An image sensor includes a pixel array and a color filter array covering the pixel array, where the color filter array includes a plurality of color filter elements, the plurality of color filter elements include at least one first color filter element and at least one second color filter element, each first color filter element includes a basic color filter and an extended color filter, and each second color filter element includes a plurality of basic color filters. A color of the extended color filter is different from a color of the basic color filter. An optical signal passing through the basic color filter is at least for imaging, and an optical signal passing through the extended color filter is for spectral measurement.