Efficient way to combine intersecting bounding rectangles

Question

I\'m trying to simplify the following image using OpenCV:

What we have

Answer 1

Given two bounding box contours in the form of (x,y,w,h), here's a function to create a single bounding box (assuming the boxes are touching or within each other). Returns (x,y,w,h) of the combined bounding box i.e, top-left x, top-left y, width, and height. Here's an illustration

(x1,y1)       w1                           (x3,y3)         w3
  ._____________________.                    .____________________________.
  |                     |                    |                            | 
  |                     |  h1                |                            |
  |   (x2,y2)           |                    |                            |
  |     ._______________|_______.      -->   |                            |
  |     |               |       |            |                            |  h3
  ._____|_______________.       |            |                            |
        |                       |  h2        |                            |
        |                       |            |                            |
        |           w2          |            |                            |
        ._______________________.            .____________________________.

Code

def combineBoundingBox(box1, box2):
    x = min(box1[0], box2[0])
    y = min(box1[1], box2[1])
    w = box2[0] + box2[2] - box1[0]
    h = max(box1[1] + box1[3], box2[1] + box2[3]) - y
    return (x, y, w, h)

---

Example

With these two bounding boxes,

>>> print(box1)
>>> print(box2)
(132, 85, 190, 231)
(264, 80, 121, 230)

>>> new = combineBoundingBox(box1, box2) 
>>> print(new)
(132, 80, 253, 236)

Here's the visual result: Before -> After