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, wherein selecting the image window at left side or right side or upper side of the center of the region where the preset common feature of the wheel is located comprises: determining a size of the image window based on a radius of the region where the preset common feature of the wheel is located; and determining a position of the image window based on the radius of the region where the preset common feature of the wheel is located and the center of the region where the preset common feature of the wheel is located.