隨著無人機與雲端儲存技術的普及，空拍影像廣泛應用於環境監測、城市巡查與災後勘查等場景，多透過無線網路即時上傳至雲端，然而影像常含有地理資訊與人員活動等敏感內容，若未經妥善加密即上傳，將可能造成隱私洩漏與資訊安全風險；傳統圖像加密方法雖具高度保密性，但其全遮蔽式特性使雲端無法預覽影像內容，不利於快速檢索與即時應用。
為兼顧影像的安全性與可用性，本論文提出以縮圖保留為核心的輕量影像加密架構，稱為4PX-TPE（Four-Pixel Thumbnail-Preserving Encryption）方案，以四像素為加密單元，結合混沌置換與總和保留加密（Sum-Preserving Encryption, SPE），保留加密後影像的低解析度視覺輪廓，並透過像素組生成公式化，提升處理效率與結構可逆性。
本論文於Raspberry Pi嵌入式平台整合相機模組與加密演算，模擬無人機端即時拍攝、加密與雲端上傳流程，驗證4PX-TPE在維持隱私保護的同時，可保留縮圖辨識性並具即時處理能力，具備應用於智慧城市、空拍巡查與圖像授權平台等場景之潛力。

With the widespread development of UAV imaging and the proliferation of cloud storage services, aerial images are increasingly used in environmental monitoring, urban inspection, and disaster response. These images, often transmitted via wireless networks and stored in the cloud, commonly include sensitive information such as geographic coordinates and human activities. If uploaded without proper protection, they pose severe privacy and security risks. Traditional encryption methods, although highly secure, render images unreadable and remove all visual features, making them incompatible with cloud preview and unsuitable for resource-constrained or real-time applications.
To address these challenges, this thesis proposes 4PX-TPE (Four-Pixel Thumbnail-Preserving Encryption), a lightweight encryption architecture designed to preserve thumbnail-level visual structure while protecting content. The method adopts four-pixel units, combining chaotic permutation and formula-based sum-preserving encryption (SPE) to maintain visual consistency and reversibility.
The 4PX-TPE scheme is implemented on a Raspberry Pi embedded platform integrated with a camera module, simulating UAV-based real-time image capture, encryption and cloud upload. The system aims to enable low-resolution recognizability without disclosing sensitive image content. Experimental results demonstrate that 4PX-TPE provides a practical trade-off between usability and privacy, making it suitable for smart city surveillance, cloud-based preview systems, and secure aerial data services.

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