/** Flips the image from top to bottom */
public static void flipVertical(ImageFloat32 img) {
int h2 = img.height / 2;
for (int y = 0; y < h2; y++) {
int index1 = img.getStartIndex() + y * img.getStride();
int index2 = img.getStartIndex() + (img.height - y - 1) * img.getStride();
int end = index1 + img.width;
while (index1 < end) {
float tmp = img.data[index1];
img.data[index1++] = img.data[index2];
img.data[index2++] = (float) tmp;
}
}
}
/**
* Fills the whole image with the specified pixel value
*
* @param img An image.
* @param value The value that the image is being filled with.
*/
public static void fill(ImageFloat32 img, float value) {
final int h = img.getHeight();
final int w = img.getWidth();
float[] data = img.data;
for (int y = 0; y < h; y++) {
int index = img.getStartIndex() + y * img.getStride();
for (int x = 0; x < w; x++) {
data[index++] = value;
}
}
}
/**
* Sets each value in the image to a value drawn from an uniform distribution that has a range of
* min <= X < max.
*/
public static void randomize(ImageFloat32 img, Random rand, float min, float max) {
final int h = img.getHeight();
final int w = img.getWidth();
float range = max - min;
float[] data = img.data;
for (int y = 0; y < h; y++) {
int index = img.getStartIndex() + y * img.getStride();
for (int x = 0; x < w; x++) {
data[index++] = rand.nextFloat() * range + min;
}
}
}
/** Adds Gaussian/normal i.i.d noise to each pixel in the image. */
public static void addGaussian(
ImageFloat32 img, Random rand, double sigma, float min, float max) {
final int h = img.getHeight();
final int w = img.getWidth();
float[] data = img.data;
for (int y = 0; y < h; y++) {
int index = img.getStartIndex() + y * img.getStride();
for (int x = 0; x < w; x++) {
float value = (data[index]) + (float) (rand.nextGaussian() * sigma);
if (value < min) value = min;
if (value > max) value = max;
data[index++] = value;
}
}
}
