A residue collector is adapted for coupling to a prep-board. When appropriate, multiple images at a single\u2014slightly underexposed\u2014exposure value are captured and local tone mapping applied to each image. The first transponder has a first memory arrangement that stores a first key. Covers prevent unauthorized persons from viewing confidential inputs to the keypad. The imaging device is capable of mixing a plurality of the pixel signals. The noise figure is calculated using a plurality of corresponding noise figure correction values at a plurality of wavelengths based on an effective number of channels.