Images of outdoor scenes could be degraded by haze, fog, and smoke in the atmosphere. In this paper, we propose a novel single image haze removal algorithm by introducing a minimal color channel and a sky region compensation term. A simplified dark channel is computed via the minimal color channel. The transmission map is first estimated by using the simplified dark channel. To avoid amplifying noise in the sky, a non-negative sky region compensation term is proposed to adjust the transmission map in the sky. The map is then refined via a content adaptive guided image filter and is finally applied to recover the haze image. Experimental results on outdoor images with haze and without haze demonstrate that the proposed algorithm outperforms existing algorithms.