f1stach
Posts: 5
Joined: Mon Dec 08, 2014 3:44 pm

Improving the noIR picture/camera quality

Mon Dec 08, 2014 3:59 pm

Hello!

I'm in progress of writing a very important document about making pictures using noIR PI camera but I have a problem. The quality of pictures is very low. Despite a very good lighting, it is not satisfying. Pictures are kind of grainy, sharpness is not correct despite the fact I changed it and in general it is fainted. To make it easier to identify the problem, I attached two pictures to compare. The first one ('worse1') is a picture made by me using noIR camera. The second one ('better') is the one made in perfect quality which is not available for me to gain.

Thank you guys in advance for your help!

Greetings,
f1stach
Last edited by f1stach on Thu Jan 29, 2015 12:59 pm, edited 1 time in total.

bablokb
Posts: 25
Joined: Fri Nov 07, 2014 7:45 am

Re: Improving the noIR picture/camera quality

Tue Dec 09, 2014 7:28 pm

f1stach wrote: I'm in progress of writing a very important document about making pictures using noIR PI camera but I have a problem. The quality of pictures is very low. Despite a very good lighting, it is not satisfying. Pictures are kind of grainy, sharpness is not correct despite the fact I changed it and in general it is fainted. To make it easier to identify the problem, I attached two pictures to compare. The first one ('worse1') is a picture made by me using noIR camera. The second one ('better') is the one made in perfect quality which is not available for me to gain.
Please give some more information what you are trying to do. If yo want to do IR-photography, you should add a IR-filter in front of the lens (e.g. a 720nm or 830nm filter). The NOIR-sensor is sensible for the whole spectrum, and since every wavelength has a different focal-plane, you typically have a problem with sharpness. Limiting the spectrum usually gives sharper results (that's one of the reason why cameras have an IR-filter in front of the sensor).h

tchiwam
Posts: 43
Joined: Mon Nov 24, 2014 4:01 pm

Re: Improving the noIR picture/camera quality

Tue Dec 09, 2014 10:24 pm

I am getting myself an IR lens mounted on a CS adapter where the IR and other colours will hit the sensor at the same place. For example the 13FM22IR from tamron. Narrower field of view will let you add filters. While I will shoot 2 cameras at the same time and remove the R from the IR, at least that's the plan (R1+IR1) - (R2 + 0IR2), should give me 650nm - ... nm

But that will only work if you focus to infinity far away.

f1stach
Posts: 5
Joined: Mon Dec 08, 2014 3:44 pm

Re: Improving the noIR picture/camera quality

Wed Dec 10, 2014 12:49 am

@bablokb
Do you think about some regular IR filter or some special one used only in the PI camera? I'm trying to make an IR-photography in 860nm wavelength. As far as I'm concerned, the noIR PI camera has an IR filter in about 850 - 870 nm but that is just a piece of information from the Web. To be honest, I discovered by accident that the 70 Watts light bulb which was pointed in my hand, gave an extra result because I was able to see all the veins in my hand in good quality. And here is the tricky part because I need to gain the same result using only a few diodes of 1 W of power (I used 3 of them).
Basically, I think that @tchiwam may be right about the narrower view thing.

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jbeale
Posts: 3517
Joined: Tue Nov 22, 2011 11:51 pm
Contact: Website

Re: Improving the noIR picture/camera quality

Wed Dec 10, 2014 5:30 pm

If you are trying to take a picture of anything closer than about 2 meters away, it will start going out of focus. It gets increasingly out of focus as you get closer. Both the normal camera and the Pi No-IR camera use a fixed-focus lens, which works best for distant objects. If you want to focus at a specific distance like 1 meter or 50 cm, etc. you have to grip the tiny plastic edge of the lens with pliers or something, grip the outer camera module housing with another set of pliers, and twist the lens until it is focused. The lens was not made to be adjustable. It is not really hard to do, but you have to be careful not to damage the camera.

Another alternative without risk of damaging the camera, is to use an external close-up lens. Simple reading glasses work OK.

see also: http://elinux.org/Rpi_Camera_Module#Adj ... Lens_Focus
Adjusting Lens Focus

The camera is fixed-focus (at infinity) as delivered. The thread-locking glue dots can be scraped off allowing manual lens focus, as close as 2.5 cm. To change the focus to FL cm, unscrew the lens (turn counter-clockwise) by D degrees, where D = 360 * (3.5 cm / FL). For example, to focus at 10 cm, unscrew lens 360 * (3.5 / 10) = 126 degrees. Values are approximate. The closest achievable focus is about 25 mm, after unscrewing the lens roughly 2 full turns. At this point it is loose and must be held in place by other means.

Unscrewing more than 2 turns results in removal of the lens, allowing use of other optical systems. The lens thread size is believed to be M6 x 0.35.

f1stach
Posts: 5
Joined: Mon Dec 08, 2014 3:44 pm

Re: Improving the noIR picture/camera quality

Thu Jan 29, 2015 1:01 pm

Hi, guys, I know it's kinda late reply but I'd like to thank you for your help. Everything works just fine so this camera rotating thing was the main issue.

Greetings,
f1stach

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