how to apply bitwise_and on cv::Mat? - c++

Question

I am trying to apply cartoon filter to a UIImage, with the help of OpenCV. My code is as the following
+ (UIImage *)createCartoonizedImageFromImage:(UIImage *)inputImage {
int num_down = 2; //number of downsampling steps
cv::Mat image_rgb = [self cvMatFromUIImage:inputImage];
cv::Mat image_color;
cv::cvtColor(image_rgb, image_color, cv::COLOR_RGBA2RGB);
//downsample image using Gaussian pyramid
for(int i = 0; i < num_down; i++)
{
cv::pyrDown(image_color, image_color);
}
// apply bilateral filter
cv::Mat image_bilateral = image_color.clone();
cv::bilateralFilter(image_color, image_bilateral, 9, 9, 7);
// upsample image to original size
for(int i = 0; i < num_down; i++)
{
cv::pyrUp(image_color, image_color);
}
// convert to grayscale
cv::Mat image_gray;
cv::cvtColor(image_rgb, image_gray, cv::COLOR_RGB2GRAY);
// apply median blur
cv::Mat image_blur;
cv::medianBlur(image_gray, image_blur, 7);
// detect and enhance edges
cv::Mat image_edge;
cv::adaptiveThreshold(image_blur, image_edge, 255, cv::ADAPTIVE_THRESH_MEAN_C, cv::THRESH_BINARY, 9, 2);
// convert back to color, bit-AND with color image
cv::cvtColor(image_edge, image_edge, cv::COLOR_GRAY2RGB);
cv::Mat image_cartoon;
cv::bitwise_and(image_bilateral, image_edge, image_cartoon);
UIImage *cartoonImage = [self UIImageFromCVMat:image_cartoon];
return cartoonImage;
}
on the line
cv::bitwise_and(image_bilateral, image_edge, image_cartoon);
the above code gives me a following error
OpenCV Error: Sizes of input arguments do not match (The operation is neither 'array op array' (where arrays have the same size and type), nor 'array op scalar', nor 'scalar op array') in binary_op, file /Users/kyle/code/opensource/opencv/modules/core/src/arithm.cpp, line 225
libc++abi.dylib: terminating with uncaught exception of type cv::Exception: /Users/kyle/code/opensource/opencv/modules/core/src/arithm.cpp:225: error: (-209) The operation is neither 'array op array' (where arrays have the same size and type), nor 'array op scalar', nor 'scalar op array' in function binary_op
My Question
I know that the problem is with the incorrect sizes of input arrays. but how can i correct them and make them of the same size without effecting the end result ?

Answer 1

As clearly Stated in the OpenCV Error: "Sizes of input arguments do not match". i.e image_bilateral.size != image_edge.size(). A simple debug print will do the trick! So next time try to use your debugger! Here is your modified code!
int num_down = 2; //number of downsampling steps
cv::Mat image_rgb = imread(FileName1,1);
cv::Mat image_color;
cv::cvtColor(image_rgb, image_color, cv::COLOR_RGBA2RGB);
//downsample image using Gaussian pyramid
for(int i = 0; i < num_down; i++)
{
cv::pyrDown(image_color, image_color);
}
// apply bilateral filter
cv::Mat image_bilateral = image_color.clone();
cv::bilateralFilter(image_color, image_bilateral, 9, 9, 7);
// upsample image to original size
for(int i = 0; i < num_down; i++)
{
cv::pyrUp(image_color, image_color);
cv::pyrUp(image_bilateral, image_bilateral);//Bug <-- Here Missing to Resize the bilateralFilter image?
}
// convert to grayscale
cv::Mat image_gray;
//cv::cvtColor(image_rgb, image_gray, cv::COLOR_RGB2GRAY);//Bug <-- Using RGBA instead of RGB
cv::cvtColor(image_color, image_gray, cv::COLOR_RGB2GRAY);
// apply median blur
cv::Mat image_blur;
cv::medianBlur(image_gray, image_blur, 7);
// detect and enhance edges
cv::Mat image_edge;
cv::adaptiveThreshold(image_blur, image_edge, 255, cv::ADAPTIVE_THRESH_MEAN_C, cv::THRESH_BINARY, 9, 2);
// convert back to color, bit-AND with color image
cv::cvtColor(image_edge, image_edge, cv::COLOR_GRAY2RGB);
cv::Mat image_cartoon;
//cv::bitwise_and(image_bilateral, image_edge, image_cartoon);//Bug <-- Here Size of image_bilateral is 1/4 of the image_edge
cv::bitwise_and(image_bilateral, image_edge, image_cartoon);
imshow("Cartoon ",image_cartoon);