1. A method for measuring a spectrum of at least one point in a scene using a camera which comprises a three-color filter array and an array of photosensors, the method comprising: calibrating the camera by measuring transmittance values of the filters of the three-color filter array for each one of a multiplicity of synthetic spectral bands at a multiplicity of angles of incidence; moving the camera to a first location comprising a position and an orientation so that a scene is within a field of view of the camera; capturing a first image of the scene while the camera is at said first location; moving the camera to a second location comprising approximately the same position and a different orientation so that the scene is within the field of view of the camera; capturing a second image of the scene while the camera is at said second location; transferring the first and second images from the camera to a computer system; and computing the spectrum of a point in the scene based on image data of said first and second images acquired by respective photosensors receiving light from said point and measured transmittance values of respective filters of the three-color filter array disposed in front of the respective sensors receiving light from said point, said computing being performed by the computer system.