Original question:
Tool/software: TI-RTOS
Hi,
Anybody know how to enable GLBCE in 12-bit linear mode ? Image sensor used is OV10640.
Hi Mayank,
Thanks for your reply !!!.
We were trying to improve low light performance by enabling GLBCE in 12-bit linear mode. Is this GLBCE is capable of improving low light performance ? What kind of result we can expect by enabling it ?
We tried enabling GLBCE as you suggested. We configured GLBCE parametrs values as recommended values mentioned in TRM and GLBCE tuning guide.
static vpsissGlbceConfig_t glbceCfg_ov10640 =
{
TRUE, /* ENABLE */
128u,//240u, /* IR Strength */
0, /* blackLevel */
65535, /* White Level */
12, /* Intensity variance */
7, /* Spacial variance */
0,//6, /* Bright Amplification Limit */
0,//6, /* Dark Amplification Limit */
VPS_ISS_GLBCE_NO_DITHER, //VPS_ISS_GLBCE_DITHER_FOUR_BIT,
72, //64, /* MAX Slope Limit */
64, //72, /* MIN Slope Limit */
{
0,5377,10218,14600,18585,22224,25561,28631,31466,34092,36530,
38801,40921,42904,44764,46511,48156,49706,51171,52557,53870,
55116,56299,57425,58498,59520,60497,61429,62322,63176,63995,
64781,65535
}
};
We tried reading GLBCE parameters while streaming (black level, White Level, Intensity variance, Spacial variance etc). These are same as updated values as in vpsissGlbceConfig_t structure.
As per our knowledge it is recommended that all parameters be set statically to their recommended values other than the iridix strength parameter, which should be controlled dynamically with scene content. But the iridix strength we are getting as a constant value of 128 while streaming. It is not varying as per scene changes.
Could you please update on our few queries.
1. Is this GLBCE is capable of improving low light performance ? What kind of result we can expect by enabling it ?
2. What all things we need to take care while enabling GLBCE in linear mode ?
3. Where is thing iridix strenth calculation and and updation as scene changes happening in software code ?
Please check below images captured in our lab. These are captured with GLBCE ON and OFF for same scene.
GLBCE OFF
GLBCE ON
Hi Mayank,
We enabled GLBCE by making pPassCfg->openPrms.isModuleReq[VPS_ISS_ISP_MODULE_GLBCE] = (UInt32)TRUE; in IssM2mIspLink_drvCreateDrv() function. GLBCE control 0 register (0x52051008) is 0x00000009 while streaming; which means GLBCE enabled. Is this changes alone is sufficient for GLBCE ?
1. For WDR mode (which having GLBCE enabled) we could see pPassCfg->ispPrms.glbcePath = VPS_ISS_GLBCE_PATH_ISP; instead of pPassCfg->ispPrms.glbcePath = VPS_ISS_GLBCE_PATH_DISABLED;
Is this needed for GLBCE in 12-bit also ? After changing this GLBCE_PATH_ISP; GLBCE control 0 register (0x52051008) is 0x00000009 when streaming starts later it changes to control 0 register (0x52051008) is 0x00000008 ; which means GLBCE disabled. A pink color observed around light sources. But the headlight in dark environments looks better.
2. Shifting up input before GLBCE and shifting down by 4-bits after GLBCE is handled for WDR mode and monochroma mode only. Is this needed for linear mode as linear mode has 12-bit data ?
/* For monochroma path and 16bit WDR mode, it is required to shift up the input before GLBCE and shift down by 4 bits after GLBCE. */
if ((ISSM2MISP_LINK_OPMODE_12BIT_MONOCHROME == operatingMode) ||
(ISSM2MISP_LINK_OPMODE_1PASS_WDR == operatingMode))
{
}
Pink color disappeared after adding ISSM2MISP_LINK_OPMODE_12BIT_LINEAR mode here for shifting i/p and o/p . But light sources in dark environments (dynamic range scene) become worse as more spreading observed.
3. This picture is captured after enabling following.
pPassCfg->openPrms.isModuleReq[VPS_ISS_ISP_MODULE_GLBCE] = (UInt32)FALSE;
pPassCfg->ispPrms.glbcePath = VPS_ISS_GLBCE_PATH_ISP;
Having a pink tint.
4. Please give your suggestions regarding our queries.
