Multispectral imaging captures image data in specific wavelength regions of the electromagnetic spectrum. Wavelengths may be separated by filters or acquired using instruments sensitive to specific wavelengths.
In spectral imaging (multispectral and hyperspectral), also wavelength ranges outside the visible spectrum are used, i.e. light of frequencies beyond the visible range (infrared and ultraviolet). By using these bands of the wavelength spectrum, information can be obtained that cannot be detected by the human eye with its receptors for green, blue, and red.
The difference to hyperspectral imaging is the number of spectral bands measured. While multispectral imaging measures rather few bands (up to about 15), hyperspectral imaging can measure hundreds of contiguous spectral bands.