In this paper, we present a new dichromatic-based method for estimating illuminant chromaticity using a single image. In the proposed method, specular pixels are roughly extracted from an input image and projected into the threedimensional dichromatic line space according to their image chromaticities and dichromatic slopes. Reliable dichromatic lines are then obtained by detecting local maxima in the dichromatic line space. Illuminant chromaticity is ﬁnally estimated by ﬁnding the intersections of the resulting dichromatic lines. The proposed method has some advantages. The proposed method can deal with highly textured images since it does not require precise color segmentation. In addition, the proposed method does not suffer from nearly parallel dichromatic lines and it can estimate artiﬁcial illuminant chromaticity.