Conference Paper

An illuminance-reflectance nonlinear video enhancement model for homeland security applications

Dept. of Electr. & Comput. Eng., Old Dominion Univ., Norfolk, VA
DOI: 10.1109/AIPR.2005.14 Conference: Applied Imagery and Pattern Recognition Workshop, 2005. Proceedings. 34th
Source: DBLP

ABSTRACT

A illuminance-reflectance model based video stream enhancement algorithm is proposed for improving the visual quality of digital video streams captured by surveillance camera under insufficient and/or nonuniform lighting conditions. The paper presents computational methods for estimation of scene illuminance and reflectance, adaptive dynamic range compression of illuminance, and adaptive enhancement for mid-tone frequency components. The images are processed in a similar way as human eyes sensing a scene. The algorithm demonstrates high quality of enhanced images, robust performance and fast processing speed. Compared with Retinex and multi-scale retinex with color restoration (MSRCR), the proposed method shows a better balance between luminance enhancement and contrast enhancement as well as a more consistent and reliable color rendition without introducing incorrect colors. This is an effective technique for image enhancement with simple computational procedures, which makes real-time enhancement for homeland security application successfully realized. The application of this image enhancement technique to the FRGC images yields improved face recognition results

Full-text preview

Available from: lw23.com
  • Source
    • "Other image enhancement techniques are local in nature, i.e., the output value depends not only on the input pixel value but also on pixel values in the neighborhood of pixel. These techniques are able to improve local contrast under various illumination conditions [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Recently, we proposed an enhancement technique for uniformly and non-uniformly illuminated dark images that provides high color accuracy and better balance between the luminance and the contrast in images to improve the visual representations of digital images. In this paper we define an improved version of the proposed algorithm to enhance aerial images in order to reduce the gap between direct observation of a scene and its recorded image.
    Full-text · Article · Jan 2011
  • Source
    • "and IRME (Illuminance-Reflectance Model for Nonlinear Enhancement) [16] are two other novel techniques proposed by Li et al. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, a new wavelet-based dynamic range compression algorithm is proposed to improve the visual quality of digital images captured in the high dynamic range scenes with non-uniform lighting conditions. Wavelet transform is used especially for dimension reduction such that a dynamic range compression with local contrast enhancement algorithm is applied only to the approximation coefficients which are obtained by low-pass filtering and down-sampling the original intensity image. The normalized approximation coefficients are transformed using a hyperbolic sine curve and the contrast enhancement is realized by tuning the magnitude of the each coefficient with respect to surrounding coefficients. The transformed coefficients are then de-normalized to their original range. The detail coefficients are also modified to prevent the edge deformation. The inverse wavelet transform is carried out resulting in a low dynamic range and contrast enhanced intensity image. A color restoration process based on relationship between spectral bands and the luminance of the original image is applied to convert the enhanced intensity image back to a color image.
    Full-text · Conference Paper · Apr 2008
  • Source
    • "To make a comparison with their performances, AINDANE, IRME, and MWIS algorithms were also implemented in MATLAB. In the implementations of these algorithms, the parameters in references [6], [10], and [13] were used. The results are also compared with MSRCR [7] results produced using the commercial software " Photo Flair ® " with default settings without white balance. "
    [Show abstract] [Hide abstract]
    ABSTRACT: An adaptive technique for image enhancement based on a specifically designed nonlinear function is presented in this paper. The enhancement technique constitutes three main processes-adaptive intensity enhancement, contrast adjustment, and color restoration. A sine function with an image dependent parameter is used to tune the intensity of each pixel in the luminance image. This process provides dynamic range compression by boosting the luminance of darker pixels while reducing the intensity of brighter pixels and maintaining local contrast. The normalized reflectance image is added to the enhanced image to preserve the details. The quality of the enhanced image is improved by applying a local contrast enhancement followed by a contrast stretch process. A basic linear color restoration process based on the chromatic information of the original image is employed to convert the enhanced intensity image back to a color image. The performance of the algorithm is compared with other state of the art enhancement techniques and evaluated using a statistical image quality evaluation method.
    Full-text · Conference Paper · Apr 2008
Show more