METAL DETECTOR WITH FIRST AND SECOND NESTED RECTANGULAR COILS

Copying apparatus includes a document reader for generating a series of electrical signals which are representative of imagewise information in an original document, a printer device, and electrical means for (1) transforming, (2) storing, (3) processing and (4) applying the signals to the printer for producing on print material an imagewise representation of the information contained in these signals. The copying apparatus includes means for generating electrical color signals, means for providing different electrical bandwidths for the several color signals, a color difference matrix for generating two mutually orthogonal chrominance signals, an electrical unsharp mask for suppressing noise in at least one of the signals and for enhancing the edge contrast of the final print, means to convert the signals to forms more efficient for applying corrective functions thereto, a buffer and data transmission link, table look-up means to enhance color reproduction and to correct for various characteristics which would result in inferior prints, and means to convert the signals to a form more efficient for controlling a color printer.