gistfile1.cs

private void StartOcrConversion(Stream photoStream)
{
    byte[] photoBuffer = MainPage.StreamToByteArray(photoStream);

    OcrService.RecognizeImageAsync(
        HawaiiClient.HawaiiApplicationId,
        photoBuffer,
        (output) =>
        {
            this.Dispatcher.BeginInvoke(() => OnOcrCompleted(output));
        });
}