The Warwick Pyramid Machine (WPM) is an M-SIMD (Multiple-Single Instruction Multiple Data) heterogeneous pyramid architecture for image understanding. Details of the implementation are given. The properties and performance of the architecture are discussed. A generic image analysis task is the detection and identification of compact, convex, blob-like objects. The detection of such blobs is illustrated in detail with a modification of the circle Hough transform. This is shown to suit the global SIMD nature of the architecture. The subsequent stage of segmentation demonstrates the local processing capabilities of the M-SIMD architecture. The image analysis examples reported use forward-looking infrared images of vehicles, and electron micrographs of virus particles. In both cases the aim is to detect candidate regions of the image for further detailed analysis.