There are two images, one is original image with value, another let's call it shape image, with irregular shapes. I want to detect the shape, and add different value to the value img, corresponding to the shape img. shapes won't intersect with each other. I've been looking through multiple libs, including open cv2, yet find hard to accomplish this goal. Would anyone be able to help? Thanks.
possible shape image
I wish to add +1/-1 alternatively from outside to inside
To detect shapes, you can use cv2.findContours() and the cv2.RETR_TREE flag. To determine the inner contours, we can use hierarchy to filter for each inner layer. Here's a good tutorial on contour hierarchy. Essentially, we iterate through each layer and alternate marking each contour (-1 or 1). To add the label, you can use cv2.putText(). You may have to change the offset of the label depending on the image that you're using.
Here's the results
import cv2
image = cv2.imread('1.png')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray,120, 255,cv2.THRESH_BINARY_INV)[1]
cnts, h = cv2.findContours(thresh, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
label = '1'
count = 0
# Get inner list of hierarchy
for layer in zip(cnts, h[0]):
contour = layer[0]
hierarchy = layer[1]
# If we find new contour (not inner) reset label
if hierarchy[1] >= 0:
label = '1'
# Ensure that we only have outer contour
if count % 2 == 0:
cv2.drawContours(image, [contour], -1, (36, 255, 12), 2)
x,y,w,h = cv2.boundingRect(contour)
cv2.putText(image, label, (x +50,y+ 70), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (36,255,12), 3)
label = str(int(label) * -1)
count += 1
cv2.imshow('thresh', thresh)
cv2.imshow('image', image)
cv2.waitKey()
