A high image sample rate was used to investigate the transient dynamics of salt water intrusion, which rendered analysis by visual observation unsuitable.
Classic signal processing theory dictates that, in order to faithfully reconstruct a band-limited signal (e.g., an image), the sampling rate must be at least twice the maximum frequency contained within the signal, i.e., the Nyquist frequency.
For example, to process a 1024 × 1024 image, when the sampling rate is 50% and the data is with double precision floating-point, there are 512 K measurements.
The experimental device, stiff enough to be non-intrusive on the system response up to several kHz, provides the contact force, vibration velocity and contact image with a high sampling rate.
The basic parameters took a little bit of time to render on my system, but not long enough where I felt the need to decrease image size or sampling rates to speed things up.
CS theory states that it is possible to reconstruct an aliasing-free image even at sampling rates dramatically lower than the Nyquist sampling limit, as long as the nonzero signal is sparse and sampled incoherently.
An optimal sampling rate in the image plane, as determined by the pixel pitch, is found by the use of an information theoretic performance measure.
In Sections 4.2 and 4.3, we used, in order to speed up the simulations, smaller 64 × 32 images, keeping the subsampling and the sampling rate the same.
image data acquired with different spatial and/or temporal sampling rates, image structures of different spatial and/or temporal extent, objects at different distances from the camera, the linear component of relative motions between objects in the world and the observer, and the linear component of perspective deformations.
