作者：
Power, GJAFRL SNAT
Target Recognit Branch Air Force Res Lab Wright Patterson AFB OH 45433 USA
When evaluating an imaging system, it is important to have a confident evaluation measure as well as an understanding of the limitations of the evaluation measure. The signal-to-noise ratio (SNR) and several variants ...
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ISBN:
(纸本)0819444863
When evaluating an imaging system, it is important to have a confident evaluation measure as well as an understanding of the limitations of the evaluation measure. The signal-to-noise ratio (SNR) and several variants such as the peak signal-to-noise ratio (PSNR) have been used abundantly as quality measures in imaging and video systems. A debate as to whether or not SNR accurately reflects human perception in some cases has attempted to dissuade the use of SNR but SNR is still used in basic research as a quality measure. Recent work for evaluating video sequences suggests that SNR can follow the human perception trend if the proper formulation is used. This paper suggests that SNR can be a valid measure and follow human perception for evaluating quality if a proper formulation of SNR is constructed. The proper formulation must be based on recognition of vision system attributes. In particular, this paper suggests a new variant of the basic PSNR measure for evaluating single frame images based on recognition of the vision spatial attributes. In addition, this paper suggests a new integrated and motion-compensated variant of the PSNR which evaluates video sequences based on vision attributes of temporal integration, motion blur and motion sharpening. The new variants of PSNR are introduced and demonstrated by an example along with justification based on actual measurements of human visual response.
The proceedings contains 12 papers from the conference on Proceedings of SPIE: Reconfigurable Technology: FPGAs and Reconfigurable Process for Computing and communications IV. Topics discussed include: single-instruct...
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The proceedings contains 12 papers from the conference on Proceedings of SPIE: Reconfigurable Technology: FPGAs and Reconfigurable Process for Computing and communications IV. Topics discussed include: single-instruction set architectures for imageprocessing;design flow for the reconfigurable HW platform XPP;framework for development and distribution of hardware acceleration;optimizing parallel programs for hardware implementation;defect tolerant fine-grained parallel testing of a cell matrix;parameterizing reconfigurable designs for image warping;and reconfigurable logic design case.
The Retinex Theory first introduced by Edwin Land forty years ago has been widely used for a range of applications. It was first introduced as a model of our own visualprocessing but has since been used to perform a ...
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The Retinex Theory first introduced by Edwin Land forty years ago has been widely used for a range of applications. It was first introduced as a model of our own visualprocessing but has since been used to perform a range of imageprocessing tasks including illuminant correction, dynamic range compression, and gamut mapping. In this paper we show how the theory can be extended to perform yet another imageprocessing task: that of removing shadows from images. Our method is founded on a simple modification to the original, path based retinex computation such that we incorporate information about the location of shadow edges in an image. We demonstrate that when the location of shadow edges is known the algorithm is able to remove shadows effectively. We also set forth a method for the automatic location of shadow edges which makes use of a 1-d illumination invariant image proposed in previous work. In this case the location of shadow edges is imperfect but we show that even so, the algorithm does a good job of removing the shadows.
Current rate control schemes in video coding standards do not have efficient frame-level bit allocation because of the inherent constraints in real-time encoding. In this paper, we assume an offline video encoding env...
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Current rate control schemes in video coding standards do not have efficient frame-level bit allocation because of the inherent constraints in real-time encoding. In this paper, we assume an offline video encoding environment and proposed a rate control scheme based on optimal bit allocation for low bit rate streaming applications. Specifically, we apply a ρ-domain rate-distortion (R-D) model, originally applied at macroblock (MB) level, to frame-level. Based on this frame-level R-D model and a two-pass encoding method, we are able to allocate bits among video frames in an optimal way so that video sequences can be coded at low bit rate with an improved quality. Experimental results demonstrate the proposed scheme is able to achieve not only noticeable reduction in average distortion but also a more consistent and smoother visual quality.
This paper explores a human-robot mutual communication system, which human users can either communicate with or use as an information terminal. In particular, we propose the deformation based facial expression system....
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ISBN:
(纸本)0780372727
This paper explores a human-robot mutual communication system, which human users can either communicate with or use as an information terminal. In particular, we propose the deformation based facial expression system. We also propose a robotic vision system, which changes its visual attention according to the environment. Firstly, the system must have advanced abilities to express their intention by means of making facial expressions, gestures, or speech. Above all, facial expression. Reconsidering the facial action coding system and action unit from the point of What expression of the robot human recognize easily. We propose the deformation based expression system. Secondly, to realize fluent communication between human and robots, we propose a robot vision system changing its gazing communication according to the environment and situation based on visual recognition. We developed an original character robot (CR) and evaluated the proposed methods. Consequently, it was shown that human-robot mutual communication is achievable.
We present three distinct improvements to the neck and limb-based approach to partitioning of visual form [1], where pairs of negative curvature minima with good continuation of their respective tangents constitute li...
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We present three distinct improvements to the neck and limb-based approach to partitioning of visual form [1], where pairs of negative curvature minima with good continuation of their respective tangents constitute limbs, and locally shortest lines through the shape constitute necks. The numerous conflicting limb and neck hypotheses are resolved through a notion of salience, leading to intuitive parts for smooth shapes. We improve on this approach in three ways. First a significant difficulty is dealing with scale, e.g., in partitioning noisy shapes where some perceptually valid limbs are not marked by salient negative curvature minima, and where numerous hypotheses arise due to noise. We present an approach which can reliably construct and detect coarse-scale negative curvature extremas. Second, we device a multiscale partitioning scheme, thus minimizing the coarse-scale interaction of part-lines arising from features at different scales. Third, we employ an Euler Spiral as the part-curve instead of a straight part-line for partitioning shape thus improving the partitioning results.
In the context of mobile telephony there is a need for low resource, computationally efficient noise compensation and speech enhancement approaches. This paper assesses the performance of efficient quantile-based nois...
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In the context of mobile telephony there is a need for low resource, computationally efficient noise compensation and speech enhancement approaches. This paper assesses the performance of efficient quantile-based noise estimation integrated into a nonlinear spectral subtraction framework. The approach has been implemented in real-time with minimal latency on a 500Mhz processor and is well within the processing capabilities. Experiments are reported on the AURORA 2 and AURORA 3 corpa. Results show an average relative improvement of 15% on the clean and multicondition training sets of the AURORA 2 database and an overall average relative improvement of 20% across the four AURORA 3 databases. It is acknowledged that these are not state-of-the-art results and further optimisation is anticipated.
The perceived colors of an image seen on a self-luminous display are affected by viewing flare and perceptual phenomena, both of which vary with the ambient illumination. A framework for a display system that is capab...
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The perceived colors of an image seen on a self-luminous display are affected by viewing flare and perceptual phenomena, both of which vary with the ambient illumination. A framework for a display system that is capable of adapting its output to varying viewing environments is introduced. The proposed system uses a light sensor such as a CCD camera to estimate properties of ambient illumination around a display and then adjusts display colorimetry for those lighting conditions. The emphasis of this paper is on accounting for various illumination-dependent visual effects through color appearance modeling. The effects of different parameter choices in CIECAM97s were investigated in a series of visual experiments. Paired comparison technique was used to subjectively evaluate the appearance of pictorial images adjusted using CIECAM97s and viewed on an LCD display under three different ambient illumination conditions.
We present an optimization technique to find hue constant RGB sensors. The hue representation is based on a log RGB opponent color space that is invariant to brightness and gamma. While modeling the visual response di...
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We present an optimization technique to find hue constant RGB sensors. The hue representation is based on a log RGB opponent color space that is invariant to brightness and gamma. While modeling the visual response did not derive the opponent space, the hue definition is similar to the ones found in CIE Lab and IPT. Finding hue constant RGB sensors through this optimization might be applicable in color engineering applications such as finding RGB sensors for color image encodings.
In order to estimate a user's head pose at a relative large scale environment for virtual reality (VR) applications, multiple cameras set around him/her are used in conventional approaches, such as a motion captur...
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ISBN:
(纸本)3540002626
In order to estimate a user's head pose at a relative large scale environment for virtual reality (VR) applications, multiple cameras set around him/her are used in conventional approaches, such as a motion capture. This paper proposes a method of estimating head pose from spherical images. A user wears a helmet on which a visual sensor is mounted and the head pose can be estimated by observing the fiducial markers put around him/her. Since a spherical image has a full view, our method can cope with a big head rotation motion compared with a normal camera. Since a head pose at every time is directly estimated from the observed markers, there is no accumulated errors in our method compared with a inertial sensor. Currently, an omnidirectional image sensor is used to acquire the most part of a spherical image in our experiment.
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