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std::vector to cv::Mat
Concatenating two std::vectorsHow to find out if an item is present in a std::vector?How do I erase an element from std::vector<> by index?What is the easiest way to initialize a std::vector with hardcoded elements?Appending a vector to a vectorGet frame from video with libvlc smem and convert it to opencv Mat. (c++)Fastest way to apply color matrix to RGB image using OpenCV 3.0?Colorizing 16 bit Greyscale Mat produces only half of imageHow to reassign an individual element of a 2D parallel vector with a 1D vector?Convertion of Mat to 2d array and access the pixel values in c++
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;
what is the best way to convert a vector containing R,G and B color values in a cv::Vec3b vector to a cv::Mat? The position of the pixel does not matter, I just want to perform the cv::split operation and then put all three color levels to a histogramm.
I tried this, but it does not work as the split operation is returning a cv::Mat with only one plane of colors:
cv::Mat GetOnlyColoredPixel(cv::Mat& Gray, cv::Mat& Col)
std::vector<cv::Vec3b> ColorStack;
cv::Vec3b vec;
int nPixel = 0;
for (int y = 0; y < Gray.rows; y++)
for (int x = 0; x < Gray.cols; x++)
if (Gray.at<unsigned char>(y, x) == 255)
ColorStack.push_back(Col.at<cv::Vec3b>(y, x));
nPixel++;
return cv::Mat(1, nPixel, CV_8UC3, &ColorStack[0]);
The strange thing is, that I really should have only yellow pixel but when printing the MAT object, I get all possible colors. The Col.at<cv::Vec3b>(y, x) returns the correct color but in RGB order - I thought, OpenCV is using BGR.
Thank you,
Jan
opencv vector colors mat
asked Mar 27 at 15:12
Jan021981Jan021981
12812 bronze badges
add a comment |
what is the best way to convert a vector containing R,G and B color values in a cv::Vec3b vector to a cv::Mat? The position of the pixel does not matter, I just want to perform the cv::split operation and then put all three color levels to a histogramm.
I tried this, but it does not work as the split operation is returning a cv::Mat with only one plane of colors:
cv::Mat GetOnlyColoredPixel(cv::Mat& Gray, cv::Mat& Col)
std::vector<cv::Vec3b> ColorStack;
cv::Vec3b vec;
int nPixel = 0;
for (int y = 0; y < Gray.rows; y++)
for (int x = 0; x < Gray.cols; x++)
if (Gray.at<unsigned char>(y, x) == 255)
ColorStack.push_back(Col.at<cv::Vec3b>(y, x));
nPixel++;
return cv::Mat(1, nPixel, CV_8UC3, &ColorStack[0]);
The strange thing is, that I really should have only yellow pixel but when printing the MAT object, I get all possible colors. The Col.at<cv::Vec3b>(y, x) returns the correct color but in RGB order - I thought, OpenCV is using BGR.
Thank you,
Jan
opencv vector colors mat
asked Mar 27 at 15:12
Jan021981Jan021981
12812 bronze badges
if that vector isn't changed anymore and doesn't go out of scope while you use the mat (before splitting), you can use the memory directly:cv::Mat testMat = cv:Mat(height, width, CV_8UC3, ColorStack.data());then you can either split testMat or .clone it or whatever you like. Might be one copying of the data less than your approach, but will fail if the vector goes out of scope until you have done everything with testMat.
– Micka
Mar 27 at 16:07
add a comment |
what is the best way to convert a vector containing R,G and B color values in a cv::Vec3b vector to a cv::Mat? The position of the pixel does not matter, I just want to perform the cv::split operation and then put all three color levels to a histogramm.
I tried this, but it does not work as the split operation is returning a cv::Mat with only one plane of colors:
cv::Mat GetOnlyColoredPixel(cv::Mat& Gray, cv::Mat& Col)
std::vector<cv::Vec3b> ColorStack;
cv::Vec3b vec;
int nPixel = 0;
for (int y = 0; y < Gray.rows; y++)
for (int x = 0; x < Gray.cols; x++)
if (Gray.at<unsigned char>(y, x) == 255)
ColorStack.push_back(Col.at<cv::Vec3b>(y, x));
nPixel++;
return cv::Mat(1, nPixel, CV_8UC3, &ColorStack[0]);
The strange thing is, that I really should have only yellow pixel but when printing the MAT object, I get all possible colors. The Col.at<cv::Vec3b>(y, x) returns the correct color but in RGB order - I thought, OpenCV is using BGR.
Thank you,
Jan
opencv vector colors mat
asked Mar 27 at 15:12
Jan021981Jan021981
12812 bronze badges
what is the best way to convert a vector containing R,G and B color values in a cv::Vec3b vector to a cv::Mat? The position of the pixel does not matter, I just want to perform the cv::split operation and then put all three color levels to a histogramm.
I tried this, but it does not work as the split operation is returning a cv::Mat with only one plane of colors:
cv::Mat GetOnlyColoredPixel(cv::Mat& Gray, cv::Mat& Col)
std::vector<cv::Vec3b> ColorStack;
cv::Vec3b vec;
int nPixel = 0;
for (int y = 0; y < Gray.rows; y++)
for (int x = 0; x < Gray.cols; x++)
if (Gray.at<unsigned char>(y, x) == 255)
ColorStack.push_back(Col.at<cv::Vec3b>(y, x));
nPixel++;
return cv::Mat(1, nPixel, CV_8UC3, &ColorStack[0]);
The strange thing is, that I really should have only yellow pixel but when printing the MAT object, I get all possible colors. The Col.at<cv::Vec3b>(y, x) returns the correct color but in RGB order - I thought, OpenCV is using BGR.
Thank you,
Jan
opencv vector colors mat
opencv vector colors mat
asked Mar 27 at 15:12
Jan021981Jan021981
12812 bronze badges
asked Mar 27 at 15:12
Jan021981Jan021981
12812 bronze badges
edited Mar 27 at 15:49
Jan021981
asked Mar 27 at 15:12
Jan021981Jan021981
12812 bronze badges
asked Mar 27 at 15:12
Jan021981Jan021981
12812 bronze badges
asked Mar 27 at 15:12
Jan021981Jan021981
12812 bronze badges
12812 bronze badges
if that vector isn't changed anymore and doesn't go out of scope while you use the mat (before splitting), you can use the memory directly:cv::Mat testMat = cv:Mat(height, width, CV_8UC3, ColorStack.data());then you can either split testMat or .clone it or whatever you like. Might be one copying of the data less than your approach, but will fail if the vector goes out of scope until you have done everything with testMat.
– Micka
Mar 27 at 16:07
add a comment |
if that vector isn't changed anymore and doesn't go out of scope while you use the mat (before splitting), you can use the memory directly:cv::Mat testMat = cv:Mat(height, width, CV_8UC3, ColorStack.data());then you can either split testMat or .clone it or whatever you like. Might be one copying of the data less than your approach, but will fail if the vector goes out of scope until you have done everything with testMat.
– Micka
Mar 27 at 16:07
if that vector isn't changed anymore and doesn't go out of scope while you use the mat (before splitting), you can use the memory directly:
cv::Mat testMat = cv:Mat(height, width, CV_8UC3, ColorStack.data()); then you can either split testMat or .clone it or whatever you like. Might be one copying of the data less than your approach, but will fail if the vector goes out of scope until you have done everything with testMat.– Micka
Mar 27 at 16:07
if that vector isn't changed anymore and doesn't go out of scope while you use the mat (before splitting), you can use the memory directly:
cv::Mat testMat = cv:Mat(height, width, CV_8UC3, ColorStack.data()); then you can either split testMat or .clone it or whatever you like. Might be one copying of the data less than your approach, but will fail if the vector goes out of scope until you have done everything with testMat.– Micka
Mar 27 at 16:07
add a comment |
1 Answer
1
active
oldest
votes
Ok, the returning is wrong. This code works fine:
cv::Mat GetOnlyColoredPixel(cv::Mat& Gray, cv::Mat& Col)
std::vector<cv::Vec3b> ColorStack;
cv::Vec3b vec, vec2;
cv::imwrite("C:\HomeC\Test.bmp", Col);
for (int y = 0; y < Gray.rows; y++)
for (int x = 0; x < Gray.cols; x++)
if (Gray.at<unsigned char>(y, x) == 255)
//ColorStack.push_back(Col.at<cv::Vec3b>(y, x));
vec = Col.at<cv::Vec3b>(y, x);
ColorStack.push_back(vec);
cv::Mat RetVal = cv::Mat(1, ColorStack.size(), CV_8UC3);
memcpy(RetVal.data, ColorStack.data(), ColorStack.size() * sizeof(cv::Vec3b));
return RetVal;
answered Mar 27 at 16:03
Jan021981Jan021981
12812 bronze badges
add a comment |
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Ok, the returning is wrong. This code works fine:
cv::Mat GetOnlyColoredPixel(cv::Mat& Gray, cv::Mat& Col)
std::vector<cv::Vec3b> ColorStack;
cv::Vec3b vec, vec2;
cv::imwrite("C:\HomeC\Test.bmp", Col);
for (int y = 0; y < Gray.rows; y++)
for (int x = 0; x < Gray.cols; x++)
if (Gray.at<unsigned char>(y, x) == 255)
//ColorStack.push_back(Col.at<cv::Vec3b>(y, x));
vec = Col.at<cv::Vec3b>(y, x);
ColorStack.push_back(vec);
cv::Mat RetVal = cv::Mat(1, ColorStack.size(), CV_8UC3);
memcpy(RetVal.data, ColorStack.data(), ColorStack.size() * sizeof(cv::Vec3b));
return RetVal;
answered Mar 27 at 16:03
Jan021981Jan021981
12812 bronze badges
add a comment |
Ok, the returning is wrong. This code works fine:
cv::Mat GetOnlyColoredPixel(cv::Mat& Gray, cv::Mat& Col)
std::vector<cv::Vec3b> ColorStack;
cv::Vec3b vec, vec2;
cv::imwrite("C:\HomeC\Test.bmp", Col);
for (int y = 0; y < Gray.rows; y++)
for (int x = 0; x < Gray.cols; x++)
if (Gray.at<unsigned char>(y, x) == 255)
//ColorStack.push_back(Col.at<cv::Vec3b>(y, x));
vec = Col.at<cv::Vec3b>(y, x);
ColorStack.push_back(vec);
cv::Mat RetVal = cv::Mat(1, ColorStack.size(), CV_8UC3);
memcpy(RetVal.data, ColorStack.data(), ColorStack.size() * sizeof(cv::Vec3b));
return RetVal;
answered Mar 27 at 16:03
Jan021981Jan021981
12812 bronze badges
add a comment |
Ok, the returning is wrong. This code works fine:
cv::Mat GetOnlyColoredPixel(cv::Mat& Gray, cv::Mat& Col)
std::vector<cv::Vec3b> ColorStack;
cv::Vec3b vec, vec2;
cv::imwrite("C:\HomeC\Test.bmp", Col);
for (int y = 0; y < Gray.rows; y++)
for (int x = 0; x < Gray.cols; x++)
if (Gray.at<unsigned char>(y, x) == 255)
//ColorStack.push_back(Col.at<cv::Vec3b>(y, x));
vec = Col.at<cv::Vec3b>(y, x);
ColorStack.push_back(vec);
cv::Mat RetVal = cv::Mat(1, ColorStack.size(), CV_8UC3);
memcpy(RetVal.data, ColorStack.data(), ColorStack.size() * sizeof(cv::Vec3b));
return RetVal;
answered Mar 27 at 16:03
Jan021981Jan021981
12812 bronze badges
Ok, the returning is wrong. This code works fine:
cv::Mat GetOnlyColoredPixel(cv::Mat& Gray, cv::Mat& Col)
std::vector<cv::Vec3b> ColorStack;
cv::Vec3b vec, vec2;
cv::imwrite("C:\HomeC\Test.bmp", Col);
for (int y = 0; y < Gray.rows; y++)
for (int x = 0; x < Gray.cols; x++)
if (Gray.at<unsigned char>(y, x) == 255)
//ColorStack.push_back(Col.at<cv::Vec3b>(y, x));
vec = Col.at<cv::Vec3b>(y, x);
ColorStack.push_back(vec);
cv::Mat RetVal = cv::Mat(1, ColorStack.size(), CV_8UC3);
memcpy(RetVal.data, ColorStack.data(), ColorStack.size() * sizeof(cv::Vec3b));
return RetVal;
answered Mar 27 at 16:03
Jan021981Jan021981
12812 bronze badges
answered Mar 27 at 16:03
Jan021981Jan021981
12812 bronze badges
answered Mar 27 at 16:03
Jan021981Jan021981
12812 bronze badges
answered Mar 27 at 16:03
Jan021981Jan021981
12812 bronze badges
12812 bronze badges
add a comment |
add a comment |
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if that vector isn't changed anymore and doesn't go out of scope while you use the mat (before splitting), you can use the memory directly:
cv::Mat testMat = cv:Mat(height, width, CV_8UC3, ColorStack.data());then you can either split testMat or .clone it or whatever you like. Might be one copying of the data less than your approach, but will fail if the vector goes out of scope until you have done everything with testMat.– Micka
Mar 27 at 16:07