1 Solution
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#include <vector>
#include <stdio.h>
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;
void createAlphaMat(Mat &mat)
{
for (int i = 0; i < mat.rows; ++i) {
for (int j = 0; j < mat.cols; ++j) {
Vec4b& rgba = mat.at<Vec4b>(i, j);
rgba[0] = UCHAR_MAX;
rgba[1] = saturate_cast<uchar>((float (mat.cols - j)) / ((float)mat.cols) * UCHAR_MAX);
rgba[2] = saturate_cast<uchar>((float (mat.rows - i)) / ((float)mat.rows) * UCHAR_MAX);
rgba[3] = saturate_cast<uchar>(0.5 * (rgba[1] + rgba[2]));
}
}
}
int main(int argv, char **argc)
{
// Create mat with alpha channel
Mat mat(480, 640, CV_8UC4);
createAlphaMat(mat);
vector<int> compression_params;
compression_params.push_back(CV_IMWRITE_PNG_COMPRESSION);
compression_params.push_back(9);
imwrite("alpha.png", mat, compression_params);
fprintf(stdout, "Saved PNG file with alpha data.\n");
return 0;
}
Well this worked kind of.
So I have managed to write an image but it is blank :S
The camera light is coming on until script ends so making progress, any ideas to push this one forward anyone ?
#include "opencv2/opencv.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <iostream>
using namespace cv;
using namespace std;
int main(int, char**)
{
VideoCapture cap(-1);
if (!cap.isOpened()) // if not success, exit program
{
cout << "Cannot open the video cam" << endl;
return -1;
} else {
cout << "Opened Cam" << endl;
}
Mat save_img; cap >> save_img;
if(save_img.empty())
{
cout << "Something is wrong with the webcam, could not get frame." << endl;
} else {
cout << "Writing Image." << endl;
imwrite("test.jpg", save_img); // A JPG FILE IS BEING SAVED
cout << "Written Image test.jpg" << endl;
}
return 0;
}
root@quark00a8ee:~# chmod 755 /tmp/TASS;/tmp/TASS ;exit
VIDIOC_QUERYMENU: Invalid argument
VIDIOC_QUERYMENU: Invalid argument
VIDIOC_QUERYMENU: Invalid argument
VIDIOC_QUERYMENU: Invalid argument
VIDIOC_QUERYMENU: Invalid argument
VIDIOC_QUERYMENU: Invalid argument
VIDIOC_QUERYMENU: Invalid argument
Opened Cam
select timeout
Writing Image.
Written Image test.jpg
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