Problem getting information from the Azure Cognitive Service (OCR)

Question

I’m developing a windows service that downloads a web image, "flips" it horizontally and sends it to the cognitive service of Azure (OCR), the idea is to capture the text of this image. However, when sending the image via request the return is empty.

I have tested the same method with different images and worked normally.

I have also tested, via the online test of Azure(https://azure.microsoft.com/pt-br/services/cognitive-services/computer-vision/) which also worked normally (with both images).

public void FlipaImagem(string url)
{
    using (var wc = new WebClient())
    {
        using (var imgStream = new MemoryStream(wc.DownloadData(url)))
        {
            using (var objImage = System.Drawing.Image.FromStream(imgStream))
            {
               objImage.RotateFlip(RotateFlipType.Rotate180FlipY);
                if (File.Exists("arquivoFlipado.jpeg"))
                    File.Delete("arquivoFlipado.jpeg");
                objImage.Save("arquivoFlipado.jpeg", ImageFormat.Jpeg);
                objImage.Dispose();
            }
        }
    }
}

The above method saves the "flied" image, if I take this saved image and send it via online test (which I mentioned above), it works.

Below how I’m sending to Azure(Remembering that if I pass other images URL works normally):

public RespostaAzure PostServicoAsync(string urlImagem)
    {
        httpClient = new HttpClient();
        httpClient.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", subscriptionkey);
        FlipaImagem(urlImagem);
        var imagem = Image.FromFile(@"arquivoFlipado.jpeg");

        ImageConverter _imageConverter = new ImageConverter();
        byte[] xByte = (byte[])_imageConverter.ConvertTo(imagem, typeof(byte[]));

        MemoryStream stream = new MemoryStream(xByte);



        var streamContent = new StreamContent(stream);

        streamContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
        var queryString = HttpUtility.ParseQueryString(string.Empty);
        queryString["language"] = "pt";
        queryString["detectOrientation "] = "true";
        var novo = urlAzure + queryString;

        try
        {
            var response = httpClient.PostAsync(novo, streamContent).Result;

            var x = response.Content.ReadAsStringAsync().Result;

            var obj = JsonConvert.DeserializeObject<RespostaAzure>(x);


             return obj;
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            _imageConverter = null;
            xByte = null;
            imagem.Dispose();
        }
    }

Any idea what it might be?

Thank you.

===================UPDATE===================

When testing directly from the API(https://brazilsouth.dev.cognitive.microsoft.com/docs/services/5adf991815e1060e6355ad44/operations/56f91f2e778daf14a499e1fc/console), I realized that it shows the same behavior, unsuccessfully recognizing "easy to analyze" images, but on the Azure site works perfectly.

Ps: In Azure he says he is using API 2.0 but when using it, it has the same behavior as 1.0, and when checking via console I saw that the Azure site sends the request to a totally different URL that I believe is restricted only to them.

Maybe it’s clearer if I leave an image I’m trying to read and the problem occurs, along with the links:

• Azure link(Here returns the texts correctly): https://azure.microsoft.com/pt-br/services/cognitive-services/computer-vision/

• API link (Does not return text):
  https://brazilsouth.dev.cognitive.microsoft.com/docs/services/5adf991815e1060e6355ad44/operations/56f91f2e778daf14a499e1fc/console

• Sample image:https://www.grupoescolar.com/a/b/o-que-e-um-texto-D5.jpg

Answer 1

Apparently the Azure example API is another, in the case of Recognition Text. I took as "solution" this topic. As much as it wasn’t what I was looking for it circumvents the problem and delivers the same answer from website.