(C#) Google Cloud Vision Text Detection

Demonstrates calling the Google Cloud Vision for text detection (performs Optical Character Recognition). "Detects and extracts text within an image with support for a broad range of languages. It also features automatic language identification." See https://cloud.google.com/vision/docs/detecting-text

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// Build the following request:

// {
//   "requests": [
//     {
//       "image": {
//         "content": "/9j/7QBEUGhvdG9zaG9...base64-encoded-image-content...fXNWzvDEeYxxxzj/Coa6Bax//Z"
//       },
//       "features": [
//         {
//           "type": "TEXT_DETECTION"
//         }
//       ]
//     }
//   ]
// }

// Use this online tool to generate the code from sample JSON: 
// Generate Code to Create JSON

// Load an image file.
Chilkat.BinData imageData = new Chilkat.BinData();
// This image file contains some text...
bool success = imageData.LoadFile("qa_data/jpg/text.jpg");
if (success != true) {
    Debug.WriteLine("Failed to load image file.");
    return;
}

// Create the above JSON.
Chilkat.JsonObject json = new Chilkat.JsonObject();
json.UpdateBd("requests[0].image.content","base64",imageData);
json.UpdateString("requests[0].features[0].type","TEXT_DETECTION");

// Send the following POST with the HTTP request body containing the above JSON.
// POST https://vision.googleapis.com/v1/images:annotate?key=YOUR_API_KEY

Chilkat.Http http = new Chilkat.Http();
Chilkat.StringBuilder sb = new Chilkat.StringBuilder();
string url = "https://vision.googleapis.com/v1/images:annotate?key=YOUR_API_KEY";
Chilkat.HttpResponse resp = http.PostJson3(url,"application/json",json);
if (http.LastMethodSuccess != true) {
    Debug.WriteLine(http.LastErrorText);
    return;
}

Debug.WriteLine("status = " + Convert.ToString(resp.StatusCode));

// A 200 response status indicate success.
if (resp.StatusCode != 200) {
    Debug.WriteLine(resp.BodyStr);
    Debug.WriteLine("Failed.");

    return;
}

Chilkat.StringBuilder sbResponseBody = new Chilkat.StringBuilder();
resp.GetBodySb(sbResponseBody);
sbResponseBody.WriteFile("qa_output/textDetectResponse.json","utf-8",false);
json.LoadSb(sbResponseBody);

// The response is a JSON document like this:

// Use this online tool to generate parsing code from sample JSON: 
// Generate Parsing Code from JSON

// {
//   "responses": [
//     {
//       "textAnnotations": [
//         {
//           "locale": "en",
//           "description": "Chilkat is a cross-language, cross-platform\nAPl providing 90+ classes for many Internet\nprotocols, formats, and algorithms.\n",
//           "boundingPoly": {
//             "vertices": [
//               {
//                 "x": 17,
//                 "y": 14
//               },
// 	...
//             ]
//           }
//         ],
//         "text": "Chilkat is a cross-language, cross-platform\nAPl providing 90+ classes for many Internet\nprotocols, formats, and algorithms.\n"
//       }
//     }
//   ]
// }

// The parsing code generated from the online tool:

int i;
int count_i;
string fullTextAnnotationText;
int j;
int count_j;
string locale;
string description;
int k;
int count_k;
int x;
int y;
int width;
int height;
string languageCode;
string blockType;
int i1;
int count_i1;
Chilkat.JsonObject json1 = null;
int j1;
int count_j1;
int k1;
int count_k1;
string text;
string propertyDetectedBreakType;
int i2;
int count_i2;
Chilkat.JsonObject json2 = null;

i = 0;
count_i = json.SizeOfArray("responses");
while (i < count_i) {
    json.I = i;
    fullTextAnnotationText = json.StringOf("responses[i].fullTextAnnotation.text");
    j = 0;
    count_j = json.SizeOfArray("responses[i].textAnnotations");
    while (j < count_j) {
        json.J = j;
        locale = json.StringOf("responses[i].textAnnotations[j].locale");
        description = json.StringOf("responses[i].textAnnotations[j].description");
        k = 0;
        count_k = json.SizeOfArray("responses[i].textAnnotations[j].boundingPoly.vertices");
        while (k < count_k) {
            json.K = k;
            x = json.IntOf("responses[i].textAnnotations[j].boundingPoly.vertices[k].x");
            y = json.IntOf("responses[i].textAnnotations[j].boundingPoly.vertices[k].y");
            k = k + 1;
        }

        j = j + 1;
    }

    j = 0;
    count_j = json.SizeOfArray("responses[i].fullTextAnnotation.pages");
    while (j < count_j) {
        json.J = j;
        width = json.IntOf("responses[i].fullTextAnnotation.pages[j].width");
        height = json.IntOf("responses[i].fullTextAnnotation.pages[j].height");
        k = 0;
        count_k = json.SizeOfArray("responses[i].fullTextAnnotation.pages[j].property.detectedLanguages");
        while (k < count_k) {
            json.K = k;
            languageCode = json.StringOf("responses[i].fullTextAnnotation.pages[j].property.detectedLanguages[k].languageCode");
            k = k + 1;
        }

        k = 0;
        count_k = json.SizeOfArray("responses[i].fullTextAnnotation.pages[j].blocks");
        while (k < count_k) {
            json.K = k;
            blockType = json.StringOf("responses[i].fullTextAnnotation.pages[j].blocks[k].blockType");

            json1 = json.ObjectOf("responses[i].fullTextAnnotation.pages[j].blocks[k]");
            i1 = 0;
            count_i1 = json1.SizeOfArray("property.detectedLanguages");
            while (i1 < count_i1) {
                json1.I = i1;
                languageCode = json1.StringOf("property.detectedLanguages[i].languageCode");
                i1 = i1 + 1;
            }

            json1 = json.ObjectOf("responses[i].fullTextAnnotation.pages[j].blocks[k]");
            i1 = 0;
            count_i1 = json1.SizeOfArray("boundingBox.vertices");
            while (i1 < count_i1) {
                json1.I = i1;
                x = json1.IntOf("boundingBox.vertices[i].x");
                y = json1.IntOf("boundingBox.vertices[i].y");
                i1 = i1 + 1;
            }

            json1 = json.ObjectOf("responses[i].fullTextAnnotation.pages[j].blocks[k]");
            i1 = 0;
            count_i1 = json1.SizeOfArray("paragraphs");
            while (i1 < count_i1) {
                json1.I = i1;
                j1 = 0;
                count_j1 = json1.SizeOfArray("paragraphs[i].property.detectedLanguages");
                while (j1 < count_j1) {
                    json1.J = j1;
                    languageCode = json1.StringOf("paragraphs[i].property.detectedLanguages[j].languageCode");
                    j1 = j1 + 1;
                }

                j1 = 0;
                count_j1 = json1.SizeOfArray("paragraphs[i].boundingBox.vertices");
                while (j1 < count_j1) {
                    json1.J = j1;
                    x = json1.IntOf("paragraphs[i].boundingBox.vertices[j].x");
                    y = json1.IntOf("paragraphs[i].boundingBox.vertices[j].y");
                    j1 = j1 + 1;
                }

                j1 = 0;
                count_j1 = json1.SizeOfArray("paragraphs[i].words");
                while (j1 < count_j1) {
                    json1.J = j1;
                    k1 = 0;
                    count_k1 = json1.SizeOfArray("paragraphs[i].words[j].property.detectedLanguages");
                    while (k1 < count_k1) {
                        json1.K = k1;
                        languageCode = json1.StringOf("paragraphs[i].words[j].property.detectedLanguages[k].languageCode");
                        k1 = k1 + 1;
                    }

                    k1 = 0;
                    count_k1 = json1.SizeOfArray("paragraphs[i].words[j].boundingBox.vertices");
                    while (k1 < count_k1) {
                        json1.K = k1;
                        x = json1.IntOf("paragraphs[i].words[j].boundingBox.vertices[k].x");
                        y = json1.IntOf("paragraphs[i].words[j].boundingBox.vertices[k].y");
                        k1 = k1 + 1;
                    }

                    k1 = 0;
                    count_k1 = json1.SizeOfArray("paragraphs[i].words[j].symbols");
                    while (k1 < count_k1) {
                        json1.K = k1;
                        text = json1.StringOf("paragraphs[i].words[j].symbols[k].text");
                        propertyDetectedBreakType = json1.StringOf("paragraphs[i].words[j].symbols[k].property.detectedBreak.type");

                        json2 = json1.ObjectOf("paragraphs[i].words[j].symbols[k]");
                        i2 = 0;
                        count_i2 = json2.SizeOfArray("property.detectedLanguages");
                        while (i2 < count_i2) {
                            json2.I = i2;
                            languageCode = json2.StringOf("property.detectedLanguages[i].languageCode");
                            i2 = i2 + 1;
                        }

                        json2 = json1.ObjectOf("paragraphs[i].words[j].symbols[k]");
                        i2 = 0;
                        count_i2 = json2.SizeOfArray("boundingBox.vertices");
                        while (i2 < count_i2) {
                            json2.I = i2;
                            x = json2.IntOf("boundingBox.vertices[i].x");
                            y = json2.IntOf("boundingBox.vertices[i].y");
                            i2 = i2 + 1;
                        }

                        k1 = k1 + 1;
                    }

                    j1 = j1 + 1;
                }

                i1 = i1 + 1;
            }

            k = k + 1;
        }

        j = j + 1;
    }

    i = i + 1;
}

Debug.WriteLine("Success.");