An optical apparatus may include a plurality of Fabry-Perot cavities and a controller. The plurality of Fabry-Perot cavities receives an incoming image. The controller controls a group of adjacent Fabry-Perot cavities of the plurality of Fabry-Perot cavities to sample spectral information from a pixel of the incoming image. The group maybe designated to the pixel. Sizes of the cavities within the group may differ from one another. The sizes of the cavities within the group may be fixed during the spectral information synthesis operation.