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LightCrafter4500 1bit Pattern Projection or Virtual Beam Scanning

Adnan Kurt
Intellectual 665 points

Hi,

I am developing hardware for a research grade confocal microscope. For this purpose, I am using a hacked LightCrafter4500 unit. Illumination and projection hardware are removed, only using the DMD unit for beam steering and shaping.

I understand that there are limits for number of patters stored internally. So, my questions are:

0. I am willing to use 1bit depth patterns.

1. Is there any method to increase number of patterns to about 10,000? Are we limited by the DDR Ram size? 

2. I also need fast scanning, less than 100uS per pattern. Any foreseen limitation? 

3. If it were possible using external flash, or USB download; would there be any trick to put data (patterns) into the image buffer? Might be slower but would be very convenient and flexible.

I would appreciate your comments and advise a lot.

Regards,
Adnan Kurt

  • 0
    TI__Genius 13235 points

    Hi Adnan,

    The external flash memory can support up to 64 images (24-bits each). If you could store 64 images @ 24 bits per image, you could store ~1500 1-bit planes. Any pattern that is projected will be loaded in as a 24-bit image into the image buffer, which can hold 2 24-bit images (48 1-bit patterns).

    If you need to project ~10,000 unique 1-bit patterns, you will need to stream them in over the video port. Using this method, 1-bit patterns can be displayed at 2880 Hz, with a minimum exposure time of 235us. That value, 235us, is the minimum exposure time for this device. Included in this time is the image buffer load time.

    Please see table 4-1 Allowable Pattern Combinations in the LightCrafter4500 user's guide (http://www.ti.com/lit/pdf/dlpu011) for more information on the pattern rates.


    Thanks,
    Clinton

  • 0 in reply to Clinton Rodgers
    Intellectual 665 points
    Hi Clinton,

    Thanks for your prompt and clear answer. Now I can see my path clearly. I will try the proposed schemes. I will check video streaming which seems to be well suited for the task as well. Though I cannot see what kind of problems I will face :).

    Best Regards,
    Adnan Kurt
  • 0 in reply to Clinton Rodgers
    Intellectual 665 points
    Dear Clinton,

    I am still busy with this pattern projection problem. I have another question:

    When delivering 1bit patterns over video port, how should I set the video display settings on the PC? I have tried the relevant settings on the LightCrafter interface, to pattern sequence for example. And I can prepare 1-bit patterns on the PC. However, I could not figure out how to send the image files. Would you please give me a hint about it?

    Regards,
    Adnan