Zoom magnification is an essential element of video-based low vision enhancement systems. However, since optical
zoom systems are bulky and power intensive, digital zoom is an attractive alternative. This paper determines the visual
acuity of 15 subjects when a letter chart is viewed through a video system with various levels of digital zoom. A strategy
in which the 1:1 magnified image is obtained by combining optical magnification with digital minification gives the best
result, provided background scene information is know from the other cameras. A real-time FPGA based system for
simultaneous zoom and smoothing is also demonstrated for text reading and enhancement.