An accurate prediction of the number of pixels on a target is critical in modeling the performance of a cameras ability to perform a task. This requires an accurate knowledge of the angle subtended by a pixel of interest, which can be calculated from a specification sheet or lens prescription. When such information is not available, it can be retrieved through a measurement of a known sized target at a known distance. In this correspondence, we utilize canonical images (ideal simple functions) together with non-linear optimization to provide sub-pixel target localization. This allows for accurate and repeatable measurement of the angular sampling of a camera. Additionally, the use of well-defined shapes and accurate location determination can be used to determine the blur, rotation, motion, contrast, distortion, and other camera metrics.
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