A Privacy-Preserving Image Retrieval Scheme with a Mixture of Plain and EtC Images

TL;DR

This paper introduces a privacy-preserving image retrieval method that effectively uses both plain and encrypted images, maintaining high retrieval accuracy while protecting image privacy.

Contribution

It presents a novel scheme combining plain and EtC encrypted images for content-based retrieval, with extended descriptors enabling effective mixed-image retrieval.

Findings

Retrieval performance with mixed images is comparable to plain images.

The scheme preserves privacy without sacrificing accuracy.

Effective use of encrypted images in content-based retrieval.

Abstract

In this paper, we propose a novel content-based image-retrieval scheme that allows us to use a mixture of plain images and compressible encrypted ones called "encryption-then-compression (EtC) images." In the proposed scheme, extended SIMPLE descriptors are extracted from EtC images as well as from plain ones, so the mixed use of plain and encrypted images is available for image retrieval. In an experiment, the proposed scheme was demonstrated to have almost the same retrieval performance as that for plain images, even with a mixture of plain and encrypted images.