Secret image camouflage recovery method by combining secret key and random orthogonal tensor basis

The invention discloses a secret image camouflage recovery method by combining a secret key and random orthogonal tensor basis. The method comprises the following steps: firstly dividing a secret image and a public image into equal number of small matrix blocks, and constructing random orthogonal tensor basis by using a unit orthogonal matrix generated by the secret key; secondly, performing sufficient and effective linear expression on small secret image blocks by solving the projections on the random orthogonal tensor basis on the small secret image blocks, selecting the front k projection coefficients with large amplitude and energy from the projection and recording an index location to construct a line sequence and a row sequence; and secondly embedding the selected projection coefficient, the line sequence and the row sequence into the corresponding public small image blocks through a secret-writing method for performing tiny adjusting and large-capacity embedding on the public image, thereby forming a c