An array emitter including a plurality of emitting portions can be used to individually emit selected energy, such as x-ray radiation, from the emitter ray rather than powering or emitting radiation from all portions of the emitter array. According, providing a plurality of cells within an emitter array, and selectively emitting x-rays from individual cells can allow for selection of which cells to emit x-rays from to acquire selected image data. A process is disclosed for selecting, including automatically, which portions to power to emit energy.