Raw-rs: use camera white balance when available (#1941)

* add new White Balance Tag

* merge raw_to_image step with demosiacing

* Use white balance from camera in scale colors step

* Nit

---------

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

libraries/raw-rs/src/preprocessing/camera_data.rs

@@ -49,7 +49,13 @@ pub fn calculate_conversion_matrices(mut raw_image: RawImage) -> RawImage {
 	}
 	let rgb_to_camera = transpose(pseudoinverse(camera_to_rgb));
 
-	raw_image.white_balance_multiplier = Some(white_balance_multiplier);
+	let cfa_white_balance_multiplier = if let Some(white_balance) = raw_image.camera_white_balance_multiplier {
+		white_balance
+	} else {
+		raw_image.cfa_pattern.map(|index| white_balance_multiplier[index as usize])
+	};
+
+	raw_image.white_balance_multiplier = Some(cfa_white_balance_multiplier);
 	raw_image.camera_to_rgb = Some(camera_to_rgb);
 	raw_image.rgb_to_camera = Some(rgb_to_camera);
 

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

@@ -1,4 +1,3 @@
 pub mod camera_data;
-pub mod raw_to_image;
 pub mod scale_colors;
 pub mod subtract_black;

libraries/raw-rs/src/preprocessing/raw_to_image.rs

@@ -1,17 +0,0 @@
-use crate::RawImage;
-
-pub fn raw_to_image(mut raw_image: RawImage) -> RawImage {
-	let mut image = Vec::with_capacity(raw_image.width * raw_image.height * 3);
-
-	for row in 0..raw_image.height {
-		for col in 0..raw_image.width {
-			let mut pixel = [0_u16; 3];
-			let color_index = raw_image.cfa_pattern[2 * (row % 2) + (col % 2)];
-			pixel[color_index as usize] = raw_image.data[row * raw_image.width + col];
-			image.extend_from_slice(&pixel);
-		}
-	}
-
-	raw_image.data = image;
-	raw_image
-}

libraries/raw-rs/src/preprocessing/scale_colors.rs

@@ -22,12 +22,14 @@ pub fn scale_colors(mut raw_image: RawImage) -> RawImage {
 		let scale_to_16bit_multiplier = u16::MAX as f64 / raw_image.maximum as f64;
 		white_balance_multiplier.map(|x| x / normalize_white_balance * scale_to_16bit_multiplier)
 	} else {
-		[1., 1., 1.]
+		[1., 1., 1., 1.]
 	};
 
-	for i in 0..(raw_image.height * raw_image.width) {
-		for (c, multiplier) in final_multiplier.iter().enumerate() {
-			raw_image.data[3 * i + c] = ((raw_image.data[3 * i + c] as f64) * multiplier).min(u16::MAX as f64).max(0.) as u16;
+	for row in 0..raw_image.height {
+		for column in 0..raw_image.width {
+			let index = row * raw_image.width + column;
+			let cfa_index = 2 * (row % 2) + (column % 2);
+			raw_image.data[index] = ((raw_image.data[index] as f64) * final_multiplier[cfa_index]).min(u16::MAX as f64).max(0.) as u16;
 		}
 	}