openCV creating a 3D matrix with different sizes - c++

Question

accroding to this
http://answers.opencv.org/question/15917/how-to-access-data-from-a-cvmat/
I have tried to create a 3D matrix
void AutomaticMacbethDetection::DrawMacbethROI(ColorCheckerBatchRGB ColorCheckerBatchRGB, int *** raw_frame,int _width, int _height,int colorOrder)
{
cv::Mat src;
if (colorOrder == -1)
{
const int sizes[3]={_height,_width,3};
src = cv::Mat::zeros(3, sizes, CV_32F);
}else
{
const int sizes[3]={_height,_width,1};
src = cv::Mat::zeros(3, sizes, CV_32F);
}
std::vector<float> channel;
if (colorOrder == -1)
{
for (int w = 0; w < _width; w++)
{
for (int h = 0; h < _height; h++)
{
float temp =raw_frame[h][w][0];
channel.push_back(temp);
src.at<float>(h,w,0) = temp;
src.at<float>(h,w,1) = raw_frame[h][w][1];
src.at<float>(h,w,2) = raw_frame[h][w][2];
}
}
}
else
{
for (int w = 0; w < _width; w++)
{
for (int h = 0; h < _height; h++)
{
float temp =raw_frame[h][w][0];
channel.push_back(temp);
src.at<float>(h,w,0) = temp;
}
}
float divider = Utilities::tprctile(channel,99.2);
src = src/divider;
}
cv::imshow("test", src);
cv::waitKey(0);
}
my function supports both RGB and Raw Image so I need to create a 100x100x1 matrix or a 100x100x3 matrix, depending on the image type.
however I get an exception in imshow()
OpenCV Error: Assertion failed (p[-1] <= 2) in cv::Mat::MSize::operator (), file
C:\buildslave64\win64_amdocl\2_4_PackSlave-win64-vc11-shared\opencv\modules\cor
e\include\opencv2/core/mat.hpp, line 712
can you please explain what is the problem?

Answer 1

It looks to me that you are trying to set a 3-layer zero mat in both cases:
const int sizes[3]={_height,_width,1};
src = cv::Mat::zeros(3, sizes, CV_32F);
C++: static MatExpr Mat::zeros(int ndims, const int* sz, int type) states that the first argument is the dimentions. This should here be 1 if you want a 1-layer mat.

Answer 2

The solution I have found for this is using CV_32FC3 which means each cell of the matrix (x,y) has 3 values in it.
this is how you init the 3D matrix.
src = cv::Mat::zeros(_height,_width, CV_32FC3);
and now you have 3 cells which you need to access like so:
src.at<cv::Vec3f>(h,w)[0]
src.at<cv::Vec3f>(h,w)[1]
src.at<cv::Vec3f>(h,w)[2]
Please notice I'm using Vec3f and not float like i'm using in CV_32F
void AutomaticMacbethDetection::DrawMacbethROI(ColorCheckerBatchRGB ColorCheckerBatchRGB, int *** raw_frame,int _width, int _height,int colorOrder)
{
cv::Mat src;
std::vector<float> channel;
if (colorOrder != -1 )
{
src = cv::Mat::zeros(_height,_width, CV_32F);
for (int w = 0; w < _width; w++)
{
for (int h = 0; h < _height; h++)
{
float temp =raw_frame[h][w][0];
channel.push_back(temp);
src.at<float>(h,w) = temp;
}
}
float divider = Utilities::tprctile(channel,99.2);
src = src/divider;
}
else
{
src = cv::Mat::zeros(_height,_width, CV_32FC3);
for (int w = 0; w < _width; w++)
{
for (int h = 0; h < _height; h++)
{
float temp =raw_frame[h][w][0];
channel.push_back(temp);
src.at<cv::Vec3f>(h,w)[0] = raw_frame[h][w][0];
src.at<cv::Vec3f>(h,w)[1] = raw_frame[h][w][1];
src.at<cv::Vec3f>(h,w)[2] = raw_frame[h][w][2];
}
}
float divider = Utilities::tprctile(channel,99.2);
src = src/divider;
}
cv::resize(src,src,cv::Size(),0.3,0.3,cv::INTER_LINEAR);
cv::imshow("detected", src);
cv::waitKey(0);