A variety of methods for color constancy have been proposed in order to come up with the ability of the human visual system which recognizes the inherent colors of objects under different illuminants. The methods based on the low-level statistics are widely used due to their low computational complexity and satisfactory results with adequate parameters. However, none of these methods utilize color channel correlation explicitly to improve the color constancy. In this paper, we propose a novel color constancy method using the color correlation. From a lot of observations, we find tendencies according to saturation values and finally incorporate a saturation weighting function into the existing methods. Experiments are performed on two widely used datasets and the results demonstrate that the proposed method improves the color constancy with a simple and effective manner.

Although each application service has its own quality of service (QoS) requirements, the resource allocation for multiclass services has not been studied mainly in multiuser orthogonal frequency division multiplexing (OFDM) systems. In this paper, we investigate the resource allocation in an effort to satisfy the QoS of multiclass services. A power minimization problem is examined for the various data rates and bit-error rate (BER) traffic. Lagrangian relaxation and a subcarrier timesharing factor are used to find an optimal solution. We propose an iterative algorithm to find optimal power consumption and a low complex suboptimal algorithm for practical implementation. The main contribution of this paper is that we apply the optimal solution obtained from the power minimization problem into the proposed algorithms. We execute extensive simulations under various multiclass service scenarios. These scenarios provide a more complete assessment of the proposed algorithms. Simulations results show that the proposed algorithms significantly outperform in total transmit power consumption compared to existing resource allocation algorithms.