Abstract: An imaging spectrometer that includes a mask (214) that has an array of n rows (302) and n columns (304) of transmissive elements (306) for transmitting the light from a plurality of locations of an image and of opaque elements (308) for blocking light from a plurality of locations of the image. The transmissive and opaque elements are arranged in a Hadamard pattern having rows (and columns) that are different cyclic iterations of an m-sequence. A grating (110) disperses the transmitted light from the transmissive elements (306) in a linear spatial relationship in a predetermined relationship to the wavelength of the transmitted light. A detector array (406) has a plurality of detector elements (408) arranged in a row to receive the dispersed transmitted light from the grating (110). Each detector element (408) provides an intensity signal indicative of the intensity of the light impinging thereon.