The human eye is mostly sensitive to only three bands of the electromagnetic spectrum—red, green, and blue (RGB)—in the visible range. In contrast, off-the-shelf smartphone camera sensors are potentially hyperspectral in nature, meaning that each pixel is sensitive to far more spectral bands. Now scientists have found a simple way for any conventional smartphone camera to serve as a hyperspectral sensor—by placing a card with a chart on it within its view. The new patent-pending technique may fi...