Austin's Imaging Blog

Testing the linearity of a camera using the Camcal CC-560

Numerous camera manufacturers claim **% nonlinearity on their sensors. Are you certain that this specification is accurate? One way to test this is to simply increase your exposure time against a constant emission source. The Camcal CC-560 can be used for this type of application.  In this example, I’ve tested an Andor Clara camera for intensity linearity in exposure time. I’ve increased the exposure by 10ms in each frame, and the results indicate an excellent linearity:

First, we can acquire images of the standard over an hour, to ensure the source is consistent:

Linearity of the emission source over 57 minutes (<1%)

Second, we can acquire an increasing exposure time of images, using a simple macro.

Increasing exposure time from an Andor Clara, stepped at 200ms per exposure.

This is what we expect to see. As the exposure time increases, we see a linear response from the camera.

I’d be very curious to see how other systems compare, especially older EM Gain cameras and cameras which don’t ship with individual performance reports.

Camera with Calibrator Mounted

 

 

 

 

 

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