An image processing method includes: obtaining, a first image by a camera, and a first lens position by a position sensor at a first timestamp; obtaining, by an inertial measurement unit sensor, an IMU signal indicating a movement of the camera between the first timestamp and a second timestamp; obtaining, a second image by the camera, and a second lens position by the position sensor at the second timestamp; calculating, by a processing circuit, a relative geometry value of the first image and the second image according to the first lens position, the second lens position, and the IMU signal; and performing, by the processing circuit, a depth calculation to the first image and the second image based on the relative geometry value on the condition that the relative geometry value meets a geometry threshold.