The perception of suprathreshold contrast and fast adaptive filtering
The perception of suprathreshold contrast and fast adaptive filtering
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DOI：
10.1167/7.12.1
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发表时间：
2007-01-01
影响因子：
1.8
通讯作者：
Langley, Keith
中科院分区：
文献类型：
--
作者：
Bex, Peter J.;Langley, Keith
我们研究动态噪声图像的感知对比度如何取决于时间频率 (TF) 和平均亮度。一种新颖的逐步阈上匹配范例表明，阈值和阈上对比敏感度函数都可以通过倒 U 形描述为 TF 的函数。调谐函数的形状和峰值 TF 随测量条件的不同而变化。时空视觉在低亮度水平 (0.8 cd/m(2)) 下具有弱带通性，但在高亮度 (40-400 cd/m2) 下具有更强的带通性。带通函数的峰值时间频率随着测试信号的平均亮度和对比度的增加而增加。作为增加图像对比度的函数，我们的结果表明视觉系统拓宽了其信号检测机制的时空带宽，特别是在高平均亮度下。我们的结果表明与适应性信号传输系统一致，其中早期依赖于亮度的增益控制机制与通过自相关函数的对比度在线估计相结合，导致高时间频率下时空视觉的自适应增强。
We examine how the perceived contrast of dynamic noise images depends upon temporal frequency (TF) and mean luminance. A novel stepwise suprathreshold matching paradigm shows that both threshold and suprathreshold contrast sensitivity functions may be described by an inverted-U shape as a function of TF. The shape and the peak TF of the tuning function vary with the conditions under which it is measured. Spatiotemporal vision is weakly band-pass at low luminance levels (0.8 cd/m(2)) but becomes more strongly band-pass at high luminances (40-400 cd/m2). The peak temporal frequencies of the band-pass functions increase with the mean luminance and contrast of the test signals. As a function of increasing image contrast, our results demonstrate that the visual system broadens the spatiotemporal bandwidth of its signal detection mechanisms, especially at high mean luminances. Our results are shown to be consistent with an adaptable signal transmission system in which early luminance-dependent gain control mechanisms, in combination with on-line estimates of contrast via the autocorrelation function lead to an adaptive enhancement of spatiotemporal vision at high temporal frequencies.