DLP3010EVM-LC: Display 2D patterns in synchronization with trigger out signal in external pattern mode

Hello Vivek,

Thanks for your answer!

There is one more thing I'm curious about. I'm sending binary patterns (black and white images) to the DLP, but when I set the bit depth to be 1-Bit, the patterns just seem awkward. Is it because black and white images are still 8-Bit images? Do you have any idea on how can I encode the patterns? Thank you!

Best,

Jieliyue

Hi Arthur,

Thanks for the reply. Now I'm setting 24 patterns on each bit of one 24-Bit frame. And I want to make a video of those frames to display a series of patterns.

I have 2 more questions:

1. What's the maximum frame rate I can set in external pattern mode?

2. I noticed that if I set the pattern per frame to be 24, there will be an extra dark time in each frame, just as the figure shows. How long is it exactly?

Best,

Jieliyue

Hi Philippe,

Hi Philippe,

I used an oscilloscope to measure the trigger of the DLP. When I set the frame rate to be 10Hz and the pattern per frame to be 24 on the software, the frame rate that the oscilloscope shows is 5Hz, and only 12 patterns per frame. See the figures below.

Actually, no matter how I set the exposure time and dark time, the pattern trigger seems to be always at 60Hz. Is there something wrong with the DLP? Or something wrong with the output trigger? Can I change the pattern rate?

Best,

Jieliyue

Hi Philippe,

I repeat the experiment using the same parameter. I hit the 'Get' button to see the actual setting for the DLP and the frame rate is 2.5Hz, which is correct for displaying 24 patterns at the exposure time of 16666 us.

Still, the frame rate measured by the oscilloscope is 5Hz, and 12 pattern triggers between 2 frame triggers.

Also, I tried different exposure time. This time the pattern rate should be 24Hz.

But the actual pattern rate measured by the oscilloscope is 60Hz.

Hello Jieliyen,

How are you sending the pattern? Could you please capture the Vsync of input data and see what is incoming frame rate?

regards,

Vivek

Hi Vivek,

I sent the patterns through HDMI port. The DLP will project the interface on my laptop. I don't know how to capture the Vsync. Could you offer some advice?

Also I'm wondering if I can send pictures/video as file to the DLP through HDMI port, so the DLP will show only the pattern, not the entire computer interface. 

Thank you!

Best,

Jieliyue

Jieliyue,

The DLP will receive images like a standard display would over the HDMI signal. If you want to prevent it from receiving your computer interface, you will need to adjust your frontend (which in this case sounds like your computer) to prevent it from being sent to the external display in the first place.

Vivek is suggesting above that you trigger an oscilloscope with the VSYNC signal of your video output to see what the incoming frame rate is.

Regards,

Philippe

Thank you. I noticed the Vsync is the same as the refresh rate of my laptop.

Do I need specific software to open the image? I encode the 2D black and white patterns into each bit plane of the 24-bit image. Then I opened it with Matlab, connect to the DLP, and set the bit depth = 1, patterns per frame = 1 in DLP's light control mode. But I noticed that the displayed patterns is slightly different from the first bit plane of the image. For example, this is the first bit plane of the image:

This is the displayed patterns:

You can see that especially around the edges, they are not the same. So does other patterns I tried. But I need the patterns to be displayed correctly. Is it because of the DLP or other factors?

Also, when I move the picture around, the pattern change its shape too, like

Best,

Jieliyue

Hi Jieliyue,

If you are showing one pattern per frame it may be best to use a 1 bit .BMP intead of 24 bit image.

I also notice that your image resolution is 1368x572. instead of 1280x720

Are you showing 1 pattern per frame at 60 Hz or 24 Patterns per frame at 2.5 Hz?

Regards,

Arthur

Hi Arthur,

How should I open the 1-bit BMP file? If I opened it with software like Photo Viewer or Matlab, it will convert to 8-bit automatically. 

I resized the image on my laptop screen when I opened it. 

I'm showing 1 pattern per frame at 60 Hz. The setting is pre-exposure dark time = 1000us, exposure time = 14000us, post dark time = 1666us, bit depth = 1, pattern per frame = 1, illumination with only red LED. 

Also, can I upload the 1-bit pattern to the flash drive and display them? I'm thinking that the artifacts might be caused by the streaming mode. 

Best,

Jieliyue

Jieliyue,

I tested this and what you need to do is make your image the same resolution as the DMD, so make your image 1280x720. make sure that the video input to the EVM from your laptop is 1280x720, and make sure that the image is full screen on the projector

1) create pattern that is 1280x720

2) in display settings on my laptop select 'extend display', and on my 2nd display (EVM) make sure the resolution is 1280x720

3)open desired.bmp in windows photo viewer on the display of the EVM

4) press F11 to make image fullscreen, and do not zoom - this will give the artifacts you are seeing

Regards,

Arthur

Hi Arthur, I did exact the same thing as you suggested. Here's the image I displayed on my laptop:

which is a 1280*720 .bmp file generated by Paint.

The DLP displays:  

I made sure that the resolution on both screen is 1280*720, and pressed F11 for display. The setting for external pattern mode is

But I can still see some artifacts. Can you show me the result you got using the same image as mine? Thank you.

Best,

Jieliyue

Sorry the image on my laptop should be this:

Hi Jieliyue,

I think that something about your video source is incorrect

your GUI configuration looks OK, and your .bmp is good. please make sure your video source resolution is correct. double check and image scaling other features that may be having an effect

Regards,

Arthur

Hi Arthur,

I double checked on my laptop and it's correct, 1280*720 for resolution. I even used 2 laptop for testing and in both case the artifacts will appear. Can you send me your result using the same image if possible? Also can I load the images to the flash drive and display them as 2D patterns?

Thanks!

Best,

Jillian

Hi Jieliyue

I was testing on a DLP4710EVM-LC which is the 1080p cousin of your EVM. I still believe the artifact is the same. I will need a day to find a 3010EVM to reproduce your issue as a 1:1 comparison

Yes, You can load this pattern into the splash screen index using the "Update splash image" section in the firmware tab.

you can then go to "splash patterns" in the Light control tab and display the image there

Regards,

Arthur

Hi Arthur,

Thanks. Looking forward to your result. 

I just loaded this pattern into the splash images. I set the bit depth = 1, pattern per frame = 1. The displayed pattern is exactly what I wanted without any artifacts.

So, are the artifacts generated in former experiments due to the external streaming mode? 

And I need to project a series of binary patterns. Is it possible that I upload .bin file into the flash drive (because then I can store more patterns) and project them using API? I'm not sure the EVM offers those permissions to users.

Thanks,

Jieliyue 

Hi Arthur,

Thank you so much! You're right that they need to be carefully aligned. Now there is no artifacts. 

Best,

Jieliyue