The invention relates to a local non-reference visual safety evaluation method and
system, and belongs to the technical field of visual safety evaluation. The method comprises the following steps: carrying out image preprocessing, converting an encrypted image to be detected from an RGB space to a
YCbCr color space, and segmenting the image into analysis units with different sizes by adopting a multi-
scale sliding window and a
pyramid scaling strategy aiming at a Y channel; performing
encryption block positioning, calculating statistical characteristics such as a gray
histogram, edge energy and texture entropy for each analysis unit, generating a binary
encryption block
mask, and realizing reliable positioning of a local
encryption region; performing local security evaluation, taking each positioned encryption region as an independent evaluation unit, independently calculating a DCT high-frequency sub-band statistical offset parameter of each positioned encryption region, and fitting generalized
Gaussian distribution through a moment
estimation method; and according to the area proportion, the scores of the regions are aggregated to obtain the overall safety
score of the whole graph, so that the evaluation accuracy is ensured, and the real-time and lightweight deployment requirements are met.