(VB.NET) 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.
Dim imageData As New Chilkat.BinData
' This image file contains some text...
Dim success As Boolean = imageData.LoadFile("qa_data/jpg/text.jpg")
If (success <> True) Then
    Debug.WriteLine("Failed to load image file.")
    Exit Sub
End If


' Create the above JSON.
Dim json As 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

Dim http As New Chilkat.Http
Dim sb As New Chilkat.StringBuilder
Dim url As String = "https://vision.googleapis.com/v1/images:annotate?key=YOUR_API_KEY"
Dim resp As Chilkat.HttpResponse = http.PostJson3(url,"application/json",json)
If (http.LastMethodSuccess <> True) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("status = " & resp.StatusCode)

' A 200 response status indicate success.
If (resp.StatusCode <> 200) Then
    Debug.WriteLine(resp.BodyStr)
    Debug.WriteLine("Failed.")

    Exit Sub
End If


Dim sbResponseBody As 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:


Dim i As Integer
Dim count_i As Integer
Dim fullTextAnnotationText As String
Dim j As Integer
Dim count_j As Integer
Dim locale As String
Dim description As String
Dim k As Integer
Dim count_k As Integer
Dim x As Integer
Dim y As Integer
Dim width As Integer
Dim height As Integer
Dim languageCode As String
Dim blockType As String
Dim i1 As Integer
Dim count_i1 As Integer
Dim json1 As Chilkat.JsonObject
Dim j1 As Integer
Dim count_j1 As Integer
Dim k1 As Integer
Dim count_k1 As Integer
Dim text As String
Dim propertyDetectedBreakType As String
Dim i2 As Integer
Dim count_i2 As Integer
Dim json2 As Chilkat.JsonObject

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
        End While
        j = j + 1
    End While
    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
        End While
        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
            End While


            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
            End While


            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
                End While
                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
                End While
                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
                    End While
                    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
                    End While
                    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
                        End While


                        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
                        End While

                        k1 = k1 + 1
                    End While
                    j1 = j1 + 1
                End While
                i1 = i1 + 1
            End While

            k = k + 1
        End While
        j = j + 1
    End While
    i = i + 1
End While




Debug.WriteLine("Success.")