如何转换相机图像以在 tflite 中使用它

Question

I have an android app in Kotlin which depends on CameraX to analyze images and pass them to tensorflow lite image detection model ( not classification ). The problem is we get YUV or RGBA Output images and we need an argb bitmap to pass to tflite model to detect objects we have been struggling for weeks and we have a deadline soon help please.

    ImageAnalysis.Analyzer {
    private val supportedImages = listOf(ImageFormat.FLEX_RGBA_8888, ImageFormat.FLEX_RGB_888)
    private var data = ""

    @SuppressLint("UnsafeOptInUsageError")
    override fun analyze(image: ImageProxy) {
        if (image.format in supportedImages) {
            val options = ObjectDetector.ObjectDetectorOptions.builder()
                .setScoreThreshold(0.2F)
                .setBaseOptions(BaseOptions.builder().build())
                .build()
            val objectDetector =
                ObjectDetector.createFromFileAndOptions(
                    context, Model.createModel(context, "model.tflite").path, options
                )
            val bitmap = toBitmap(image)
            val tfImage = TensorImage.fromBitmap(bitmap)
            val results: List<Detection> = objectDetector.detect(tfImage)
            for (result in results) {
                val categories = result.categories
                for (category in categories) {
                    val label = category.label
                    val boundingBox = result.boundingBox
                    data += "label : $label | bounding : $boundingBox"
                }
            }
            listener(data)
            image.close()
        }
    }

    private fun toBitmap(image: ImageProxy): Bitmap {
        val r = image.planes[0].buffer.int
        val g = image.planes[1].buffer.int
        val b = image.planes[2].buffer.int
        val a = image.planes[3].buffer.int
        var color = Color.argb(a, r, g, b)
        val rect = Rect(0, 0, 1, 1)
        color = ColorUtils.compositeColors(color, Color.WHITE)
        val bitmap = Bitmap.createBitmap(rect.width(), rect.height(), Bitmap.Config.ARGB_8888)
        val canvas = Canvas(bitmap)
        val paint = Paint()
        paint.color = color
        canvas.drawRect(rect, paint)
        savePic(bitmap = bitmap!!, display_name = Random(100000L).toString())
        return bitmap
    }
    private fun savePic(bitmap: Bitmap, display_name: String): Boolean {
        val mediaCollection = latest {
            MediaStore.Images.Media.getContentUri(MediaStore.VOLUME_EXTERNAL_PRIMARY)
        } ?: MediaStore.Images.Media.EXTERNAL_CONTENT_URI
        val contentValues = ContentValues().apply {
            put(MediaStore.Images.Media.DISPLAY_NAME, "${display_name}.jpg")
            put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg")
            put(MediaStore.Images.Media.WIDTH, bitmap.width)
            put(MediaStore.Images.Media.HEIGHT, bitmap.height)
        }
        return try {
            context.contentResolver.insert(mediaCollection, contentValues)?.also { uri ->
                context.contentResolver.openOutputStream(uri).use { outputStream ->
                    if (!bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream)) {
                        throw IOException("could not save bitmap!")
                    }
                }
            } ?: throw IOException("could not create media store entry")
            return true
        } catch (e: IOException) {
            e.printStackTrace()
            false
        }
    }

}```

Answer 1

Here is the function that converts YUV_420_888 imageproxy into argb format bitmap.

I know a late answer but providing for others.

fun imageToBitmap(image: Image): Bitmap {
    val planes: Array<Image.Plane> = image.planes
    val yBuffer: ByteBuffer = planes[0].buffer
    val uBuffer: ByteBuffer = planes[1].buffer
    val vBuffer: ByteBuffer = planes[2].buffer
    val ySize = yBuffer.remaining()
    val uSize = uBuffer.remaining()
    val vSize = vBuffer.remaining()
    val nv21 = ByteArray(ySize + uSize + vSize)
    //U and V are swapped
    yBuffer[nv21, 0, ySize]
    vBuffer[nv21, ySize, vSize]
    uBuffer[nv21, ySize + vSize, uSize]
    val yuvImage = YuvImage(nv21, ImageFormat.NV21, image.width, image.height, null)
    val out = ByteArrayOutputStream()
    yuvImage.compressToJpeg(Rect(0, 0, yuvImage.width, yuvImage.height), 75, out)
    val imageBytes: ByteArray = out.toByteArray()
    return BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.size)
}

Provide imageproxy from cameraX analyser to this function and it will provide the bitmap.