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