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R8913/ImageProcessing.pde
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ImageProcessing.pde
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final String FILENAME = "board1.jpg";
// Main constants
final float[][] gaussianKernel = {
{9, 12, 9},
{12, 15, 12},
{9, 12, 9}};
final float discretizationStepsPhi = 0.06f;
final float discretizationStepsR = 2.5f;
Hough hough;
BlobDetection detect ;
// Main processing methods
void settings() {
size(1440, 360);
}
void setup() {
PImage boardImg = loadImage(FILENAME);
boardImg.resize(480, 360);
image(boardImg, 0, 0);
PImage filtered = thresholdHSB(boardImg, 100, 135, 35, 255, 17, 175);
PImage gaussian = convolute(filtered, gaussianKernel, 99);
PImage brightness = brightnessThreshold(gaussian, 5);
detect = new BlobDetection() ;
PImage detectBoard = detect.findConnectedComponents(brightness, true);
PImage scharr = scharr(brightness);
hough = new Hough(scharr, 6);
QuadGraph graph = new QuadGraph();
List<PVector> edges = graph.findBestQuad(hough.lines, width, height, width*height, width*height/64, false);
graph.displayLines(edges);
graph.displayCorners(edges);
image(scharr, boardImg.width, 0);
image(detectBoard, boardImg.width + detectBoard.width, 0);
noLoop();
}
PImage convolute(PImage img, float[][] kernel, float normFactor) {
PImage result = createImage(img.width, img.height, ALPHA);
img.loadPixels();
for (int i = 1; i < img.height-1; i++) {
for (int j = 1; j < img.width-1; j++) {
float val = 0;
for (int row = 0; row < 3; row++) {
for (int column = 0; column < 3; column++) {
//control to keep a one-pixel wide border around the image
int x_pixel = (j + column) - 1;
int y_pixel = (i + row) -1;
if (x_pixel < 0) x_pixel=0;
if (x_pixel > img.width-1) x_pixel=img.width-1;
if (y_pixel < 0) y_pixel=0;
if (y_pixel > img.height-1) y_pixel=img.height-1;
val += brightness(img.pixels[y_pixel * img.width + x_pixel]) * kernel[row][column];
}
}
result.pixels[i * img.width + j] = color(val / normFactor);
}
}
result.updatePixels();
return result;
}
PImage thresholdHSB(PImage img, int minH, int maxH, int minS, int maxS, int minB, int maxB) {
PImage result = createImage(img.width, img.height, HSB);
img.loadPixels();
result.loadPixels();
for (int i = 0; i < img.width*img.height; ++i)
if (hue(img.pixels[i]) >= minH && hue(img.pixels[i]) <= maxH &&
saturation(img.pixels[i]) >= minS && saturation(img.pixels[i]) <= maxS &&
brightness(img.pixels[i]) >= minB && brightness(img.pixels[i]) <= maxB)
result.pixels[i] = color(255);
else result.pixels[i] = color(0);
result.updatePixels();
return result;
}
PImage HueThres(PImage img, int min, int max) {
// create a new, initially transparent, ’result’ image
PImage result = createImage(img.width, img.height, HSB);
img.loadPixels();//loadPixels
for (int i = 0; i < img.width * img.height; i++) {
// do something with the pixel img.pixels[i]
if ( (hue(img.pixels[i]) > min) && (hue(img.pixels[i]) < max))
{
result.pixels[i] = color(hue(img.pixels[i]));
} else
{
result.pixels[i] = img.pixels[i];
}
}
return result;
}
PImage brightnessThreshold(PImage image, int threshold) {
image.loadPixels();
PImage result = createImage(image.width, image.height, RGB);
for (int i = 0; i < image.width * image.height; i++) {
if (brightness(image.pixels[i]) >= threshold) {
result.pixels[i] = color(255);
} else {
result.pixels[i] = color(0);
}
}
result.updatePixels();
return result;
}
PImage scharr(PImage img) {
float[][] vKernel = {
{ 3, 0, -3 },
{ 10, 0, -10 },
{ 3, 0, -3 } };
float[][] hKernel = {
{ 3, 10, 3 },
{ 0, 0, 0 },
{ -3, -10, -3 } };
PImage result = createImage(img.width, img.height, ALPHA);
// clear the image
for (int i = 0; i < img.width * img.height; i++) {
result.pixels[i] = color(0);
}
float max=0;
float[] buffer = new float[img.width * img.height];
float sum_h = 0;
float sum_v = 0;
float sum = 0;
for (int i = 0; i < img.height-1; ++i) {
for (int j = 0; j < img.width-1; ++j) {
sum_h = 0;
sum_v = 0;
// we assume here that the kernel matrix is 3x3
for (int row = 0; row < 3; row++) {
for (int column = 0; column < 3; column++) {
//control to keep a one-pixel wide border around the image
int x_pixel = (j + column) - 1;
int y_pixel = (i + row) -1;
if (x_pixel < 0) x_pixel=0;
if (x_pixel > img.width-1) x_pixel=img.width-1;
if (y_pixel < 0) y_pixel=0;
if (y_pixel > img.height-1) y_pixel=img.height-1;
sum_h += brightness(img.get(x_pixel, y_pixel))*hKernel[row][column];
sum_v += brightness(img.get(x_pixel, y_pixel))*vKernel[row][column];
}
}
sum = sqrt(pow(sum_h, 2) + pow(sum_v, 2));
buffer[i*result.width+j] = sum;
if (sum > max) {
max = sum;
}
}
}
for (int y = 2; y < img.height - 2; y++) { // Skip top and bottom edges
for (int x = 2; x < img.width - 2; x++) { // Skip left and right
int val=(int) ((buffer[y * img.width + x] / max)*255);
result.pixels[y * img.width + x]=color(val);
}
}
return result;
}
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