我假设捕获请求被配置为将输出编码为JPEG格式？
如果是这样的话，你需要将字节读入一个字节数组，然后将jpeg转换为Bitmap。

val buffer = image?.?planes[0]?.buffer ?: return
val jpegData = ByteArray(buffer.remaining()).apply { buffer.get(this) }
val bitmap = BitmapFactory.decodeByteArray(jpegData, 0, jpegData.size)

你有没有考虑过CameraX？它可以简化拍摄过程，并且可以处理很多问题。https://developer.android.com/training/camerax/take-photo
下面是一些你可以尝试的东西的快速概述：

class CameraActivity : AppCompatActivity() {
    ...

    val cameraController = LifecycleCameraController(this)
    cameraController.bindToLifecycle(this as LifecycleOwner)

    // Attach the CameraController to PreviewView
    val previewView = findViewById(R.id.preview_view)
    previewView.setController(cameraController)

    // Take a picture
    cameraController.takePicture(
        ContextCompat.getMainExecutor(this), object : ImageCapture.OnImageCapturedCallback {
            override fun onCaptureSuccess(image: ImageProxy) {
                val buffer = image.planes[0].buffer
                val jpegData = ByteArray(buffer.remaining()).apply { buffer.get(this) }
                val bitmap BitmapFactory.decodeByteArray(jpegData, 0, jpegData.size)
                // show bitmap
            }

            override fun onError(exception: ImageCaptureException) {
                Log.e(TAG, "Error: $exception")
            }
    })  
}