Method and system for predictive scaling of colour mapped images

A method for determining a scaled colour map of a scaled image obtained by scaling an original image, implemented by a computing device having a processor, the method comprising:

• obtaining an original colour map of the original image;
• and
• transforming the original colour map into the scaled colour map using the original colour map and the original image only, comprising:
• provided Nmin<N<Nmax, forming the scaled colour map, comprising:
• (iv-1) selecting a sub-set of colours in the original colour map, comprising determining a number of colours Ms in the selected subset of colours as follows
• M
• s
• =
• E
• ⁡
• (
• 1
• 2
• +
• 1
• 2
• ⁢
• 1
• +
• 8
• ⁢
• (
• N
• max
• -
• N
• )
• )
• provided N(N+1)>2Nmax, wherein E(x)=[x] provided “x” is a natural number, otherwise E(x)=[x]+1;
• (iv-2) increasing a number of colours in the selected sub-set, thus forming a resulting sub-set of colours;
• and
• (iv-3) adding the resulting sub-set with increased number of colours to the original colour map;
• wherein N is a number of colours in the original colour map, Nmin and Nmax are respective predetermined minimum and maximum thresholds for respective numbers of colours in the original colour map, and Ms is a number of colours in the selected subset of colours.

A system for determining a scaled colour map of a scaled image obtained by scaling an original image, the system comprising:

• a processor and a non-transitory computer readable storage medium having computer readable instructions stored thereon for execution by the processor, causing the processor to:
• obtain an original colour map of the original image;
• and
• transform the original colour map into the scaled colour map using the original colour map and the original image only, comprising:
• provided Nmin<N<Nmax, forming the scaled colour map:
• (iv-1) select a sub-set of colours in the original colour map;
• (iv-2) increase a number of colours in the selected sub-set, thus forming a resulting sub-set of colours;
• and
• (iv-3) add the resulting sub-set with increased number of colours to the original colour map, comprising determining the increased number of colours in the resulting sub-set of colours as
• 1
• 2
• ⁢
• M
• s
• ⁡
• (
• M
• s
• -
• 1
• )
• ,
• wherein N is a number of colours in the original colour map, Nmin and Nmax are respective predetermined minimum and maximum thresholds for respective numbers of colours in the original colour map, and Ms is a number of colours in the selected subset of colours.

A system for determining a scaled colour map of a scaled image obtained by scaling an original image, the system comprising:

• a processor and a non-transitory computer readable storage medium having computer readable instructions stored thereon for execution by the processor, causing the processor to:
• obtain an original colour map of the original image;
• and
• transform the original colour map into the scaled colour map using the original colour map and the original image only, comprising:
• provided Nmin<N<Nmax, form the scaled colour map, comprising causing the computer readable instructions to select a sub-set of colours in the original colour map and to determine a number of colours Ms in the selected subset of colours as
• M
• s
• =
• E
• ⁡
• (
• 1
• 2
• +
• 1
• 2
• ⁢
• 1
• +
• 8
• ⁢
• (
• N
• max
• -
• N
• )
• )
• provided N(N+1)>2Nmax, wherein E(x)=[x] provided “x” is a natural number, otherwise E(x)=[x]+1;
• increasing a number of colours in the selected sub-set, thus forming a resulting sub-set of colours;
• and
• adding the resulting sub-set with increased number of colours to the original colour map.