Multli-spectral image compression with bounded loss

Abstract

A system and method for generating bounded-loss color transformations employed in the compression and decompression of multi-spectral images is provided. The bounded-loss color space transformations provide transformations from a first color space to a second color space and back to the first color space with bounded loss or error. The bounded loss or error allows for the near lossless compression and reconstruction of multi-spectral images transformed from a first color space to a second color space and ultimately back to the first color space.

We claim:  
     
         1 . A computer-implemented method for compressing a digital multi-spectral image represented by a first color space, the method comprising the steps of: 
 (a) transforming a first set of first color space components to a plurality of second color space components;    (b) compressing the second color space components; and    (c) reconstructing and transforming the compressed second color space components into a second set of first color space components such that the difference between each of the first set of first color space components and the second set of first color space components is bound by a predetermined range of values.    
     
     
         2 . The method of    claim 1    further comprising the step of determining a noise-level within an image and wherein predetermined range of values is based on the determined noise-level.  
     
     
         3 . The method of    claim 1    wherein the step of transforming a first set of first color space components to a second color space comprises the step of inputting the first set of first color space components into a first transformer having the following transformation equations embedded therein:  
         Y ′=Round( aR+bG+cB )  Cb ′=Round(( B−Y ′)/3+128)  Cr ′Round(( R−Y ′)/3+128)  
       and wherein the first color space comprises an RGB color space and the second color space comprises an Y′Cb′Cr′ color space.  
     
     
         4 . The method of    claim 3    wherein the step of reconstructing and transforming the compressed second color space components into a second set of first color space components such that the difference between each of the first set of first color space components and the second set of first color space components is bound by a predetermined range of values comprises the step of inputting the second color space components into a second transformer having the following transformation equations embedded therein:  
         R   1 =( Cr*+Y ′)  G   1 =Round( Y ′−(( a/b ) Cr *)−(( c/b ) Cb *))  B   1 =( Cb*+Y ′) where:  Cb*= 3( Cb′− 128)  Cr*= 3( Cr′− 128)  
       and wherein the first color space comprises an RGB color space and the second color space comprises an Y′Cb′Cr′ color space.  
     
     
         5 . The method of    claim 1    wherein the step of transforming a first set of first color space components to a second color space comprises the step of inputting the first set of first color space components into a first transformer having the following transformation equations embedded therein:  
         C ′=Round((255− R )/ D )  M ′=Round((255− G )/ D )  Y ′=Round((255− B )/ D )  
       and D=2 (E)+1, wherein E is the desired loss and wherein the first color space comprises an RGB color space and the second color space comprises a C′M′Y′ color space.  
     
     
         6 . The method of    claim 5    wherein the step of reconstructing and transforming the compressed second color space components into a second set of first color space components such that the difference between each of the first set of first color space components and the second set of first color space components is bound by a predetermined range of values comprises the step of inputting the second color space components into a second transformer having the following transformation equations embedded therein:  
         R   1 =(255− D ( C ′))  G   1 =(255− D ( M ′))  B   1 =(255− D ( Y ′))  
       and D=2 (E)+1, wherein E is the desired loss and wherein the first color space comprises an RGB color space and the second color space comprises an C′M′Y′ color space.  
     
     
         7 . The method of    claim 5    wherein E is equal to one.  
     
     
         8 . The method of    claim 6    wherein E is equal to one.  
     
     
         9 . The method of    claim 1    wherein the step of compressing the second color space components comprises the step of compressing via a JPEG standard.