Dessin de rectangle sur l'image opencv?

Vous pouvez penser que le processus de rendu dans tout autre rendu API comme l'OpenGL: mettre quelque chose sur l'écran, vous pouvez le nettoyer, puis tirer sur la zone propre.

Dans ce contexte, le nettoyage moyens de ramener l'image d'origine. S'appuyant sur cela signifie l'ajout de votre rectangles ou quoi que ce soit.

Donc, ce que je recommande est la création d'un draw méthode qui ne s'occupe que de cela. Appeler chaque fois qu'un changement pour le rendu de la cible est censé être fait.

Un rapide extrait de code (pas de python véritable, juste pseudo-code):

source_image = Mat()
image = Mat()
rect = Rect()
# general logic and stuff ...
# set a mouseCallbackListener
def listener(evt):
rect.x = evt.x   # uptade de rect properly (...)
draw()
# apply the drawing logic
def draw():
image = source_image.clone()
rectangle(image, rect, Scalar(0,255,0), 1, 8, 0)
imshow(WINDOW_NAME, image)

Si vous souhaitez voir un exemple concret, voici un C++11 code qui vous permettra d'attirer plus d'un triangle, puis obtenir leurs centres de sortie en réponse à une saisie au clavier: https://gist.github.com/cirocosta/9f7a57bddb40c4e5cbca

OriginalL'auteur Ciro Costa

Je suis juste de travailler à le même problème. La solution que j'ai trouvé est basée sur:

http://www.pyimagesearch.com/2015/03/09/capturing-mouse-click-events-with-python-and-opencv/

Tout fonctionne, mais je suis un peu malheureux sur les variables globales.

# initialize the list of points for the rectangle bbox,
# the temporaray endpoint of the drawing rectangle
# the list of all bounding boxes of selected rois
# and boolean indicating wether drawing of mouse
# is performed or not
rect_endpoint_tmp = []
rect_bbox = []
bbox_list_rois = []
drawing = False
def select_rois(img):
"""
Interactive select rectangle ROIs and store list of bboxes.
Parameters
----------
img :
image 3-dim.
Returns
-------
bbox_list_rois : list of list of int
List of bboxes of rectangle rois.
"""
# mouse callback function
def draw_rect_roi(event, x, y, flags, param):
# grab references to the global variables
global rect_bbox, rect_endpoint_tmp, drawing
# if the left mouse button was clicked, record the starting
# (x, y) coordinates and indicate that drawing is being
# performed. set rect_endpoint_tmp empty list.
if event == cv2.EVENT_LBUTTONDOWN:
rect_endpoint_tmp = []
rect_bbox = [(x, y)]
drawing = True
# check to see if the left mouse button was released
elif event == cv2.EVENT_LBUTTONUP:
# record the ending (x, y) coordinates and indicate that
# drawing operation is finished
rect_bbox.append((x, y))
drawing = False
# draw a rectangle around the region of interest
p_1, p_2 = rect_bbox
cv2.rectangle(img, p_1, p_2, color=(0, 255, 0),thickness=1)
cv2.imshow('image', img)
# for bbox find upper left and bottom right points
p_1x, p_1y = p_1
p_2x, p_2y = p_2
lx = min(p_1x, p_2x)
ty = min(p_1y, p_2y)
rx = max(p_1x, p_2x)
by = max(p_1y, p_2y)
# add bbox to list if both points are different
if (lx, ty) != (rx, by):
bbox = [lx, ty, rx, by]
bbox_list_rois.append(bbox)
# if mouse is drawing set tmp rectangle endpoint to (x,y)
elif event == cv2.EVENT_MOUSEMOVE and drawing:
rect_endpoint_tmp = [(x, y)]
# clone image img and setup the mouse callback function
img_copy = img.copy()
cv2.namedWindow('image')
cv2.setMouseCallback('image', draw_rect_roi)
# keep looping until the 'c' key is pressed
while True:
# display the image and wait for a keypress
if not drawing:
cv2.imshow('image', img)
elif drawing and rect_endpoint_tmp:
rect_cpy = img.copy()
start_point = rect_bbox[0]
end_point_tmp = rect_endpoint_tmp[0]
cv2.rectangle(rect_cpy, start_point, end_point_tmp,(0,255,0),1)
cv2.imshow('image', rect_cpy)
key = cv2.waitKey(1) & 0xFF
# if the 'c' key is pressed, break from the loop
if key == ord('c'):
break
# close all open windows
cv2.destroyAllWindows()
return bbox_list_rois

OriginalL'auteur tin man