1. A motion determination system in a machine, comprising: one or more memories storing instructions; and a controller configured to execute the instructions to perform operations including: calculating one or more visual-odometry outputs; determining a plurality of figure of merits, wherein each of the plurality of figure of merits is associated with one of a plurality of parameters affecting the calculation of the one or more visual-odometry outputs, and each of the plurality of figure of merits is indicative of an accuracy of the visual-odometry outputs; calculating a combined figure of merit based on the plurality of figure of merits; and calculating an error estimate for the one or more visual-odometry outputs based on the combined figure of merit.