I use Python, but the main idea is the same. If you directly do cvtColor: bgr -> gray for img2, then you must fail. Because the gray becames difficulty to distinguish the regions: Related answers: How to detect colored patches in an image using OpenCV? Edge detection on colored background using OpenCV OpenCV C++/Obj-C: Detecting … Read more
Since there aren’t that many good examples how to create new blank image filled with a color using cv2, here’s one: Create OpenCV image of certain (R, G, B) color: import cv2 import numpy as np def create_blank(width, height, rgb_color=(0, 0, 0)): “””Create new image(numpy array) filled with certain color in RGB””” # Create black … Read more
On iOS 5 you can use CoreImage (CIDetector, CIFeature, CIFaceFeature should be named as the relevant keywords) for that task. Check out the SquareCam example App from Apple, it includes face detection. If you’re targeting older iOS versions, openCV seems to be a good approach. http://developer.apple.com/library/ios/#samplecode/SquareCam/Introduction/Intro.html Edit_: Argh, soory. CoreImage can only detect faces but … Read more
OK, I figured it out but it works for Release and Win32 configuration only (No debug or x64). There are many linking errors under Debug configuration. So, 1. First of all, download prepared library folder(Tesseract + Leptonica) here: Mirror 1(Google Drive) Mirror 2(MediaFire) 2. Extract tesseract.zip to C:\ 3. In Visual Studio, go under C/C++ … Read more
Change this line cvtColor( image, gray_image, CV_RGB2GRAY ); to std::vector<cv::Mat> channels; cv::Mat hsv; cv::cvtColor( image, hsv, CV_RGB2HSV ); cv::split(hsv, channels); gray_image = channels[0]; The problem seems to be that your hand in gray scale is very close to the gray background. I have applied Canny on the hue (color) because the skin color should be … Read more
(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
Looks like we can call the camera using a proper GStreamer pipeline like below: VideoCapture cap(“mfw_v4lsrc ! ffmpegcolorspace ! video/x-raw-rgb ! appsink”) as the camera output is in YUV, we need to convert that to RGB to pass the frames to OpenCV. This is where OpenCV makes sure it gets RGB colorspace.
The function fitEllipse returns a RotatedRect that contains all the parameters of the ellipse. An ellipse is defined by 5 parameters: xc : x coordinate of the center yc : y coordinate of the center a : major semi-axis b : minor semi-axis theta : rotation angle You can obtain these parameters like: RotatedRect e … 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
After canny 1- you need to reduce noises with gaussian blur and find all the contours 2- find and list all the contours’ areas. 3- the largest contour will be nothing but the painting. 4- now use perpective transformation to transform your shape to a rectangle. check sudoku solver examples to see the similar processing … Read more