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The present invention is a method and apparatus for improving the appearance of electronic images, and more specifically, to the efficient use of template rotation within a template matching process to enhance such images. The invention reduces the number of entries that are stored in a look up tabl

The present invention is a method and apparatus for improving the appearance of electronic images, and more specifically, to the efficient use of template rotation within a template matching process to enhance such images. The invention reduces the number of entries that are stored in a look up table by eliminating identical patterns that differ only by the angle at which they are output. The appropriate templates are then rotated it by the required angle for output subsequent to their retrieval from the lookup table.

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1. A method of reducing a number of entries stored in a look-up table, comprising:identifying a look-up table having look up table entries associated with multiple output signals;examining said look-up table entries and said output signals, to identify said look-up table entries that possess similar

1. A method of reducing a number of entries stored in a look-up table, comprising:identifying a look-up table having look up table entries associated with multiple output signals;examining said look-up table entries and said output signals, to identify said look-up table entries that possess similarity via a rotation of corresponding template patterns about an angle in a multi-dimensional space; andreducing a number of output signals that will be generated based upon similarities between said identified look-up table entries and similarities in said output signals. 2. A method of reducing a number of entries stored in a look-up table as claimed in claim 1 further comprising identifying multiple symmetries of a template pattern stored in the look-up table at different rotation angles and generating a single output signal for said multiple pattern symmetries. 3. A method of reducing a number of entries stored in a look-up table as claimed in claim 1 further comprising identifying output signals that differ only by a rotation angle at which they will be generated and associating all look-up table entries associated with said identified output signals with a single output signal. 4. A method of reducing a number look-up tables, wherein each of said look-up tables includes a plurality of entries, each entry being associated with an output signal, the method comprising:examining said look-up table entries and said associated output signals to identify said look-up table entries that possess similarity via a rotation of corresponding template patterns about an angle in a multi-dimensional space, andreducing a number of look-up tables based upon similarities between said identified look-up table entries and similarities between said associated output signals. 5. A method of reducing a number of look-up tables as claimed in claim 4 further comprising identifying multiple symmetries of a pattern stored in said plurality of look-up tables and generating a single output signal to be associated with each of said multiple pattern symmetries. 6. A method of reducing a number of entries stored in a look-up table as claimed in claim 4 further comprising identifying output signals that differ only by a rotation angle at which they will be generated and associating all look-up table entries in said plurality of look-up tables that are associated with said identified output signals with a single output signal. 7. The method according to claim 4, wherein the rotation of corresponding template patterns about an angle in a multi-dimensional space comprises at least one of a flip horizontal, flip vertical, flip right diagonal or flip left diagonal symmetry operation. 8. A symmetry reduction method for reducing a number of entries stored in a look-up table, comprising:examining said look-up table entries, to identify a group of said look-up table entries that possess similarity via a rotation of corresponding template patterns about an angle in a multi-dimensional space;reducing said corresponding template patterns to a common symmetry; andreplacing said group of said look-up table entries with a single entry based upon the common symmetry. 9. The method according to claim 8, wherein the common symmetry is a least common symmetry. 10. The method according to claim 8, wherein the common symmetry is the greatest common symmetry. 11. The method according to claim 8, wherein each of said look-up table entries comprises a vector representation of the corresponding template pattern and the step of reducing said corresponding template patterns to a common symmetry, comprises:determining a plurality of vector values from said vector representation; andcomparing said plurality of vector values to identify said common symmetry. 12. The method according to claim 11, wherein the step of determining a plurality of vector values, comprises:separating said vector representation into a plurality of individual bits;using selected ones of said plurality of individual bits to index to a symmetry operation look-up table, said symmetry option look-up table having an output value associated with each index; and,summing the output values from the look-up table. 13. The method according to claim 8, wherein the rotation of corresponding template patterns about an angle in a multi-dimensional space comprises at least one of a flip horizontal, flip vertical, flip right diagonal or flip left diagonal symmetry operation. 14. A symmetry reduction method for reducing a number of entries stored in a look-up table wherein each of said look-up table entries comprises a vector representation of a template pattern, comprising:examining said look-up table entries, to identify a group of said look-up table entries that possess similarity via a rotation of corresponding template patterns about an angle in multi-dimensional space;reducing said corresponding template patterns to a common symmetry, said step of reducing including determining a plurality of vector values from said vector representation and comparing said plurality of vector values to identify said common symmetry; andreplacing said group of said look-up table entries with a single entry based upon the common symmetry. 15. The method according to claim 14, wherein the common symmetry is a least common symmetry. 16. The method according to claim 14, wherein the common symmetry is the greatest common symmetry. 17. The method according to claim 14, wherein the step of determining a plurality of vector values, comprises:separating said vector representation into a plurality of individual bits;using selected ones of said plurality of individual bits to index to a symmetry operation look-up table, said symmetry option look-up table having an output value associated with each index; and;summing the output values from the look-up table.