Vision detects smallest visual angle {visual acuity} {acuity, vision}.
If they look at too few lines {undersampling}, people estimate grating size incorrectly {aliasing}.
Visual angles land on retinal areas, which send to larger visual-cortex surface areas {cortical magnification}.
Good vision means that people can see at 20 feet what perfect-vision people can detect at 20 feet {twenty-twenty}. In contrast, 20-40 means that people can see at 20 feet what perfect-vision people can detect at 40 feet.
Scene features have diameter, whose ends define rays that go to eye-lens center to form angle {visual angle}.
1-Consciousness-Sense-Vision-Physiology
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Date Modified: 2022.0225