/* * Programming introduction with the SOD Embedded Image Processing API. * Copyright (C) PixLab | Symisc Systems, https://sod.pixlab.io */ /* * Compile this file together with the SOD embedded source code to generate * the executable. For example: * * gcc sod.c license_plate_detection.c -lm -Ofast -march=native -Wall -std=c99 -o sod_img_proc * * Under Microsoft Visual Studio (>= 2015), just drop `sod.c` and its accompanying * header files on your source tree and you're done. If you have any trouble * integrating SOD in your project, please submit a support request at: * https://sod.pixlab.io/support.html */ /* * This simple program is a quick introduction on how to embed and start * experimenting with SOD without having to do a lot of tedious * reading and configuration. * * Make sure you have the latest release of SOD from: * https://pixlab.io/downloads * The SOD Embedded C/C++ documentation is available at: * https://sod.pixlab.io/api.html */ #include #include #include #include #include #include #include "sod.h" #include "get_time.h" /* * Frontal License Plate detection without deep-learning. Only image processing code. */ static int filter_cb(int width, int height) { /* A filter callback invoked by the blob routine each time * a potential blob region is identified. * We use the `width` and `height` parameters supplied * to discard regions of non interest (i.e. too big or too small). */ if ((width > 300 && height > 200) || width < 45 || height < 45) { /* Ignore small or big boxes (You should take in consideration * U.S plate size here and adjust accordingly). */ return 0; /* Discarded region */ } return 1; /* Accepted region */ } #define MAX_IMG_SIZE (1024*1024) int main(int argc, char *argv[]) { // struct stat stbf; unsigned char *zInpbuf = NULL; unsigned long long s = get_time(), e; /* Input image (pass a path or use the test image shipped with the samples ZIP archive) */ // const char *zInput = argc > 1 ? argv[1] : "./plate.jpg"; // /* Processed output image path */ // const char *zOut = argc > 2 ? argv[2] : "./out_plate.jpg"; // int r = stat(zInput, &stbf); // if (r < 0) { // perror("stat"); // return -1; // } // zInpbuf = malloc(stbf.st_size); // //memset(zInpbuf, 0, stbf.st_size); // int zIfd = open(zInput, O_RDONLY); // if (zIfd < 0) { // perror("open"); // return -1; // } // r = read(zIfd, zInpbuf, stbf.st_size); // if (r < stbf.st_size) { // perror("read"); // return -1; // } // close(zIfd); zInpbuf = malloc(MAX_IMG_SIZE); if (!zInpbuf) return -1; size_t zImgSz = read(0, zInpbuf, MAX_IMG_SIZE); if (zImgSz <= 0) { if (zImgSz < 0) perror("read"); free(zInpbuf); return -1; } /* Load the input image in the grayscale colorspace */ //sod_img imgIn = sod_img_load_grayscale(zInput); sod_img imgIn = sod_img_load_from_mem(zInpbuf, zImgSz, SOD_IMG_GRAYSCALE); if (imgIn.data == 0) { /* Invalid path, unsupported format, memory failure, etc. */ puts("Cannot load input image..exiting"); return 0; } /* A full color copy of the input image so we can draw rose boxes * marking the plate in question if any. */ //sod_img imgCopy = sod_img_load_color(zInput); sod_img imgCopy = sod_img_load_from_mem(zInpbuf, zImgSz, SOD_IMG_COLOR); /* Obtain a binary image first */ sod_img binImg = sod_threshold_image(imgIn, 0.5); /* * Perform Canny edge detection next which is a mandatory step */ sod_img cannyImg = sod_canny_edge_image(binImg, 1/* Reduce noise */); /* * Dilate the image say 12 times but you should experiment * with different values for best results which depend * on the quality of the input image/frame. */ sod_img dilImg = sod_dilate_image(cannyImg, 12); /* Perform connected component labeling or blob detection * now on the binary, canny edged, Gaussian noise reduced and * finally dilated image using our filter callback that should * discard small or large rectangle areas. */ sod_box *box = 0; int i, nbox; sod_image_find_blobs(dilImg, &box, &nbox, filter_cb); /* Draw a box on each potential plate coordinates */ for (i = 0; i < nbox; i++) { sod_image_draw_bbox_width(imgCopy, box[i], 5, 255., 0, 225.); // rose box } sod_image_blob_boxes_release(box); /* Finally save the output image to the specified path */ sod_img_save_as_jpeg(imgCopy, NULL, 0); /* Cleanup */ sod_free_image(imgIn); sod_free_image(cannyImg); sod_free_image(binImg); sod_free_image(dilImg); sod_free_image(imgCopy); free(zInpbuf); e = get_time(); print_time(s, e); return 0; }