An electronic device, comprising: one or more processors; memory; one or more programs, the one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for: obtaining a data set comprising a plurality of images of a tissue of interest, each respective image in the plurality of images resolved at a different spectral band in a predetermined set of eight to twelve spectral bands, and comprising an array of pixel values; registering, using the processor, the plurality of images on a pixel-by-pixel basis, to form a plurality of registered images of the tissue; and performing spectral analysis at a plurality of points in a two-dimensional area of the plurality of registered images of the tissue, the spectral analysis including determining approximate values of oxyhemoglobin levels and deoxyhemoglobin levels at each respective point in the plurality of points, wherein the predetermined set of eight to twelve spectral bands includes spectral bands having central wavelengths of: 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, 620±3 nm, and 660±3 nm, wherein the spectral bands having central wavelengths of 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, and 620±3 nm have a full width at half maximum of less than 15 nm, and wherein the spectral band having the central wavelength of 660±3 nm has a full width at half maximum of less than 20 nm. one or more processors; memory; one or more programs, the one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for: obtaining a data set comprising a plurality of images of a tissue of interest, each respective image in the plurality of images resolved at a different spectral band in a predetermined set of eight to twelve spectral bands, and comprising an array of pixel values; registering, using the processor, the plurality of images on a pixel-by-pixel basis, to form a plurality of registered images of the tissue; and performing spectral analysis at a plurality of points in a two-dimensional area of the plurality of registered images of the tissue, the spectral analysis including determining approximate values of oxyhemoglobin levels and deoxyhemoglobin levels at each respective point in the plurality of points, wherein the predetermined set of eight to twelve spectral bands includes spectral bands having central wavelengths of: 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, 620±3 nm, and 660±3 nm, wherein the spectral bands having central wavelengths of 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, and 620±3 nm have a full width at half maximum of less than 15 nm, and wherein the spectral band having the central wavelength of 660±3 nm has a full width at half maximum of less than 20 nm. obtaining a data set comprising a plurality of images of a tissue of interest, each respective image in the plurality of images resolved at a different spectral band in a predetermined set of eight to twelve spectral bands, and comprising an array of pixel values; registering, using the processor, the plurality of images on a pixel-by-pixel basis, to form a plurality of registered images of the tissue; and performing spectral analysis at a plurality of points in a two-dimensional area of the plurality of registered images of the tissue, the spectral analysis including determining approximate values of oxyhemoglobin levels and deoxyhemoglobin levels at each respective point in the plurality of points, wherein the predetermined set of eight to twelve spectral bands includes spectral bands having central wavelengths of: 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, 620±3 nm, and 660±3 nm, wherein the spectral bands having central wavelengths of 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, and 620±3 nm have a full width at half maximum of less than 15 nm, and wherein the spectral band having the central wavelength of 660±3 nm has a full width at half maximum of less than 20 nm.