/* Types of thresholding */ #define CV_THRESH_BINARY 0 /* value = value > threshold ? max_value : 0 */ #define CV_THRESH_BINARY_INV 1 /* value = value > threshold ? 0 : max_value */ #define CV_THRESH_TRUNC 2 /* value = value > threshold ? threshold : value */ #define CV_THRESH_TOZERO 3 /* value = value > threshold ? value : 0 */ #define CV_THRESH_TOZERO_INV 4 /* value = value > threshold ? 0 : value */ #define CV_THRESH_MASK 7 #define CV_THRESH_OTSU 8 /* use Otsu algorithm to choose the optimal threshold value; combine the flag with one of the above CV_THRESH_* values */ /* Applies fixed-level threshold to grayscale image. This is a basic operation applied before retrieving contours */ CVAPI(double) cvThreshold( const CvArr* src, CvArr* dst, double threshold, double max_value, int threshold_type ); #define CV_ADAPTIVE_THRESH_MEAN_C 0 #define CV_ADAPTIVE_THRESH_GAUSSIAN_C 1 /* Applies adaptive threshold to grayscale image. The two parameters for methods CV_ADAPTIVE_THRESH_MEAN_C and CV_ADAPTIVE_THRESH_GAUSSIAN_C are: neighborhood size (3, 5, 7 etc.), and a constant subtracted from mean (...,-3,-2,-1,0,1,2,3,...) */ CVAPI(void) cvAdaptiveThreshold( const CvArr* src, CvArr* dst, double max_value, int adaptive_method CV_DEFAULT(CV_ADAPTIVE_THRESH_MEAN_C), int threshold_type CV_DEFAULT(CV_THRESH_BINARY), int block_size CV_DEFAULT(3), double param1 CV_DEFAULT(5));opencv 调用如下:
cvAdaptiveThreshold( s, dst, 255, CV_ADAPTIVE_THRESH_GAUSSIAN_C, CV_THRESH_BINARY_INV, 5, 15 );s:输入单通道数据
dst :输出单通道数据
block_size CV_Assert( blockSize % 2 == 1 && blockSize > 1 ) 为奇数 为邻域大小
param1 加权平均减去的值