A paper featured in the Optical Society’s journal, Optica, on 14 November explains that by adding an array of lenses to an ordinary smartphone, a user can securely display 3D images by scanning a series of QR codes. The team of optical engineers from the University of Connecticut behind the research said this can be done without accessing the internet, reducing security risks.
The team say the data storage and display scheme used could have exciting implications for personal 3D entertainment, product visualisations for manufacturing and marketing, and secure 3D data storage and transmission.
Bahram Javidi, the project team leader and co-author on the paper said: ‘The QR codes we developed store compressed and encrypted images, which can be easily scanned, decrypted, and decompressed by commercial smartphones for secure 3D visual communication.’
The image can contain either a single 3D object or an entire 3D scene. Once the image has been selected, it is broken down into many 2D images from different perspectives, known as elemental images. This is done using a lens array that can capture the image from slightly offset perspectives.
Each elemental image is then split into the angular and intensity information, which relate to the images position and the shades of grey from each pixel. This information is recorded digitally, passed through encryption software that also compresses the data, and is stored as a QR code. A smartphone with a commercial QR reader can then retrieve that data by sequentially scanning multiple codes.
A separate decryption app with a unique security key is needed to decompress and reconstruct the image and only a smartphone with the correct key would be able to access the data.
For the purpose of this research, the data was exported to an external computer where a specialised programme decompressed and decrypted the image.
The engineers also addressed a security flaw with QR codes. If a smartphone scans a code that contains a link to a website, the device will link straight to the website and access the data stored there; this data could contain dangerous programming.
‘In our proposed method, we store self-contained slices of data in the QR codes themselves. It’s then possible to receive and visualie 3D images without using the Internet,’ Javidi said.
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