9. A non-volatile storage medium storing computer-readable instructions that, when executed by one or more processors, perform the following operations: receiving an image file of a vehicle driving license; extracting candidate contour regions from the image file according to a contour extraction rule, and selecting from among the extracted candidate contour regions at least one candidate contour region containing an annual inspection validity period; extracting all character contours from within each selected candidate contour region; acquiring a smallest circumscribed rectangle of each character contour in the selected candidate contour region, and dividing image blocks bound by the acquired smallest circumscribed rectangles one by one into individual single-character blocks; sorting these single-character blocks according to their respective positions in the selected candidate contour region; recognizing a corresponding character of each single-character block; generating a character string representing the annual inspection validity period using the recognized characters based on the sorting; and extracting time data in the character string and taking the time data as the annual inspection validity period of the selected candidate contour region.
9. A non-volatile storage medium storing computer-readable instructions that, when executed by one or more processors, perform the following operations: receiving an image file of a vehicle driving license; extracting candidate contour regions from the image file according to a contour extraction rule, and selecting from among the extracted candidate contour regions at least one candidate contour region containing an annual inspection validity period; extracting all character contours from within each selected candidate contour region; acquiring a smallest circumscribed rectangle of each character contour in the selected candidate contour region, and dividing image blocks bound by the acquired smallest circumscribed rectangles one by one into individual single-character blocks; sorting these single-character blocks according to their respective positions in the selected candidate contour region; recognizing a corresponding character of each single-character block; generating a character string representing the annual inspection validity period using the recognized characters based on the sorting; and extracting time data in the character string and taking the time data as the annual inspection validity period of the selected candidate contour region. 20. The non-volatile storage medium of claim 9 , wherein the selecting the at least one candidate contour region comprises: entering the extracted candidate contour regions to a trained first deep convolutional neural network (CNN) model; determining a confidence level of each extracted candidate contour region containing an annual inspection validity period; and choosing the extracted candidate contour region as a candidate contour region containing an annual inspection validity period, when the confidence level of the extracted candidate contour region is greater than a predetermined threshold.