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Minimum exposure time and maximumf rame rate

Scot Smith
Prodigy 50 points
Other Parts Discussed in Thread: DLP4500, DLPC350

Using the DLP LightCrafter 4500 Development Platform,

1. What is the maximum bit depth of a monchrome(red) image that can generated in 1.7 ms? 

2. If the unit is run in  a sequence mode what is the maximum bit depth of a monochrome(red) image that can support a frame rate of 80 hz for a total of a 100 images? 

3. Can the projector lens of the kit be removed easily?

4.  When loading/streaming an external image does the image need to be loaded by individual bit planes or can an n bit monochrome image be loaded/streamed directly?

  • 0
    TI__Expert 4720 points

    Hello Scot,

    Please read my responses below and let me know if anything needs further clarification.

    1. If you reference the DLPC350 datasheet, Table 6 "Allowed Pattern Combinations" shows the maximum rates. 1/1.7ms = 588Hz so the maximum bitdepth for the DLP4500 at that speed is 4.
    2. When you say 100 hundred images, do you mean a 1-8 bitdepth pattern or an 24-bit RGB image? Depending on how well the prestored images are compressed, up to 256 images can be stored on the flash.
    3. Yes the optics can be removed. Light Engine Removal
    4. When streaming images through the DLPC350 video port for pattern sequence mode, you need to send a 24bit RGB image and the controller will slice it up per the set LUT definitions.

    Best regards,

    Blair

  • 0 in reply to Blair Conner
    Prodigy 50 points

    Thanks for the responses.  For question 2, I will try to provide a more detailed question.

    What I ultimately would like to do is be able to display a sequence of images at the maximum bit depth possible at the frame rate I need. (More bit depth would be better but 4 will suffice).  Given a monochrome(red only) 4 bit image, I will need to display more than the (12??) that the two 24 bit buffers can store.  If I load up to the maximum number of 4 bit images into flash (384??) what is the maximum rate that I can display the 4 bit monochrome images given the overhead time required to load images to the buffer from flash?

  • 0 in reply to Scot Smith
    TI__Expert 4720 points

    Hi Scot,

    Thank you for the clarification. Unfortunately, I can't give you a direct answer on the maximum rate due to the overheard. When the images are uploaded to the DLPC350, they are also compressed which can change the overhead time to load the buffer depending on the complexity of the image. Some images load into the buffer in about 80ms, while others can take upwards of 300ms. 

    The DLPC350 can address up to 256 images, so you may be able to optimize the compression by only storing one or two patterns in the 24-bit RGB image. If you were to pack as many 4-bit patterns into the flash images (6) you could store are total of 1536 four bit patterns. 

    The fastest way to load data into the buffer, and also allows an essentially infinite number of patterns, is to use the video port data rather than flash in pattern sequence mode. You can load full 24-bit RGB images at 120Hz.

    Let me know if you have any more questions!

    Best regards,

    Blair