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Color constancy (CC) or white balance (WB) is an important image processing step in digital camera and machine vision. This paper presents a robust computational algorithm that offers an accurate solution for CC. The proposed CC measure exploits the scanning strategy of RGB channel gain adjustment. In addition, the suppressing mechanism of grayscale pixel maximization (GPM) is used to locate potential...
There is an increasing demand for high quality real time graphics nowadays. Shadows play an important role to the realism of computer-generated images, enhancing depth, curvature and localization senses. Due to their global nature, shadows introduce overwhelming complexity to rendering algorithms. Recently, screen-space ambient occlusion techniques started to flourish, and are now the de facto standard...
Illumination variation is one of the critical factors affecting face recognition rate. In the paper, we propose a novel Retinex method based on bilateral filtering to compensate the illumination for face image. The proposed method estimates the illumination using the bilateral filtering, and applies the Retinex theory to obtain the reflectance image which is illumination invariant. The experimental...
Nowadays, unmanned substation is a new trend for electrical power system with the fast development of new science and technology. Fire detection technology is the major part of unmanned substation. How to judge the fire flame is the key of image-type fire detecting technology. In this paper, a unmanned substation in the environment of the specific process of fire detection and testing process for...
In this paper, we propose a method to recognize periodic gestures from images. The proposed method uses a amplitude spectrum and a phase spectrum that are obtained by applying Fast Fourier Transform (FFT) to a time series of intensity images. FFT is applied to each pixel of low-resolution images. The method consists of 2 steps. First, the method detects periodic motion regions from the amplitude spectrum...
As one of the most important part of the Concentrated Photovoltaic (CPV) system, the tracking accuracy and sensitivity of the solar tracker has a significant influence on the lighting rate and power generation rate of CPV system. The CPV solar tracker based on ARM tracks the sun mainly by using the CMOS sensor. In order to improve the tracking sensitivity, a method of sun spot center orientation based...
Current video and image systems are typically of limited use in poor visibility conditions such as in poor illumination, rain, fog, smoke, and haze. These conditions severely limit the range and effectiveness of imaging systems because of the severe reduction in contrast. The contrast of any image is a very important characteristic which decides the quality of image. Our chief goal in this paper is...
Due to the advancement of digital media, a large number of electronic books are digitized from old paper books through digital cameras or scanners. The scanned image often contains the distractions such as noises outside the page boundary, skewed pages, and irregular distributions of image illumination that may degrade the quality of scanned images. As for this paper, we propose an alternative algorithm...
This paper describes an integrated approach for segmenting foreground, namely a moving object, from a stationary background using image intensities and textural information. The proposed technique is based on the accumulative difference image (ADI) technique. Textural information is utilized with the unit gradient vectors (UGVs) of an image. Experimental results show that the UGV-based ADI technique...
Vessel segmentation is very important in an automatic screening system for fundus images. Vessels are often segmented and removed from retinal images before the other residual lesions are detected. Incomplete vessel removal usually causes a false positive in lesion detection, especially for Microaneurysms detection. Segmenting vessels in spatial image domain makes miss detection due to non illumination...
The vehicle shadow's detection and elimination work basically for extracting and tracking the vehicle characteristics, and it also plays a very important role in highway video surveillance and incident detection, affecting the post-processing of video image directly, such as vehicle tracking and speed measurement. On study of Kimmel variational and multi-scale Retinex algorithm to eliminate the vehicle...
Image records are of extreme importance in the security technology. Recent color photographic cameras are mostly constructed in a single-chip sensor configuration and the color splitting structure is designed as a planar filter array, therefore some interpolation technique has to be used to compute full-color image. The final image quality is affected by selected interpolation technique. The applied...
We present preliminary results of an algorithm for detecting obstacle-free regions in indoor environments using both color and texture information for visual robot navigation. By modeling color information in the L*u*v* color space, a color-based segmentation is performed to find similar regions. This segmentation yields a set of regions that are joined together into single areas using texture information...
With illumination varying condition, face features gotten from image is distorted nonlinearly by variant lighting intensity and direction, so face recognition becomes very difficult. According the "common assumption" that illumination vary slowly and the face intrinsic feature (including 3D surface and reflectance) vary rapidly in local area, we can consider that high frequency features...
The study of traffic sign recognition system has been of great interests for many years. This problem is often addressed by a three-stage procedure involving detection, tracking and classification. In this paper, a novel approach combining detection and classification of circular traffic signs is proposed. The position and scale of sign candidates within the scene are captured by detecting the center...
A novel algorithm is presented for detecting a target placed in background and degraded by non-uniform illumination and additive noise. The algorithm includes two steps. First, the input scene is preprocessed with estimated illumination function. Then the processed scene is correlated with a designed optimum filter based on Wiener filtering. Simulation results show effectiveness of the proposed method...
Traditional background subtraction methods perform poorly at night. In this paper, a robust method is proposed for automatic visual surveillance in low-light level environment which has quality problems of low brightness, low contrast and high-level noise. The novel method includes techniques of illumination compensation and illumination-invariant background subtraction to solve the low-quality problem...
This paper presents a facial expression recognition system employing Bézier curves approximation technique. The system is based on facial features extraction using the knowledge of the face geometry and approximated by 3rd order Bézier curves representing the relationship between the motion of features and changes of expressions. For face detection, color segmentation based on the novel idea of...
Considering the limitations of traditional centre / surround Retinex algorithm, an improved Retinex algorithm is proposed in this paper. The improved algorithm uses bilateral filtering on the each pixel and its neighborhood instead of employing traditional Gaussian filter, which makes the estimated background luminance maintain a good discontinuity in light mutation. Therefore, the proposed approach...
Based on the analysis of Maxwell color triangle, a segmentation algorithm for traffic sign is presented. An characteristic segmentation formula is proposed for the red, yellow and blue traffic signs, and the criteria is presented to confirm the range of threshold group through a number of experiments. Accordingly, the traffic sign is segmented by region growth with maximum and minimum threshold group...
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