1. A multispectral medical imaging device comprising: a plurality of illumination devices arranged to illuminate a target tissue, the plurality of illumination devices comprising near-infrared illumination devices configured to emit light of different near-infrared wavelength bands and a visible-light illumination device configured to emit visible light to illuminate the target tissue; an objective lens; a near-infrared image sensor positioned to sequentially capture image frames of near-infrared light reflected from the target tissue through the objective lens; a visible-light image sensor positioned to capture image frames of visible light reflected from the target tissue through the objective lens; an image capture buffer coupled to the near-infrared image sensor and the visible-light image sensor, the image capture buffer configured to store the image frames sequentially captured by the near-infrared image sensor and the image frames captured by the visible-light image sensor; a processor connected to the near-infrared image sensor, the visible-light image sensor, the plurality of illumination devices, and the image capture buffer, the processor configured to modulate near-infrared light output of the plurality of illumination devices to illuminate the target tissue by sequentially driving the near-infrared illumination devices to emit light of the different near-infrared wavelength bands, the processor further configured to: perform rolling processing on the image frames sequentially captured by the near-infrared image sensor that are stored in the image buffer to form output frames, each output frame comprising an image frame sequentially captured by the near-infrared image sensor for each one of the different near-infrared wavelength bands emitted by the near-infrared sensor; use the near-infrared image sensor to capture an ambient infrared image frame of the target tissue when controlling all of the illumination devices to not illuminate the target tissue; for each respective output frame, subtract the ambient infrared image frame from each image frame of the respective output frame; determine reflectance intensities from the image frames; perform delta processing on the reflective intensities for each one of the different near-infrared wavelength bands for each respective output frame to generate delta processed reflective intensities for each one of the different near-infrared wavelength bands for each respective output frame; and, combine the delta processed reflective intensities for each one of the different near-infrared wavelength bands for each respective output frame to generate a dynamic tissue oxygen saturation map of the target tissue; and an output device connected to the processor for displaying the dynamic tissue oxygen saturation map.