ref: 9dbbbd181257cc2a62664a6f52197d466c2c108e
dir: /tools/3D-Reconstruction/sketch_3D_reconstruction/MotionField.pde/
class MotionField { int block_size; ArrayList<PVector> motion_field; MotionField(int block_size) { this.block_size = block_size; motion_field = new ArrayList<PVector>(); } void update(Camera last_cam, Camera current_cam, PointCloud point_cloud, BVH bvh) { // clear motion field motion_field = new ArrayList<PVector>(); int r_num = height / block_size, c_num = width / block_size; for (int i = 0; i < r_num * c_num; i++) motion_field.add(new PVector(0, 0, 0)); // estimate motion vector of each point in point cloud for (int i = 0; i < point_cloud.size(); i++) { PVector p = point_cloud.getPosition(i); PVector p0 = current_cam.project(p); PVector p1 = last_cam.project(p); int row = int((p0.y + height / 2.0f) / block_size); int col = int((p0.x + width / 2.0f) / block_size); if (row >= 0 && row < r_num && col >= 0 && col < c_num) { PVector accu = motion_field.get(row * c_num + col); accu.x += p1.x - p0.x; accu.y += p1.y - p0.y; accu.z += 1; } } // if some blocks do not have point, then use ray tracing to see if they are // in triangles for (int i = 0; i < r_num; i++) for (int j = 0; j < c_num; j++) { PVector accu = motion_field.get(i * c_num + j); if (accu.z > 0) { continue; } // use the center of the block to generate view ray float cx = j * block_size + block_size / 2.0f - width / 2.0f; float cy = i * block_size + block_size / 2.0f - height / 2.0f; float cz = 0.5f * height / tan(current_cam.fov / 2.0f); PVector dir = new PVector(cx, cy, cz); float[] camMat = current_cam.getCameraMat(); dir = MatxVec3(transpose3x3(camMat), dir); dir.normalize(); Ray r = new Ray(current_cam.pos, dir); // ray tracing float[] param = new float[4]; param[0] = Float.POSITIVE_INFINITY; if (bvh.intersect(r, param)) { PVector p = new PVector(param[1], param[2], param[3]); PVector p0 = current_cam.project(p); PVector p1 = last_cam.project(p); accu.x += p1.x - p0.x; accu.y += p1.y - p0.y; accu.z += 1; } } // estimate the motion vector of each block for (int i = 0; i < r_num * c_num; i++) { PVector mv = motion_field.get(i); if (mv.z > 0) { motion_field.set(i, new PVector(mv.x / mv.z, mv.y / mv.z, 0)); } else // there is nothing in the block, use -1 to mark it. { motion_field.set(i, new PVector(0.0, 0.0, -1)); } } } void render() { int r_num = height / block_size, c_num = width / block_size; for (int i = 0; i < r_num; i++) for (int j = 0; j < c_num; j++) { PVector mv = motion_field.get(i * c_num + j); float ox = j * block_size + 0.5f * block_size; float oy = i * block_size + 0.5f * block_size; stroke(255, 0, 0); line(ox, oy, ox + mv.x, oy + mv.y); } } void save(String path) { int r_num = height / block_size; int c_num = width / block_size; String[] mvs = new String[r_num]; for (int i = 0; i < r_num; i++) { mvs[i] = ""; for (int j = 0; j < c_num; j++) { PVector mv = motion_field.get(i * c_num + j); if (mv.z != -1) { mvs[i] += str(mv.x) + "," + str(mv.y); } else // there is nothing { mvs[i] += "-,-"; } if (j != c_num - 1) mvs[i] += ";"; } } saveStrings(path, mvs); } }