At step 802, the relative positions of the feature point of the object in the i-th and (i+1)-th images captured by the image capturing module are determined, where i is an integer and 1≤i<m, and m is the total number of the images captured by the first image capturing module.

In this embodiment, in order to facilitate determining the number of pixels that the image of the object has traveled through per unit time on the imaging plane, a feature point may be selected on the object. The number of pixels on the imaging plane that the image of the object traveled through during moving per unit time can be determined by determining the number of pixels on the imaging plane that the feature point passed through per unit time during moving.

Step 803: determining the number of pixels between the relative positions of the feature point in the i-th image and in the (i+1)-th image.

At step 803, the number of pixels n between the determined two relative positions.

In this embodiment, according to the two relative positions of the feature point of the object in the i-th image and in the (i+1)-th image, the number of pixels for the feature point of the object between the two relative positions can be determined.

Step 804: calculating the number of pixels on the imaging plane that the image of the object passed through per unit time.

In this embodiment, the number of pixels V_p passed through by the image of the object per unit time on the imaging plane of the first image capturing module may be determined according to the following formula;
V_p=n/t;