Although the advantages of holography for particle measurements have long been recognized, practical application of the technique has awaited the development of automatic systems for image data analysis. An automated holographic diagnostic is ideally suited for the simultaneous measurement of drop-size distributions, trajectories, and velocities in combustion systems, for example, liquid fuel sprays. We propose an approach for automatic analysis of holograms of spherical droplets that is based on analysis of patterns in two or more nonimage planes. With this method, we have found that both the particle size and location can be recovered with an accuracy greater than that obtained by the time-consuming plane-by-plane search for sharpest focus. Thus, this simple approach represents a significant economy in image analysis and greatly enhances the prospects for development of automated systems for holographic particle measurement.