A method of extracting data from an identifiable monochromatic pattern. The method comprises separating a polychromatic optical signal, received from an object having identifiable monochromatic pattern, into a plurality of wavelength components, separately capturing each of the wavelength components, reconstructing a plurality of images each from a different wavelength component, detecting the identifiable monochromatic pattern in one or more of the images, and extracting data associated with or encoded by the detected identifiable monochromatic pattern. The images have different depths of field.