Page Comparison

Here are results (SNR (dB)) for runs with 4, 8, and 16 files.

For 4 files, temporal SNR (thin dotted lines) is slightly better than standard noise. Temporal SNR is slightly lower for 8 files and very slightly lower for 16 files.

For 8 and 16 files results are closer to the results for 2 files (though differences between 8 and 16 files are very small).

The bottom line: We recommend the two-file (difference) method because it is accurate and relatively fast. The multi file method is slower for acquiring and analyzing images— at least 8 images are recommended, so why bother?

Click on any of the images below to view them full-sized.

For direct data acquisition, make sure the camera and Device Manager are set to correctly capture the image of interest. The Preview has to be turned off to enable the adjustments. Click Save when the image in the Device Manager is correct.

In the Flatfield Interactive window, set Signal averaging to a large number (128 reads here), and check Calculate image^2 while averaging.

Because of the sequence of operations in Flatfield Interactive, you may need to read an image (before you have the correct settings), then make the settings, then reread.

You may want to crop the image when you read it to make it easier to examine specific regions of interest.

Here is the original image (cropped).

This image is virtually noiseless because the L = 128 averages increases the SNR (Signal-to-Noise Ratio) by 21 dB (3*log₂(L)).

Here is the noise image displayed auto-lightened. This gives a good picture of the noise, but lacks quantitative information.

As expected, noise is largest near sharp edges and low in smooth areas of the chart.

There is no noise in the white part of the registration mark because it’s fully saturated (pure white).

Here is the noise image displayed in pseudocolor, which a numeric scale on the right.

Finally, here is the pseudocolor image greatly enlarged. The 8×8 pixel JPEG artifacts, characteristic of medium-low quality JPEG compression, are plainly visible.