• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 100 subscribers
  • Views 269 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TDA4VM: ISP AE flicker problem

Cherry Zhou
Mastermind 22235 points
Part Number: TDA4VM

Hi team,

Here's an issue from the customer may need your help:

The AE algorithm has flicker in the video under the environment of changing light and dark, such as the entrance and exit of the underground garage. From the perspective of the printed log, it is caused by the large difference of exposure parameters between frames. How can the algorithm optimize the flicker problem?

Could you help loo into this case? Thanks.

Best Regards,

Cherry

  • 0
    TI__Guru 52935 points

    Hi Cherry,

    This flickering issue is probably related to sensor WDR.
    Please share more information on the sensor WDR details about PWL companding curve, sensor exposure range, and sensor gain range.

    BTW, please also inform me about the customer project details (name, use case, ...) via email.

  • 0 in reply to Gang Hua
    TI__Guru 52935 points

    Hi Cherry,

    Flickering in WDR case is typically caused by the combination of large sensor exposure changes and delay in the response of local tone mapping.

    In “TI_aaa_ae.c”, there is function controlling the sensor exposure adjustment.
    The current code allows adjusting sensor exposure in large steps, i.e., up to 4x.

    static void TIAE_adj_exposure(

            int32_t           currentY,

            tiae_exp_t      * prev_exp,

            tiae_exp_t      * next_exp,

            tiae_exp_prog_t * exp_prog)

     

    You may change this function such that there is no large adjustment of sensor exposure change in a single frame.

    For 20-bit sensors, around 10% exposure change per frame would be fine.