对图像二值化函数cvThreshold的理解
Threshold
对数组元素进行固定阈值操作
void cvThreshold( const CvArr* src, CvArr* dst, double threshold, double max_value, int threshold_type );
- src
- 原始数组 (单通道 , 8-bit of 32-bit 浮点数).
- dst
- 输出数组,必须与 src 的类型一致,或者为 8-bit.
- threshold
- 阈值
- max_value
- 使用 CV_THRESH_BINARY 和 CV_THRESH_BINARY_INV 的最大值.
- threshold_type
- 阈值类型 (见讨论)
函 数 cvThreshold 对单通道数组应用固定阈值操作。该函数的典型应用是对灰度图像进行阈值操作得到二值图像。(cvCmpS 也可以达到此目的) 或者是去掉噪声,例如过滤很小或很大象素值的图像点。本函数支持的对图像取阈值的方法由 threshold_type 确定:
threshold_type=CV_THRESH_BINARY:
dst(x,y) = max_value, if src(x,y)>threshold 0, otherwise.
threshold_type=CV_THRESH_BINARY_INV:
dst(x,y) = 0, if src(x,y)>threshold; dst(x,y) = max_value, otherwise.
threshold_type=CV_THRESH_TRUNC:
dst(x,y) = threshold, if src(x,y)>threshold; dst(x,y) = src(x,y), otherwise.
threshold_type=CV_THRESH_TOZERO:
dst(x,y) = src(x,y), if (x,y)>threshold ; dst(x,y) = 0, otherwise.
threshold_type=CV_THRESH_TOZERO_INV:
dst(x,y) = 0, if src(x,y)>threshold ; dst(x,y) = src(x,y), otherwise.
左面是图形化的阈值描述:
引自:http://blog.163.com/[email protected]/blog/static/300367392009226407387/