an electron emitter and an x - ray tube comprising such electron emitter are presented . the electron emitter comprises a cathode and an anode wherein the cathode comprises an electron emission pattern of a plurality of local areas spaced apart from each other , each area being adapted for locally emitting electrons via field emission upon application of an electrical field between the cathode and the anode . electron beams emitted from the local areas may generate several x - ray source intensity maxima in a specific geometric pattern . an apparent loss in spatial resolution due to overlapping images on a detector can be corrected by using specific intensity patterns for the x - ray source and by applying dedicated decoding algorithms on the acquired image such as coded source imaging .