning

confidence: 99%

Computational Cameras: Convergence of Optics and Processing

Zhou

Nayar

2011

IEEE Trans. on Image Process.

103

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Abstract-A computational camera uses a combination of optics and processing to produce images that cannot be captured with traditional cameras. In the last decade, computational imaging has emerged as a vibrant field of research. A wide variety of computational cameras has been demonstrated to encode more useful visual information in the captured images, as compared with conventional cameras. In this paper, we survey computational cameras from two perspectives. First, we present a taxonomy of computational camera designs according to the coding approaches, including object side coding, pupil plane coding, sensor side coding, illumination coding, camera arrays and clusters, and unconventional imaging systems. Second, we use the abstract notion of light field representation as a general tool to describe computational camera designs, where each camera can be formulated as a projection of a high-dimensional light field to a 2-D image sensor. We show how individual optical devices transform light fields and use these transforms to illustrate how different computational camera designs (collections of optical devices) capture and encode useful visual information.

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Active Aperture Control and Sensor Modulation for Flexible Imaging

Abstract: In the paper, we describe an optical system which is capable of providing external access to both the sensor and the lens aperture (i.e., projection

Cited by 7 publications

References 18 publications

Dual-sensor foveated imaging system

Dual-sensor foveated imaging system

High Dynamic Range Camera using Reflective Liquid Crystal

Computational Cameras: Convergence of Optics and Processing

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