Sampling Motion

 

 

 

There is a difference between sampling rate and image quality. It is an important distinction that is often missed. Delivered image quality can be changed even though the underlying mechanisms of distortion do not change. This is an important concept in this day when more and more pixels are being squeezed onto smaller and smaller displays. As ever larger images are captured at one time with ever larger sensor arrays, any transport motion will induce distortions that are in-phase over the entire acquisition region. Positional errors that were incurred on a pixel by pixel basis were composed of very high spatial frequencies. As the in-phase error increased with sensor size, the spatial composition shifted to lower spatial frequencies to which the visual system was more sensitive. The end result was that the efficiencies gained by the use of larger sensors were tempered by the increased constraints on the relative motion of the sensor and paper transport system. The sweet spot for any given technology can be determined by computing a device’s image transfer function. This effect is an appreciable concern since it has been shown that combinations of sensor sampling patterns and transport mechanism motion can induce Vernier-level sensitivities to image distortions.