Re:The Remarkable “Curvature Blindness” Illusion
by coldtea on Saturday December 09, 2017 @03:40PM
(#15887990)
>I don't find this at all "remarkable" because I don't think this has anything to do with the curvature itself, but the relative contrast of the lines against different backgrounds, and the, for lack of a better term, dithering that occurs in the brain as it is interpreting the borders of contrast
That's because you didn't understand it.
For one, the "the relative contrast of the lines against different backgrounds" is the same between the lines that appear curved and those that appear "straight", because both are the same exact line (both curved) against the same exact background part (the gray).
Re:The Remarkable “Curvature Blindness” Illusion
by matt-attack on Saturday December 09, 2017 @04:01PM
(#15888125)
Correct. The effect is based on where the interchange from black to white occurs. If the interchange occurs at the peak or valley of the sine wave, we perceive no curves. If the interchange occurs at the straight part of the sine way, we accurately perceive the curvature. Really neat!
Re:The Remarkable “Curvature Blindness” Illusion
by teilo on Sunday December 10, 2017 @02:47AM
(#15890452)
No, you didn't understand me, sorry. I understood it just fine, but didn't explain myself well enough.
The relative contrast at the point of curvature causes an aliasing effect in the brain where the line colors are (depending on the color) added to or subtracted from the gray value. In effect this causes an apparent sharpening of the curve. However, on those lines where the transition takes place on the straight portion of the wave, no such aliasing takes place because there is no curvature.
It's like anti-aliasing in reverse.
If the lines were a solid color, instead of alternating bands, or if the crossover happened somewhere other than a crest of a trough, this effect would disappear.