Disable "Auto" Exposure

Hey All,

Does anyone know how I can tell my iSight (built in) camera to stop Auto White Balencing / doing Auto Exposure. I’ve tried looking in the setting windows on both OS X and Win XP and neither one has an option available. Is there some code I could put somewhere? It’s causing quite alot of problems.

Thanks,

Jon

hi - I moved this to xcode when I saw the word “i-sight”, but I now realize you are referring to mac and PC - I don’t have an isight available to take a look , but somehow I remember that it’s possible somewhere in the settings to control via quicktime. via directshow I don’t think you have options.

can you try a quicktime app like “hackTv” and see if you get any additional settings windows that appear?

take care!
zach

Hey Zach,

Thanks for getting back to me. I’ve had a play with a few different apps, including HackTv and I always get the same Setting box as I do when pressing “S” in the OF example apps. I hooked up my Camcorder via Firewire to see if that gave any different settings and it did, but nothing to do with Auto Exposure / White Balence / Gain.

I found a few references to exposure by doing a seach in xCode but nothing came up that looked like it might be relevant. I think it’s all for exif data and so on.

What do you think?

Cheers,

Jon

Is you isight integrated or external?

there is a post here:

http://aaronadams.net/2006/07/05/isight-…-d-jupiter/

# Stefan Says:
July 7th, 2006 at 9:22 am

a little remark:

iSight settings can be accessed via the system dialogue “Video Device Settings” which can be activated e.g. within Quartz Composer, maybe other applications, too. You have the tab “Adjustments” with sub-categories Color, Image and Mechanics. Among others, you can tweak color temperature/white balance, gain, shutter, exposure, edge enhancement, and auto/manual focus (with manual focus, the focus can be set between about 2cm distance and infinite.

which gives some hope… I swear that I have seen the same “adjustments” panel before as well when working with a student. I’m sorry I don’t have one to look at now.

maybe someone else out there has an isight and can dig around a bit?

take care
zach

It’s integrated.

The thing is I can see that settings window but on the Adjustments tab “Colour” and “Mechanics” are grayed out, leaving only the “Image” sub category available, and there’s nothing useful in that. This isn’t unique to OF either, it’s the same across all other applications that pull up the same settings window.

I’ve tried software like iGlasses as well but it doesn’t seem to have the options either.

All I can think is that Apple have hard coded it into the drivers, which is odd and annoying, but maybe someone will find a hack one day.

Of course, it may be possible for me to write some code in OF that would kind of counter act it, but it’s not ideal, and I’ll probably just use the external camera instead. It’s a shame though because, although it’s only a cheap and nasty little camera it’s quite nice for showing quick demos to Tutors and Friends.

Anyway, I’ll have a little play with Quartz Composer and see if that helps at all.

Thanks again for your help, take care,

Jon

oh — I guess there maybe some limitation of the integrated isight. If so, than that’s a terrible design decision… I remember that dialog with my students external firewire. I read somewhere that it’s not a firewire camera (like the external), but actually a usb 2.0 cam. the firewire cams (IIDC) typically have manual controls for most things (shutter speed, white balance, etc). Perhaps it’s worth a call to apple, or a post on an apple discussion forum?

we will add some examples in opencv addon in terms of slowly integrating background, etc, which might help compensate for some of the problems of the camera, but I’d look for another cheap cam if in the end you can’t control those automatic properties.

good luck !
zach

http://developer.apple.com/mac/library/-…-a1421.html
This is a link to Technical Q&A QA1421: iSight - Configuring gain settings for IIDC cameras

I saw discussion on expertsexchange that someone was able to control camera settings with this function.
It seems like it is the way to do the trick, but I don’t have enough C++ skill to get it working. Maybe someone with more oF knowledge could make use of it?

EDIT: This may be just a OSX only solution, depending on how iSight is used on Windows computers…

I got iglasses to lock the exposure in 10.6, I built the app as a 32 bit app because they said that it needs to be 32 bit to control the video driver.


Go to your Applications folder in the Finder and open the iGlasses folder.

Right-click (or ctrl-click) on iGlasses Manager and select Show Package Contents.

Drill down to Contents/Resources.

You need to edit the file apps.plist. I use Apple’s own Property List Editor which comes with the Developer Tools

You need to add a new sibling. If you’re using Property List Editor, just click select one of the existing items (under Root – IGSupportedApplications) and click the Add New Sibling button. If you’re using a text editor, copy and paste one of the existing strings onto a new line and edit it.

The sibling should be called com.yourcompany.openFrameworks (this is the bundle identifier that is packaged in the apps that are built) Its class is String (the same as the others) and its value should be OF (or anything really, this is just the name iGlasses uses).

Save the Plist file (if you’re using a text editor, don’t forget to convert it back to binary – see instructions at link above).

Go back to your Applications/iGlasses folder and double-click on iGlasses Manager to open it.
You should see a new entry in the list for OF, but it will be unchecked. Tick it, then click Apply. You’ll have to type in your admin password.

Quit and reopen your app. You should now see the iGlasses Settings item under the File Menu.


Those steps worked for me. You can switch back and forth between the videograbber settings and iglasses it seems, although I need to test this further.

Wish there was a better way to do this.

Anyone else have any luck?