Modified computational integral imaging-based double image encryption using fractional Fourier transform

TLDR: An image encryption technique to simultaneously encrypt double or multiple images into one encrypted image using computational integral imaging (CII) and fractional Fourier transform (FrFT) is proposed.

About: This article is published in Optics and Lasers in Engineering.The article was published on 2015-03-01 and is currently open access. It has received 48 citations till now. The article focuses on the topics: Fractional Fourier transform & Integral imaging.

Figures

Table 1. PSNR values of each color image channel in case 1.

Table 2. PSNR values of each color image channel in case 2.

Figure 8. Reconstructed plane images based on proposed method with all correct keys in both cases: (a) reconstructed plane images using all correct keys in first case, (b) reconstructed plane images using all correct keys in second case.

Figure 9. Reconstructed images with incorrect keys (case 2): (a) and (b) reconstructed plane images with incorrect pickup distances located at 9 mm and 33 mm, respectively, (c) and (d) reconstructed images with incorrect fraction order (0.4 0.5 0.5 0.5), (e) and (f) reconstructed images with wrong AT scrambled time t.

Figure 1. Schematic of double images optical pickup and encryption: (a) pickup process, (b) encoding process.

Table 4. PSNR values of each channel of decrypted image where 40% and 50% pixels are occluded.

Frequently asked questions

Q1. What are the contributions mentioned in the paper "Modified computational integral imaging-based double image encryption using fractional fourier transform" ?

In this paper, the authors propose an image encryption technique to simultaneously encrypt double or multiple images into one encrypted image using computational integral imaging ( CII ) and fractional Fourier transform ( FrFT ). To further improve the solution of the reconstructed plane images, a block matching algorithm is also introduced. 

Q2. What is the advantage of optical encryption using FrFT?

The remarkable advantage of optical encryption using FrFT is the fractional orders, which greatly enhance the key space and further increase the security of encryption systems. 

Q3. What is the method for reconstructed double images?

Reconstruction can be achieved with two methods: optical integral imaging reconstruction (OIIR) [13,14] and computational integral imaging reconstruction (CIIR) [15-22]. 

Q4. What is the reverse pickup process for double images?

Reconstruction of the double images is a reverse pickup process performed by propagating the lights emanating from the elemental images through a similar lenslet array. 

Q5. How can the authors improve the occlusion noise results in CIIR?

In this paper, and to improve the weak points of the occlusion noise results in CIIR, the authors apply both the original picked up EIA and a simple neural network to construct a newly modified CIIR method. 

Q6. How can the reconstructed plane images be encrypted?

In the encryption, each plane image located at different distances along the pickup plane can be recorded in the form of a 2D EIA by a virtual pinhole array; furthermore, the recorded EIA can be encrypted by the FrFT method. 

Q7. What is the common optical image encryption technique?

An optical image encryption technique based on random phase encoding in the fractional Fourier transform (FrFT) domain was first presented by Unnikrishnan [6]. 

Q8. What funding was given to this work?

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2011-0028568). 

Q9. What is the way to explain the robustness of the proposed scheme?

From the simulation results described in the previous paragraphs, it is clear that their proposed scheme provides high robustness against Gaussian noise attacks. 

Q10. What is the way to improve the robustness of the encrypted images?

The computersimulation results show that this proposed method utilizes the data redundancy property of EIA to improve the robustness of the encrypted images. 

Q11. How many lenslets are used in the experiment?

The picked up EIA of the double images with 900 900 pixels was computationally synthesized, and the virtual lenslet array is assumed to have 30 30 lenslets.