Dynamic MTF improvement scheme and its validation for CCD operating in TDI mode for Earth imaging applications

The paper presents the scheme for improving the image contrast in the remote sensing images and highlights the novelty in hardware & software design in the test system developed for measuring image contrast function. Modulation transfer function (MTF) is the most critical quality element of the high-resolution imaging payloads for earth observation consisting of TDI-CCD (Time Delayed Integration Charge Coupled Device) image. From the mathematical model for MTF Smear MTF of 65% (35% degradation) is observed. Then a operating method for TDI-CCD is developed, using which 96% of Motion Smear MTF will occur within the imaging operation. As a major part of the validation, indigenously designed and developed a test system for measuring the dynamic MTF of TDI Sensors which consists of the optical scanning system, TDI-CCD camera drive & video processing electronics, thermal control system and telecentric uniform illumination system. The experimental results confirm that image quality improvement can be achieved by this method. This method is now implemented in the flight model hardware of the remote sensing payload.