Example embodiments relate to imaging systems and methods for acquisition of multi-spectral images. One example imaging system includes a detector that includes an array of light sensitive elements arranged in rows and columns. Each light sensitive element is configured to generate a signal dependent on an intensity of light incident onto the light sensitive element. The imaging system also includes a plurality of wavelength separating units. Each wavelength separating unit is configured to spatially separate incident light within a wavelength range into a number of wavelength bands distributed along a line. The line is a straight line. Each wavelength band along the line is associated with a mutually unique light sensitive element. Further, the imaging system includes a processing unit configured to define a number of mutually unique clusters of light sensitive elements for summing signals from the light sensitive elements within the respective clusters.