* * *
displacement threshold.Medical dictionary. 2011.
Vernier scale — A vernier scale is an additional scale which allows a distance or angle measurement to be read more precisely than directly reading a uniformly divided straight or circular measurement scale. It is a sliding secondary scale that is used to… … Wikipedia
Vernier — Pierre, French mathematician, 1580–1637. See V. acuity. * * * n. a device for obtaining accurate measurements of length, to 1/10th, 1/100th or smaller fractions of a unit. It consists of a fixed graduated main scale against which a shorter… … Medical dictionary
acuity — 1. Sharpness, clearness, distinctness. 2. Severity. [thr. Fr., fr. L. acuo, pp. acutus, sharpen] absolute intensity threshold a. the minimal light that can be seen. resolution a. detection of a target having two or more parts, often measured by… … Medical dictionary
Visual acuity — 20/15 and 20/15 vision redirect here. For other uses, see 2020 (disambiguation). Typical Snellen chart used for visual acuity testing. Visual acuity (VA) is acuteness or clearness of vision, which is dependent on the sharpness of the retinal… … Wikipedia
grating acuity — n the aspect of visual acuity involving the ability to distinguish the elements of a fine grating composed of alternating dark and light stripes or squares compare HYPERACUITY, STEREOACUITY, VERNIER ACUITY … Medical dictionary
Optimum HDTV viewing distance — is the distance that provides the viewer with the optimum immersive visual HDTV experience. Although opinions vary on the exact screen size to distance relationship, formal research and recommendations suggest closer is preferred to further[not… … Wikipedia
stereoacuity — ste·reo·acui·ty .ster ē ō ə kyü ət ē, .stir n, pl ties the ability to detect differences in distance using stereoscopic cues that is measured by the smallest difference in the images presented to the two eyes that can be detected reliably compare … Medical dictionary
hyperacuity — hy·per·acu·ity .hī pə rə kyü ət ē n, pl ities greater than normal acuteness esp. of a sense specif visual acuity that is better than twenty twenty compare GRATING ACUITY, STEREOACUITY, VERNIER ACUITY … Medical dictionary
Backstaff — Not to be confused with Ballastella. Davis quadrant from the beginning of the 18th century The backstaff or back quadrant is a navigational instrument that was used to measure the altitude of a celestial body, in particular the sun or moon. When… … Wikipedia
displacement threshold — the threshold of perception of a break in the continuity of a contour or of a border; called also Vernier acuity … Medical dictionary
