How to find rectangle shape in this image using python?

Question

enter image description here can you help me to segment rectangular objects in this image, tried otsu but it is not working because background and forground have same values.

is there any other method to do the same.

Can somebody please tell me how to find a rectangle object in these images? Images are results of canny edge detection. Actually I want to track these rectangles in a video, if you know how to do it please tell me. OR at least I want to find whether a rectangle is present or not. enter image description here

Answer 1

You can look at rows and columns of pixels. For example, the top border row of your rectangle contains many more black pixels than the row above. So I would suggest you to use vertical (through rows) and horizontal (through columns) passes to find the borders. Here's my script to do it:

from PIL import Image

FACTOR = 1.5 # a threashold

img = Image.open("path/to/your/image")
pix = img.load()
size = img.size

# vertical pass
sum_color_arr = []
for row_num in xrange(size[1]):
    sum_color = 0 # calculating of brightness for each row separately
    for i in xrange(size[0]):
        sum_color += pix[i, row_num]
    sum_color_arr.append(sum_color)

for row_num in xrange(size[1] - 1):
    if sum_color_arr[row_num] > FACTOR * sum_color_arr[row_num + 1]:
        print "Top border: y =", (row_num + 1)
    if sum_color_arr[row_num + 1] > FACTOR * sum_color_arr[row_num]:
        print "Bottom border: y =", row_num

# horizontal pass
sum_color_arr = []
for col_num in xrange(size[0]):
    sum_color = 0 # calculating of brightness for each column separately
    for i in xrange(size[1]):
        sum_color += pix[col_num, i]
    sum_color_arr.append(sum_color)

for col_num in xrange(size[0] - 1):
    if sum_color_arr[col_num] > FACTOR * sum_color_arr[col_num + 1]:
        print "Left border: x =", (col_num + 1)
    if sum_color_arr[col_num + 1] > FACTOR * sum_color_arr[col_num]:
        print "Right border: x =", col_num