Implement Android Facial Recognition

Inject it

Author: Wavesonics

app/src/main/kotlin/com/darkrockstudios/app/securecamera/AppModule.kt

@@ -8,6 +8,8 @@ import com.darkrockstudios.app.securecamera.camera.ThumbnailCache
 import com.darkrockstudios.app.securecamera.gallery.GalleryViewModel
 import com.darkrockstudios.app.securecamera.import.ImportPhotosViewModel
 import com.darkrockstudios.app.securecamera.introduction.IntroductionViewModel
+import com.darkrockstudios.app.securecamera.obfuscation.FacialDetection
+import com.darkrockstudios.app.securecamera.obfuscation.MlFacialDetection
 import com.darkrockstudios.app.securecamera.obfuscation.ObfuscatePhotoViewModel
 import com.darkrockstudios.app.securecamera.preferences.AppPreferencesDataSource
 import com.darkrockstudios.app.securecamera.security.DeviceInfo
@@ -52,6 +54,7 @@ val appModule = module {
 	factoryOf(::VerifyPinUseCase)
 	factoryOf(::CreatePinUseCase)
 	factoryOf(::PinSizeUseCase)
+	factoryOf(::MlFacialDetection) bind FacialDetection::class
 
 	viewModelOf(::ObfuscatePhotoViewModel)
 	viewModelOf(::ViewPhotoViewModel)

app/src/main/kotlin/com/darkrockstudios/app/securecamera/obfuscation/AndroidFacialDetection.kt

@@ -0,0 +1,95 @@
+package com.darkrockstudios.app.securecamera.obfuscation
+
+import android.graphics.Bitmap
+import android.graphics.PointF
+import android.graphics.Rect
+import android.media.FaceDetector
+import androidx.core.graphics.createBitmap
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import timber.log.Timber
+
+class AndroidFacialDetection : FacialDetection {
+	override suspend fun processForFaces(bitmap: Bitmap): List<FacialDetection.FoundFace> =
+		withContext(Dispatchers.Default) {
+			// Android's FaceDetector requires RGB_565 format
+			val bitmapForDetection = if (bitmap.config != Bitmap.Config.RGB_565) {
+				try {
+					createBitmap(bitmap.width, bitmap.height, Bitmap.Config.RGB_565).also { targetBitmap ->
+						val canvas = android.graphics.Canvas(targetBitmap)
+						canvas.drawBitmap(bitmap, 0f, 0f, null)
+					}
+				} catch (e: Exception) {
+					Timber.e(e, "Failed to convert bitmap to RGB_565")
+					return@withContext emptyList<FacialDetection.FoundFace>()
+				}
+			} else {
+				bitmap
+			}
+
+			// Maximum number of faces to detect
+			val maxFaces = 100
+
+			try {
+				val detector = FaceDetector(bitmapForDetection.width, bitmapForDetection.height, maxFaces)
+				val faces = arrayOfNulls<FaceDetector.Face>(maxFaces)
+
+				// Find faces in the bitmap
+				val facesFound = detector.findFaces(bitmapForDetection, faces)
+				Timber.d("Found $facesFound faces using Android FaceDetector")
+
+				// Convert the detected faces to our FoundFace format
+				val foundFaces = mutableListOf<FacialDetection.FoundFace>()
+
+				for (i in 0 until facesFound) {
+					faces[i]?.let { face ->
+						val midPoint = PointF()
+						face.getMidPoint(midPoint)
+
+						// Calculate the bounding box based on the face's position and confidence
+						val eyeDistance = face.eyesDistance()
+						val confidence = face.confidence()
+
+						// Use eye distance to estimate face size
+						// The multipliers are approximations and may need adjustment
+						val faceWidth = (eyeDistance * 2.5f).toInt()
+						val faceHeight = (eyeDistance * 3.0f).toInt()
+
+						val left = (midPoint.x - faceWidth / 2).toInt().coerceAtLeast(0)
+						val top = (midPoint.y - faceHeight / 2).toInt().coerceAtLeast(0)
+						val right = (midPoint.x + faceWidth / 2).toInt().coerceAtMost(bitmap.width)
+						val bottom = (midPoint.y + faceHeight / 2).toInt().coerceAtMost(bitmap.height)
+
+						val boundingBox = Rect(left, top, right, bottom)
+
+						// Calculate approximate eye positions based on the midpoint and eye distance
+						val leftEyeX = midPoint.x - eyeDistance / 2
+						val rightEyeX = midPoint.x + eyeDistance / 2
+						val eyeY = midPoint.y - eyeDistance / 8  // Slight adjustment for eye height
+
+						val eyes = FacialDetection.FoundFace.Eyes(
+							left = PointF(leftEyeX, eyeY),
+							right = PointF(rightEyeX, eyeY)
+						)
+
+						foundFaces.add(
+							FacialDetection.FoundFace(
+								boundingBox = boundingBox,
+								eyes = eyes
+							)
+						)
+					}
+				}
+
+				// Clean up if we created a new bitmap
+				if (bitmapForDetection != bitmap) {
+					bitmapForDetection.recycle()
+				}
+
+				foundFaces
+			} catch (e: Exception) {
+				Timber.e(e, "Error detecting faces with Android FaceDetector")
+				emptyList()
+			}
+		}
+}

app/src/main/kotlin/com/darkrockstudios/app/securecamera/obfuscation/ObfuscatePhotoViewModel.kt

@@ -18,11 +18,10 @@ import timber.log.Timber
 
 class ObfuscatePhotoViewModel(
 	private val appContext: Context,
-	private val imageManager: SecureImageRepository
+	private val imageManager: SecureImageRepository,
+	private val facialDetection: FacialDetection,
 ) : BaseViewModel<ObfuscatePhotoUiState>() {
 
-	private val facialDetection = MlFacialDetection()
-
 	override fun createState() = ObfuscatePhotoUiState()
 
 	fun toggleRegionObfuscation(index: Int) {