我正在尝试编写一个函数来补偿OpenCV项目中的镜头渐晕 . 问题是,当我尝试访问Mat中的第一个像素时,出现内存访问错误 . 这可能是一个愚蠢的错误,但如果你能指出我,我会很感激 . 这是功能:
void EckOpCam::FlatField(cv::Mat & parmI)
{
// workaround for access violation error
cv::Mat I = parmI;
const int channels = I.channels();
if (flatField.rows == 0)
MakeFlatFieldMat(I.rows);
// accept only char type matrices
ASSERT(I.depth() == CV_8U);
// make sure the matrices are the same size
ASSERT(I.cols == flatField.cols);
ASSERT(channels == flatField.channels());
// Try the really slow way...
int nRows = I.rows;
int nCols = I.cols;
unsigned int ipix0, ipix1, ipix2; // B,G,r values of pixel in I
float fpix0, fpix1,fpix2; // B,G,r values of pixel in flatField
float pix0, pix1, pix2;
switch (channels)
{
case 1:
for (int y = 0; y < nRows; ++y)
for (int x = 0; x < nCols; ++x)
{
{
ipix0 = I.at<cv::Vec3b>(x, y)[0];
fpix0 = flatField.at<cv::Vec3f>(x, y)[0];
pix0 = ipix0 * fpix0;
I.at<cv::Vec3b>(x, y)[0] = (pix0 > 255) ? 255 : uchar(pix0);
}
}
break;
case 3:
for (int y = 0; y < nRows; ++y)
for (int x = 0; x < nCols; ++x)
{
{
ipix0 = static_cast<uchar>(I.at<cv::Vec3b>(x, y)[0]); //<<< memory access error!
ipix1 = static_cast<uchar>(I.at<cv::Vec3b>(x, y)[1]);
ipix2 = static_cast<uchar>(I.at<cv::Vec3b>(x, y)[2]);
fpix0 = flatField.at<cv::Vec3f>(x, y)[0];
fpix1 = flatField.at<cv::Vec3f>(x, y)[1];
fpix2 = flatField.at<cv::Vec3f>(x, y)[2];
pix0 = ipix0 * fpix0;
pix1 = ipix1 * fpix1;
pix2 = ipix2 * fpix2;
I.at<cv::Vec3b>(x, y)[0] = (pix0 > 255) ? 255 : uchar(pix0);
I.at<cv::Vec3b>(x, y)[1] = (pix1 > 255) ? 255 : uchar(pix1);
I.at<cv::Vec3b>(x, y)[2] = (pix2 > 255) ? 255 : uchar(pix2);
}
}
}
}
错误是:抛出异常:读取访问冲突 . cv :: Vec :: operator返回0x240C37EC4A8 .
给出的地址正是I.data的地址 . 怎么了?谢谢你的帮助 .
2 回答
读取此Accessing elements of a cv::Mat with at<float>(i, j). Is it (x,y) or (row,col)?,您应该在代码中访问矩阵元素的所有位置交换
x
和y
.嗯...没关系 . 事实证明,异常是真实的,而不是这个代码的问题 . 我正在使用Point Grey的示例代码 . 它使用Mat构造函数从Point Grey ImagePtr转换为Mat,该构造函数只是将指针复制到数据 . ImagePtr超出了范围,因此当我尝试使用它时数据无效 . Mat.CopyTo()解决了这个问题 . 如果您需要快速解决类似问题的方法,我强烈建议您阅读this .