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我有以下Android代码：

class MainActivity : AppCompatActivity(), TtsSpeaker.Listener, PocketSphinx.Listener {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

                val ocvLoaded = OpenCVLoader.initDebug()
        if (ocvLoaded) {
            loadModel(this)    // to be sure model in sot alled before initiation openCV
        } else {
            Log.d("openCV", "loader: ${OpenCVLoader.initDebug()}")
        }
   }
}

并使用以下人脸检测类：

package hasan.tts_mobile

import android.app.Activity
import android.graphics.Bitmap
import org.opencv.core.Mat
import org.opencv.core.MatOfRect
import org.opencv.core.Size
import org.opencv.imgproc.Imgproc
import org.opencv.objdetect.CascadeClassifier
import java.io.File
import org.opencv.core.CvType
import android.opengl.ETC1.getWidth
import android.opengl.ETC1.getHeight



object FaceDetection {

    private val faceModel = "haarcascade_frontalface_default.xml" //lateinit var faceModel: String // = "haarcascade_frontalface_default.xml"

    private lateinit var faceCascade: CascadeClassifier

    fun loadModel(activity: Activity) {
        println("started loading the model")
        faceCascade = CascadeClassifier(File(activity.filesDir, "das").apply {
            writeBytes(activity.assets.open(faceModel).readBytes())
        }.path)
        println("completed loading the model")
        tts!!.say("I'm 100% ready!")
    }

    fun detectFaces(activity: Activity, image: Bitmap?): Long {
       // bitmap
        val matImage = Mat(image!!.height, image.width, CvType.CV_8UC1)
        val bmpImage = image.copy(Bitmap.Config.ARGB_8888, true)
        Utils.bitmapToMat(bmpImage, matImage)
        val rectangles = MatOfRect()  //RectVector()  //MatOfRect()
        val grayScaled = matImage .prepare()
      //  loadModel(activity)
        faceCascade.detectMultiScale(
            grayScaled, rectangles, 1.2, 10, 0,
            Size(40.0, 40.0),
            null)
        return rectangles.size() as Long
    }

    private fun Mat.toGrayScale(): Mat =
        if (channels() >= 3) Mat().apply {
            Imgproc.cvtColor(
                this@toGrayScale,
                this,
                Imgproc.COLOR_BGR2GRAY
            )
        }
        else this

    private fun Mat.prepare(): Mat {
        val mat = toGrayScale()
        Imgproc.equalizeHist(mat, mat)
        return mat
    }
}

使用以下代码从相机成功拍摄照片后调用人脸检测功能：

    private fun startCamera() {
        val fileName = System.currentTimeMillis().toString() + ".jpeg"
        output = File(
            this.getExternalFilesDir(Environment.DIRECTORY_PICTURES),
            fileName
        )
        val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
        outPutFileUri = this?.let { it1 ->
            FileProvider.getUriForFile(
                it1,
                BuildConfig.APPLICATION_ID,
                output!!
            )
        }
        intent.putExtra(MediaStore.EXTRA_OUTPUT, outPutFileUri)
        startActivityForResult(intent, REQUEST_IMAGE_CAPTURE)
    }

    @SuppressLint("MissingSuperCall")
    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == Activity.RESULT_OK) {
            val bitmap = outPutFileUri?.let { getCapturedImage(it) }
            imageView.setImageBitmap(bitmap)
            FaceDetection.detectFaces(this, bitmap) // Calling facedetection
        }
    }

    private fun getCapturedImage(selectedPhotoUri: Uri): Bitmap {
        val bitmap = when {
            Build.VERSION.SDK_INT < 28 -> MediaStore.Images.Media.getBitmap(
                this.contentResolver,
                selectedPhotoUri
            )
            else -> {
                val source = ImageDecoder.createSource(this.contentResolver, selectedPhotoUri)
                ImageDecoder.decodeBitmap(source)
            }
        }

        return when (ExifInterface(contentResolver.run { openInputStream(selectedPhotoUri) }).getAttributeInt(
            ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED)) {
            ExifInterface.ORIENTATION_ROTATE_90 -> Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, Matrix().apply { postRotate(90F) }, true)
            ExifInterface.ORIENTATION_ROTATE_180 -> Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, Matrix().apply { postRotate(180F) }, true)
            ExifInterface.ORIENTATION_ROTATE_270 -> Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, Matrix().apply { postRotate(270F) }, true)
            else -> bitmap
        }
    }

我得到的完整错误是：

D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: hasan.tts_mobile, PID: 14110
    java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=-1, data=Intent {  }} to activity {hasan.tts_mobile/hasan.tts_mobile.MainActivity}: java.lang.NullPointerException: Attempt to read from field 'double org.opencv.core.Size.width' on a null object reference
        at android.app.ActivityThread.deliverResults(ActivityThread.java:4845)
        at android.app.ActivityThread.handleSendResult(ActivityThread.java:4886)
        at android.app.servertransaction.ActivityResultItem.execute(ActivityResultItem.java:51)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
     Caused by: java.lang.NullPointerException: Attempt to read from field 'double org.opencv.core.Size.width' on a null object reference
        at org.opencv.objdetect.CascadeClassifier.detectMultiScale(CascadeClassifier.java:156)
        at hasan.tts_mobile.FaceDetection.detectFaces(FaceDetection.kt:38)
        at hasan.tts_mobile.MainActivity.onActivityResult(MainActivity.kt:173)
        at android.app.Activity.dispatchActivityResult(Activity.java:8110)
        at android.app.ActivityThread.deliverResults(ActivityThread.java:4838)
        at android.app.ActivityThread.handleSendResult(ActivityThread.java:4886) 
        at android.app.servertransaction.ActivityResultItem.execute(ActivityResultItem.java:51) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:214) 
        at android.app.ActivityThread.main(ActivityThread.java:7356) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 
I/Process: Sending signal. PID: 14110 SIG: 9
Process 14110 terminated.

我加

        println("pic size: ${grayScaled.size()}")
        println("faceCascade: ${faceCascade.originalWindowSize}")

前

        faceCascade.detectMultiScale(
            grayScaled, rectangles, 1.2, 10, 0,
            Size(40.0, 40.0),
            null)

并得到以下信息：

I/System.out: pic size: 960x1280 
    faceCascade: 24x24
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: hasan.tts_mobile, PID: 15177

更新 看起来问题是我将 as 定义maxSize为null，它应该是Size()或全尺寸为：Size(40.0, 40.0)现在我将其更改为：

        faceCascade.detectMultiScale(
            grayScaled, rectangles, 1.1, 3, 0,
            Size(30.0, 30.0), Size()
            )
        println("rectangles ${rectangles.size()}")

我没有挂起或崩溃，而是返回rectangles.size()as ：

I/System.out: pic size: 3264x2448
    faceCascade: 24x24
I/System.out: rectangles 1x0

这是否意味着它没有检测到任何人脸，如果是，如何解决？

4

1 回答 1

0

我想通了，人脸检测过程的结果是在过程本身完成之前读取的，所以解决方案是使用asynccall，在 Kotlin 中是通过 using 来完成的coroutine。

在 Kotlin 中有coroutine-core，coroutine-android所以我应该小心选择正确的，即：

implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.1'

在 Kotlin 协程中，有：

suspend fun mySuspendMethodThatWaitsForChildCoroutinesToFinish() {
    coroutineScope {
        launch { mySyspendMethod() }
    }
}
// or
suspend fun mySuspendMethodThatWaitsForChildCoroutinesToFinish() = coroutineScope {
        launch { mySyspendMethod() }
}

但这将继续要求在所有层次结构中传播暂停，并且一旦到达onActivityResult拍照后触发的那个就会卡住，因此解决方案是 used MainScope() coroutine，即允许使用coroutinefromnon-suspended函数，您可以在其中：

1-声明coroutine scope为val scope = MainScope()

2-执行coroutineasscope.launch { }

完整的图片如下：

import kotlinx.coroutines.*

class MainActivity : AppCompatActivity() {
    private val scope = MainScope()

    override fun onCreate(savedInstanceState: Bundle?) { }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) { 
              detectFace(this, image, textView)
    }
}

private fun detectFace(context: Context, image: Bitmap, facesValue: TextView) {
    val frame = AndroidFrameConverter().convert(image)
    val mat = OpenCVFrameConverter.ToMat().convert(frame)
    scope.launch {
            val numberOfFaces = FaceDetection.detectFaces(mat).toString()
            (context as Activity).runOnUiThread {
                facesValue.text = numberOfFaces
            }
        }
    }

所以我的也不MainActivity是：

class MainActivity : AppCompatActivity() {   
    private val scope = MainScope()
    val REQUEST_IMAGE_CAPTURE = 1

    private var output: File? = null
    var outPutFileUri: Uri? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        if (!isPermissionGranted(permission.RECORD_AUDIO)) {
            requestAudioPermission(this)
        } else {
            Toast.makeText(
                this@MainActivity, "Audio permission is granted",
                Toast.LENGTH_SHORT
            ).show()
        }

        val ocvLoaded = OpenCVLoader.initDebug()
        if (ocvLoaded) {
            loadModel(this)
            Toast.makeText(
                this@MainActivity, "OpenCV loaded",
                Toast.LENGTH_SHORT
            ).show()
        } else {
            Toast.makeText(
                this@MainActivity, "Unable to load OpenCV",
                Toast.LENGTH_SHORT
            ).show()
            Log.d("openCV", "loader: ${OpenCVLoader.initDebug()}")
        }

        btnCamera.setOnClickListener {
            if(isPermissionGranted(permission.CAMERA)) startCamera()
            else requestCameraPermission(this)
        }

        gryImage.setOnClickListener {
            val bitmap = outPutFileUri?.let { getCapturedImage(it) }
            val matImage = Mat(bitmap!!.height, bitmap.width, CvType.CV_8UC1)
            val bmpImage = bitmap.copy(Bitmap.Config.ARGB_8888, true)
            Utils.bitmapToMat(bmpImage, matImage)

            val bmp = Bitmap.createBitmap(matImage.cols(), matImage.rows(), Bitmap.Config.ARGB_8888)
            Imgproc.cvtColor(matImage, matImage, Imgproc.COLOR_RGB2GRAY)
            Utils.matToBitmap(matImage, bmp)

            imageView.setImageBitmap(bmp)
        }

    }

    private fun startCamera() {
        val fileName = System.currentTimeMillis().toString() + ".jpeg"
        output = File(
            this.getExternalFilesDir(Environment.DIRECTORY_PICTURES),
            fileName
        )
        val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
        outPutFileUri = this.let { it ->
            FileProvider.getUriForFile(
                it,
                BuildConfig.APPLICATION_ID,
                output!!
            )
        }
        intent.putExtra(MediaStore.EXTRA_OUTPUT, outPutFileUri)
        startActivityForResult(intent, REQUEST_IMAGE_CAPTURE)
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        val activity = this
        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == Activity.RESULT_OK) {
            val bitmap = outPutFileUri?.let { getCapturedImage(it) }
            imageView.setImageBitmap(bitmap)
            outPutFileUri?.let {
                scope.launch {
                    val detectedFaces = FaceDetection.detectFaces(bitmap)
                    println("Detected Faces = $detectedFaces")
                    Toast.makeText(
                        this@MainActivity, "Detected Faces = $detectedFaces",
                        Toast.LENGTH_SHORT
                    ).show()
                }
            }
        }
    }

    private fun getCapturedImage(selectedPhotoUri: Uri): Bitmap {

        return when {
            Build.VERSION.SDK_INT < 28 -> MediaStore.Images.Media.getBitmap(
                contentResolver,
                selectedPhotoUri
            )
            else -> {
                val source = ImageDecoder.createSource(contentResolver, selectedPhotoUri)
                ImageDecoder.decodeBitmap(source)
            }
        }
        // If the image is rotated, fix it
    /*    return when (ExifInterface(contentResolver.run { openInputStream(selectedPhotoUri) }).getAttributeInt(
            ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED)) {
            ExifInterface.ORIENTATION_ROTATE_90 ->
                Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, Matrix().apply {
                    postRotate(90F) }, true)
            ExifInterface.ORIENTATION_ROTATE_180 ->
                Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, Matrix().apply {
                    postRotate(180F) }, true)
            ExifInterface.ORIENTATION_ROTATE_270 ->
                Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, Matrix().apply {
                    postRotate(270F) }, true)
            else -> bitmap
        } */
    }

    override fun onRequestPermissionsResult(
        requestCode: Int, permissions: Array<String>,grantResults: IntArray) =
        onPermissionsRequestResult(this@MainActivity,
            requestCode, permissions, grantResults)
}

我的FaceDetection功能是：

object FaceDetection {

    private const val faceModel = "haarcascades/haarcascade_frontalface_default.xml"  // main/assets/haarcascades
    private lateinit var faceCascade: CascadeClassifier

    fun loadModel(activity: Activity) {
        faceCascade = CascadeClassifier(File(activity.filesDir, "das").apply {
            writeBytes(activity.assets.open(faceModel).readBytes())
        }.path))
    }

    fun detectFaces(image: Bitmap?): Int {
        val matImage = Mat(image!!.height, image.width, CvType.CV_8UC1)  // CV_8UC1 is gray scale image
        val bmpImage = image.copy(Bitmap.Config.ARGB_8888, true)
        Utils.bitmapToMat(bmpImage, matImage)

        val faceDetections = MatOfRect()

        val grayScaled = matImage.prepare()
        faceCascade.detectMultiScale(matImage, faceDetections, 1.1, 7, 0,
            Size(250.0, 40.0), Size())
        // process faces found
        for (rect in faceDetections.toArray()) {
            println("face found")
           // Imgproc.rectangle(
           //     image,
             //   Point(rect.x, rect.y),
             //   Point(rect.x + rect.width, rect.y + rect.height),
           //     Scalar(0.0, 255.0, 0.0)
           // )
        }

        return faceDetections.toArray().size
    }

    private fun Mat.toGrayScale(): Mat =
        if (channels() >= 3) Mat().apply {
            Imgproc.cvtColor(
                this@toGrayScale,
                this,
                Imgproc.COLOR_BGR2GRAY
            )
        }
        else this

    private fun Mat.prepare(): Mat {
        val mat = toGrayScale()
        Imgproc.equalizeHist(mat, mat)
        return mat
    }
}
于 2019-09-24T05:00:10.993 回答