DLPDLCR2010EVM: Actual full content frame rate / Color bending

Rinalds,

Welcome to the E2E forums, and thanks for your interest in our DLP technology.

On the DLPDLCR2010EVM, the maximum refresh rate available is 240 Hz. This means that the system will refresh the full image content at a rate of 240 Hz.

Can you please describe your use case in more detail? It sounds like you are sending a content frame on 1 of each 4 frames, maintaining a 240 Hz rate. Is this correct? If so, what content are you using that you observe color banding in?

Regards,

Philippe

Philippe

Philippe Dollo said:

It sounds like you are sending a content frame on 1 of each 4 frames, maintaining a 240 Hz rate. Is this correct?

Yes, you are correct.

System architecture is as follows.

Video input goes to the frame buffer (854*1920"60Hz, 4 frames of 854x480 resolution).

Frame buffer splits this one large frame into four smaller frames 854x480 and pass this video to Lightcrafter at 240Hz FR.

Philippe Dollo said:

If so, what content are you using that you observe color banding in?

Image is Color spectrum chart.

Philippe

Quick update!

First test setup - If green color is removed from spectrum chart  (not displayed), there are no color banding, thus green color is a cause of such effect.

Second test setup:

1) lightcrafter connected directly to PC (240Hz)

2) different types of images are fed to the lightcrafter

3) lightcrafter projection sistem output is fed to the pm400 optical power meter. From measurements can be seen that green color is shown twice - in the beginning and at the end of the each frame.

Could it explain this strange effect?

Thanks in advance,

Rinalds

Hello Rinalds,

It is likely we will show some colors (such as green) more than once each frame. Are you seeing the same effect at 60 Hz and 120 Hz? Could you please also clarify a bit what exactly is meant by color banding? I just want to make sure we are on the same page. If possible an image capture (or illustration of the effect) would be useful.

Thanks,

Kyle 

Hello Kyle,

Have a look at the picture attached.

P.S. Will try run same test with 60Hz  / 120Hz

Rinalds

Hi Rinalds,

Thanks for the image. Could you show what it's supposed to look like? I'm a bit confused what I'm looking at.

Thanks,

Kyle

Original image.

Difference between this image and image posted earlier is that:

a) one of them is captured upside down

b) image, that posted earlier is from lightcrafter 2010 and is shown 1/4 of 240Hz FR. That means 1 frame is this image, next 3 images are just black.

Hi Rinalds,

So the exposure period in the previous image is (1/240)/4 = 1.04ms? Or is it a exposure period of 4*(1/240) = 1/60 = 16.67ms? Is there movement in this image? 

Thanks,

Kyle

Hi Kyle,

Exposure period is 16.67ms.

There are no movement in the image.

Rinalds

Hi Rinalds,

I'm honestly not sure why the capture looks so much different than the input image. Are you able to feed the same output to a separate video display so we can eliminate the front-end from being a potential problem? Also could you confirm the image capture is approximately what is visually seen in-person as well?

Thanks,

Kyle

Hello Rinalds,

I will also add it is likely the interface between the front end and input to EVM may have incorrect timings, or incorrect Vsync/Hsync signals.

Could you try capturing VSYNC and HSYNC as well? Also please try with a monochrome primary color first and see how the image looks.  

Thanks,

Kyle