Topic
Colour cast
About: Colour cast is a research topic. Over the lifetime, 57 publications have been published within this topic receiving 421 citations.
Papers published on a yearly basis
Papers
22 Nov 2010
TL;DR: An Unsupervised Colour Correction Method (UCM) is proposed for underwater image enhancement based on colour balancing, contrast correction of RGB colour model and contrast Correction of HSI colour model that has produced better results than the existing methods.
Abstract: Underwater images are affected by reduced contrast and non-uniform colour cast due to the absorption and scattering of light in the aquatic environment. This affects the quality and reliability of image processing and therefore colour correction is a necessary pre-processing stage. In this paper, we propose an Unsupervised Colour Correction Method (UCM) for underwater image enhancement. UCM is based on colour balancing, contrast correction of RGB colour model and contrast correction of HSI colour model. Firstly, the colour cast is reduced by equalizing the colour values. Secondly, an enhancement to a contrast correction method is applied to increase the Red colour by stretching red histogram towards the maximum (i.e., right side), similarly the Blue colour is reduced by stretching the blue histogram towards the minimum (i.e., left side). Thirdly, the Saturation and Intensity components of the HSI colour model have been applied for contrast correction to increase the true colour using Saturation and to address the illumination problem through Intensity. We compare our results with three well known methods, namely Gray World, White Patch and Histogram Equalisation using Adobe Photoshop. The proposed method has produced better results than the existing methods.
474 citations
TL;DR: A normalised gamma transformation-based contrast-limited adaptive histogram equalisation (CLAHE) with colour correction in Lab colour space for sand-dust image enhancement is proposed in this study and can obtain the highest percentage of new visible edges for all testing images.
Abstract: Images captured in the sand-dust weather often suffer from serious colour cast and poor contrast, and this has serious implications for outdoor computer vision systems. To address these problems, a normalised gamma transformation-based contrast-limited adaptive histogram equalisation (CLAHE) with colour correction in Lab colour space for sand-dust image enhancement is proposed in this study. This method consists of image contrast enhancement and image colour correction. To avoid producing new colour deviation, the input sand-dust images are first transformed from red, green, and blue colour space into Lab colour space. Then, the contrast of the lightness component (L channel) of the sand-dust image is enhanced using CLAHE. To avoid unbalanced contrast, as well as to reduce the overincreased brightness caused by CLAHE, a normalised gamma correction function is introduced to CLAHE. After that, the a and b chromatic components are recovered by a grey-world-based colour correction method. Experiments on real sand-dust images demonstrate that the proposed method can obtain the highest percentage of new visible edges for all testing images. The contrast restoration exhibits good colour fidelity and proper brightness.
77 citations
Patent•
24 Jun 1996
TL;DR: In this paper, a method and an apparatus for the analysis and correction of colour casts in a digitally represented image is described, where the crominance contents of the image may be transformed by use of a Hough-transformation or the like transformation, wherein the line structures in the carthesic system of co-ordinates for the CCC content is transformed to a representation in a HOUGH-diagram in the form of a polar system of coordinates, since such line structure is hereby transformed into a point structure.
Abstract: The invention relates to a method and an apparatus for the analysis and correction of colour casts in a digitally represented image. According to a preferred embodiment, the crominance contents of the image may be transformed by use of a Hough-transformation or the like transformation, wherein the line structures in the carthesic system of co-ordinates for the crominance content is transformed to a representation in a Hough-diagram in the form of a polar system of co-ordinates, since such line structure is hereby transformed into a point structure. The Hough-diagram is examined with a view to finding a cell in the diagram which has the highest value and the cell found is saved. subsequently cells are neutralized in the Hough-diagram within a predetermined angular distance, and the Hough-diagram is re-examined with a view to finding that diagram cell which, following neutralization, has the highest value. The cell found is saved and the cells saved which represent the maximae in the Hough-diagram are used to determine the intersecting points for lines in the crominance content system, and said intersecting points are used to evaluate the discolouration of the image.
29 citations
TL;DR: An integrated approach for biometric-based image retrieval and processing which addresses the two issues related to the poor visibility of the images produced by the embedded and distributed surveillance cameras and the effective image retrieval based on the user query is proposed.
24 citations
1 Dec 2019
TL;DR: The experimental results demonstrate that the proposed luminosity conserving and contrast enhancing method for enhancement of the underwater images can enhance the images.
Abstract: Enhancement of the underwater images is essential because of the poor illumination, dispersion and scattering losses of the environment. This paper proposes a luminosity conserving and contrast enhancing method for enhancement of the underwater images. In the proposed method, initially, the images are subjected to white balance in order to remove the unwanted colour cast. A modified approach adopted from Gray World algorithm is used for colour correction. The processed image is subsequently subjected to unsharp masking and contrast limited histogram equalization to ensure the enhancement of edges and contrast respectively. The experimental results demonstrate that the proposed method can enhance the images.
22 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 3 |
| 2019 | 9 |
| 2018 | 9 |
| 2017 | 7 |
| 2016 | 3 |
| 2015 | 5 |