Computer Vision

Image Analysis for Machine Learning

Investigate images to get sensitive/secret data or sensitive information hidden in the images.

In advance, load an image using Pillow (PIL).

import numpy as np
from PIL import Image

img = Image.open("example.png")

Basic Information

# Filename
img.filename

# Image information
img.info

# Image format (PNG, JPG, etc.)
img.format

# Color mode (RPG, CMYK, etc.)
img.mode

# Image size
img.size

# Bytes
img.tobytes()

# Pixels
np.array(img.getdata())

Plot Images

import matplotlib.pyplot as plt

plt.imshow(img)
plt.axis('off') # Turn off axis and labels
plt.show()

Hidden Information

Find hidden data in the image by slightly changing.

Resize Image & Get Bytes

img1 = img.resize((128, 128))
print(img1.tobytes())

XOR Image Bytes

# Convert image to bytes
bytes = img.tobytes()

key = 2 # specify the XOR key

xored = []
for byte in bytes:
    xored.append(byte ^ key)
xored_np = np.array(xored)
print(xored_np)