private static List<double[]> findNeighbors(
List<double[]> data, double[] target, double maxDistance, int maxN) {
List<double[]> ret = new ArrayList<double[]>();
List<double[]> found = new ArrayList<double[]>();
GrowQueue_F64 distances = new GrowQueue_F64();
GrowQueue_I32 indexes = new GrowQueue_I32();
for (int i = 0; i < data.size(); i++) {
double[] d = data.get(i);
double dx = d[0] - target[0];
double dy = d[1] - target[1];
double dist = dx * dx + dy * dy;
if (dist <= maxDistance) {
distances.add(dist);
found.add(d);
}
}
indexes.resize(distances.size);
maxN = Math.min(maxN, distances.size);
QuickSelectArray.selectIndex(distances.data, maxN, distances.size, indexes.data);
for (int i = 0; i < maxN; i++) {
ret.add(found.get(indexes.data[i]));
}
return ret;
}
public static void process(ImageFloat32 input, ImageFloat32 output, int radius, float storage[]) {
int w = 2 * radius + 1;
if (storage == null) {
storage = new float[w * w];
} else if (storage.length < w * w) {
throw new IllegalArgumentException("'storage' must be at least of length " + (w * w));
}
for (int y = 0; y < radius; y++) {
int minI = y - radius;
int maxI = y + radius + 1;
if (minI < 0) minI = 0;
if (maxI > input.height) maxI = input.height;
for (int x = 0; x < input.width; x++) {
int minJ = x - radius;
int maxJ = x + radius + 1;
// bound it ot be inside the image
if (minJ < 0) minJ = 0;
if (maxJ > input.width) maxJ = input.width;
int index = 0;
for (int i = minI; i < maxI; i++) {
for (int j = minJ; j < maxJ; j++) {
storage[index++] = input.get(j, i);
}
}
// use quick select to avoid sorting the whole list
float median = QuickSelectArray.select(storage, index / 2, index);
output.set(x, y, median);
}
}
for (int y = input.height - radius; y < input.height; y++) {
int minI = y - radius;
int maxI = y + radius + 1;
if (minI < 0) minI = 0;
if (maxI > input.height) maxI = input.height;
for (int x = 0; x < input.width; x++) {
int minJ = x - radius;
int maxJ = x + radius + 1;
// bound it ot be inside the image
if (minJ < 0) minJ = 0;
if (maxJ > input.width) maxJ = input.width;
int index = 0;
for (int i = minI; i < maxI; i++) {
for (int j = minJ; j < maxJ; j++) {
storage[index++] = input.get(j, i);
}
}
// use quick select to avoid sorting the whole list
float median = QuickSelectArray.select(storage, index / 2, index);
output.set(x, y, median);
}
}
for (int y = radius; y < input.height - radius; y++) {
int minI = y - radius;
int maxI = y + radius + 1;
for (int x = 0; x < radius; x++) {
int minJ = x - radius;
int maxJ = x + radius + 1;
// bound it ot be inside the image
if (minJ < 0) minJ = 0;
if (maxJ > input.width) maxJ = input.width;
int index = 0;
for (int i = minI; i < maxI; i++) {
for (int j = minJ; j < maxJ; j++) {
storage[index++] = input.get(j, i);
}
}
// use quick select to avoid sorting the whole list
float median = QuickSelectArray.select(storage, index / 2, index);
output.set(x, y, median);
}
}
for (int y = radius; y < input.height - radius; y++) {
int minI = y - radius;
int maxI = y + radius + 1;
for (int x = input.width - radius; x < input.width; x++) {
int minJ = x - radius;
int maxJ = x + radius + 1;
// bound it ot be inside the image
if (minJ < 0) minJ = 0;
if (maxJ > input.width) maxJ = input.width;
int index = 0;
for (int i = minI; i < maxI; i++) {
for (int j = minJ; j < maxJ; j++) {
storage[index++] = input.get(j, i);
}
}
// use quick select to avoid sorting the whole list
float median = QuickSelectArray.select(storage, index / 2, index);
output.set(x, y, median);
}
}
}