DLP4500: LightCrafter 4500 Monochrome mode for external light source?

Will,
Is your video source RGB24-bit monochrome or color? I am presuming your content is monochrome. For monochrome mode, you can select Pattern Sequence Mode, refer to user's guide for the configuration steps.
Regards,
Sanjeev

Hello Sanjeev,

The video is sent over HDMI, and the video is monochrome yes.  If I am in pattern sequence mode I can still send my video over HDMI, yes?  I will review the LightCrafter user guide again but it did not seem clear to me in answering this question.

Thank you

Will

Hi Will,
Yes you can use pattern sequence mode with video data coming from the HDMI port. Let me know if you face issues while referring to User Guide and setting up the hardware.
Regards,
Sanjeev

Hello Sanjeev,

I have attempted to set up pattern sequence mode by doing the following:

Color settings: RED
Pattern source: Video Port
Trigger mode: VSYNC
Frame index: 0
Bit Depth: 8
Pattern: R0-R7
Clear DMD after exposure: YES
Pattern exposure time: 9000
Patterns period: 9000
Pattern Sequence play once/repeat: REPEAT

I then "Send" this, "validate" it, and press play.

At three different camera shutter speeds (30Hz, 60Hz, 120Hz) the video is very bad quality and shows a "strobe" effect. If I place an image or the LightCrafter control software window onto that output it pulses very badly through the different frames. The light and dark areas of each bitplane can be seen change "in slow motion".

I expected that the DMD would refresh fast enough that my camera at 30Hz would not see these transitions? I will post some screenshots shortly.

Thank you,
Will

Hi Will,
What kind of camera you are using? Note for the pattern sequence mode you must input the video of resolution 912x1140, if your camera can support trigger input then you can use the trigger output signal on the kit to synchronize the out put video capture.
Regards,
Sanjeev

Hello Sanjeev,

I have checked that the video resolution is appropriate, and I have connected to the Trigger 1 output on the DLP4500 EVM board.  At the same settings that I have set above, I am seeing the output trigger go low (3V3 to 0V) every 16.5ms approximately from just looking at the trace on an oscilloscope.  This would be the near-60Hz frame sync I imagine.  However, adjusting the exposure time and the number of bitplanes doesn't appear to change any output triggering.  In trying to run the device in monochrome mode I can't seem to adjust how fast the frames are displayed.  In section 3.3.1 of the documentation (DLPU011F) page it says that trigger 1 frames the exposure time of the pattern, but when I have changed the exposure time this trigger output does not appear to change.

Thank you for your help

Will

Hi Will,
In streaming mode the pattern exposure and rates limited to the highest supported rate. In you case you can only be able to display only one 8-bit pattern at 120Hz. The controller can receive maximum 120Hz vsync. If you need to increase it beyond then you will have to reduce the bit-depth and try to display more than one pattern.
Regards,
SAnjeev

Hello Sanjeev,

Based on what you say, and the information in pages 42-45 of the DLP4500 document DLPU011F, if I reduce the bit depth of the image that I send in pattern sequence mode I will be able to expose these for less time, and speed up the frame rate? We are still using video input as the source. If I am in pattern sequence mode, and I choose 6-bit color, is the 6-bit color spread over the same 256 bit partition as mentioned on page 42 (figure 4-2)? or is it shorter in time at 6 bits than it is at 8 bits as the table 4-1 seems to suggest?

Thank you for your help
Will