Moya A, Esteve-Taboada J J, García J, Ferreira C
Departament Interuniversitari d'Optica, Facultat de Física, Universitat de València, c/Doctor Moliner 50, 46100 Burjassot, València, Spain.
Appl Opt. 2000 Oct 10;39(29):5347-52. doi: 10.1364/ao.39.005347.
The phase-only logarithmic radial harmonic (LRH) filter has been shown to be suitable for scale-invariant block object recognition. However, an important set of objects is the collection of contour functions that results from a digital edge extraction of the original block objects. These contour functions have a constant width that is independent of the scale of the original object. Therefore, since the energy of the contour objects decreases more slowly with the scale factor than does the energy of the block objects, the phase-only LRH filter has difficulties in the recognition tasks when these contour objects are used. We propose a modified LRH filter that permits the realization of a shift- and scale-invariant optical recognition of contour objects. The modified LRH filter is a complex filter that compensates the energy variation resulting from the scaling of contour objects. Optical results validate the theory and show the utility of the newly proposed method.
仅相位对数径向谐波（LRH）滤波器已被证明适用于尺度不变的块状物体识别。然而，一类重要的物体是通过对原始块状物体进行数字边缘提取得到的轮廓函数集合。这些轮廓函数具有恒定的宽度，该宽度与原始物体的尺度无关。因此，由于轮廓物体的能量随比例因子的下降比块状物体的能量下降更慢，当使用这些轮廓物体时，仅相位LRH滤波器在识别任务中存在困难。我们提出了一种改进的LRH滤波器，它能够实现轮廓物体的平移和尺度不变光学识别。改进的LRH滤波器是一种复滤波器，它补偿了轮廓物体缩放导致的能量变化。光学实验结果验证了该理论，并展示了新提出方法的实用性。
