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jlesquer
Contributor
Contributor
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Registered: ‎10-08-2013

Gamma LUT how to update the tables

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Hi all,

I'm trying to figure out how to load the registers LUT values for each color manually (accessing to the register addresses). I've seen the pg285 but there's not clear explanation about how to do it. Also I've seen this  related topic but unfortunatelly there's not answer to this...

Given the next gamma 1 table:

 

unsigned char gamma_lut_values[256] = {
		0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
		20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
		38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,
		56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,
		74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91,
		92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
		108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121,
		122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135,
		136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
		150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163,
		164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177,
		178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191,
		192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205,
		206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219,
		220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233,
		234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247,
		248, 249, 250, 251, 252, 253, 254, 255
};

 

 

And given the next LUT offsets:

 

GAMMA_RED         0x0800
GAMMA_GREEN	  0x1000
GAMMA_BLUE	  0x1800

 

 

I'm loading the values like this (repeating for all colors the same):

 

0x0800 -> 0x00010000
0x0808 -> 0x00030002
0x0810 -> 0x00050004
        ....... 

But the resulting image is very noise and saturated on high lights...

 

Does anyone know how to update properly the table values?

 

 

 

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jlesquer
Contributor
Contributor
482 Views
Registered: ‎10-08-2013

Hi @watari , thanks for the answer, already solved the problem, it was an addressing issue. It works like that:

0x0800 -> 0x00010000
0x0804 -> 0x00030002
0x0808 -> 0x00050004
        ....... 

 

View solution in original post

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2 Replies
watari
Teacher
Teacher
533 Views
Registered: ‎06-16-2013

Hi @jlesquer 

 

Would you make sure endian in gamma lut ?

 

Best regards,

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jlesquer
Contributor
Contributor
483 Views
Registered: ‎10-08-2013

Hi @watari , thanks for the answer, already solved the problem, it was an addressing issue. It works like that:

0x0800 -> 0x00010000
0x0804 -> 0x00030002
0x0808 -> 0x00050004
        ....... 

 

View solution in original post

0 Kudos