Work around of using 1D-LUT instead of 2D-LUT

[Jason]

Dear All,

I originally have a look up table of size UInt8[256][256].

However, there is a restriction that just 1D look up table of size
UInt8[256] can be use. The no. of UInt8[256] tables to be used is not
limited.

Are there any simple method for me to constructing many 1D look up
tables of UInt8[256] so that the same result can be obtained as if the
2D-LUT UInt8[256][256] is used?

Note that the 1D-LUT can just have max. no. of element of 256. Ans
just +,-,*,/ operations can be used.


Thank you,
Jason

 

[Barry Schwarz]

Dear All,

I originally have a look up table of size UInt8[256][256].

However, there is a restriction that just 1D look up table of size
UInt8[256] can be use. The no. of UInt8[256] tables to be used is not
limited.

Are there any simple method for me to constructing many 1D look up
tables of UInt8[256] so that the same result can be obtained as if the
2D-LUT UInt8[256][256] is used?

Note that the 1D-LUT can just have max. no. of element of 256. Ans
just +,-,*,/ operations can be used.


Thank you,
Jason

If you are allowed to use 2d subscript notation, then

UInt8 lut_000[256];
UInt8 lut_001[256];
.....
UInt8 lut_255[256];
UInt8 *lut[] = {lut_000, lut_001, ..., lut_255};

contains only 1d tables each with only 256 elements but lut[j]
provides a method of accessing all 65K objects.

If not, you are going to have to explain the intent and the
restrictions more clearly.


<<Remove the del for email>>

 

[Rob Thorpe]

Dear All,

I originally have a look up table of size UInt8[256][256].

However, there is a restriction that just 1D look up table of size
UInt8[256] can be use. The no. of UInt8[256] tables to be used is not
limited.

Are there any simple method for me to constructing many 1D look up
tables of UInt8[256] so that the same result can be obtained as if the
2D-LUT UInt8[256][256] is used?

Note that the 1D-LUT can just have max. no. of element of 256. Ans
just +,-,*,/ operations can be used.


Thank you,
Jason

Can you explain why only 1D lookup tables can be used?