TMS320DM368: Flickering

Jishana Shaji

Part Number: TMS320DM368

Hi,

Hi,

We had the issue of flickering when camera facing to light and on mobile flash, for that issue we made a fix by setting the minimum exposure to 10ms as reffered from TIE2E. And provided an option for flicker control enable, this exposure limit is applicable for only when flicker detect is enabled. That code part shown bellow setting the lower limit of exposure value.

Now another issue generated that is If flicker detect is enabled in day mode video is over exposed. Botht the two issue are not there in reffernce camera, which is using the same sensor ARO330 but processor is AMBERELLA.

And another issue is also there in some specific lighiting condition inside closed room with PAL light flickering is happening and the walls in that rom are painted with bright colour.

In the doc "Flicker Detect on DM36x IPNC" I found 2 known issues on Camera Conditions

Issue 1: The IPNC camera is pointed directly at a light source.
Issue 2: The IPNCE camera is in the presence if a weak NTSC or PAL light source.

Do these two issues have connection with what i stated above, and what does it meant by weak NTSC or PAL light source.

Suggest me any solution if there.

int DRV_imgsSetEshutter(Uint32 eshutterInUsec, int setRegDirect)
{
#if 1
int status;
Uint16 regAddr;
Uint16 regValue;

Set_Shutter = eshutterInUsec;
if (eshutterInUsec <= shutterSet_User) {
if (flicker_detection == 1) {
if (eshutterInUsec <= 8333)
eshutterInUsec = 8333; /* Min Exposure time for NTSC(60 Hz) */
} else if (flicker_detection == 2) {
if (eshutterInUsec <= 10000)
eshutterInUsec = 10000; /* Min Exposure time for PAL(50 Hz) */
}
regAddr = AR0331_COARSE_IT_TIME_A;
regValue = (float)(eshutterInUsec/ROW_TIME);
} else {
regAddr = AR0331_COARSE_IT_TIME_A;
regValue = (float)(shutterSet_User/ROW_TIME);
}
status = DRV_i2c16Write16(&gDRV_imgsObj.i2cHndl, &regAddr, &regValue, 1);
if(status!=OSA_SOK) {
OSA_ERROR("DRV_i2c16Write16()\n");
return status;
}

Thank you

over 9 years ago

0 Anuj Kumar Gupta over 9 years ago

Genius 4030 points

Hi,
I will inform IPNC team to look into this issue.
Meanwhile you can search for similar e2e threads.

Regards,
Anuj
PathPartner Technology Pvt Ltd

0 Ravikiran HV over 9 years ago

Mastermind 8715 points

Hi,

based on the light source yoe, you can switch between 60Hz vs 50Hz flicker control. Changing this option based on light source might help.

0 Jishana Shaji over 9 years ago in reply to Ravikiran HV

Intellectual 445 points

Hi,

Over exposure issue is still there. Even though I switch between 50hz or 60hz.

But i have made change in minimum exposure to 10ms in TI_2A_config function, in av_capture/framework/alg/src/alg_aewb.c file.

Now step size and exposure both are 10000, now the flicker inside a closed room with bright painted walls disappear when i select shutter speed to 1/50. but flicker will be there if I choose shutter speed to 1/25.

Can we do any fix to avoid the flicker in 1/25 shutter speed? and also how to remove this over exposure issue?

int TI_2A_config(int flicker_detection, int saldre)
{
IAE_DynamicParams aeDynamicParams;
int i;
int retval;

i = 0; aewbFrames = 0;

#ifdef FD_DEBUG_MSG
OSA_printf("\n\n\n\n\nTI_2A_config: flicker detection = %d\n\n", flicker_detection);
OSA_printf("Aew_ext_parameter.env_50_60Hz = %d\n", Aew_ext_parameter.env_50_60Hz);
#endif

/* set stepSize based on input from Flicker detectiom and PAL/NTSC environment */
int step_size, min_exp;
if (Aew_ext_parameter.env_50_60Hz == VIDEO_NTSC)
{
step_size = 8333;
if (flicker_detection == 1)
{
min_exp = 8333;
}
}
else if (Aew_ext_parameter.env_50_60Hz == VIDEO_PAL)
{
step_size = 10000;
if (flicker_detection == 1)
{
min_exp = 10000;
}
}
else if (Aew_ext_parameter.env_50_60Hz == VIDEO_NONE)
{
step_size = 0;
}

TI_2A_AE_config(&aeDynamicParams, min_exp, step_size);

if(gALG_aewbObj.vnfDemoCfg)
{
aeDynamicParams.exposureTimeStepSize = 20;
aeDynamicParams.targetBrightness = 100;
aeDynamicParams.targetBrightnessRange.min = 90;
aeDynamicParams.targetBrightnessRange.max = 110;
}

this was the part of code.

Thank you.

0 Prashant A over 9 years ago in reply to Jishana Shaji

Intellectual 760 points

Hi Jishana,

Is AEWB enabled or you are setting exposure and gain manually?

Flicker effect vary as per exposure value and different light condition.

Regards,

Prashant

PathPartner Technology Pvt Ltd

0 Jishana Shaji over 9 years ago in reply to Prashant A

Intellectual 445 points

Hi,

AEWB was enabled.

1.Do we have any solution for over exposure on video once flicker detect is on?

2.Flicker effect is gone when the shutter speed was 1/50 and also fps was 30 when I set 30. If shutter speed is 1/25 then flicker is observing and fps goes to 25 .

There is anything can I do from back end?

Thank you.

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TMS320DM368: Flickering