Nonlinear intensity mapping of the Lightcrafter DMD

Hi Pepe,

The mapping should be 1:1 if you're in pattern sequence mode. All the video functions/corrections are disabled in that mode and the EVMs are "pixel-accurate."

Why do you believe that what you are seeing is incorrect?

Thanks,
Paul

Hi Thanks for quick reply.
I am displaying a sinusoid in display mode 00: Static Image. In this mode, are those video functions/corrections also disabled?
Thanks for your support, Pepe

In static image mode, the video functions are enabled and therefore the output is NOT pixel accurate. Pattern sequence mode IS pixel accurate, so I recommend that you set up your .bmp file as a simple pattern sequence.

Interesting, I will try then in sequence mode.
Thanks Paul

Hi Paul,

I remember why I was using static mode vs sequence mode. Indeed, I cannot project an 8 bit image gray scale. This was something I posted some time ago. See
e2e.ti.com/.../496300

I decided then to use static images, and made my sequence by first loading the image in static mode then projecting it, doing this for every image in my sequence.

I also tried using the GUI and keeps on showing like binary images.
Can you help me?

Thanks

Hi Paul,

I found something. When using the sequence mode in AutoTrigger I can project gray scale images. However, when using Software trigger (which is the one I need) I cannot project gray scale images. Is this soemthing known/solvable?

Thanks a lot! pepe

Pepe,

I was able to take the image you provide in the post you linked and get an 8bit image to display using the GUI. Here are my settings:

Can you try this again on the GUI and see if it works for you?

Can you clarify what you mean by software trigger? I changed the trigger type to "Command" on the GUI and had no issue displaying the pattern.

Thanks,

Paul

Hi Paul,

Thanks for your effort.

So I tried using the GUI, first I use auto trigger with the following settings (Figure 1) and it works good, showing a good looking sine wave (Figure 2)

Figure 1:

Figure 2:

However, When I change the settings to command trigger (Figure 3), the projected images looks binary as shown in Figure 4

Figure 3:

Figure 4: I get this binary image

What can be the cause? may be the sequence in which I perform the necessary steps?
Thanks for your help, Pepe

How are you capturing the images?

Try making your exposure longer. From your image above, your exposure is 8333us, which is rather short and hard for the eye to catch. I made my exposure 1,000,000 us (1 sec) and I was able to clearly see the 8bit image.

Here's what I'm thinking - if you're using some sort of triggered camera with a very short exposure time, you could be taking an image of one of the bit planes being displayed and not allowing enough time for all the bit planes to be displayed and integrated by the camera.

-Paul

Hi Paul,

The images are taken using my phone's camera. In fact those images are clearly seen by me (the pattern is continuously many times projected, so I can see it). When using auto the image clearly looks gray scale, when using command, the image looks binary.

I will try with a exposure time longer.

In the meantime, is there a way of disbaling the video correction/functions so I can use the static image mode without the video correction?

Thanks Paul

I think if you follow the example given in table 2-106 in the DLPC300 programmer's guide: www.ti.com/.../dlpu004b.pdf, you'll get what you want. In that example there are functions used for turning off some of the video features.

I'm honestly stumped on why your image would be binary....I'm able to see a grayscale version and with the same settings that you have. You haven't done any modification to your LCr?

The only other thing I could suggest would be to reload the FW onto the device, maybe something got corrupted.

-Paul

Hi Paul,

By setting exposure time to 1,000,000 microseconds, I can see the sinusoid for (I guess) 1 second after I click the next button, then it comes back to binary (???). May be I didn't understand the 'command way' of sequencing patterns. The way it works is that at every click on next button, the following pattern is projected ONLY ONCE by exposure time microseconds?
When using autotriger, if only one pattern has been uploaded, this patterns keeps repeating.

Thanks for your help, Pepe

"Command" is used such that any time you hit the "next" button, it projects the pattern. This is equivalent to a software trigger from my understanding (which is what you said you wanted to do).

Yeah, OK. I think for now I can close this line. I will try to live with the auto trigger mode, or maybe the static mode is not so bad.

Thanks again for your time.