Abstract In this paper, a new class of image texture operators is proposed. We firstly determine that the number of gray levels in each $B\times B$ sub-block is a fundamental property of the local image texture. Thus, an occurrence histogram for each $B\times B$ sub-block can be utilized to describe the texture of the image. Moreover, using a new multi-bit plane strategy, i.e., representing the image texture with the occurrence histogram of the first one or more significant bit-planes of the input image, more powerful operators for describing the image texture can be obtained. The proposed approach is invariant to gray scale variations since the operators are, by definition, invariant under any monotonic transformation of the gray scale, and robust to rotation. They can also be used as supplementary operators to local binary patterns (LBP) to improve their capability to resist illuminance variation, surface transformations, etc.