HDMI decoding algos

Hi Sanjeev,

Thanks for your rapid response. I will have a look at the programmer's guide.

Hi Sanjeev,

If I want a pattern rate of 1440 Hz, can I follow the steps:

1. Encoding every 24 patterns into one frame according to Table 2-104. DLPC300 24-bit RGB Input Pin to 1-bit Monochrome Image Bit Mapping

2. Making the frames into a 60 Hz video

Best Regards,

Freddie

Hello Freddie,

#1.

(a) Have built your own board? (b) Are you using LightCrafter Kit 

For (a) - if your answer is 'Yes', you must also make sure, Table 2-81. Steps to Configure DLPC300 for Pixel Accurate Video Mode with External Input from 24-bit RGB Parallel Port, setting made to the DLPC300.

For (b) - if your answer is 'Yes', you can skip Table 2-81, steps, because DM365 automatically take care of configuring the DLPC300.

#2.

Yes. Your understanding is correct.

Regards,
Sanjeev

DLPC300 Programmer's Guide link http://www.ti.com/lit/ug/dlpu004b/dlpu004b.pdf

Hi Sanjeev,

More questions, see them in the README file in the attachment, and I will also post them here.

All the 8 pictures are green and of the same pattern, but differs in brightness.
The brightness is indicated in the file name.
For example, pixels on the picture 00000000_10000000_00000000 are either in green

and of brightness 128, or totally black.

Here are my questions:

1. According to Table 2-104, are all of the 8 pictures going to be decoded into 23

black images and 1 with the information of the shape?

2. If so, according to Figure 2-20, do the 24 images have equal exposure?

3. After configuring the GUI to the "1440" mode(monochrome, 60 Hz, 1-bit), there

is still light where is supposed to be totally black. See the attached photo.

Best Regards,

Freddie

Hello Freddie,

#1. Yes

#2. Yes

#3. For others sake including the picture

Try below two options - 

A)

Create a ALL black picture and repeat the setup procedure.

If you are seeing background still with color then it is something to do with the Light Engine that is used in the LightCrafter Kit, the light that you are seeing from the projector in this case is what is called as 'off state light'. As you know when the DMD is loading '0' the light is deflected to another angle from the actual projection screen angle, ideally you need a 100% absorption system to capture the 'off state light', based on the how much off-state light is escaping determine the contrast ration. In this kit it is 685:1 so it is a bit low.  

This is mostly likely the problem you are seeing, couple of things you can mitigate this effect, use 'Blue' or 'Red' Color the LEDs not as bright as Green LED. Alternatively reduce the Green LED current. See if it helps.

B)

Make sure on the source side on PC graphics card setting, disable the gamma correction and other settings, it should send 24bit pixel data unmodified.

Regards,

Sanjeev

Hi Sanjeev,

Can the two Yes lead to the conclusion that -

The 8 pictures should look exactly the same when being projected?
I forgot ask this last time. In my case, they didn't look the same!

Best Regards,

Freddie

Hello Freddie,

yes, the 8 pictures background should look exactly the same. Can you upload the captured pictures and point which area in the pictures not looking exactly the same...

How are you capturing the images, is it a free running camera? for the best result, use the hardware trigger camera as it ensures uniform exposure across the image captures and camera integration time per captured frame remains constant.

Regards,
Sanjeev

Hi Sanjeev,

I adjusted my graphics card and my last problem is solved. See the .pdf. Thanks a lot.

Best regards,

Freddie

Pleasure is ours :) Good luck with your project.

Regards,
Sanjeev