[desktop] Better blur detection service (#1479)

## Description

Improve blur detection that better handles noise in background of faces

## Tests

Manually verified the blur detection scores are identical to those on
mobile

web/apps/photos/src/services/machineLearning/faceService.ts

@@ -145,7 +145,7 @@ class FaceService {
             imageBitmap,
         );
         const blurValues =
-            syncContext.blurDetectionService.detectBlur(faceImages);
+            syncContext.blurDetectionService.detectBlur(faceImages, newMlFile.faces);
         newMlFile.faces.forEach((f, i) => (f.blurValue = blurValues[i]));
 
         imageBitmap.close();

web/apps/photos/src/services/machineLearning/laplacianBlurDetectionService.ts

@@ -1,6 +1,7 @@
 import {
     BlurDetectionMethod,
     BlurDetectionService,
+    Face,
     Versioned,
 } from "types/machineLearning";
 import { createGrayscaleIntMatrixFromNormalized2List } from "utils/image";
@@ -16,18 +17,20 @@ class LaplacianBlurDetectionService implements BlurDetectionService {
         };
     }
 
-    public detectBlur(alignedFaces: Float32Array): number[] {
+    public detectBlur(alignedFaces: Float32Array, faces: Face[]): number[] {
         const numFaces = Math.round(
             alignedFaces.length /
                 (mobileFaceNetFaceSize * mobileFaceNetFaceSize * 3),
         );
         const blurValues: number[] = [];
         for (let i = 0; i < numFaces; i++) {
+            const face = faces[i];
+            const direction = getFaceDirection(face);
             const faceImage = createGrayscaleIntMatrixFromNormalized2List(
                 alignedFaces,
                 i,
             );
-            const laplacian = this.applyLaplacian(faceImage);
+            const laplacian = this.applyLaplacian(faceImage, direction);
             const variance = this.calculateVariance(laplacian);
             blurValues.push(variance);
         }
@@ -61,42 +64,77 @@ class LaplacianBlurDetectionService implements BlurDetectionService {
         return variance;
     }
 
-    private padImage(image: number[][]): number[][] {
+    private padImage(
+        image: number[][],
+        removeSideColumns: number = 56,
+        direction: FaceDirection = "straight",
+    ): number[][] {
+        // Exception is removeSideColumns is not even
+        if (removeSideColumns % 2 != 0) {
+            throw new Error("removeSideColumns must be even");
+        }
         const numRows = image.length;
         const numCols = image[0].length;
+        const paddedNumCols = numCols + 2 - removeSideColumns;
+        const paddedNumRows = numRows + 2;
 
         // Create a new matrix with extra padding
         const paddedImage: number[][] = Array.from(
-            { length: numRows + 2 },
-            () => new Array(numCols + 2).fill(0),
+            { length: paddedNumRows},
+            () => new Array(paddedNumCols).fill(0),
         );
 
         // Copy original image into the center of the padded image
-        for (let i = 0; i < numRows; i++) {
-            for (let j = 0; j < numCols; j++) {
-                paddedImage[i + 1][j + 1] = image[i][j];
+        if (direction === "straight") {
+            for (let i = 0; i < numRows; i++) {
+                for (let j = 0; j < paddedNumCols - 2; j++) {
+                    paddedImage[i + 1][j + 1] =
+                        image[i][j + Math.round(removeSideColumns / 2)];
+                }
+            }
+        } // If the face is facing left, we only take the right side of the face image
+        else if (direction === "left") {
+            for (let i = 0; i < numRows; i++) {
+                for (let j = 0; j < paddedNumCols - 2; j++) {
+                    paddedImage[i + 1][j + 1] = image[i][j + removeSideColumns];
+                }
+            }
+        } // If the face is facing right, we only take the left side of the face image
+        else if (direction === "right") {
+            for (let i = 0; i < numRows; i++) {
+                for (let j = 0; j < paddedNumCols - 2; j++) {
+                    paddedImage[i + 1][j + 1] = image[i][j];
+                }
             }
         }
 
         // Reflect padding
         // Top and bottom rows
-        for (let j = 1; j <= numCols; j++) {
+        for (let j = 1; j <= paddedNumCols - 2; j++) {
             paddedImage[0][j] = paddedImage[2][j]; // Top row
             paddedImage[numRows + 1][j] = paddedImage[numRows - 1][j]; // Bottom row
         }
         // Left and right columns
         for (let i = 0; i < numRows + 2; i++) {
             paddedImage[i][0] = paddedImage[i][2]; // Left column
-            paddedImage[i][numCols + 1] = paddedImage[i][numCols - 1]; // Right column
+            paddedImage[i][paddedNumCols - 1] =
+                paddedImage[i][paddedNumCols - 3]; // Right column
         }
 
         return paddedImage;
     }
 
-    private applyLaplacian(image: number[][]): number[][] {
-        const paddedImage: number[][] = this.padImage(image);
-        const numRows = image.length;
-        const numCols = image[0].length;
+    private applyLaplacian(
+        image: number[][],
+        direction: FaceDirection = "straight",
+    ): number[][] {
+        const paddedImage: number[][] = this.padImage(
+            image,
+            undefined,
+            direction,
+        );
+        const numRows = paddedImage.length - 2;
+        const numCols = paddedImage[0].length - 2;
 
         // Create an output image initialized to 0
         const outputImage: number[][] = Array.from({ length: numRows }, () =>
@@ -129,3 +167,45 @@ class LaplacianBlurDetectionService implements BlurDetectionService {
 }
 
 export default new LaplacianBlurDetectionService();
+
+type FaceDirection = "left" | "right" | "straight";
+
+const getFaceDirection = (face: Face): FaceDirection => {
+    const landmarks = face.detection.landmarks;
+    const leftEye = landmarks[0];
+    const rightEye = landmarks[1];
+    const nose = landmarks[2];
+    const leftMouth = landmarks[3];
+    const rightMouth = landmarks[4];
+
+    const eyeDistanceX = Math.abs(rightEye.x - leftEye.x);
+    const eyeDistanceY = Math.abs(rightEye.y - leftEye.y);
+    const mouthDistanceY = Math.abs(rightMouth.y - leftMouth.y);
+
+    const faceIsUpright =
+        Math.max(leftEye.y, rightEye.y) + 0.5 * eyeDistanceY < nose.y &&
+        nose.y + 0.5 * mouthDistanceY < Math.min(leftMouth.y, rightMouth.y);
+
+    const noseStickingOutLeft =
+        nose.x < Math.min(leftEye.x, rightEye.x) &&
+        nose.x < Math.min(leftMouth.x, rightMouth.x);
+
+    const noseStickingOutRight =
+        nose.x > Math.max(leftEye.x, rightEye.x) &&
+        nose.x > Math.max(leftMouth.x, rightMouth.x);
+
+    const noseCloseToLeftEye =
+        Math.abs(nose.x - leftEye.x) < 0.2 * eyeDistanceX;
+    const noseCloseToRightEye =
+        Math.abs(nose.x - rightEye.x) < 0.2 * eyeDistanceX;
+
+    // if (faceIsUpright && (noseStickingOutLeft || noseCloseToLeftEye)) {
+    if (noseStickingOutLeft || (faceIsUpright && noseCloseToLeftEye)) {
+        return "left";
+        // } else if (faceIsUpright && (noseStickingOutRight || noseCloseToRightEye)) {
+    } else if (noseStickingOutRight || (faceIsUpright && noseCloseToRightEye)) {
+        return "right";
+    }
+
+    return "straight";
+};

web/apps/photos/src/types/machineLearning/index.ts

@@ -290,7 +290,7 @@ export interface FaceEmbeddingService {
 
 export interface BlurDetectionService {
     method: Versioned<BlurDetectionMethod>;
-    detectBlur(alignedFaces: Float32Array): number[];
+    detectBlur(alignedFaces: Float32Array, faces: Face[]): number[];
 }
 
 export interface ClusteringService {