CHROMATIC DIFFERENCE STEPS OF MODERATE SIZE MEASURED ALONG THEORETICALLY CRITICAL AXES
CHROMATIC DIFFERENCE STEPS OF MODERATE SIZE MEASURED ALONG THEORETICALLY CRITICAL AXES
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DOI：
10.1002/col.5080050104
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发表时间：
1980-01-01
影响因子：
1.4
通讯作者：
KAMBE, N
中科院分区：
文献类型：
--
作者：
BOYNTON, RM;KAMBE, N
本文介绍了一种测量辨色阶跃的新方法，观察者必须指出变化发生的方向以及变化发生的事实。这个过程似乎稳定了受试者的差异标准，产生的步长更类似于赖特的“破折号”，而不是麦克亚当的椭圆。沿着变化的两个关键维度进行了沿着测试：（1）三色轴，其中辨别力最初仅取决于蓝视锥（B）激发的变化，以及（2）红-绿色轴，其中辨别力取决于红视锥（R）激发替代绿色视锥（G）激发，反之亦然。依赖于蓝色视锥的辨别能力受B-视锥兴奋水平的影响，但与R/G无关。在通过简单的比例因子考虑个体差异后，ΔB/ B + Bo= K形式的方程很好地解释了数据。蓝视锥辨别被发现与红视锥与绿色视锥激发的比率无关，最佳韦伯分数约为18%。根据红锥和绿色锥激发的交换进行区分，产生约2%的最佳韦伯分数。红-绿色比率相对于中性条件的不平衡以及蓝锥兴奋水平的增加使该比率增加，尽管不是很大。在120 td处，麦克亚当阶跃与我们的阶跃之间的比率近似恒定在约13：1。
A new method of measuring chromatic discrimination steps is described where observers must indicate in which direction a change has occurred, as well as the fact of its occurrence. This procedure seems to stabilize the subject's criterion of difference and yields step sizes more akin to those of Wright's “dashes” than MacAdam's ellipses. Tests have been made along two critical dimensions of variation: (1) the tritan axis, where discriminations depend initially only on variations in blue‐cone (B) excitation and (2) the red‐green axis, where discriminations depend on the substitution of red‐cone (R) excitation for that of green cones (G), or vice versa. Discriminations dependent on blue cones are affected by the level of B‐cone excitation but are independent of R/G. After individual differences are taken into account by a simple scaling factor, an equation of the form ΔB/ B + Bo= K accounts well for the data. Blue‐cone discrimination is found to be independent of the ratio of red‐to‐green‐cone excitation, with an optimal Weber fraction of about 18%. Discriminations dependent on the exchange of red‐and green‐cone excitation yield an optimal Weber fraction of about 2%. This ratio is increased, though not greatly, by an imbalance of the red‐green ratio relative to a neutral condition, and by increasing the level of blue‐cone excitation. At 120 td, the ratio between a MacAdam step and ours is approximately constant at about 13:1.