This invention relates to the fields of
image processing and intelligent vehicle recognition technology, and discloses a
license plate recognition method based on
image processing. The scheme establishes a unified pixel coordinate
system, records width and height indices, performs
grayscale and normalization, locates the center, and sets abnormal degradation output; it sets the maximum scanning angle and step size to generate a symmetrical angle sequence; it performs centering translation, inverse rotation, and bilinear interpolation on the output pixels angle by angle to obtain a rotated image; it calculates the vertical
grayscale difference, and generates a binary
mask based on the mean and standard deviation adaptive threshold; it accumulates the values in the row direction and takes the
peak value, first determining the angle by maximizing the
peak value and then minimizing the absolute angle; based on this, it performs inverse mapping and interpolation to generate a correction image; it recalculates the ratio of the index to the original
peak value, and if it improves, it outputs the angle, image, and index; otherwise, it backs down. The process covers input, preprocessing, scanning, mapping, statistics, filtering, and correction, avoiding missed detections, reducing subjective thresholds and interpolation artifacts, and using self-judgment backoff to suppress invalid corrections, improving stability and adaptability.