[英]Error while creating cv::Mat from UIImage
我正在嘗試使用OpenCV執行最簡單的任務-將UIImage轉換為灰色cv :: Mat並得到以下錯誤:
CGBitmapContextCreate: invalid data bytes/row: should be at least 12000
for 8 integer bits/component, 3 components, kCGImageAlphaNoneSkipLast.
我正在使用通過CocoaPods連接的OpenCV v 3.2.0,並在網上找到以下示例代碼:
- (cv::Mat)cvMatGrayFromUIImage:(UIImage *)image
{
CGColorSpaceRef colorSpace = CGImageGetColorSpace(image.CGImage);
CGFloat cols = image.size.width;
CGFloat rows = image.size.height;
cv::Mat cvMat(rows, cols, CV_8UC1); // 8 bits per component, 1 channels
CGContextRef contextRef = CGBitmapContextCreate(cvMat.data, // Pointer to data
cols, // Width of bitmap
rows, // Height of bitmap
8, // Bits per component
cvMat.step[0], // Bytes per row
colorSpace, // Colorspace
kCGImageAlphaNoneSkipLast |
kCGBitmapByteOrderDefault); // Bitmap info flags
CGContextDrawImage(contextRef, CGRectMake(0, 0, cols, rows), image.CGImage);
CGContextRelease(contextRef);
return cvMat;
}
嘗試使用以下代碼
+ (cv::Mat)cvMatGrayFromUIImage:(UIImage *)image
{
cv::Mat cvMat = [self cvMatFromUIImage:image];
cv::Mat grayMat;
if ( cvMat.channels() == 1 ) {
grayMat = cvMat;
}
else {
grayMat = cv :: Mat( cvMat.rows,cvMat.cols, CV_8UC1 );
cv::cvtColor( cvMat, grayMat, cv::COLOR_BGR2GRAY );
}
return grayMat;
}
+ (cv::Mat)cvMatFromUIImage:(UIImage *)image
{
CGColorSpaceRef colorSpace = CGImageGetColorSpace(image.CGImage);
CGFloat cols,rows;
if (image.imageOrientation == UIImageOrientationLeft
|| image.imageOrientation == UIImageOrientationRight) {
cols = image.size.height;
rows = image.size.width;
}
else{
cols = image.size.width;
rows = image.size.height;
}
cv::Mat cvMat(rows, cols, CV_8UC4); // 8 bits per component, 4 channels
CGContextRef contextRef = CGBitmapContextCreate(cvMat.data, // Pointer to backing data
cols, // Width of bitmap
rows, // Height of bitmap
8, // Bits per component
cvMat.step[0], // Bytes per row
colorSpace, // Colorspace
kCGImageAlphaNoneSkipLast |
kCGBitmapByteOrderDefault);
CGContextDrawImage(contextRef, CGRectMake(0, 0, cols, rows), image.CGImage);
CGContextRelease(contextRef);
cv::Mat cvMatTest;
cv::transpose(cvMat, cvMatTest);
if (image.imageOrientation == UIImageOrientationLeft
|| image.imageOrientation == UIImageOrientationRight) {
}
else{
return cvMat;
}
cvMat.release();
cv::flip(cvMatTest, cvMatTest, 1);
return cvMatTest;
}
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