Patent ID: 8737761

Claim:
A method for restoring and enhancing a space based image of point or spot objects, the method comprising: (1) dividing a space-variable degraded image into multiple space-invariant image sub-blocks, and constructing a point spread function for each of said image sub-blocks, the dividing and constructing comprising: (1.1) dividing a gray-scale image on a focal plane into M image sub-blocks, said image sub-block indicated by f i , i representing a serial number of each of said image sub-blocks, i=1, 2, . . . , M, a region within each of said of said image sub-blocks, i=1, 2, . . . , M, a region within each of said image sub-blocks approximated as an isoplanatic region, and M determined by a distance between a photosensitive element and a lens axis; (1.2) pre-measuring a point spread function PSF 1 (r) of each of said image sub-blocks by an optical device on the ground, and storing said point spread function in a database; (1.3) constructing a point spread function PSF 2 (x, y) under a fuzzy random degradation effect in each of said image sub-blocks corresponding to a discrete photosensitive element array in a imaging focal plane; and (1.4) constructing an total function of each of said image sub-blocks: PSF( x,y )=PSF 1 ( x,y )*PSF 2 ( x,y ) (2) correcting each of said image sub-blocks via a space-invariant image correction method whereby obtaining a corrected image {circumflex over (f)} i for each of said image sub-blocks; and (3) stitching said corrected image sub-blocks {circumflex over (f)} i altogether via a stitching algorithm whereby obtaining a complete corrected image f; wherein a correction processing step (2) comprise: (2.1) correcting each of said image sub-blocks via a maximum likelihood estimation algorithm, PSF 1 (r) being used as an iterative initial value for point spread, namely h i 0 =PSF 1 (r), f i being used as an iterative initial value for a object image, namely f i 0 =f i , N representing iteration number, and iteration being formulated as: f i n ⁡ ( x ) = f i n - 1 ⁡ ( x ) ⁢ ∑ y ∈ Y ⁢ g i ⁢ h i n - 1 ⁡ ( y - x ) ∑ z ∈ X ⁢ h i n - 1 ⁡ ( y - z ) ⁢ f i n - 1 ⁡ ( z ) , ( 1 ≤ n ≤ N ) ( 1 ) h i n ⁡ ( x ) = h i n - 1 ⁡ ( x ) ⁢ ∑ y ∈ Y ⁢ g i ⁢ f i n ⁡ ( y - x ) ∑ z ∈ X ⁢ h i n - 1 ⁡ ( z ) ⁢ f i n ⁡ ( y - z ) , ( 1 ≤ n ≤ N ) ( 2 ) where X represents a support region for said object image, Y represents a support region for an observed image, zεX, xεY, yεY, f i 0 (x) represents a corrected image after n times of iteration, h i 0 *(x) represents a point spread function after n times of iteration, g i represents an observed image, namely f i ; and (2.2) obtaining a corrected image {circumflex over (f)} i of each of said image sub-blocks, namely {circumflex over (f)} i =f i x (x), and a total point spread function ĥ i =h i x (x), after said iteration number is reached.