Hello, i'm new with OpenCV and i want to deskew an image that have a skew text:
First i read the image in GrayScale and Binarize it, then i try to do [this](http://opencvpython.blogspot.com.ar/2012/06/contours-2-brotherhood.html): import cv2 import numpy as np img = cv2.imread('m20.jpg',0) ret,byw = cv2.threshold(img,127,255,cv2.THRESH_BINARY_INV) _, contours, hierarchy = cv2.findContours(byw.copy(), cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE) cnt = contours[0] draw = cv2.cvtColor(byw, cv2.COLOR_GRAY2BGR) rect = cv2.minAreaRect(cnt) box = cv2.boxPoints(rect) box = np.int0(box) cv2.drawContours(draw, [box], 0, (0, 255, 0), 2) But doesn't work beacause findContours() expect to receive an image with a body shape. Other way that i try is to translate this code of c++: // Read image Mat3b img = imread("path_to_image"); // Binarize image. Text is white, background is black Mat1b bin; cvtColor(img, bin, COLOR_BGR2GRAY); bin = bin < 200; // Find all white pixels vector pts;
findNonZero(bin, pts);
// Get rotated rect of white pixels
RotatedRect box = minAreaRect(pts);
if (box.size.width > box.size.height)
{
swap(box.size.width, box.size.height);
box.angle += 90.f;
}
Point2f vertices[4];
box.points(vertices);
for (int i = 0; i < 4; ++i)
{
line(img, vertices[i], vertices[(i + 1) % 4], Scalar(0, 255, 0));
}
// Rotate the image according to the found angle
Mat1b rotated;
Mat M = getRotationMatrix2D(box.center, box.angle, 1.0);
warpAffine(bin, rotated, M, bin.size());
And i have this:
draw = cv2.cvtColor(byw, cv2.COLOR_GRAY2BGR)
data = np.array(byw)
subzero = np.nonzero(data)
subuno = np.reshape(subzero,(17345,2)) # this is because cv2.minAreaRect() receives a Nx2 numpy
rect = cv2.minAreaRect(subuno)
box = cv2.boxPoints(rect)
box = np.int0(box)
cv2.drawContours(draw,[box],0,(0,255,0),2)
But then again the result it's not the expected:
Also occurs to me that might try to make the 'for' like in C++ but i don't know how to obtain the vertices from the 'box = cv2.boxPoints(rect)'. Please help!
First i read the image in GrayScale and Binarize it, then i try to do [this](http://opencvpython.blogspot.com.ar/2012/06/contours-2-brotherhood.html): import cv2 import numpy as np img = cv2.imread('m20.jpg',0) ret,byw = cv2.threshold(img,127,255,cv2.THRESH_BINARY_INV) _, contours, hierarchy = cv2.findContours(byw.copy(), cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE) cnt = contours[0] draw = cv2.cvtColor(byw, cv2.COLOR_GRAY2BGR) rect = cv2.minAreaRect(cnt) box = cv2.boxPoints(rect) box = np.int0(box) cv2.drawContours(draw, [box], 0, (0, 255, 0), 2) But doesn't work beacause findContours() expect to receive an image with a body shape. Other way that i try is to translate this code of c++: // Read image Mat3b img = imread("path_to_image"); // Binarize image. Text is white, background is black Mat1b bin; cvtColor(img, bin, COLOR_BGR2GRAY); bin = bin < 200; // Find all white pixels vector
Also occurs to me that might try to make the 'for' like in C++ but i don't know how to obtain the vertices from the 'box = cv2.boxPoints(rect)'. Please help!