Increasing the Repeatability of Your Sharpness Tests

By Robert Sumner
With contributions from Ranga Burada, Henry Koren, Brienna Rogers and Norman Koren

Consistency is a fundamental aspect of successful image quality testing. Each component in your system may contribute to variation in test results. For tasks such as pass/fail testing, the primary goal is to identify the variation due to the component and ignore the variation due to noise. Being able to accurately replicate test results with variability limited to 1-5% will give you a more accurate description of how your product will perform.

Since Imatest makes measurements directly from the image pixels, any source that adds noise to the image can affect measurements. A primary source of noise in images is electronic sensor noise. Photon shot noise also contributes significantly in low-light situations. Other systemic sources of measurement variability, such as autofocus hysteresis, will not be addressed in this post.  

In order to reduce variation in your sharpness results and increase test repeatability, you should take steps to decrease the amount of noise in your image.

Here are 5 tips to limit noise in your test results: (more…)

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