So I got this image with a busy background and I want to remove the device inside it:
I wrote a basic Canny script to get a highlight of the device:
import cv2
# Read the original image
img = cv2.imread('antigen.png')
# Convert to graycsale
img_gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
# Blur the image for better edge detection
img_blur = cv2.GaussianBlur(img_gray, (3,3), 0)
# Canny Edge Detection
edges = cv2.Canny(image=img_blur, threshold1=100, threshold2=200) # Canny Edge Detection
# Display Canny Edge Detection Image
cv2.imshow('Canny Edge Detection', edges)
cv2.waitKey(0)
cv2.destroyAllWindows()
How can I use the outline from the canny image to basically cut out the device from the original pic from its background?
CodePudding user response:
You can use cv2.matchTemplate to perform template matching by finding the best matched ROI.
import cv2
import numpy as np
# Resizes a image and maintains aspect ratio
def maintain_aspect_ratio_resize(image, width=None, height=None, inter=cv2.INTER_AREA):
# Grab the image size and initialize dimensions
dim = None
(h, w) = image.shape[:2]
# Return original image if no need to resize
if width is None and height is None:
return image
# We are resizing height if width is none
if width is None:
# Calculate the ratio of the height and construct the dimensions
r = height / float(h)
dim = (int(w * r), height)
# We are resizing width if height is none
else:
# Calculate the ratio of the 0idth and construct the dimensions
r = width / float(w)
dim = (width, int(h * r))
# Return the resized image
return cv2.resize(image, dim, interpolation=inter)
# Load template, convert to grayscale, perform canny edge detection
template = cv2.imread('template.jpg')
template = cv2.cvtColor(template, cv2.COLOR_BGR2GRAY)
template = cv2.Canny(template, 50, 200)
(tH, tW) = template.shape[:2]
cv2.imshow("template", template)
# Load original image, convert to grayscale
original_image = cv2.imread('1AWH8.jpg')
(img_height, img_width)=original_image.shape[:2]
final = original_image.copy()
gray = cv2.cvtColor(original_image, cv2.COLOR_BGR2GRAY)
found = None
# Dynamically rescale image for better template matching
for scale in np.linspace(0.2, 1.0, 20)[::-1]:
# Resize image to scale and keep track of ratio
resized = maintain_aspect_ratio_resize(gray, width=int(gray.shape[1] * scale))
r = gray.shape[1] / float(resized.shape[1])
# Stop if template image size is larger than resized image
if resized.shape[0] < tH or resized.shape[1] < tW:
break
# Detect edges in resized image and apply template matching
canny = cv2.Canny(resized, 50, 200)
detected = cv2.matchTemplate(canny, template, cv2.TM_CCOEFF)
(_, max_val, _, max_loc) = cv2.minMaxLoc(detected)
# Higher correlation means better match
if found is None or max_val > found[0]:
found = (max_val, max_loc, r)
# Compute coordinates of bounding box
(_, max_loc, r) = found
(start_x, start_y) = (int(max_loc[0] * r), int(max_loc[1] * r))
(end_x, end_y) = (int((max_loc[0] tW) * r), int((max_loc[1] tH) * r))
# Draw bounding box on ROI to remove
cv2.rectangle(original_image, (start_x, start_y), (end_x, end_y), (0,255,0), 2)
cv2.imshow('detected', original_image)
# Erase unwanted ROI (Fill ROI with white)
cv2.rectangle(final, (start_x, start_y), (end_x, end_y), (255,255,255), -1)
cv2.imwrite('final.jpg', final)
cv2.waitKey(0)