טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentYoav Grauer
SubjectBlooming Suppression in Active Imaging by an Optical
Modulator
DepartmentDepartment of Physics
Supervisor Dr. Ribak Erez
Full Thesis textFull thesis text - English Version


Abstract

Optical blooming in cameras is a phenomenon of saturation due to higher incident power distribution than the sensor dynamic range. The suppression of this is dealt in many research areas such as:  image processing, optics and electro-optics. All these research efforts aim to reduce the effect of the high incident power in direct or indirect approaches. These methods may include auto gain control of the sensor, image stitching in various exposure time, introducing optical elements such us polarizes, different passive optical filters and more.        

The research presents a study on blooming suppression in active imaging by introducing an optical modulator. Various physical parameters of the optical modulator will be presented-suppression power, sensitivity, response time, relaxation time and resolution. This element is based on an electro-optical device which is based on the Pockels effect. The optical modulator is a real-time photoconductive crystal acting as a localized, dynamic fast shutter.

In active imaging for low light level applications, the high intensity light levels is a result of retro-reflector targets versus the low signal return from Lambertian reflection.  The result of the research was to confirm a theoretical method to suppress inner scene high intensity light levels (three and more magnitudes higher than the minimum scene signal) in active imaging.