Biblio

Edge detection is one of the most important topics of image processing. In the scenario of cloud computing, performing edge detection may also consider privacy protection. In this paper, we propose an edge detection and image segmentation scheme on an encrypted image with Sobel edge detector. We implement Gaussian filtering and Sobel operator on the image in the encrypted domain with homomorphic property. By implementing an adaptive threshold decision algorithm in the encrypted domain, we obtain a threshold determined by the image distribution. With the technique of garbled circuit, we perform comparison in the encrypted domain and obtain the edge of the image without decrypting the image in advanced. We then propose an image segmentation scheme on the encrypted image based on the detected edges. Our experiments demonstrate the viability and effectiveness of the proposed encrypted image edge detection and segmentation.

As the key component of the smart grid, smart meters fill in the gap between electrical utilities and household users. Todays smart meters are capable of collecting household power information in real-time, providing precise power dispatching control services for electrical utilities and informing real-time power price for users, which significantly improve the user experiences. However, the use of data also brings a concern about privacy leakage and the trade-off between data usability and user privacy becomes an vital problem. Existing works propose privacy-utility trade-off frameworks against statistical inference attack. However, these algorithms are basing on distorted data, and will produce cumulative errors when tracing household power usage and lead to false power state estimation, mislead dispatching control, and become an obstacle for practical application. Furthermore, previous works consider power usage as discrete variables in their optimization problems while realistic smart meter data is continuous variable. In this paper, we propose a mechanism to estimate the trade-off between utility and privacy on a continuous time-series distorted dataset, where we extend previous optimization problems to continuous variables version. Experiments results on smart meter dataset reveal that the proposed mechanism is able to prevent inference to sensitive appliances, preserve insensitive appliances, as well as permit electrical utilities to trace household power usage periodically efficiently.