The present invention relates to spectral image sampling. An image is projected onto an array of optical transformation devices. Image intensity values transmitted by said array of optical transformation devices are detected at each sensor element of an image sensor. The image sensor comprises a plurality of photosensitive sensor elements configured to detect a magnitude of incident light, wherein said sensor elements are shaped as regular polygons whose aspect ratio is controlled to minimize sensor element count while obtaining a desired image quality. The detected image intensity values are processed to infer the image.