Added AverageBrightness Feature

src/Feature/mod.rs

@@ -79,9 +79,18 @@ impl Database {
     }
 }
 
-/// example feature implementation
 fn average_luminance(image: Image<f32>) -> (String, FeatureResult) {
-    (String::from("average-brightness"), FeatureResult::F32(0.0))
+    let num_pixels = image.pixels.len() as u32;
+    let total_brightness: f32 = image.pixels
+        .iter()
+        .map(|(r, g, b, _)| 0.299 * r + 0.587 * g + 0.114 * b) // Calculate Y for each pixel
+        .sum();
+    let average_brightness = total_brightness / num_pixels as f32;
+
+    let feature_name = String::from("average-brightness");
+    let feature_result = FeatureResult::F32(average_brightness);
+
+    (feature_name, feature_result)
 }
 
 #[test]