Un indicateur de fausses couleurs pour évaluer le traitement des images couleurs

National audienceDans le cas particulier du filtrage (lissage, rehaussement, etc.) d'images couleurs, les approches proposées peuvent faire apparaître dans l'image résultat des distorsions colorimétriques appelées alors "fausses couleurs", c'est-à-dire des couleurs indésirables non présentes dans l'image initiale. Parmi les nombreux indicateurs permettant d'évaluer les performances d'un filtrage, il n'existe pas actuellement de solution pour évaluer la quantité de fausses couleurs introduites dans l'image résultat. Le travail présenté propose un nouvel indicateur numérique, noté IFC pour Indicateur de Fausses Couleurs, capable de quantifier l'apparition de ces fausses couleurs. Cet indicateur peut être vu comme une mesure de performance du traitement au même titre que le rapport signal sur bruit. Les résultats proposés montrent que l'indicateur construit rend bien compte de la quantité de fausses couleurs introduites dans le résultat d'un filtrage

PDE Based Enhancement of Color Images in RGB Space

International audienceA novel method for color image enhancement is proposed as an extension of scalar diffusion-shock filter coupling model, where noisy and blurred images are denoised and sharpened. The proposed model is based on using single vectors of the gradient magnitude and the second derivatives as a technique to relate different color components of the image. This model can be viewed as a generalization of Bettahar-Stambouli filter to multi-valued images. The proposed algorithm is more efficient than the mentioned filter and some previous works on color image denoising and deblurring without creating false colors

Numerical scheme for efficient colour image denoising

International audienceIn this paper, we are interested by the enhancement of colour images, where we present a numerical scheme to implement a non-linear diffusion filter. This scheme is developed to denoise colour images corrupted by additive noise. The method is based on harmonic averaging that takes into account correlation between all colour components of the image by using a common gradient magnitude which can be computed by using the Di Zenzo idea, and a marginal gradient magnitude in order to conserve the self behaviour of each colour component. The proposed scheme is an efficient tool at image selective smoothing in presence of strong noise. This analysis shows that our method performs better than some related works, and particularly in avoiding colour artifacts

ANISOTROPIC COLOR IMAGE DENOISING AND SHARPENING

International audienceIn this paper, a new model for colour image enhancement based on diffusion-shock filter coupling is presented. The proposed method is based on the consideration of single vectors of the gradient magnitude and the second derivatives as a manner to relate the processing of the different colour components of the image. This solution avoids the apparition of colour artefacts in the enhanced image

PDE-based efficient method for colour image restoration

International audienceWe are interested in the restoration of blurred colour images corrupted by additive noise. We present a new model for colour image enhancement based on coupling diffusion to shock filter without creating colour artefacts. The suggested model is based on using single vectors of the gradient magnitude and the second derivatives in order to relate different colour components of the image

Enhancement of Multi-Valued Images Using PDE Coupling

International audienceIn this paper, we present a new model for the enhancement of noisy and blurred multi-valued images. The proposed model is based on using single vectors of the gradient mag-nitude and the second derivatives as a manner to relate dif-ferent colour components of the image. This model can be viewed as a generalization of Bettahar-Stambouli filter to multi-valued images. The proposed algorithm is more effi-cient than the mentioned filter and some previous works at colour images denoising and deblurring without creating false colour