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DLP4500NIR: DLP4500NIR and gray scale video

Part Number: DLP4500NIR
Other Parts Discussed in Thread: DLPC350, DLP4500-C350REF, DLP4500, DLPLCR4500EVM

Hi! We need to project gray scale video. We are going to use DLP4500NIR.

I am aware of image processing in PLPC350. Color processing bothers me.

If we pack three 10-bit gray frames into 30-bits bus input, can DLPC350 output these frames independently of each other and bit-plane weighted?

I.e. can these frames have equal time slots?  Will the DLPC350 control the time 10-bit-plane is exposed to light?

Thank you and I look forward to your reply.

Regards,
Alexander

  • Hello Alexander,

    I believe the DLPC350 actually only uses a 24-bit input bus (the 2 lowest bits of each channel are not used). The DLP4500-C350REF design for the schematic of the DLPC350 (this reference design is for the DLP4500 but the schematic should be nearly equivalent).

    The DLPLCR4500EVM GUI can be used to configure the display as desired. Each of the 24-bitplanes can have equal exposure time.

    Thanks,

    Kyle

  • Kyle,

    Thank you for your reply!

    I got that 10 bits are not realizable, but it's okay. We will use three 8-bit frames.

    We haven't purchased DLPLCR4500EVM yet. At first we want to determine would DLP4500 be suitable for our needs.

    The datasheet  for DPLC350 says there are two modes the pattern display mode and the video mode. In the video mode the video processing algorithms are engaged. And in the pattern mode the video processing is bypassed.

    So our choice is the pattern mode, because we don't need any video processing algorithms, but one that makes 256 levels of luminescence from 8 bits input.

    The question is can we get three 256-level grayscale images from the 24-bit input  in the pattern mode?

    Regards,

    Alexander

  • Hi Alexander, 

    You can display three 256 level grayscale images from 24bit input in pattern mode. However, you need to note the following points:

    1. The DMD shows bitplanes in a Time Division Multiplexing scheme. So the grayscale levels will be achieved by displaying each bitplane for a particular time depending on bitweights.
    2. The minimum exposure time for a 8bit grayscale pattern is approx. 8270uS. So, if you are operating at a framerate >40Hz, it is not possible to display ALL 3 8bit grayscale patterns in a single frame time. You have to chose less number of bitplanes / patterns to display.

    Hope this clarifies your doubts. 

    Thanks & Regards,

    Hirak.