TY - JOUR
T1 - Motion sharpening and contrast
T2 - Gain control precedes compressive non-linearity?
AU - Hammett, Stephen T.
AU - Georgeson, Mark A.
AU - Bedingham, Samantha
AU - Barbieri-Hesse, Gillian S.
PY - 2003/5
Y1 - 2003/5
N2 - Blurred edges appear sharper in motion than when they are stationary. We (Vision Research 38 (1998) 2108) have previously shown how such distortions in perceived edge blur may be accounted for by a model which assumes that luminance contrast is encoded by a local contrast transducer whose response becomes progressively more compressive as speed increases. If the form of the transducer is fixed (independent of contrast) for a given speed, then a strong prediction of the model is that motion sharpening should increase with increasing contrast. We measured the sharpening of periodic patterns over a large range of contrasts, blur widths and speeds. The results indicate that whilst sharpening increases with speed it is practically invariant with contrast. The contrast invariance of motion sharpening is not explained by an early, static compressive non-linearity alone. However, several alternative explanations are also inconsistent with these results. We show that if a dynamic contrast gain control precedes the static non-linear transducer then motion sharpening, its speed dependence, and its invariance with contrast, can be predicted with reasonable accuracy. © 2003 Elsevier Science Ltd. All rights reserved.
AB - Blurred edges appear sharper in motion than when they are stationary. We (Vision Research 38 (1998) 2108) have previously shown how such distortions in perceived edge blur may be accounted for by a model which assumes that luminance contrast is encoded by a local contrast transducer whose response becomes progressively more compressive as speed increases. If the form of the transducer is fixed (independent of contrast) for a given speed, then a strong prediction of the model is that motion sharpening should increase with increasing contrast. We measured the sharpening of periodic patterns over a large range of contrasts, blur widths and speeds. The results indicate that whilst sharpening increases with speed it is practically invariant with contrast. The contrast invariance of motion sharpening is not explained by an early, static compressive non-linearity alone. However, several alternative explanations are also inconsistent with these results. We show that if a dynamic contrast gain control precedes the static non-linear transducer then motion sharpening, its speed dependence, and its invariance with contrast, can be predicted with reasonable accuracy. © 2003 Elsevier Science Ltd. All rights reserved.
KW - blurred edges appear
KW - motion
KW - stationary
KW - perceived edge blur
KW - luminance contrast
KW - local contrast transducer
KW - response
KW - speed
KW - transducer
UR - http://www.scopus.com/inward/record.url?scp=12444274838&partnerID=8YFLogxK
UR - https://www.sciencedirect.com/science/article/pii/S0042698903000713?via%3Dihub
U2 - 10.1016/S0042-6989(03)00071-3
DO - 10.1016/S0042-6989(03)00071-3
M3 - Article
C2 - 12705958
SN - 0042-6989
VL - 43
SP - 1187
EP - 1199
JO - Vision Research
JF - Vision Research
IS - 10
ER -