Title: Remove Backgrounds
Slug: remove_backgrounds
Summary: How to remove the backgrounds in images using OpenCV in Python.
Date: 2017-09-11 12:00
Category: Machine Learning
Tags: Preprocessing Images
Authors: Chris Albon
In [1]:
# Load image
import cv2
import numpy as np
from matplotlib import pyplot as plt
In [2]:
# Load image
image_bgr = cv2.imread('images/plane_256x256.jpg')
In [3]:
# Convert to RGB
image_rgb = cv2.cvtColor(image_bgr, cv2.COLOR_BGR2RGB)
In [4]:
# Rectange values: start x, start y, width, height
rectangle = (0, 56, 256, 150)
In [5]:
# Create initial mask
mask = np.zeros(image_rgb.shape[:2], np.uint8)
# Create temporary arrays used by grabCut
bgdModel = np.zeros((1, 65), np.float64)
fgdModel = np.zeros((1, 65), np.float64)
# Run grabCut
cv2.grabCut(image_rgb, # Our image
mask, # The Mask
rectangle, # Our rectangle
bgdModel, # Temporary array for background
fgdModel, # Temporary array for background
5, # Number of iterations
cv2.GC_INIT_WITH_RECT) # Initiative using our rectangle
# Create mask where sure and likely backgrounds set to 0, otherwise 1
mask_2 = np.where((mask==2) | (mask==0), 0, 1).astype('uint8')
# Multiply image with new mask to subtract background
image_rgb_nobg = image_rgb * mask_2[:, :, np.newaxis]
In [6]:
# Show image
plt.imshow(image_rgb_nobg), plt.axis("off")
plt.show()