A New Framework for Retinex based Color Image Enhancement using Particle Swarm Optimization

A new approach for tuning the parameters of multiscale retinex-based (MSR) colour image enhancement algorithm using a popular optimisation method, namely, particle swarm optimisation (PSO) is presented in this paper. The image enhancement using MSR scheme heavily depends on parameters such as Gaussian surround space constant, number of scales, gain and offset, etc. Selection of these parameters, empirically and its application to MSR scheme to produce inevitable results are the major blemishes. The method presented here results in huge savings of computation time as well as improvement in the visual quality of an image, since the PSO exploited maximises the MSR parameters. The objective of PSO is to validate the visual quality of the enhanced image iteratively using an effective objective criterion based on entropy and edge information of an image. The PSO method of parameter optimisation of MSR scheme achieves a very good quality of reconstructed images, far better than that possible with the other existing methods. Finally, the quality of the enhanced colour images obtained by the proposed method are evaluated using novel metric, namely, wavelet energy (WE). The experimental results presented show that colour images enhanced using the proposed scheme are clearer, more vivid and efficient.