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DLPC350: min. exposure setting

heekong Lee
Prodigy 20 points
Part Number: DLPC350

I'd like to use as the shortest exposure as possible to keep a camera from overexposed.  

According to DLPS029–APRIL 2013 doc. about dlp 4500 dmd, it is said that a time slot  is 2.78ms and max. freq. is 120Hz.

So, I tried to set the exposure time of dlp under 8.44ms,  but invalid. 

As I understand, 8 bit planes are displayed in one time slot. 2.78ms exposure setting not possible? 

  • 0
    TI__Mastermind 28005 points

    Heekong Lee,

    Welcome to the E2E forums and thanks for your interest in our DLP technology.

    Is it possible for you to share your pattern configuration? It is unclear from your testimony above how you are setting up the system.

    Regards,

    Philippe

  • 0
    Prodigy 20 points

    Hello, Philippe Dollo,

    Thanks for your response.

    For structured light application, 8 bit 8 patterns sequence projected using pattern sequence mode from flash memory. 

    We found out the min.  val of both period and exposure  is  about 8.3 milliseconds.

    Camera captured by trigger out 1 of dlpc 350, and its exposure determined by trigger pulse width.

    We need the shortest exposure time of projector to prevent an image from being overexposed.

    Is there any way to reduce trigger-out-1 pulse width under the same exposure?

    Regards.

  • 0 in reply to heekong Lee
    TI__Expert 3825 points

    Heekong Lee,

    Please refer to table 4-1 in the LCR4500 EVM user guide for the minimum exposure time required shown below.

    Regards,

    Akhil

  • 0 in reply to Akhil Guntumadugu
    Prodigy 20 points

    We apply those min. exposure time, but try to find the way to reduce it for camera's overexposure. Thanks, anyway

  • 0 in reply to heekong Lee
    Prodigy 20 points

    Hello, Philippe Dollo,

    Thanks for your response.

    For structured light application, 8 bit 8 patterns sequence projected using pattern sequence mode from flash memory. 

    We found out the min.  val of both period and exposure  is  about 8.3 milliseconds.

    Camera captured by trigger out 1 of dlpc 350, and its exposure determined by trigger pulse width.

    We need the shortest exposure time of projector to prevent an image from being overexposed.

    If we use only blue LED,  can we set freq. as 360Hz instead of 120Hz?

    Regards.

  • 0 in reply to heekong Lee
    TI__Mastermind 28005 points

    Heekong,

    If you use a single color LED, it does not change the minimum exposure time per bit. Rather, it simply reduces the total number of bitplanes being shown. You may want to see if you can use a more suitable camera for your application.

    Regards,

    Philippe