CONTRAST DETECTION IN LUMINANCE AND CHROMATIC NOISE
CONTRAST DETECTION IN LUMINANCE AND CHROMATIC NOISE
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DOI：
10.1364/josaa.9.001880
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发表时间：
1992-11-01
影响因子：
1.9
通讯作者：
KIPER, DC
中科院分区：
文献类型：
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作者：
GEGENFURTNER, KR;KIPER, DC
我们测量了嵌入在时空宽带噪声中的垂直方向的每度1.2周正弦波光栅的探测阈值。噪声和信号在等能量白点周围的颜色空间中以不同的方向进行调制。当信号和噪声被同向调制时，我们观察到噪声谱密度与阈值信号能量之间的线性关系。无论调制是沿着亮度轴还是红绿轴，该函数的斜率都是相同的。如果信号在一个轴上，而噪声在另一个轴上，则没有观察到掩蔽。这些结果支持两个独立和同样有效的机制根据这些方向进行调整的概念。然后，我们测量了具有色度和亮度分量的掩模的阈值高度。当信号和噪声沿同一条线调制时(例如，亮红色和深绿色)，阈值会升高。当我们将噪声的颜色分量相对于亮度分量(亮绿色和暗红色)的相位反转时，掩蔽效果消失了，即使假定的亮度和颜色机制中的噪声量与以前完全相同。这意味着检测性能受到对亮度和彩色对比度信号都敏感的机制的限制。我们通过它们的光谱调谐曲线来表征这些机制。
We measured detection thresholds for a vertically oriented 1.2-cycle-per-degree sine-wave grating embedded in spatiotemporal broadband noise. Noise and signal were modulated in different directions in color space around an equal-energy white point. When signal and noise were modulated in the same direction, we observed a linear relationship between noise spectral density and signal energy at threshold. The slope of this function was the same whether the modulation was along a luminance axis or a red-green axis. If the signal was on one axis and the noise was on the other, no masking was observed. These results support the notion of two independent and equally efficient mechanisms tuned to these directions. We then measured threshold elevations for masks with both chromatic and luminance components. When signal and noise were modulated along the same line (for example, bright red and dark green), thresholds were elevated. When we inverted the phase of the chromatic component of the noise relative to the luminance component (bright green and dark red), the masking effect disappeared, even though the amount of noise in the putative luminance and chromatic mechanisms was exactly the same as before. This implies that detection performance is limited by mechanisms sensitive to both luminance and chromatic contrast signals. We characterized these mechanisms by their spectral tuning curves.