人类视觉系统的方向选择性

It is known that an object is less detectable when it is viewed against a background containing structures similar to the object. The effect of changing the orientation between the object and background is investigated.2. Gratings of variable contrast were generated on two oscilloscopes; these were superimposed optically. The angle of orientation between them could be changed. The threshold of one grating, the test grating, was determined in the presence of the other, the masking grating.3. When the gratings were presented with the same orientation (and locked in phase) the increment threshold of the test grating was found to be proportional to the suprathreshold contrast of the masking grating.4. As the angle between the test and masking gratings was increased the masking effect fell exponentially.5. At 12 degrees on either side of a vertical test grating the masking effect was reduced by a factor of two with respect to its maximum value. This angle was independent of the contrast level of masking, the focus, and also the phase coherence of the masking grating.6. If the test grating was presented obliquely the effect of masking was slightly less.7. The narrow orientationally tuned channels found psychophysically by this masking technique are compared with the orientationally sensitive cells discovered electrophysiologically in the visual cortex of the cat.

众所周知，当一个物体在包含与该物体相似结构的背景下被观察时，它就不太容易被察觉。研究了物体与背景之间方向变化的影响。
在两台示波器上生成对比度可变的光栅；这些光栅通过光学方式叠加。它们之间的方向角度可以改变。在另一光栅（掩蔽光栅）存在的情况下，确定其中一个光栅（测试光栅）的阈值。
当光栅以相同方向呈现（且锁相）时，发现测试光栅的增量阈值与掩蔽光栅的超阈值对比度成正比。
随着测试光栅与掩蔽光栅之间的角度增加，掩蔽效果呈指数下降。
在垂直测试光栅两侧各12度处，掩蔽效果相对于其最大值降低了一半。这个角度与掩蔽的对比度水平、焦点以及掩蔽光栅的相位相干性无关。
如果测试光栅倾斜呈现，掩蔽效果会略小一些。
将通过这种掩蔽技术在心理物理学上发现的窄方向调谐通道与在猫的视觉皮层中通过电生理学发现的方向敏感细胞进行比较。

Orientational selectivity of the human visual system.