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To achieve high subpixel accuracy, it is necessary to find a balance among the camera's features, the object to camera distance, and the object’s speed. These parameters collectively define the final pixel-to-millimeter ratio, which ultimately determines the method’s accuracy. Additionally, selecting the appropriate algorithm is fundamental for accurately determining the target’s position. In our case, we employ normalized cross-correlation between images with analytic interpolation of the correlation peak. A drawback of subpixel tracking approach is that tracking targets with subpixel accuracy makes the system highly sensitive to thermal errors. Heating of the electronics can lead to the expansion of the camera casing and sensor, resulting in drifts and distortions in the final image. In our presentation, we will show different combinations that ensure precise subpixel accuracy while accounting for observed thermal distortions. Following our results with Basler cameras, our recommendation is to use the lowest target speed with a temporal resolution to achieve an apparent interframe shift of less than 0.004 pixels and at least 2 hours of stabilization time. |
