feat: ocr(ios)

android/src/main/java/com/swmansion/rnexecutorch/OCR.kt

@@ -0,0 +1,87 @@
+package com.swmansion.rnexecutorch
+
+import android.util.Log
+import com.facebook.react.bridge.Promise
+import com.facebook.react.bridge.ReactApplicationContext
+import com.swmansion.rnexecutorch.utils.ETError
+import com.swmansion.rnexecutorch.utils.ImageProcessor
+import org.opencv.android.OpenCVLoader
+import com.swmansion.rnexecutorch.models.ocr.Detector
+import com.swmansion.rnexecutorch.models.ocr.RecognitionHandler
+import com.swmansion.rnexecutorch.models.ocr.utils.Constants
+import org.opencv.imgproc.Imgproc
+
+class OCR(reactContext: ReactApplicationContext) :
+  NativeOCRSpec(reactContext) {
+
+  private lateinit var detector: Detector
+  private lateinit var recognitionHandler: RecognitionHandler
+
+  companion object {
+    const val NAME = "OCR"
+  }
+
+  init {
+    if (!OpenCVLoader.initLocal()) {
+      Log.d("rn_executorch", "OpenCV not loaded")
+    } else {
+      Log.d("rn_executorch", "OpenCV loaded")
+    }
+  }
+
+  override fun loadModule(
+    detectorSource: String,
+    recognizerSourceLarge: String,
+    recognizerSourceMedium: String,
+    recognizerSourceSmall: String,
+    symbols: String,
+    promise: Promise
+  ) {
+    try {
+      detector = Detector(reactApplicationContext)
+      detector.loadModel(detectorSource)
+
+      recognitionHandler = RecognitionHandler(
+        symbols,
+        reactApplicationContext
+      )
+
+      recognitionHandler.loadRecognizers(
+        recognizerSourceLarge,
+        recognizerSourceMedium,
+        recognizerSourceSmall
+      ) { _, errorRecognizer ->
+        if (errorRecognizer != null) {
+          throw Error(errorRecognizer.message!!)
+        }
+
+        promise.resolve(0)
+      }
+    } catch (e: Exception) {
+      promise.reject(e.message!!, ETError.InvalidModelSource.toString())
+    }
+  }
+
+  override fun forward(input: String, promise: Promise) {
+    try {
+      val inputImage = ImageProcessor.readImage(input)
+      val bBoxesList = detector.runModel(inputImage)
+      val detectorSize = detector.getModelImageSize()
+      Imgproc.cvtColor(inputImage, inputImage, Imgproc.COLOR_BGR2GRAY)
+      val result = recognitionHandler.recognize(
+        bBoxesList,
+        inputImage,
+        (detectorSize.width * Constants.RECOGNIZER_RATIO).toInt(),
+        (detectorSize.height * Constants.RECOGNIZER_RATIO).toInt()
+      )
+      promise.resolve(result)
+    } catch (e: Exception) {
+      Log.d("rn_executorch", "Error running model: ${e.message}")
+      promise.reject(e.message!!, e.message)
+    }
+  }
+
+  override fun getName(): String {
+    return NAME
+  }
+}

android/src/main/java/com/swmansion/rnexecutorch/RnExecutorchPackage.kt

@@ -25,6 +25,8 @@ class RnExecutorchPackage : TurboReactPackage() {
       ObjectDetection(reactContext)
     } else if (name == SpeechToText.NAME) {
       SpeechToText(reactContext)
+    } else if (name == OCR.NAME){
+      OCR(reactContext)
     }
     else {
       null
@@ -85,6 +87,15 @@ class RnExecutorchPackage : TurboReactPackage() {
         false,  // isCxxModule
         true
       )
+
+      moduleInfos[OCR.NAME] = ReactModuleInfo(
+        OCR.NAME,
+        OCR.NAME,
+        false,  // canOverrideExistingModule
+        false,  // needsEagerInit
+        false,  // isCxxModule
+        true
+      )
       moduleInfos
     }
   }

android/src/main/java/com/swmansion/rnexecutorch/models/ocr/Detector.kt

@@ -0,0 +1,79 @@
+package com.swmansion.rnexecutorch.models.ocr
+
+import android.util.Log
+import com.facebook.react.bridge.ReactApplicationContext
+import com.swmansion.rnexecutorch.models.BaseModel
+import com.swmansion.rnexecutorch.models.ocr.utils.Constants
+import com.swmansion.rnexecutorch.models.ocr.utils.DetectorUtils
+import com.swmansion.rnexecutorch.models.ocr.utils.OCRbBox
+import com.swmansion.rnexecutorch.utils.ImageProcessor
+import org.opencv.core.Mat
+import org.opencv.core.Scalar
+import org.opencv.core.Size
+import org.pytorch.executorch.EValue
+
+class Detector(reactApplicationContext: ReactApplicationContext) :
+  BaseModel<Mat, List<OCRbBox>>(reactApplicationContext) {
+  private lateinit var originalSize: Size
+
+  fun getModelImageSize(): Size {
+    val inputShape = module.getInputShape(0)
+    val width = inputShape[inputShape.lastIndex]
+    val height = inputShape[inputShape.lastIndex - 1]
+
+    val modelImageSize = Size(height.toDouble(), width.toDouble())
+
+    return modelImageSize
+  }
+
+  override fun preprocess(input: Mat): EValue {
+    originalSize = Size(input.cols().toDouble(), input.rows().toDouble())
+    val resizedImage = ImageProcessor.resizeWithPadding(
+      input,
+      getModelImageSize().width.toInt(),
+      getModelImageSize().height.toInt()
+    )
+
+    return ImageProcessor.matToEValue(
+      resizedImage,
+      module.getInputShape(0),
+      Constants.MEAN,
+      Constants.VARIANCE
+    )
+  }
+
+  override fun postprocess(output: Array<EValue>): List<OCRbBox> {
+    val outputTensor = output[0].toTensor()
+    val outputArray = outputTensor.dataAsFloatArray
+    val modelImageSize = getModelImageSize()
+
+    val (scoreText, scoreLink) = DetectorUtils.interleavedArrayToMats(
+      outputArray,
+      Size(modelImageSize.width / 2, modelImageSize.height / 2)
+    )
+    var bBoxesList = DetectorUtils.getDetBoxesFromTextMap(
+      scoreText,
+      scoreLink,
+      Constants.TEXT_THRESHOLD,
+      Constants.LINK_THRESHOLD,
+      Constants.LOW_TEXT_THRESHOLD
+    )
+    bBoxesList =
+      DetectorUtils.restoreBoxRatio(bBoxesList, (Constants.RECOGNIZER_RATIO * 2).toFloat())
+    bBoxesList = DetectorUtils.groupTextBoxes(
+      bBoxesList,
+      Constants.CENTER_THRESHOLD,
+      Constants.DISTANCE_THRESHOLD,
+      Constants.HEIGHT_THRESHOLD,
+      Constants.MIN_SIDE_THRESHOLD,
+      Constants.MAX_SIDE_THRESHOLD,
+      Constants.MAX_WIDTH
+    )
+
+    return bBoxesList.toList()
+  }
+
+  override fun runModel(input: Mat): List<OCRbBox> {
+    return postprocess(forward(preprocess(input)))
+  }
+}

android/src/main/java/com/swmansion/rnexecutorch/models/ocr/RecognitionHandler.kt

@@ -0,0 +1,114 @@
+package com.swmansion.rnexecutorch.models.ocr
+
+import com.facebook.react.bridge.Arguments
+import com.facebook.react.bridge.ReactApplicationContext
+import com.facebook.react.bridge.WritableArray
+import com.swmansion.rnexecutorch.models.ocr.utils.CTCLabelConverter
+import com.swmansion.rnexecutorch.models.ocr.utils.Constants
+import com.swmansion.rnexecutorch.models.ocr.utils.OCRbBox
+import com.swmansion.rnexecutorch.models.ocr.utils.RecognizerUtils
+import com.swmansion.rnexecutorch.utils.ImageProcessor
+import org.opencv.core.Core
+import org.opencv.core.Mat
+
+class RecognitionHandler(
+  symbols: String,
+  reactApplicationContext: ReactApplicationContext
+) {
+  private val recognizerLarge = Recognizer(reactApplicationContext)
+  private val recognizerMedium = Recognizer(reactApplicationContext)
+  private val recognizerSmall = Recognizer(reactApplicationContext)
+  private val converter = CTCLabelConverter(symbols)
+
+  private fun runModel(croppedImage: Mat): Pair<List<Int>, Double> {
+    val result: Pair<List<Int>, Double> = if (croppedImage.cols() >= Constants.LARGE_MODEL_WIDTH) {
+      recognizerLarge.runModel(croppedImage)
+    } else if (croppedImage.cols() >= Constants.MEDIUM_MODEL_WIDTH) {
+      recognizerMedium.runModel(croppedImage)
+    } else {
+      recognizerSmall.runModel(croppedImage)
+    }
+
+    return result
+  }
+
+  fun loadRecognizers(
+    largeRecognizerPath: String,
+    mediumRecognizerPath: String,
+    smallRecognizerPath: String,
+    onComplete: (Int, Exception?) -> Unit
+  ) {
+    try {
+      recognizerLarge.loadModel(largeRecognizerPath)
+      recognizerMedium.loadModel(mediumRecognizerPath)
+      recognizerSmall.loadModel(smallRecognizerPath)
+      onComplete(0, null)
+    } catch (e: Exception) {
+      onComplete(1, e)
+    }
+  }
+
+  fun recognize(
+    bBoxesList: List<OCRbBox>,
+    imgGray: Mat,
+    desiredWidth: Int,
+    desiredHeight: Int
+  ): WritableArray {
+    val res: WritableArray = Arguments.createArray()
+    val ratioAndPadding = RecognizerUtils.calculateResizeRatioAndPaddings(
+      imgGray.width(),
+      imgGray.height(),
+      desiredWidth,
+      desiredHeight
+    )
+
+    val left = ratioAndPadding["left"] as Int
+    val top = ratioAndPadding["top"] as Int
+    val resizeRatio = ratioAndPadding["resizeRatio"] as Float
+    val resizedImg = ImageProcessor.resizeWithPadding(
+      imgGray,
+      desiredWidth,
+      desiredHeight
+    )
+
+    for (box in bBoxesList) {
+      var croppedImage = RecognizerUtils.getCroppedImage(box, resizedImg, Constants.MODEL_HEIGHT)
+      if (croppedImage.empty()) {
+        continue
+      }
+
+      croppedImage = RecognizerUtils.normalizeForRecognizer(croppedImage, Constants.ADJUST_CONTRAST)
+
+      var result = runModel(croppedImage)
+      var confidenceScore = result.second
+
+      if (confidenceScore < Constants.LOW_CONFIDENCE_THRESHOLD) {
+        Core.rotate(croppedImage, croppedImage, Core.ROTATE_180)
+        val rotatedResult = runModel(croppedImage)
+        val rotatedConfidenceScore = rotatedResult.second
+        if (rotatedConfidenceScore > confidenceScore) {
+          result = rotatedResult
+          confidenceScore = rotatedConfidenceScore
+        }
+      }
+
+      val predIndex = result.first
+      val decodedTexts = converter.decodeGreedy(predIndex, predIndex.size)
+
+      for (bBox in box.bBox) {
+        bBox.x = (bBox.x - left) * resizeRatio
+        bBox.y = (bBox.y - top) * resizeRatio
+      }
+
+      val resMap = Arguments.createMap()
+
+      resMap.putString("text", decodedTexts[0])
+      resMap.putArray("bbox", box.toWritableArray())
+      resMap.putDouble("confidence", confidenceScore)
+
+      res.pushMap(resMap)
+    }
+
+    return res
+  }
+}

android/src/main/java/com/swmansion/rnexecutorch/models/ocr/Recognizer.kt

@@ -0,0 +1,56 @@
+package com.swmansion.rnexecutorch.models.ocr
+
+import com.facebook.react.bridge.ReactApplicationContext
+import com.swmansion.rnexecutorch.models.BaseModel
+import com.swmansion.rnexecutorch.models.ocr.utils.RecognizerUtils
+import com.swmansion.rnexecutorch.utils.ImageProcessor
+import org.opencv.core.Mat
+import org.opencv.core.Size
+import org.pytorch.executorch.EValue
+
+class Recognizer(reactApplicationContext: ReactApplicationContext) :
+  BaseModel<Mat, Pair<List<Int>, Double>>(reactApplicationContext) {
+
+  private fun getModelOutputSize(): Size {
+    val outputShape = module.getOutputShape(0)
+    val width = outputShape[outputShape.lastIndex]
+    val height = outputShape[outputShape.lastIndex - 1]
+
+    return Size(height.toDouble(), width.toDouble())
+  }
+
+  override fun preprocess(input: Mat): EValue {
+    return ImageProcessor.matToEValueGray(input)
+  }
+
+  override fun postprocess(output: Array<EValue>): Pair<List<Int>, Double> {
+    val modelOutputHeight = getModelOutputSize().height.toInt()
+    val tensor = output[0].toTensor().dataAsFloatArray
+    val numElements = tensor.size
+    val numRows = (numElements + modelOutputHeight - 1) / modelOutputHeight
+    val resultMat = Mat(numRows, modelOutputHeight, org.opencv.core.CvType.CV_32F)
+    var counter = 0
+    var currentRow = 0
+    for (num in tensor) {
+      resultMat.put(currentRow, counter, floatArrayOf(num))
+      counter++
+      if (counter >= modelOutputHeight) {
+        counter = 0
+        currentRow++
+      }
+    }
+
+    var probabilities = RecognizerUtils.softmax(resultMat)
+    val predsNorm = RecognizerUtils.sumProbabilityRows(probabilities, modelOutputHeight)
+    probabilities = RecognizerUtils.divideMatrixByVector(probabilities, predsNorm)
+    val (values, indices) = RecognizerUtils.findMaxValuesAndIndices(probabilities)
+
+    val confidenceScore = RecognizerUtils.computeConfidenceScore(values, indices)
+    return Pair(indices, confidenceScore)
+  }
+
+
+  override fun runModel(input: Mat): Pair<List<Int>, Double> {
+    return postprocess(module.forward(preprocess(input)))
+  }
+}