Conventional transparent film thickness measurement methods such as spectroscopy are essentially capable of measuring only a single point at a time, and their spatial resolution is limited. We have developed a wide-view film thickness measurement system based on an extended global model-fitting algorithm developed for three-wavelength interferometric surface profiling. It estimates the film thickness distribution from an interference color image captured by a color camera with three-wavelength illumination. The basic performance was experimentally proved, and the system was successfully applied to measure the air gap thickness of Newton's rings and the thickness of a vertical flowing soap film. Its key features are : (1) high spatial resolution, (2) high-speed measurement, (3) low cost and simple optics, and (4) no preliminary calibration required.