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use crate::{Akaze, EvolutionStep, KeyPoint};
use bitarray::BitArray;
impl Akaze {
pub fn extract_descriptors(
&self,
evolutions: &[EvolutionStep],
keypoints: &[KeyPoint],
) -> Vec<BitArray<64>> {
keypoints
.iter()
.map(|keypoint| self.get_mldb_descriptor(keypoint, evolutions))
.collect()
}
fn get_mldb_descriptor(
&self,
keypoint: &KeyPoint,
evolutions: &[EvolutionStep],
) -> BitArray<64> {
let mut output = BitArray::zeros();
let max_channels = 3usize;
debug_assert!(self.descriptor_channels <= max_channels);
let mut values: Vec<f32> = vec![0f32; (16 * max_channels) as usize];
let size_mult = [1.0f32, 2.0f32 / 3.0f32, 1.0f32 / 2.0f32];
let ratio = (1u32 << keypoint.octave) as f32;
let scale = f32::round(0.5f32 * (keypoint.size as f32) / ratio);
let xf = keypoint.point.0 / ratio;
let yf = keypoint.point.1 / ratio;
let co = f32::cos(keypoint.angle);
let si = f32::sin(keypoint.angle);
let mut dpos = 0usize;
let pattern_size = self.descriptor_pattern_size as f32;
for (lvl, multiplier) in size_mult.iter().enumerate() {
let val_count = (lvl + 2usize) * (lvl + 2usize);
let sample_size = f32::ceil(pattern_size * multiplier) as usize;
self.mldb_fill_values(
&mut values,
sample_size,
keypoint.class_id,
xf,
yf,
co,
si,
scale,
&evolutions,
);
mldb_binary_comparisons(
&values,
output.bytes_mut(),
val_count,
&mut dpos,
self.descriptor_channels,
);
}
output
}
#[allow(clippy::too_many_arguments)]
fn mldb_fill_values(
&self,
values: &mut [f32],
sample_step: usize,
level: usize,
xf: f32,
yf: f32,
co: f32,
si: f32,
scale: f32,
evolutions: &[EvolutionStep],
) {
let pattern_size = self.descriptor_pattern_size;
let nr_channels = self.descriptor_channels;
let mut valuepos = 0;
for i in (-(pattern_size as i32)..(pattern_size as i32)).step_by(sample_step) {
for j in (-(pattern_size as i32)..(pattern_size as i32)).step_by(sample_step) {
let mut di = 0f32;
let mut dx = 0f32;
let mut dy = 0f32;
let mut nsamples = 0usize;
for k in i..(i + (sample_step as i32)) {
for l in j..(j + (sample_step as i32)) {
let l = l as f32 + 0.5;
let k = k as f32 + 0.5;
let sample_y = yf + (l * co * scale + k * si * scale);
let sample_x = xf + (-l * si * scale + k * co * scale);
let y1 = f32::round(sample_y) as isize;
let x1 = f32::round(sample_x) as isize;
let y1 = y1 as usize;
let x1 = x1 as usize;
let ri = evolutions[level].Lt.get(x1, y1);
di += ri;
if nr_channels > 1 {
let rx = evolutions[level].Lx.get(x1, y1);
let ry = evolutions[level].Ly.get(x1, y1);
if nr_channels == 2 {
dx += f32::sqrt(rx * rx + ry * ry);
} else {
let rry = rx * co + ry * si;
let rrx = -rx * si + ry * co;
dx += rrx;
dy += rry;
}
}
nsamples += 1;
}
}
di /= nsamples as f32;
dx /= nsamples as f32;
dy /= nsamples as f32;
values[valuepos] = di;
if nr_channels > 1 {
values[valuepos + 1] = dx;
}
if nr_channels > 2 {
values[valuepos + 2] = dy;
}
valuepos += nr_channels;
}
}
}
}
fn mldb_binary_comparisons(
values: &[f32],
descriptor: &mut [u8],
count: usize,
dpos: &mut usize,
nr_channels: usize,
) {
for pos in 0..nr_channels {
for i in 0..count {
let ival = values[nr_channels * i + pos];
for j in (i + 1)..count {
let res = if ival > values[nr_channels * j + pos] {
1u8
} else {
0u8
};
descriptor[*dpos >> 3usize] |= res << (*dpos & 7);
*dpos += 1usize;
}
}
}
}