Raw-rs: Add preprocessing and demosaicing steps (#1796)

* add subtract black step

* add scale colors step

* add raw to image step

* implement linear demosiacing and fix errors in previous code

* fix missing variable

* make dependencies of tests optional

* fix error in raw-rs tests

* fix typo in "demosiacing"

* use camera data from ADC and remove downloader

* cargo fmt

* use file_stem instead of file_name

* remove old camera data

* use equality instead of subtring to find model

* store camera_to_xyz in decimal form

* Code review

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

libraries/raw-rs/src/demosaicing/linear_demosaicing.rs

@@ -0,0 +1,77 @@
+use crate::{Image, RawImage};
+
+fn average(data: &[u16], indexes: impl Iterator<Item = i64>) -> u16 {
+	let mut sum = 0;
+	let mut count = 0;
+	for index in indexes {
+		if index >= 0 && (index as usize) < data.len() {
+			sum += data[index as usize] as u32;
+			count += 1;
+		}
+	}
+
+	(sum / count) as u16
+}
+
+pub fn linear_demosaic(raw_image: RawImage) -> Image<u16> {
+	match raw_image.cfa_pattern {
+		[0, 1, 1, 2] => linear_demosaic_rggb(raw_image),
+		_ => todo!(),
+	}
+}
+
+fn linear_demosaic_rggb(mut raw_image: RawImage) -> Image<u16> {
+	let width = raw_image.width as i64;
+	let height = raw_image.height as i64;
+
+	for row in 0..height {
+		let row_by_width = row * width;
+
+		for col in 0..width {
+			let pixel_index = row_by_width + col;
+
+			let vertical_indexes = [pixel_index + width, pixel_index - width];
+			let horizontal_indexes = [pixel_index + 1, pixel_index - 1];
+			let cross_indexes = [pixel_index + width, pixel_index - width, pixel_index + 1, pixel_index - 1];
+			let diagonal_indexes = [pixel_index + width + 1, pixel_index - width + 1, pixel_index + width - 1, pixel_index - width - 1];
+
+			match (row % 2 == 0, col % 2 == 0) {
+				(true, true) => {
+					let indexes = cross_indexes.iter().map(|x| 3 * x + 1);
+					raw_image.data[3 * (pixel_index as usize) + 1] = average(&raw_image.data, indexes);
+
+					let indexes = diagonal_indexes.iter().map(|x| 3 * x + 2);
+					raw_image.data[3 * (pixel_index as usize) + 2] = average(&raw_image.data, indexes);
+				}
+				(true, false) => {
+					let indexes = horizontal_indexes.iter().map(|x| 3 * x);
+					raw_image.data[3 * (pixel_index as usize)] = average(&raw_image.data, indexes);
+
+					let indexes = vertical_indexes.iter().map(|x| 3 * x + 2);
+					raw_image.data[3 * (pixel_index as usize) + 2] = average(&raw_image.data, indexes);
+				}
+				(false, true) => {
+					let indexes = vertical_indexes.iter().map(|x| 3 * x);
+					raw_image.data[3 * (pixel_index as usize)] = average(&raw_image.data, indexes);
+
+					let indexes = horizontal_indexes.iter().map(|x| 3 * x + 2);
+					raw_image.data[3 * (pixel_index as usize) + 2] = average(&raw_image.data, indexes);
+				}
+				(false, false) => {
+					let indexes = cross_indexes.iter().map(|x| 3 * x + 1);
+					raw_image.data[3 * (pixel_index as usize) + 1] = average(&raw_image.data, indexes);
+
+					let indexes = diagonal_indexes.iter().map(|x| 3 * x);
+					raw_image.data[3 * (pixel_index as usize)] = average(&raw_image.data, indexes);
+				}
+			}
+		}
+	}
+
+	Image {
+		channels: 3,
+		data: raw_image.data,
+		width: raw_image.width,
+		height: raw_image.height,
+	}
+}

libraries/raw-rs/src/demosaicing/mod.rs

@@ -0,0 +1 @@
+pub mod linear_demosaicing;