Modulation Transfer Function Measurement System at Different Contrasts for CCD Camera

In order to achieve MTFs at different contrasts, the MTF measurement system is designed and developed. Two integrating spheres are used to illuminate the face and back of the test target uniformly. The target luminance and background luminance of the test target are regulated by adjusting the attenuators near the entrance of each integrating sphere. The many groups’ experimental results indicate that the luminance differences between the values by the system and those by L88 first level luminance meter, which is checked by National Institute of Metrology P. R. China, are within ±0.3 cd/m2. Thereby the measurement precision can be ensured in MTF test. MTFs of Sony camera and Cannon camera at different contrasts are measured by this system. The measurement values show that MTFs at different contrasts can demonstrate the imaging quality fully and objectively. This study provides an effective method to evaluate the imaging quality of visible imaging systems.