better way of finding the best level.

README.md

@@ -1,3 +1,5 @@
 # VidOilTank
 
-measure the level of a hearoiltank via RPi Cammera
+measure the level of a hearoiltank via RPi Cammera
+
+

image.c

@@ -40,7 +40,7 @@ int image_save(ImageRaw *i, char *fn, int quality) {
   int row_stride;		/* physical row width in image buffer */
 
   if (i == NULL) {
-	  printf ("image_save no image i == NULL\n");
+	  printf ("%s:%d image_save no image i == NULL\n", __FILE__, __LINE__);
 	  exit (1);
   }
 
@@ -48,7 +48,7 @@ int image_save(ImageRaw *i, char *fn, int quality) {
   jpeg_create_compress(&cinfo);
 
   if ((outfile = fopen(fn, "wb")) == NULL) {
-	fprintf(stderr, "can't open %s\n", fn);
+	fprintf(stderr, "%s:%d can't open %s error:%s\n", __FILE__, __LINE__, fn, strerror(errno));
 	exit(1);
   }
   jpeg_stdio_dest(&cinfo, outfile);

main.c

@@ -1,4 +1,8 @@
 
+//
+// for testing: make && ./vidoiltank -rotate 270 -samples 1 -debug /mnt/heizoel-data
+//
+
 #include <stdlib.h>
 #include <stdio.h>
 #include <time.h>
@@ -13,6 +17,7 @@ int conf_iomode = IOM_MMAP;
 int conf_samples = 25;
 int conf_rotate = 0;
 Rect conf_rect = { .x = 315, .y = 0, .w = 70, .h = 1910 };
+char conf_outdate[LEN_FILENAME];
 
 int detect_level(ImageFloat *imgf);
 
@@ -44,14 +49,13 @@ int main(int argc, char **argv) {
 	ImageRaw *tmpimg = NULL;
 	ImageFloat *imgf = NULL;
 	char fn[3*LEN_FILENAME];
-	char outdate[LEN_FILENAME];
-	time_t curtime = time(NULL);
-	struct tm *curtime_tm = NULL;
 	int i, c, b, level, cont, bright, min, max;
 
 	// for debugging only
+	time_t curtime = time(NULL);
+	struct tm *curtime_tm = NULL;
 	curtime_tm = localtime(&curtime);
-	strftime(outdate, LEN_FILENAME-1, "%Y%m%d-%H%M%S", curtime_tm);
+	strftime(conf_outdate, LEN_FILENAME-1, "%Y%m%d-%H%M%S", curtime_tm);
 
 	for (int i = 1; i < argc; i++) {
 		if (strcmp(argv[i], "-dev") == 0) {
@@ -141,7 +145,7 @@ int main(int argc, char **argv) {
 		}
 
 		if (i == 0) {
-			snprintf (fn, 3*LEN_FILENAME, "%s/%s-img-%02d-%02d.jpg", conf_debugout, outdate, bright, cont);
+			snprintf (fn, 3*LEN_FILENAME, "%s/%s-img-%02d-%02d.jpg", conf_debugout, conf_outdate, bright, cont);
 			image_draw_rect(img, &conf_rect, 0x00FFFF);
 			if (strlen(conf_debugout) > 0) image_save(img, fn, 98);
 		}
@@ -151,7 +155,7 @@ int main(int argc, char **argv) {
 	video = NULL;
 
 	tmpimg = image_copyF(imgf);
-	snprintf (fn, 3*LEN_FILENAME, "%s/%s-imgf-%03d.jpg", conf_debugout, outdate, conf_samples);
+	snprintf (fn, 3*LEN_FILENAME, "%s/%s-imgf-%03d.jpg", conf_debugout, conf_outdate, conf_samples);
 	if (strlen(conf_debugout) > 0) image_save(tmpimg, fn, 98);
 
 	printf ("detect level\n");
@@ -160,18 +164,28 @@ int main(int argc, char **argv) {
 	tmpimg = image_copyF(imgf);
 	Rect r = {.x = 0,  .y = level, .w = 10, .h = 1};
 	image_draw_rect(tmpimg,  &r, 0x0000FF00);
-	snprintf (fn, 3*LEN_FILENAME, "%s/%s-img-data.jpg", conf_debugout, outdate);
+	snprintf (fn, 3*LEN_FILENAME, "%s/%s-img-data.jpg", conf_debugout, conf_outdate);
 	if (strlen(conf_debugout) > 0) image_save(tmpimg, fn, 98);
 
-	printf ("%s Found Level: %5.2f    Y-Pos: %d\n", outdate, 100.0 * (1.0-(float)level/(float)imgf->h), level);
-
+	printf ("%s Found Level: %5.2f    Y-Pos: %d\n", conf_outdate, 100.0 * (1.0-(float)level/(float)imgf->h), level);
 	return 0;
 };
 
 
 int detect_level(ImageFloat *imgf) {
-	int y, x, ylow, level;
+	int y, x, level;
 	float v = 0.0, vmin, vmax;
+	FILE * outfile;
+	float deltamin = 0, deltamax = 0;
+	int deltamin_y = 0, deltamax_y = 0;
+	
+	if (imgf == NULL) return -1;
+	
+	float *deltas = malloc(sizeof(float) * imgf->h);
+	if (deltas == NULL) {
+		printf ("%s:%d could not allocate memory. Error:%s\n", __FILE__, __LINE__, strerror(errno));
+		return -1;
+	}
 
 	//
 	// calculate average, and save value in left row
@@ -194,28 +208,60 @@ int detect_level(ImageFloat *imgf) {
 		imgf->data[x + y * imgf->w] = (imgf->data[x + y * imgf->w]-vmin)/(vmax-vmin);
 	}
 
-	//
-	// search for the level from below
 	vmin = 1.0;
 	vmax = 0.0;
-	int avg = 8;
+	int outavg_with = 8;
 
+	// generate average and delta
 	level = 0;
-	for (ylow = 0; ylow < imgf->h; ylow++) {
-		if (ylow == 0) v = imgf->data[(ylow) * imgf->w];
-		v = ((float)avg-1.0) * v/(float)avg + imgf->data[(ylow) * imgf->w]/(float) avg;
-		for (x = 0; x < 8; x++) imgf->data[x + (ylow) * imgf->w] = v;
+	float delta = 0.0;
+	for (y = 0; y < imgf->h; y++) {
+		// average
+		v = 0.0;
+		for (x = 0; x < imgf->w; x++) v += imgf->data[x + (y) * imgf->w];
+		v /= (float)imgf->h;
+
+		// output
+		for (x = 0; x < outavg_with; x++) imgf->data[x + (y) * imgf->w] = v;
+
+		// delta
+		if (y > 0) delta = imgf->data[0 + y * imgf->w] - imgf->data[0 + (y-1) * imgf->w];
+		else {
+			deltamin_y = 0;
+			deltamax_y = 0;
+			deltamin = delta;
+			deltamax = delta;
+		}
+		if (deltamin > delta) {
+			deltamin = delta;
+			deltamin_y = y;
+		}
+		if (deltamax > delta) {
+			deltamax = delta;
+			deltamax_y = y;
+		}
+		deltas[y] = delta;
 	}
-	for (ylow = imgf->h - 1; ylow >= 0; ylow--) {
-		if (ylow == imgf->h - 1) v = imgf->data[(ylow) * imgf->w];
-		v = ((float)avg-1.0) * v/(float)avg + imgf->data[(ylow) * imgf->w]/(float) avg;
-		for (x = 4; x < 16; x++) imgf->data[x + (ylow) * imgf->w] = v;
-		if (v > 0.1) {
-			level = ylow;
-			break;
+
+	// debugging write output
+	if (strlen(conf_debugout) > 0) {
+		char fn[3*LEN_FILENAME];
+		snprintf (fn, 3*LEN_FILENAME, "%s/%s-data.csv", conf_debugout, conf_outdate);
+		if ((outfile = fopen(fn, "wb")) == NULL) {
+			fprintf(stderr, "%s:%d can't open %s error:%s\n", __FILE__, __LINE__, fn, strerror(errno));
+			exit(1);
+		}
+		for (y = 0; y < imgf->h; y++) {
+			fprintf(outfile, "%05d\t%f\t%f\n", y, imgf->data[y * imgf->w], deltas[y]);
 		}
+		fclose (outfile);
 	}
 
+	//
+	// search for the level from below
+	level = deltamin_y;
+
+	free(deltas);
 	return level;
 };