Evaluation of an Optical Flow Method for Measuring 2D and 3D Corn Seedling Growth. - John L. Barron; Albert Liptay (Theoretical Foundations of Computer Vision, 1998)

Plant Growth Measurement Techniques using Near-Infrared Imagery. - Amr Aboelela; Albert Liptay; John L. Barron (Int. J. Robotics Autom., 2005)