Drawing a rectangle around all contours in OpenCV Python
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1
i have a code which identifies contours after applying filters on video frames. Now in my case i get 3 contours and i show them by drawing rectangles around them, what i want to do is drawing a rectangle around all these 3 contour rectangles. like it will be a larger rectangle, containing 3 detected rectangles.
Here's my simple code of detecting and drawing rectangles around contours.
im2, contours, hierarchy = cv2.findContours(canny_img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy =
# computes the bounding box for the contour, and draws it on the frame,
for contour, hier in zip(contours, hierarchy):
(x,y,w,h) = cv2.boundingRect(contour)
if w > 80 and h > 80:
cv2.rectangle(frame, (x,y), (x+w,y+h), (255, 0, 0), 2)
cv2.imshow('Motion Detector',frame)
python python-2.7 opencv
edited Oct 23 '16 at 14:43
sisanared
2,22811633
asked Oct 23 '16 at 14:20
Moeed KundiMoeed Kundi
18117
add a comment |
1
i have a code which identifies contours after applying filters on video frames. Now in my case i get 3 contours and i show them by drawing rectangles around them, what i want to do is drawing a rectangle around all these 3 contour rectangles. like it will be a larger rectangle, containing 3 detected rectangles.
Here's my simple code of detecting and drawing rectangles around contours.
im2, contours, hierarchy = cv2.findContours(canny_img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy =
# computes the bounding box for the contour, and draws it on the frame,
for contour, hier in zip(contours, hierarchy):
(x,y,w,h) = cv2.boundingRect(contour)
if w > 80 and h > 80:
cv2.rectangle(frame, (x,y), (x+w,y+h), (255, 0, 0), 2)
cv2.imshow('Motion Detector',frame)
python python-2.7 opencv
edited Oct 23 '16 at 14:43
sisanared
2,22811633
asked Oct 23 '16 at 14:20
Moeed KundiMoeed Kundi
18117
What have you tried? Take a piece of paper and draw it yourself and then think about the algorithm you used.
– Dan Mašek
Oct 23 '16 at 14:32
Did you try to create one point set from all contours and calculate theboundingRecton that set? Maybe this works.
– PSchn
Oct 23 '16 at 19:21
add a comment |
1
1
1
3
i have a code which identifies contours after applying filters on video frames. Now in my case i get 3 contours and i show them by drawing rectangles around them, what i want to do is drawing a rectangle around all these 3 contour rectangles. like it will be a larger rectangle, containing 3 detected rectangles.
Here's my simple code of detecting and drawing rectangles around contours.
im2, contours, hierarchy = cv2.findContours(canny_img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy =
# computes the bounding box for the contour, and draws it on the frame,
for contour, hier in zip(contours, hierarchy):
(x,y,w,h) = cv2.boundingRect(contour)
if w > 80 and h > 80:
cv2.rectangle(frame, (x,y), (x+w,y+h), (255, 0, 0), 2)
cv2.imshow('Motion Detector',frame)
python python-2.7 opencv
edited Oct 23 '16 at 14:43
sisanared
2,22811633
asked Oct 23 '16 at 14:20
Moeed KundiMoeed Kundi
18117
i have a code which identifies contours after applying filters on video frames. Now in my case i get 3 contours and i show them by drawing rectangles around them, what i want to do is drawing a rectangle around all these 3 contour rectangles. like it will be a larger rectangle, containing 3 detected rectangles.
Here's my simple code of detecting and drawing rectangles around contours.
im2, contours, hierarchy = cv2.findContours(canny_img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy =
# computes the bounding box for the contour, and draws it on the frame,
for contour, hier in zip(contours, hierarchy):
(x,y,w,h) = cv2.boundingRect(contour)
if w > 80 and h > 80:
cv2.rectangle(frame, (x,y), (x+w,y+h), (255, 0, 0), 2)
cv2.imshow('Motion Detector',frame)
python python-2.7 opencv
python python-2.7 opencv
edited Oct 23 '16 at 14:43
sisanared
2,22811633
asked Oct 23 '16 at 14:20
Moeed KundiMoeed Kundi
18117
edited Oct 23 '16 at 14:43
sisanared
2,22811633
asked Oct 23 '16 at 14:20
Moeed KundiMoeed Kundi
18117
edited Oct 23 '16 at 14:43
sisanared
2,22811633
edited Oct 23 '16 at 14:43
sisanared
2,22811633
edited Oct 23 '16 at 14:43
sisanared
2,22811633
2,22811633
asked Oct 23 '16 at 14:20
Moeed KundiMoeed Kundi
18117
asked Oct 23 '16 at 14:20
Moeed KundiMoeed Kundi
18117
asked Oct 23 '16 at 14:20
Moeed KundiMoeed Kundi
18117
18117
What have you tried? Take a piece of paper and draw it yourself and then think about the algorithm you used.
– Dan Mašek
Oct 23 '16 at 14:32
Did you try to create one point set from all contours and calculate theboundingRecton that set? Maybe this works.
– PSchn
Oct 23 '16 at 19:21
add a comment |
What have you tried? Take a piece of paper and draw it yourself and then think about the algorithm you used.
– Dan Mašek
Oct 23 '16 at 14:32
Did you try to create one point set from all contours and calculate theboundingRecton that set? Maybe this works.
– PSchn
Oct 23 '16 at 19:21
What have you tried? Take a piece of paper and draw it yourself and then think about the algorithm you used.
– Dan Mašek
Oct 23 '16 at 14:32
What have you tried? Take a piece of paper and draw it yourself and then think about the algorithm you used.
– Dan Mašek
Oct 23 '16 at 14:32
Did you try to create one point set from all contours and calculate the
boundingRect on that set? Maybe this works.– PSchn
Oct 23 '16 at 19:21
Did you try to create one point set from all contours and calculate the
boundingRect on that set? Maybe this works.– PSchn
Oct 23 '16 at 19:21
add a comment |
2 Answers
2
active
oldest
votes
7
Maybe try something like this:
im2, contours, hierarchy = cv2.findContours(canny_img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy =
height, width, _ = canny_img.shape
min_x, min_y = width, height
max_x = max_y = 0
# computes the bounding box for the contour, and draws it on the frame,
for contour, hier in zip(contours, hierarchy):
(x,y,w,h) = cv2.boundingRect(contour)
min_x, max_x = min(x, min_x), max(x+w, max_x)
min_y, max_y = min(y, min_y), max(y+h, max_y)
if w > 80 and h > 80:
cv2.rectangle(frame, (x,y), (x+w,y+h), (255, 0, 0), 2)
if max_x - min_x > 0 and max_y - min_y > 0:
cv2.rectangle(frame, (min_x, min_y), (max_x, max_y), (255, 0, 0), 2)
Essentially you want to keep track of what the smallest x and y coordinates are and what the largest x and y coordinates (including the width and height) are, and then just draw a rectangle with those coordinates.
answered Oct 23 '16 at 14:55
pzppzp
4,9641832
add a comment |
0
Using numpy:
boxes =
for c in cnts:
(x, y, w, h) = cv2.boundingRect(c)
boxes.append([x,y, x+w,y+h])
boxes = np.asarray(boxes)
# need an extra "min/max" for contours outside the frame
left = np.min(boxes[:,0])
top = np.min(boxes[:,1])
right = np.max(boxes[:,2])
bottom = np.max(boxes[:,3])
cv2.rectangle(frame, (left,top), (right,bottom), (255, 0, 0), 2)
answered Nov 24 '18 at 15:50
lorenzolorenzo
14418
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
7
Maybe try something like this:
im2, contours, hierarchy = cv2.findContours(canny_img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy =
height, width, _ = canny_img.shape
min_x, min_y = width, height
max_x = max_y = 0
# computes the bounding box for the contour, and draws it on the frame,
for contour, hier in zip(contours, hierarchy):
(x,y,w,h) = cv2.boundingRect(contour)
min_x, max_x = min(x, min_x), max(x+w, max_x)
min_y, max_y = min(y, min_y), max(y+h, max_y)
if w > 80 and h > 80:
cv2.rectangle(frame, (x,y), (x+w,y+h), (255, 0, 0), 2)
if max_x - min_x > 0 and max_y - min_y > 0:
cv2.rectangle(frame, (min_x, min_y), (max_x, max_y), (255, 0, 0), 2)
Essentially you want to keep track of what the smallest x and y coordinates are and what the largest x and y coordinates (including the width and height) are, and then just draw a rectangle with those coordinates.
answered Oct 23 '16 at 14:55
pzppzp
4,9641832
add a comment |
7
Maybe try something like this:
im2, contours, hierarchy = cv2.findContours(canny_img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy =
height, width, _ = canny_img.shape
min_x, min_y = width, height
max_x = max_y = 0
# computes the bounding box for the contour, and draws it on the frame,
for contour, hier in zip(contours, hierarchy):
(x,y,w,h) = cv2.boundingRect(contour)
min_x, max_x = min(x, min_x), max(x+w, max_x)
min_y, max_y = min(y, min_y), max(y+h, max_y)
if w > 80 and h > 80:
cv2.rectangle(frame, (x,y), (x+w,y+h), (255, 0, 0), 2)
if max_x - min_x > 0 and max_y - min_y > 0:
cv2.rectangle(frame, (min_x, min_y), (max_x, max_y), (255, 0, 0), 2)
Essentially you want to keep track of what the smallest x and y coordinates are and what the largest x and y coordinates (including the width and height) are, and then just draw a rectangle with those coordinates.
answered Oct 23 '16 at 14:55
pzppzp
4,9641832
add a comment |
7
7
7
Maybe try something like this:
im2, contours, hierarchy = cv2.findContours(canny_img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy =
height, width, _ = canny_img.shape
min_x, min_y = width, height
max_x = max_y = 0
# computes the bounding box for the contour, and draws it on the frame,
for contour, hier in zip(contours, hierarchy):
(x,y,w,h) = cv2.boundingRect(contour)
min_x, max_x = min(x, min_x), max(x+w, max_x)
min_y, max_y = min(y, min_y), max(y+h, max_y)
if w > 80 and h > 80:
cv2.rectangle(frame, (x,y), (x+w,y+h), (255, 0, 0), 2)
if max_x - min_x > 0 and max_y - min_y > 0:
cv2.rectangle(frame, (min_x, min_y), (max_x, max_y), (255, 0, 0), 2)
Essentially you want to keep track of what the smallest x and y coordinates are and what the largest x and y coordinates (including the width and height) are, and then just draw a rectangle with those coordinates.
answered Oct 23 '16 at 14:55
pzppzp
4,9641832
Maybe try something like this:
im2, contours, hierarchy = cv2.findContours(canny_img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy =
height, width, _ = canny_img.shape
min_x, min_y = width, height
max_x = max_y = 0
# computes the bounding box for the contour, and draws it on the frame,
for contour, hier in zip(contours, hierarchy):
(x,y,w,h) = cv2.boundingRect(contour)
min_x, max_x = min(x, min_x), max(x+w, max_x)
min_y, max_y = min(y, min_y), max(y+h, max_y)
if w > 80 and h > 80:
cv2.rectangle(frame, (x,y), (x+w,y+h), (255, 0, 0), 2)
if max_x - min_x > 0 and max_y - min_y > 0:
cv2.rectangle(frame, (min_x, min_y), (max_x, max_y), (255, 0, 0), 2)
Essentially you want to keep track of what the smallest x and y coordinates are and what the largest x and y coordinates (including the width and height) are, and then just draw a rectangle with those coordinates.
answered Oct 23 '16 at 14:55
pzppzp
4,9641832
answered Oct 23 '16 at 14:55
pzppzp
4,9641832
answered Oct 23 '16 at 14:55
pzppzp
4,9641832
answered Oct 23 '16 at 14:55
pzppzp
4,9641832
4,9641832
add a comment |
add a comment |
0
Using numpy:
boxes =
for c in cnts:
(x, y, w, h) = cv2.boundingRect(c)
boxes.append([x,y, x+w,y+h])
boxes = np.asarray(boxes)
# need an extra "min/max" for contours outside the frame
left = np.min(boxes[:,0])
top = np.min(boxes[:,1])
right = np.max(boxes[:,2])
bottom = np.max(boxes[:,3])
cv2.rectangle(frame, (left,top), (right,bottom), (255, 0, 0), 2)
answered Nov 24 '18 at 15:50
lorenzolorenzo
14418
add a comment |
0
Using numpy:
boxes =
for c in cnts:
(x, y, w, h) = cv2.boundingRect(c)
boxes.append([x,y, x+w,y+h])
boxes = np.asarray(boxes)
# need an extra "min/max" for contours outside the frame
left = np.min(boxes[:,0])
top = np.min(boxes[:,1])
right = np.max(boxes[:,2])
bottom = np.max(boxes[:,3])
cv2.rectangle(frame, (left,top), (right,bottom), (255, 0, 0), 2)
answered Nov 24 '18 at 15:50
lorenzolorenzo
14418
add a comment |
0
0
0
Using numpy:
boxes =
for c in cnts:
(x, y, w, h) = cv2.boundingRect(c)
boxes.append([x,y, x+w,y+h])
boxes = np.asarray(boxes)
# need an extra "min/max" for contours outside the frame
left = np.min(boxes[:,0])
top = np.min(boxes[:,1])
right = np.max(boxes[:,2])
bottom = np.max(boxes[:,3])
cv2.rectangle(frame, (left,top), (right,bottom), (255, 0, 0), 2)
answered Nov 24 '18 at 15:50
lorenzolorenzo
14418
Using numpy:
boxes =
for c in cnts:
(x, y, w, h) = cv2.boundingRect(c)
boxes.append([x,y, x+w,y+h])
boxes = np.asarray(boxes)
# need an extra "min/max" for contours outside the frame
left = np.min(boxes[:,0])
top = np.min(boxes[:,1])
right = np.max(boxes[:,2])
bottom = np.max(boxes[:,3])
cv2.rectangle(frame, (left,top), (right,bottom), (255, 0, 0), 2)
answered Nov 24 '18 at 15:50
lorenzolorenzo
14418
edited Nov 24 '18 at 16:14
answered Nov 24 '18 at 15:50
lorenzolorenzo
14418
answered Nov 24 '18 at 15:50
lorenzolorenzo
14418
answered Nov 24 '18 at 15:50
lorenzolorenzo
14418
14418
add a comment |
add a comment |
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What have you tried? Take a piece of paper and draw it yourself and then think about the algorithm you used.
– Dan Mašek
Oct 23 '16 at 14:32
Did you try to create one point set from all contours and calculate the
boundingRecton that set? Maybe this works.– PSchn
Oct 23 '16 at 19:21