We perform a uniformity test to verify that every element within a sensor produces the same result. The problem with this test is there is no set standard for performing uniformity and this leads to variances in reported values. We will cover two common ways to specify uniformity: Offset Uniformity method and Response Uniformity method.
Offset uniformity is calculated by capturing a single image and determining the reported value of every column and row of pixels within a sensor or region of a sensor. It is based purely on the measured value of every pixel in a sensor or region.
The response uniformity method analyzes the response of every pixel using images taken at two different temperatures and then calculating the change in signal vs. the change in temperature for every pixel in a sensor or region of a sensor.
We calculate uniformity for different reasons including: 1) to characterize, calibrate and detect failures in a camera, 2) to compare devices within a specific model series and 3) compare different camera models- but we need to ensure the same formulas were used to collect the uniformity value.
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