Department of Computer Science, University of Tsukuba, Tsukuba, Japan.
Neural Netw. 2012 Sep;33:257-74. doi: 10.1016/j.neunet.2012.05.006. Epub 2012 Jun 7.
Determination of the figure region in an image is a fundamental step toward surface construction, shape coding, and object representation. Localized, asymmetric surround modulation, reported neurophysiologically in early-to-intermediate-level visual areas, has been proposed as a mechanism for figure-ground segregation. We investigated, computationally, whether such surround modulation is capable of yielding consistent and robust determination of figure side for various stimuli. Our surround modulation model showed a surprisingly high consistency among pseudorandom block stimuli, with greater consistency for stimuli that yielded higher accuracy of, and shorter reaction times in, human perception. Our analyses revealed that the localized, asymmetric organization of surrounds is crucial in the detection of the contrast imbalance that leads to the determination of the direction of figure with respect to the border. The model also exhibited robustness for gray-scaled natural images, with a mean correct rate of 67%, which was similar to that of figure-side determination in human perception through a small window and of machine-vision algorithms based on local processing. These results suggest a crucial role of surround modulation in the local processing of figure-ground segregation.
图像中图形区域的确定是曲面构建、形状编码和目标表示的基本步骤。局部、非对称的环绕调制已在早期到中期视觉区域的神经生理学中报告，被提议作为图形-背景分离的机制。我们通过计算来研究这种环绕调制是否能够为各种刺激产生一致且稳健的图形侧确定。我们的环绕调制模型在伪随机块刺激中表现出非常高的一致性，对于那些在人类感知中产生更高准确性和更短反应时间的刺激，一致性更高。我们的分析表明，环绕的局部、非对称组织对于检测导致相对于边界确定图形方向的对比度失衡至关重要。该模型对灰度自然图像也具有鲁棒性，平均正确率为 67%，这与通过小窗口进行的人类感知中的图形侧确定以及基于局部处理的机器视觉算法的正确率相似。这些结果表明，环绕调制在图形-背景分离的局部处理中起着关键作用。
