How to modify Gamma table by custom's gamma value?

Star zhou,

Which device, peripheral/accelerator, and software package is this question related to?

Marcus

Sorry.

I am using DM368, Our custom wan to use Gamma correction in the evening, they want to adjust gamma value(such as 0.1 ~ 3.5), We want  to use RAM Gamma table of  the DM368, But  we dont know how to calcute the offset and slope of  RAM gamma  table?

 another question, if a pixel input gamma correction, the output_of_gamma_value = offset + slope ?? in Figure 75. Gamma Correction Module Block Diagram of dm365 VPFE, maybe the Figure 75 have a problem.

 Can you give me some suggestions,

 Zhou

Please refer to Figure 4-41 and 4-42 in DM365 VPFE document (http://focus.ti.com/lit/ug/sprufg8c/sprufg8c.pdf).

The 9-bit input for offset part is the 9MSBs of the 12-bit input.

The 6-bit input for slope part is the 3LSBs of the 12-bit input.

 Thank you very much!  Gang Hua.

We want to use our offset and slope for RAM table,

We always set slope is 1, and offset is calculated form gamma correction equeation. (we can't use piece-wise interpolation for RAM table.)

Does this is okay?

Thank you!

Star

No, you cannot set slope always to 1.

You have to follow Figure 4-42.

Is there a more detailed explanation for this available somewhere?

The figure in the documentation is unclear. 

Is there a more detailed example available for creating a custom gamma table? (for ex. gamma = 0.45 or gamma = 1) ?