1. A method of producing an image containing depth information, comprising: detecting a radiation wavefield emanating from the scene and taking at least two images of the scene at different planes relative to the scene to produce a first image comprised of a first set of intensity data values and a second image comprised of a second set of intensity data values; determining an intensity variation of data values in the first set of data values relative to other data values in the first set of data values to produce a first set of intensity variances, and determining an intensity variation of data values in the second set of values relative to other data values in the second set of values to produce a second set of intensity variance data; processing the first and second sets of intensity variance data to obtain image data of the scene containing depth information; and coding the image data which have the same depth information with a code reference to identify the different depth information in the image data.