CV Feature Harris

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Harris Corner

Reference

• 1988 A COMBINED CORNER AND EDGE DETECTOR
• Harris Corner Detector - wikipedia
• 图像处理特征不变算子系列之Harris算子
• Harris Corner Detection - OpenCV
• An Analysis and Implementation of the Harris Corner Detector
• slides - Harris Corner Detector
• A Comparative Study between Moravec and Harris Corner Detection of Noisy Images Using Adaptive Wavelet Thresholding Technique
• feature - ppt
• Harris 角点 - 计算机视觉 北京邮电大学 鲁鹏
• The Shi-Tomasi Corner Detector
• Subpixel Corners: Increasing accuracy
• 亚像素角点的求法

Brief

• 1988 Harris Corner Detector Harris&Stephens

检测原理

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公式推导

响应公式
窗口函数

窗口图解

通过 泰勒展开式 简化 为 u,v 相关的函数

Pipelines

1. Compute Gaussian derivatives at each pixel
2. Compute second moment matrix M in a Gaussian window around each pixel
3. Compute corner response function R
4. Threshold R
5. Find local maxima of response function(NMS)

扩展

Shi-Tomasi

• 减少计算量
• ==>

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Harris vs Shi-Tomasi

Subpixel Corners

• 增加精确度
• Pixel - (56, 120)
  • Subpixel - (56.768, 120.1432)

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