(1) Use cv2.copyMakeBorder to enlarge the image, to avoid the warpped points going out of range of the original image size. cv2.copyMakeBorder(…) copyMakeBorder(src, top, bottom, left, right, borderType[, dst[, value]]) -> dst . @brief Forms a border around an image. . . The function copies the source image into the middle of the destination image. … Read more
I guess it depends on what you mean by “mono-chrome”https://stackoverflow.com/”black & white”… public class TestBlackAndWhite { public static void main(String[] args) { new TestBlackAndWhite(); } public TestBlackAndWhite() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (Exception ex) { } JFrame frame = new JFrame(“Test”); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.add(new TestPane()); frame.pack(); frame.setLocationRelativeTo(null); … Read more
I took a quick look and fixed a few other problems along the way. Essentially my changes do this: Draw the bounding box on a temporary image, set its alpha transparency, and then blit this over top of the main image. Avoid extraneous drawing cycles (when the mouse isn’t moving, no sense in drawing the … Read more
When use cv2.imshow, you should know: imshow(winname, mat) -> None . The function may scale the image, depending on its depth: . – If the image is 8-bit unsigned, it is displayed as is. . – If the image is 16-bit unsigned or 32-bit integer, the pixels are divided by 256. That is, the value … Read more
This is how I am getting a color from an image at a touch location. I translated this answer: https://stackoverflow.com/a/12579413/359578 (This sample does no error checking for nil) func createARGBBitmapContext(inImage: CGImage) -> CGContext { var bitmapByteCount = 0 var bitmapBytesPerRow = 0 //Get image width, height let pixelsWide = CGImageGetWidth(inImage) let pixelsHigh = CGImageGetHeight(inImage) // … Read more
Take a look at this bounding box technique demonstrated with OpenCV code: Input: Eroded: Result:
I will propose an answer that works fast and perfectly if you are looking for exact match both in size and in image values. The idea is to calculate a brute force search of the wanted h x w template in a larger H x W image. The bruteforce approach would consist in looking at … Read more
Take for reference my original code, which simply detects squares on an image. That means that in the main method of the application you would write something like the following pseudo-code to call find_squares(): Mat image = imread(“test.jpg”, 1); // Detect all regions in the image that are similar to a rectangle vector<vector<Point> > squares; … Read more
As you already got, you don’t need ellipse fitting, but ellipse detection. You can find in my other answer two papers with C++ code available. I’ll report here for completeness: L. Libuda, I. Grothues, K.-F. Kraiss, Ellipse detection in digital image data using geometric features, in: J. Braz, A. Ranchordas, H. Arajo, J. Jorge (Eds.), … Read more
$image1 = imagecreatefrompng(‘a.png’); //300 x 300 $image2 = imagecreatefrompng(‘b.png’); //150 x 150 imagecopymerge($image1, $image2, 0, 0, 75, 75, 150, 150, 50); this should be all you need. $image1 should hold the merged image where image2 has been overlayed with 50% opacity. the last argument is the alpha of the merged copy. http://php.net/manual/en/function.imagecopymerge.php