Figure 8

Error estimation. Surface zenith angles of artificial setups were measured with an inclinometer and compared to respective estimated leaf angles from stereo reconstruction. Estimation errors were quantified by the normalized root mean square error (NRMSE): artificial plant leaves (red) displayed a NRMSE of 2.5%; planarly-fixed sugar beet leaf in various orientations (blue) displayed a NRMSE of 4.6%. The dashed line indicates where angle estimates are known to be unreliable [27].