Measurement of image sensor tilt based on amplitude and phase of image

Abstract

In this study, we present a new method for measuring the tilt of an image sensor to the lens. The assembly accuracy of the lens and image sensor units has a significant influence on the image quality for users. Any misalignment causes non-uniform defocus and distortion in the camera image. Our approach measures the tilt of the image sensor based on the amplitude (i.e., contrast or defocus) and phase (i.e., distortion) included in the camera image without special devices and precisely calibrated references. The amplitude and phase were separated in the frequency domain. The validity of the proposed method was confirmed through a numerical simulation using optical design software. The sensor tilt can be measured from the chart tilt, which does not cause any non-uniform defocus or distortion. This study achieved the simultaneous measurement and analysis of two parameters and can contribute to increase the productivity of manufacturers and improve the image quality for users.journal articl