Capturing images with the Infragram DIY Plant Analysis Webcam

[altin...@gmail.com]

Hello,

I have an Infragram DIY Plant Analysis Webcam that I purchased some time ago, but unfortunately the camera was discontinued, and I do not exactly know the specs nor how to acquire an image from this camera using ubuntu linux.

I previously successfully acquired images with this camera and processed them, but now for some reason I can not use uvccapture.

Here are my questions:

1. First thing I need to know, what kind of filter this camera has? I am assuming it has a blue-red filter. Is this correct?

2. When I used the camera previously, it captured pinkish images, like for example in:

http://picpaste.com/thumbs/guvcview_image-9.1469022031.jpg

But when I take pictures with the camera using cheese webcam application in Ubuntu 14.04, I get brownish whitish images like in:

http://cdn.shopify.com/s/files/1/0198/8618/products/infragram-example_1024x1024.png

I believe this is called NGB mode, what is the name for the pinkish mode I mentioned previously

3. When I try to capture using uvccapture, I get a file called snap.jpg which is only about 400 bytes. I believe this is due to a driver error. Is there recommended capture tool for Ubuntu Linux? I now use cheese webcam booth app, which is limited in settings and capacity.

Any recommendations/ideas/help greatly appreciated.

Best regards,
C.

[Chris Fastie]

Those Infragram webcams were originally sold with blue filters (Rosco #2007). The photos that have an orange-brown hue for green plants are probably from cameras with blue filters. The color of the photo depends strongly on the white balance setting of the camera. Webcams generally implement an automatic white balance algorithm which gets rather confused by the infrared light mixing into all of the color channels. When a standard white balance setting is used (e.g., sunny, shady, fluorescent) the photos are often pinkish. Controlling the white balance setting is important is you want to capture photos that can be directly converted to NDVI images. This requires software that can override the automatic white balance algorithm.

Sorry, I don't know anything about Linux (and I'm sure I am better off for it).

Chris