Accuracy of vascular bundle counting. A random set of 41 transection images was used to test the accuracy of the tool. A) The vascular bundles located in the pith in 41 transections were counted by a human and by the tool. Each point in the scatter plot represents the two numbers associated with each different section. The diagonal line represents perfect agreement. B) The number of bundles automatically counted relative to the number determined by eye was converted to a percent accuracy value for each transection and presented as a frequency histogram. Fitting a normal distribution to the histogram determined the mean accuracy value to be 90%.