Robust color object detection using spatial-color joint probability functions

Object detection in unconstrained images is an important image understanding problem with many potential applications. There has been little success in creating a single algorithm that can detect arbitrary objects in unconstrained images; instead, algorithms typically must be customized for each specific object. Consequently, it typically requires a large number of exemplars (for rigid objects) or a large amount of human intuition (for non-rigid objects) to develop a robust algorithm. We present a robust algorithm designed to detect a class of compound color objects given a single model image. A compound color object is defined as having a set of multiple, particular colors arranged spatially in a particular way, including flags, logos, cartoon characters, people in uniform, etc. Our approach is based on a particular type of spatial-color joint probability function called the color edge cooccurrence histogram (CECH). In addition, our algorithm employs perceptual color naming to handle color variation, and pre-screening to limit the search scope (i.e., size and location) of the object. Experimental results demonstrated that the proposed algorithm is insensitive to object rotation, scaling, partial occlusion, and folding, outperforming a closely related algorithm by a decisive margin.