Gamma or glass filter

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Hey guys

after working for a while with my LCD I think it has a problem or maybe myself! because for seeing a picture on it I have problem. actually the problem is viewing angle or maybe brightness(I'm not sure). yes I know that it's a disadvantages for LCDs:

 

Limited viewing angle, causing color, saturation, contrast and brightness to vary, even within the intended viewing angle, by variations in posture.

I cannot see the picture very good on my LCD and while I'm trying to figure out the problem by changeing the viewing angle but still it's not work very good.

I think all LCDs have a glass filter and my LCD doesn't has. I'm speaking about that black plastic which set the brightness or contrast.

 my LCD is this:

 

figure1

Maybe that's because of the Gamma!?

now that I'm seeing the LCD it has that plastic.

 

a question,

What's the difference between contrast and brightness?

 

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

Last Edited: Tue. Feb 24, 2015 - 05:51 PM
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For an LCD, there is usually a pin where you apply a DC voltage to control the contrast. But, I don't see any described on the spec sheet. There IS a "Contrast / Brightness" register at address 0x000A.

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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Amin,

 

That particular display produces very vivid colours.    Note that you should really run it at 3.3V.

 

I just use the standard Gamma Correction values from the UTFT website.   (I think)

 

Have you still got the protective sticky film cover on the LCD?

 

David.

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This is a 2.2" SPI-interfaced ILI9341-based 240x320 TFT module that usually can be run with Adafruit's TFTv2.cpp/TFTv2.h library and examples.  I'm not sure if it has a touch screen.  But I believe that it doesn't.  However the four silver flex strips shown just off the upper right corner of screen may be a touch interface connection.

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Thanks guys

 

@Jim

yes, I initialed this register 0x01

 

david.prentice wrote:

Amin,

 

That particular display produces very vivid colours.    Note that you should really run it at 3.3V.

 

I just use the standard Gamma Correction values from the UTFT website.   (I think)

 

Have you still got the protective sticky film cover on the LCD?

 

David.

I ran it at 3.3v exactly.

my LCD just have one protective sticky film cover and it's still there.

Simonetta wrote:

... I'm not sure if it has a touch screen.  But I believe that it doesn't.  However the four silver flex strips shown just off the upper right corner of screen may be a touch interface connection.

No, it doesn't has touch screen.

 

guys,

I have done one expriment. we have a "Glassy Console Table TV stand" at home. as you can see below:

 

 

when I run the LCD:

 

 

please note that the LCD isn't too bright. that's because of the camera of my  mobile phone.

and when I put it under the glass:

 

 

Result: I should use

  • an extra protective cover film for the LCD
  • I'm not sure about this optionwink but I think I get to adjust the Gamma.

 

For Gamma I think I can use these amounts to adjust it.

 

but the question is that can I solve this issue just by adjusting the Gamma?

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

Last Edited: Wed. Feb 25, 2015 - 04:42 PM
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I suggest that you post a link to your BMP file that shows the "Fierce Bear"

and a link to your program code.

 

I will display it myself on the exact same module.

 

David.

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david.prentice wrote:

I suggest that you post a link to your BMP file that shows the "Fierce Bear"

and a link to your program code.

 

I will display it myself on the exact same module.

 

David.

Do you mean the C file of the picture?

the program isn't for AVR or Atmel products. is it necessary to post it yet?

Isn't it better to PM the whole of the project, David?

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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You can do whatever is most convenient to you.   If you attach the project in a ZIP,   I can even see what you are doing.

 

First off,   you should remove the plastic film.    It is surprising just how much 'colour' it blocks out.

 

David.

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"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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To me it looks like any gamma issue here is the camera you are using to take the posted pictures! It appears to be "washed out" beyond belief. Presumably that Arduino PCB (like most Arduino PCBs) is actually a vivid blue in real life? In your photo it looks almost muddy grey.

 

I assume when you see the bear on the screen in real life what you are seeing is, again, quite a lot more vivid than the pictures you are posting here?

 

Do you have access to a decent camera? I'm guessing the above is using the camera in your phone? Unless you have one of the latest, high end smartphones the cameras are known to be pretty poor.

 

I loaded a picture above into GIMP and fiddled with the gamma and brightness/contrast a bit and got to here:

 

 

Now it's tricky to put back what isn't there in the first place but at least the blue wires and PCB look a bit more intensely blue in this although I may have over-done it because the bear picture looks too blue.

 

The real solution is a camera that captures the real colours in the first place.

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I downloaded the BMP image onto a SD Card and displayed it with the same ILI9341 module.    It renders the colours just fine. 

 

Like Cliff,   I think your phone is at fault.

 

I can't see the protective plastic film.   Have you removed it?

Since you don't seem to be using the SD Card socket,   have you just copied the 150kB BMP image into memory?

 

What software are you using to display the BMP?    Does it understand the 16-bit BMP?    Your file has a "compression method (offset 30)" = 3.

 

I happened to use the module with a NUCLEO-F40RE board and MBED.    But I can do the same with a 3.3V Arduino

 

David.

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david.prentice wrote:

...

I can't see the protective plastic film.   Have you removed it?

Since you don't seem to be using the SD Card socket,   have you just copied the 150kB BMP image into memory?

 

What software are you using to display the BMP?    Does it understand the 16-bit BMP?    Your file has a "compression method (offset 30)" = 3.

 

I happened to use the module with a NUCLEO-F40RE board and MBED.    But I can do the same with a 3.3V Arduino

 

 

If you are speaking about a transparent plastic that have a tab shaped green film glued to it like this:

 

  yes, I removed it because it was to dirty. but if you are speaking about a plastic like this(that probably that's not what we are speaking):

 

 

so No.

Yes, I have copied the image into the memory of the microcontroller.

software? Why we should use a software? I just created the C file of my image via the program that you can see into UTFT lib folder. I mean ImageConverter565.exe

and then downloaded it into MCU as said.

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

Last Edited: Thu. Feb 26, 2015 - 12:03 PM
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While I paid a lot money to have a I9192 but I don't know why its Cam doesn't work very well.

 

 

its Cam is in auto mode. Could the HDR mode improve this problem?

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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Surely you can see for yourself? If you look at a scene then take a picture of the same with any form of camera you rather expect what you see on the camera to look the same as "real life" don't you? If it looks dull, greyed, lifeless then, yes,  I would be looking at any settings the camera might have to see if there's some way to correct that.

 

This review of the phone:

 

http://www.trustedreviews.com/sa...

 

Seems to be recommending HDR. It also mentions an "expert mode" where you can tinker with things like white levels (presumably "gamma").