1. A method of producing a set of co-registered coherent change detection (CCD) products using an apparatus configured to perform the method, the method comprising: providing a set of temporally separated synthetic aperture radar (SAR) images of a target scene; determining a plurality of transformations for respectively transforming a plurality of said SAR images to a predetermined image coordinate system using the apparatus; and using said transformations to create, from a set of CCD products produced from said set of SAR images, a corresponding set of co-registered CCD products using the apparatus, wherein said using includes applying said plurality of transformations respectively to a plurality of said CCD products, wherein one of said transformations is for transforming the associated SAR image directly to said predetermined image coordinate system, and wherein another of said transformations is a compound transformation for transforming the associated SAR image to a further image coordinate system of a further said SAR image, and further for transforming said further SAR image to said predetermined image coordinate system.