Assertion Failure with cv::Size
I'm new to OpenCV and I stuck with the problem while declaring a Mat instance.
#include <opencv2opencv.hpp>
int main(int argc, char *argv) {
cv::Mat before = cv::imread("./irene.jpg", CV_LOAD_IMAGE_COLOR);
cv::imshow("before", before);
cv::waitKey(0);
cv::Mat after(cv::Size(before.rows, before.cols), CV_8UC3);
for (int y = 0; y < before.rows; y++) {
for (int x = 0; x < before.cols; x++) {
after.at<cv::Vec3b>(y, x)[0] = before.at<cv::Vec3b>(y, x)[2];
after.at<cv::Vec3b>(y, x)[1] = before.at<cv::Vec3b>(y, x)[1];
after.at<cv::Vec3b>(y, x)[2] = before.at<cv::Vec3b>(y, x)[0];
}
}
cv::imshow("after", after);
cv::waitKey(0);
return 0;
}
Just a simple code for changing color of an image.
The problem is that, when I try to use cv::Size(), the compiler returns Assertion Failure. It builds okay, but when I try to press any key to go next of the code, it makes an exception.
What the compiler references and put on the console is:
OpenCV(3.4.3) Error: Assertion failed ((unsigned)(i1 *
DataType<_Tp>::channels) < (unsigned)(size.p[1] * channels())) in
cv::Mat::at, file
c:opencv343opencvbuildincludeopencv2coremat.inl.hpp, line 1101
I'm certain on that the exception is thrown because of the Size() struct, because if I change Size(before.rows, before.cols) to before.rows, before.cols, it works fine!
I cannot figure out what is wrong, but all the tutorials say the code I tried is okay code.
opencv opencv3.0
asked Nov 19 '18 at 14:00
cadenzahcadenzah
597
add a comment |
I'm new to OpenCV and I stuck with the problem while declaring a Mat instance.
#include <opencv2opencv.hpp>
int main(int argc, char *argv) {
cv::Mat before = cv::imread("./irene.jpg", CV_LOAD_IMAGE_COLOR);
cv::imshow("before", before);
cv::waitKey(0);
cv::Mat after(cv::Size(before.rows, before.cols), CV_8UC3);
for (int y = 0; y < before.rows; y++) {
for (int x = 0; x < before.cols; x++) {
after.at<cv::Vec3b>(y, x)[0] = before.at<cv::Vec3b>(y, x)[2];
after.at<cv::Vec3b>(y, x)[1] = before.at<cv::Vec3b>(y, x)[1];
after.at<cv::Vec3b>(y, x)[2] = before.at<cv::Vec3b>(y, x)[0];
}
}
cv::imshow("after", after);
cv::waitKey(0);
return 0;
}
Just a simple code for changing color of an image.
The problem is that, when I try to use cv::Size(), the compiler returns Assertion Failure. It builds okay, but when I try to press any key to go next of the code, it makes an exception.
What the compiler references and put on the console is:
OpenCV(3.4.3) Error: Assertion failed ((unsigned)(i1 *
DataType<_Tp>::channels) < (unsigned)(size.p[1] * channels())) in
cv::Mat::at, file
c:opencv343opencvbuildincludeopencv2coremat.inl.hpp, line 1101
I'm certain on that the exception is thrown because of the Size() struct, because if I change Size(before.rows, before.cols) to before.rows, before.cols, it works fine!
I cannot figure out what is wrong, but all the tutorials say the code I tried is okay code.
opencv opencv3.0
asked Nov 19 '18 at 14:00
cadenzahcadenzah
597
1
Read the documentation of cv::Size. Doing so, you should notice that the first parameter of the constructor is width, but you're setting it to number of rows (i.e. height). | As with so many other questions here... documentation is your friend. Get familiar with it, and use it.
– Dan Mašek
Nov 19 '18 at 14:27
Also, it seems like all you're trying to do here is to swap channels 0 and 2. This is basically equivalent to a conversion between BGR and RGB. Hence, a simplecv::cvtColor(after, before, cv::COLOR_BGR2RGB)will do the same job as your two nested loops, and most likely much faster too.
– Dan Mašek
Nov 19 '18 at 14:31
You are right. the code switched them each other. Maybe it was not wrong because in many tutorials they were identical values (square matrix).
– cadenzah
Nov 19 '18 at 14:31
add a comment |
I'm new to OpenCV and I stuck with the problem while declaring a Mat instance.
#include <opencv2opencv.hpp>
int main(int argc, char *argv) {
cv::Mat before = cv::imread("./irene.jpg", CV_LOAD_IMAGE_COLOR);
cv::imshow("before", before);
cv::waitKey(0);
cv::Mat after(cv::Size(before.rows, before.cols), CV_8UC3);
for (int y = 0; y < before.rows; y++) {
for (int x = 0; x < before.cols; x++) {
after.at<cv::Vec3b>(y, x)[0] = before.at<cv::Vec3b>(y, x)[2];
after.at<cv::Vec3b>(y, x)[1] = before.at<cv::Vec3b>(y, x)[1];
after.at<cv::Vec3b>(y, x)[2] = before.at<cv::Vec3b>(y, x)[0];
}
}
cv::imshow("after", after);
cv::waitKey(0);
return 0;
}
Just a simple code for changing color of an image.
The problem is that, when I try to use cv::Size(), the compiler returns Assertion Failure. It builds okay, but when I try to press any key to go next of the code, it makes an exception.
What the compiler references and put on the console is:
OpenCV(3.4.3) Error: Assertion failed ((unsigned)(i1 *
DataType<_Tp>::channels) < (unsigned)(size.p[1] * channels())) in
cv::Mat::at, file
c:opencv343opencvbuildincludeopencv2coremat.inl.hpp, line 1101
I'm certain on that the exception is thrown because of the Size() struct, because if I change Size(before.rows, before.cols) to before.rows, before.cols, it works fine!
I cannot figure out what is wrong, but all the tutorials say the code I tried is okay code.
opencv opencv3.0
asked Nov 19 '18 at 14:00
cadenzahcadenzah
597
I'm new to OpenCV and I stuck with the problem while declaring a Mat instance.
#include <opencv2opencv.hpp>
int main(int argc, char *argv) {
cv::Mat before = cv::imread("./irene.jpg", CV_LOAD_IMAGE_COLOR);
cv::imshow("before", before);
cv::waitKey(0);
cv::Mat after(cv::Size(before.rows, before.cols), CV_8UC3);
for (int y = 0; y < before.rows; y++) {
for (int x = 0; x < before.cols; x++) {
after.at<cv::Vec3b>(y, x)[0] = before.at<cv::Vec3b>(y, x)[2];
after.at<cv::Vec3b>(y, x)[1] = before.at<cv::Vec3b>(y, x)[1];
after.at<cv::Vec3b>(y, x)[2] = before.at<cv::Vec3b>(y, x)[0];
}
}
cv::imshow("after", after);
cv::waitKey(0);
return 0;
}
Just a simple code for changing color of an image.
The problem is that, when I try to use cv::Size(), the compiler returns Assertion Failure. It builds okay, but when I try to press any key to go next of the code, it makes an exception.
What the compiler references and put on the console is:
OpenCV(3.4.3) Error: Assertion failed ((unsigned)(i1 *
DataType<_Tp>::channels) < (unsigned)(size.p[1] * channels())) in
cv::Mat::at, file
c:opencv343opencvbuildincludeopencv2coremat.inl.hpp, line 1101
I'm certain on that the exception is thrown because of the Size() struct, because if I change Size(before.rows, before.cols) to before.rows, before.cols, it works fine!
I cannot figure out what is wrong, but all the tutorials say the code I tried is okay code.
opencv opencv3.0
opencv opencv3.0
asked Nov 19 '18 at 14:00
cadenzahcadenzah
597
asked Nov 19 '18 at 14:00
cadenzahcadenzah
597
edited Nov 19 '18 at 14:09
cadenzah
asked Nov 19 '18 at 14:00
cadenzahcadenzah
597
asked Nov 19 '18 at 14:00
cadenzahcadenzah
597
asked Nov 19 '18 at 14:00
cadenzahcadenzah
597
597
1
Read the documentation of cv::Size. Doing so, you should notice that the first parameter of the constructor is width, but you're setting it to number of rows (i.e. height). | As with so many other questions here... documentation is your friend. Get familiar with it, and use it.
– Dan Mašek
Nov 19 '18 at 14:27
Also, it seems like all you're trying to do here is to swap channels 0 and 2. This is basically equivalent to a conversion between BGR and RGB. Hence, a simplecv::cvtColor(after, before, cv::COLOR_BGR2RGB)will do the same job as your two nested loops, and most likely much faster too.
– Dan Mašek
Nov 19 '18 at 14:31
You are right. the code switched them each other. Maybe it was not wrong because in many tutorials they were identical values (square matrix).
– cadenzah
Nov 19 '18 at 14:31
add a comment |
1
Read the documentation of cv::Size. Doing so, you should notice that the first parameter of the constructor is width, but you're setting it to number of rows (i.e. height). | As with so many other questions here... documentation is your friend. Get familiar with it, and use it.
– Dan Mašek
Nov 19 '18 at 14:27
Also, it seems like all you're trying to do here is to swap channels 0 and 2. This is basically equivalent to a conversion between BGR and RGB. Hence, a simplecv::cvtColor(after, before, cv::COLOR_BGR2RGB)will do the same job as your two nested loops, and most likely much faster too.
– Dan Mašek
Nov 19 '18 at 14:31
You are right. the code switched them each other. Maybe it was not wrong because in many tutorials they were identical values (square matrix).
– cadenzah
Nov 19 '18 at 14:31
1
1
Read the documentation of cv::Size. Doing so, you should notice that the first parameter of the constructor is width, but you're setting it to number of rows (i.e. height). | As with so many other questions here... documentation is your friend. Get familiar with it, and use it.
– Dan Mašek
Nov 19 '18 at 14:27
Read the documentation of cv::Size. Doing so, you should notice that the first parameter of the constructor is width, but you're setting it to number of rows (i.e. height). | As with so many other questions here... documentation is your friend. Get familiar with it, and use it.
– Dan Mašek
Nov 19 '18 at 14:27
Also, it seems like all you're trying to do here is to swap channels 0 and 2. This is basically equivalent to a conversion between BGR and RGB. Hence, a simple
cv::cvtColor(after, before, cv::COLOR_BGR2RGB) will do the same job as your two nested loops, and most likely much faster too.– Dan Mašek
Nov 19 '18 at 14:31
Also, it seems like all you're trying to do here is to swap channels 0 and 2. This is basically equivalent to a conversion between BGR and RGB. Hence, a simple
cv::cvtColor(after, before, cv::COLOR_BGR2RGB) will do the same job as your two nested loops, and most likely much faster too.– Dan Mašek
Nov 19 '18 at 14:31
You are right. the code switched them each other. Maybe it was not wrong because in many tutorials they were identical values (square matrix).
– cadenzah
Nov 19 '18 at 14:31
You are right. the code switched them each other. Maybe it was not wrong because in many tutorials they were identical values (square matrix).
– cadenzah
Nov 19 '18 at 14:31
add a comment |
1 Answer
1
active
oldest
votes
This exception occurred because I set the width and height inside the Size() in wrong order.
Right order is cv::Size(width(cols)_of_image, height(rows)_of_image)
It was not a problem for many tutorials as they usually used image of square size.
answered Nov 19 '18 at 14:34
cadenzahcadenzah
597
add a comment |
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This exception occurred because I set the width and height inside the Size() in wrong order.
Right order is cv::Size(width(cols)_of_image, height(rows)_of_image)
It was not a problem for many tutorials as they usually used image of square size.
answered Nov 19 '18 at 14:34
cadenzahcadenzah
597
add a comment |
This exception occurred because I set the width and height inside the Size() in wrong order.
Right order is cv::Size(width(cols)_of_image, height(rows)_of_image)
It was not a problem for many tutorials as they usually used image of square size.
answered Nov 19 '18 at 14:34
cadenzahcadenzah
597
add a comment |
This exception occurred because I set the width and height inside the Size() in wrong order.
Right order is cv::Size(width(cols)_of_image, height(rows)_of_image)
It was not a problem for many tutorials as they usually used image of square size.
answered Nov 19 '18 at 14:34
cadenzahcadenzah
597
This exception occurred because I set the width and height inside the Size() in wrong order.
Right order is cv::Size(width(cols)_of_image, height(rows)_of_image)
It was not a problem for many tutorials as they usually used image of square size.
answered Nov 19 '18 at 14:34
cadenzahcadenzah
597
answered Nov 19 '18 at 14:34
cadenzahcadenzah
597
answered Nov 19 '18 at 14:34
cadenzahcadenzah
597
answered Nov 19 '18 at 14:34
cadenzahcadenzah
597
597
add a comment |
add a comment |
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Read the documentation of cv::Size. Doing so, you should notice that the first parameter of the constructor is width, but you're setting it to number of rows (i.e. height). | As with so many other questions here... documentation is your friend. Get familiar with it, and use it.
– Dan Mašek
Nov 19 '18 at 14:27
Also, it seems like all you're trying to do here is to swap channels 0 and 2. This is basically equivalent to a conversion between BGR and RGB. Hence, a simple
cv::cvtColor(after, before, cv::COLOR_BGR2RGB)will do the same job as your two nested loops, and most likely much faster too.– Dan Mašek
Nov 19 '18 at 14:31
You are right. the code switched them each other. Maybe it was not wrong because in many tutorials they were identical values (square matrix).
– cadenzah
Nov 19 '18 at 14:31