@conference { , title = {Non contact pulmonary functional testing through an improved photometric stereo approach}, abstract = {A non-contact computer vision based system is developed for Pulmonary Functional Testing. The unique and novel features of the system are that it views the patients from both front and back and creates a 3D structure of the whole torso. By observing the 3D structure of the torso over time, the amount of air inhaled and exhaled is estimated. The Photometric Stereo method is used to recover local 3D surface orientation. This technique is good for recovering the local 3D surface orientation but provides no absolute depth information about the observed scene. To calculate absolute depth information from Photometric Stereo a new Lambertian Diffused Maxima Region (DMR) based algorithm is employed here. A high (0.96) correlation between breathing volume calculated from Photometric Stereo and Spirometer data is observed.}, conference = {Medical Image Understanding and Analysis 2014}, publicationstatus = {Unpublished}, url = {https://uwe-repository.worktribe.com/output/814710}, keyword = {Centre for Machine Vision, Bristol Robotics Laboratory, non contact, pulmonary functional testing, improved photometric stereo}, year = {2014}, author = {Ahmad, Jahanzeb and Sun, jiuai and Smith, Lyndon and Smith, Melvyn} }