1. Embedding Context with Photographic Steganography
Wenjia Yuan

2. Motivation QR codes Start from QR codes
To steganography method: describe the scene (intuition)
What is the context
The advantage over qr codes: time varying steganography
Visual MIMO

3. Photometric model Distortions in the visual MIMO channel
Geometric distortion
Angular distortion
Specularity distortion
How to recover the message?
The traditional method uses

4. Photometric model
𝐼 𝑜 ∝ 𝜆 [𝜌⋅𝑓 𝜃,𝜆 ]𝑠(𝜆)ⅆ𝜆

5. Photometric model Original Embedded Original Embedded Division
Alternating frames
Division
Division

6. Photographic steganography
Photometric ratio
𝐼 1 ∝ 𝜆 [𝜌⋅𝑓 𝜃,𝜆 ]𝑠(𝜆)ⅆ𝜆
𝐼 2 ∝ 𝜆 [𝜅𝜌⋅𝑓 𝜃,𝜆 ]𝑠(𝜆)ⅆ𝜆
Traditional method: additive like LSB
Cancel out
But we use ratio method to reduce the influence of the angles
Illumination invariance in computer vision
𝐼 2 𝐼 1 =𝜅

7. Photographic steganography
Receiver
Min-Group
To build the receiver, there are still some other issues:
Min-Group
Binary matrix

8. Photographic steganography
Min-Group method for reflection removal

9. Experiments
Indoor
Percentage of correctly decoded

10. Experiments
Outdoor

11. Conclusions
Develop a model for image formation of an active scene containing electronic displays
Present real-time photographic steganography for visual MIMO optical system.