# remove-background Often we need to remove monotonous background from the image. However often color of pixels is not exactly uniform due to the compression artifacts. It is expecially critical arund the object. Thus the simple fill won't work. This script takes the color of the top left pixel as a reference one and performs a fill with the whi…

remove_background.py

from scipy import misc
import glob
import numpy as np

import sys
#print len(sys.argv)
if len(sys.argv)<3:
	print "not enough arguments"
	print "try python remove_background.py infile outfile [threshold = 10]"
else:
	f_in = sys.argv[1]
	f_out = sys.argv[2]+'.bmp'

#for image_path in glob.glob("woman1.png"):
image = misc.imread(f_in)
#print image.shape
#print image.dtype

# define the threshold
# we paint all the pixels which color is within the threshold from the
# top left pixel
if len(sys.argv)==4:
	err = int(sys.argv[3])
else:
	err = 10

# get the color of top left pixel
first_pixel = [image[0,0,0], image[0,0,1], image[0,0,2]]
fpr = image[0,0,0]
fpg = image[0,0,1]
fpb = image[0,0,2]

#print [fpr, fpg, fpb]

wx = image.shape[1]
wy = image.shape[0]

image_out = image

visited = np.zeros([wy, wx], dtype=bool)

for i in range(wx):
	visited[0, i] = 1
for i in range(wx):
	visited[wy-1, i] = 1

for i in range(wy):
	visited[i, 0] = 1
for i in range(wy):
	visited[i, wx-1] = 1


#print np.amax(image)
queue = []
queue.append([1,1])

visited[1][1] = 1
while queue:
	node = queue.pop()
	y = node[0]
	x = node[1]
	#print [y,x]
	visited[y,x] = 1
	image_out[y,x,0]= 255
	image_out[y,x,1]= 255
	image_out[y,x,2]= 255
	
	if not visited[y, x-1]:
		if abs(image[y,x-1,0]-fpr)+abs(image[y,x-1,1]-fpg)+abs(image[y,x-1,2]-fpb)<err:
			queue.append([y, x-1])
			visited[y, x-1] = 1
	if not visited[y, x+1]:
		if abs(image[y,x+1,0]-fpr)+abs(image[y,x+1,1]-fpg)+abs(image[y,x+1,2]-fpb)<err:
			queue.append([y, x+1])
			visited[y, x+1] = 1
	if not visited[y-1, x]:
		if abs(image[y-1,x,0]-fpr)+abs(image[y-1,x,1]-fpg)+abs(image[y-1,x,2]-fpb)<err:
			queue.append([y-1, x])
			visited[y-1, x] = 1
	if not visited[y+1, x]:
		if abs(image[y+1,x,0]-fpr)+abs(image[y+1,x,1]-fpg)+abs(image[y+1,x,2]-fpb)<err:
			queue.append([y+1, x])
			visited[y+1, x] = 1
			
misc.imsave(f_out, image_out)