Sentence examples for cycle per degree from inspiring English sources
Two spatial frequencies, 0.5 and 2.0 cycle per degree (cpd), were presented.
At the top, from left to right: spatial frequencies of 0.6 and 2.5 cpd (cycle per degree of visual angle).
In comparison to the automated test, the hand-held version produced statistically significant higher contrast sensitivity scores for lower spatial frequencies (1.5 and 3.0 cycles per degree) and lower scores for a relatively higher spatial frequency (18.0 cycles per degree [cpd]).
To evoke an OKN response, participants were presented with a stimulus screen consisting of 100% contrast square wave gratings with a fundamental spatial frequency of 0.833 cycles per degree.
However, the function was substantially steeper under the pulsed-pedestal than under the steady-pedestal paradigm, such that a large change in optotype size produced a relatively small change in retinal spatial frequency (cycles per degree).
Considering that bees and many insects have a much lower visual acuity than most diurnal vertebrates (bees, Apis mellifera, for example have a visual acuity of ~0.25 cycles per degree (cpd 24 while archerfish have an acuity of ~3.2 cpd25 and humans have an acuity of ~72 cpd26), it seems questionable that bees would be able to detect enough detail to discriminate more than a small number of faces.
where denotes the peak frequency, denotes the contrast sensitivity, and f denotes the spatial frequency in cycles per degree.
The limit of detail that human eyes can resolve is about 60 cycles per degree, which helps us make out road signs and recognize faces from afar.
For instance, the wedge-tailed eagle of Australia can see 140 cycles per degree, more than twice the limit of human visual acuity.
But apart from some eagles, vultures and falcons, the results show that most birds see fewer than 30 cycles per degree -- less than half as much detail as humans.
