Header-based scaling and cropping of images compressed using multi-scale transforms

A method for automatically scaling and cropping an image, comprising:

• receiving a file containing a header that contains multi-scale entropy distribution information on blocks of an image;
• for each block and for each first scale of a set of scales:
• setting a cumulative entropy distribution for the block at the first scale equal to a summation of a number of bits spent to code the block for scales at and between the first scale and a maximum scale;
• and
• setting an indicator function of the block at a chosen scale and chosen width and height offsets to one upon determining that a width of the block is not greater than a first minimum value and a height of the block is not greater than a second minimum value and to zero otherwise, wherein the first minimum value is a minimum value of a set consisting of the chosen width offset and a sum of the chosen width offset with a display width scaled by the first scale, and wherein the second minimum value is a minimum value of a set consisting of the chosen height offset and a sum of the chosen height offset with a display height scaled by the first scale;
• computing a final location and a final scale that together maximize a summation consisting of cumulative entropy distribution for the block at the final scale multiplied with an indicator function of the block and by a parameter;
• and
• cropping the image at the final location and down-sampling the resulting cropped image to the final scale.

An article of manufacture having one or more computer-readable media with executable instructions stored thereon which, when executed by a computer, cause the computer to:

• receive a file containing a header that contains multi-scale entropy distribution information on blocks of an image;
• for each block, determine that the block retains significance at a scale upon determining that an entropy of a multi-scale coefficient of a block at the scale is greater than a mean entropy of multi-scale coefficients of blocks in at least one coarser scale;
• and
• scale the image to a coarsest scale at which a threshold percentage of the blocks retain significance at the scale.

An article of manufacture having one or more computer-readable media storing executable instruction thereon which, when executed by a computer, cause the computer to:

• receive a file containing a header that contains multi-scale entropy distribution information on blocks of an image;
• for each block and for each first scale of a set of scales:
• set a cumulative entropy distribution for the block at the first scale equal to a summation of a number of bits spent to code the block for scales at and between the first scale and a maximum scale;
• and
• set an indicator function of the block at a chosen scale and chosen width and height offsets to one upon determining that a width of the block is not greater than a first minimum value and a height of the block is not greater than a second minimum value and to zero otherwise, wherein the first minimum value is a minimum value of a set consisting of the chosen width offset and a sum of the chosen width offset with a display width scaled by the first scale, and wherein the second minimum value is a minimum value of a set consisting of the chosen height offset and a sum of the chosen height offset with a display height scaled by the first scale;
• compute a final location and a final scale that together maximize a summation consisting of cumulative entropy distribution for the block at the final scale multiplied with an indicator function of the block and by a parameter;
• and
• crop the image at the final location and down-sampling the resulting cropped image to the final scale.

An apparatus to adaptively scale an image, comprising:

• a receiving unit to receive a file containing a header that contains multi-scale entropy distribution information on blocks of an image;
• and
• a processing unit coupled with the receiving unit, the processing unit to for each block, determine that the block retains significance at a scale upon determining that an entropy of a multi-scale coefficient of a block at the scale is greater than a mean entropy of multi-scale coefficients of blocks in at least one coarser scale;
• and
• scale the image to a coarsest scale at which a threshold percentage of the blocks retain significance at the scale.

An apparatus to automatically scale and crop an image, comprising:

• a receiving unit to receive a file containing a header that contains multi-scale entropy distribution information on blocks of an image;
• a processing unit coupled with the receiving unit, the processing unit to for each block and for each first scale of a set of scales:
• set a cumulative entropy distribution for the block at the first scale equal to a summation of a number of bits spent to code the block for scales at and between the first scale and a maximum scale;
• and
• set an indicator function of the block at a chosen scale and chosen width and height offsets to one upon determining that a width of the block is not greater than a first minimum value and a height of the block is not greater than a second minimum value and to zero otherwise, wherein the first minimum value is a minimum value of a set consisting of the chosen width offset and a sum of the chosen width offset with a display width scaled by the first scale, and wherein the second minimum value is a minimum value of a set consisting of the chosen height offset and a sum of the chosen height offset with a display height scaled by the first scale;
• compute a final location and a final scale that together maximize a summation consisting of cumulative entropy distribution for the block at the final scale multiplied with an indicator function of the block and by a parameter;
• and crop the image at the final location and down-sampling the resulting cropped image to the final scale.