1. A method of determining a depth measurement of a scene, the method comprising: capturing at least two images of the scene with different camera parameters; selecting corresponding image patches in each scene; calculating a plurality of complex responses for each image patch using a plurality of different quadrature filters, each said complex response having a magnitude and a phase, assigning, for each quadrature filter, a weighting to the complex responses in the corresponding image patches, said weighting being determined by a relationship of the phases of the complex responses; and determining the depth measurement of the scene from a combination of the weighted complex responses.