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Panoramic Infrared Reflectography: what camera is best?

InGaAs camera

I have been looking for an InGaAs camera specifically useful for Panoramic Infrared Reflectography.

I currently own an Indigo System camera 320×256 pixels which does its work pretty well. I would like to upgrade to a 640×512 pixels camera, the advantages being obvious: bigger images mean less stitching.  I don’t plan to buy a new camera somewhat soon, since these cameras are pretty expensive. Though, I am exploring the market since I have been asked for advice by other professionals who want to develop a panoramic infrared reflectography system. So, I asked Xenics to let me test their camera.

 

Madonna and Four Angels Xenics 640
Watch On Flicker. Madonna and Four Angels, Panoramic Infrared Reflec­tog­ra­phy (4728 x 3868). Xen­ics Bob­cat 640 InGaAs camera.

First of all, I asked Xenics since it is an European company, based in Belgium. I’m now based in Europe so I like and I need to deal with European companies. We are neighbors and it is much easier and affordable to ship things back and forward. I did actually bought already a Xenics camera in 2008 for CISA3 while I was visiting researcher at University of San Diego California.  It was an InGaAs  320×256 camera.  I was pleased with the company’s customer assistance for some issues we had with the software, so I emailed their headquarter in Leuven, Belgium to see if I could get one of their new camera to be tested.

Indeed, it went better than I hoped and I get their newest camera! And also the 640×512 ones. It’s called Bobcat 640. A number of  features make this camera a perfect much for Panoramic Infrared Reflectography.

  • Impressive High Sensitivity. At its longest acquisition time of 40 milliseconds I didn’t even had to turn the halogen lamps on. Just the light sunlight was enough even with a 200mm lens mounted. I posted already on screens to reduce the heating from halogen lampsThe use of this camera makes the examination absolutely safe since it does require a ridiculous small amount of lighting.

 

  • Lightweight and small. This camera waits just 470gr (with its 25mm SWIR lens on). This is extremely less than my Indigo, 1640gr. This difference in weight is not just esthetic. It becomes relevant in Panoramic Infrared Reflectography since we can apply less weight to the panoramic head, at all advantage of its stability. Xenics Bobcat is also extremely small (55x55x85 mm). This also helps to better arrange the camera and the telephoto lens on the panoramic head.
Panoramic Infrared Reflectography
The Xenics Bobcat measures and weights less that ¼ of a traditional InGaAs camera. Indigo Merlin InGaAs camera on background.

 

  • Frame grabber. The camera is connected to a PC with a LAN cable which port is present in any laptop.  So, on your laptop screen you have a live view streaming from the camera and the images can be saved directly on the laptop without the need of a frame grabber. I did use my ARDUINO chip to automatize the acquisition process with the Gigapan Pro Panoramic Head.
  • Pixel count. The Xenics Bobcat 640×512 has roughly 4 times more pixels of the 320×256.   This translate in higher resolution, bigger images and less stitching.
Panoramic Infrared Reflectography
The AIC Photo Documentation target seen by the Xenics Bobcat (640×512 pixels) and the Indigo camera (320×256 pixels), lower-right insert, real pixel comparison. The cameras were at the same distance (2,2m) and had the same lens (200mm).

As an example, look at the images taken for the Madonna and Child, Ingels Collection, Sweden.

Panoramic Infrared Reflectography
Panoramic Infrared Reflectography, Madonna and Child, Ingels Collection, Sweden. Left, Xenics Bobcat (640×520 pixels) camera took 60 images. Right, Indigo Merlin (320×256 pixels) camera took 224 images. The cameras were at the same distance and used the same 200mm lens. The amount of stitching is about 4 times more with the smaller detector.
Ingels Madonna
Watch On Flicker. Madonna and Child, Ingels Collection, Sweden, Panoramic Infrared Reflectography (14379 x 8940). Xenics Bobcat 640 InGaAs camera.
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