1. A method for detecting a generalized passerby, comprising: acquiring an input image; determining whether a preset common feature of a wheel exists in the input image; selecting an image window at left side or right side or upper side of a center of a region where the preset common feature of the wheel is located in a case that the preset common feature of the wheel exists in the input image; and inputting the selected image window into a preset upper-body classifier, detecting whether an upper body of a passerby exists in the selected image window and outputting a first detection result, wherein the preset upper-body classifier is generated by training with a preset common feature of a generalized passerby, the preset common feature of the generalized passerby comprises a common feature of a human body, and the preset common feature of the wheel comprises a circle feature and an oval feature.