Difference between revisions of "PHP and Gamma values"
From ElphelWiki
m |
m |
||
| Line 34: | Line 34: | ||
// set gammas array and postpone setting values in the camera | // set gammas array and postpone setting values in the camera | ||
$value = intval($value); | $value = intval($value); | ||
| − | + | $gammas["GTAB_R__0816"]=$value; | |
| − | + | $gammas["GTAB_G__0816"]=$value; | |
| − | + | $gammas["GTAB_GB__0816"]=$value; | |
| − | + | $gammas["GTAB_B__0816"]=$value; | |
break; | break; | ||
case "black": | case "black": | ||
// set gammas array and postpone setting values in the camera | // set gammas array and postpone setting values in the camera | ||
$value = intval($value); | $value = intval($value); | ||
| − | + | $gammas["GTAB_R__0824"]=$value; | |
| − | + | $gammas["GTAB_G__0824"]=$value; | |
| − | + | $gammas["GTAB_GB__0824"]=$value; | |
| − | + | $gammas["GTAB_B__0824"]=$value; | |
break; | break; | ||
} | } | ||
Revision as of 11:28, 8 February 2012
How to change Gamma values in an Elphel camera
Changing Gamma and BlackLevel values at present requires some special treatment. Here is a short PHP script that does it:
<?php
// Set default frame ahead
if (!array_key_exists("ahead",$_GET))
$ahead=3;
// Special treatment for the gamma values and blacklevel.
// Get exising gamma values if a gamma parameter is requested
if (array_key_exists("gamma",$_GET) || array_key_exists("black",$_GET)) {
$gammas=array(
"GTAB_R__0816"=>"",
"GTAB_G__0816"=>"",
"GTAB_GB__0816"=>"",
"GTAB_B__0816"=>"",
"GTAB_R__0824"=>"",
"GTAB_G__0824"=>"",
"GTAB_GB__0824"=>"",
"GTAB_B__0824"=>""
);
// get existing gamma values
$gammas= elphel_get_P_arr($gammas);
}
foreach($_GET as $key=>$value) {
if(strtolower(substr($s, 0, 2))=="0x")
$value= hexdec($value);
switch ($key) {
case "gamma":
// set gammas array and postpone setting values in the camera
$value = intval($value);
$gammas["GTAB_R__0816"]=$value;
$gammas["GTAB_G__0816"]=$value;
$gammas["GTAB_GB__0816"]=$value;
$gammas["GTAB_B__0816"]=$value;
break;
case "black":
// set gammas array and postpone setting values in the camera
$value = intval($value);
$gammas["GTAB_R__0824"]=$value;
$gammas["GTAB_G__0824"]=$value;
$gammas["GTAB_GB__0824"]=$value;
$gammas["GTAB_B__0824"]=$value;
break;
}
// If any gamma value was set, set all gamma values in the camera.
// Was postponed earlier
if ($gammas != NULL) {
// values are taken from the green color
elphel_gamma_add($gammas["GTAB_G__0816"]/100, $gammas["GTAB_G__0824"]);
// Apply the values at the frame ahead
elphel_set_P_arr($gammas,$ahead);
}
//
// Add code to form the output here
}
?>
The code looks for HTTP query parameters black (level of black) and gamma and sets them at the same time.
The parameters should be integers: 1 < gamma <= 100 and 0 <= black <= 50.
The undocumented function elphel_gamma_add(int gamma, int black) is used, where the value of gamma for this function must be a float 0.1 < gamma <= 1.0. Without it the gamma values are not effected. More can be found in the file camvc.php in /mnt/flash/html.
