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(VB.NET) Amazon Rekognition - Detect Text in an Image
Detects text in the input image and converts it into machine-readable text. This example passes theimage as base64-encoded image bytes. For more information, see https://docs.aws.amazon.com/rekognition/latest/dg/API_DetectText.html
Dim rest As New Chilkat.Rest
Dim success As Boolean
Dim authAws As New Chilkat.AuthAws
authAws.AccessKey = "AWS_ACCESS_KEY"
authAws.SecretKey = "AWS_SECRET_KEY"
' Don't forget to change the region to your particular region. (Also make the same change in the call to Connect below.)
authAws.Region = "us-west-2"
authAws.ServiceName = "rekognition"
' SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
rest.SetAuthAws(authAws)
' URL: https://rekognition.us-west-2.amazonaws.com/
Dim bTls As Boolean = True
Dim port As Integer = 443
Dim bAutoReconnect As Boolean = True
' Don't forget to change the region domain (us-west-2.amazonaws.com) to your particular region.
success = rest.Connect("rekognition.us-west-2.amazonaws.com",port,bTls,bAutoReconnect)
If (success <> True) Then
Debug.WriteLine("ConnectFailReason: " & rest.ConnectFailReason)
Debug.WriteLine(rest.LastErrorText)
Exit Sub
End If
' Note: The above code does not need to be repeatedly called for each REST request.
' The rest object can be setup once, and then many requests can be sent. Chilkat will automatically
' reconnect within a FullRequest* method as needed. It is only the very first connection that is explicitly
' made via the Connect method.
' Load the JPG to be passed as base64 in the JSON.
Dim bdJpg As New Chilkat.BinData
success = bdJpg.LoadFile("qa_data/jpg/monday_keep_smiling.jpg")
If (success <> True) Then
Debug.WriteLine("Failed to load the input JPG file.")
Exit Sub
End If
' We wish to send the following JSON in the body of our HTTP request:
' {
' "Image": {
' "Bytes": "base64_image_bytes"
' }
' }
' Here is the image we used for testing:
' Convert binary image bytes to base64.
' Note: We are explicitly keeping the data inside Chilkat to avoid having to pass large strings
' as arguments to function calls. This is important for some programming languages.
Dim sbJpg As New Chilkat.StringBuilder
bdJpg.GetEncodedSb("base64",sbJpg)
Dim json As New Chilkat.JsonObject
json.UpdateSb("Image.Bytes",sbJpg)
rest.AddHeader("Content-Type","application/x-amz-json-1.1")
rest.AddHeader("X-Amz-Target","RekognitionService.DetectText")
Dim sbRequestBody As New Chilkat.StringBuilder
json.EmitSb(sbRequestBody)
Dim sbResponseBody As New Chilkat.StringBuilder
success = rest.FullRequestSb("POST","/",sbRequestBody,sbResponseBody)
If (success <> True) Then
Debug.WriteLine(rest.LastErrorText)
Exit Sub
End If
Dim respStatusCode As Integer = rest.ResponseStatusCode
Debug.WriteLine("response status code = " & respStatusCode)
If (respStatusCode >= 400) Then
Debug.WriteLine("Response Status Code = " & respStatusCode)
Debug.WriteLine("Response Header:")
Debug.WriteLine(rest.ResponseHeader)
Debug.WriteLine("Response Body:")
Debug.WriteLine(sbResponseBody.GetAsString())
Exit Sub
End If
Dim jResp As New Chilkat.JsonObject
jResp.LoadSb(sbResponseBody)
jResp.EmitCompact = False
Debug.WriteLine(jResp.Emit())
' Sample JSON response:
' (Sample code for parsing the JSON response is shown below)
' {
' "TextDetections": [
' {
' "Confidence": 95.99308776855469,
' "DetectedText": "( MONDAY IT'S",
' "Geometry": {
' "BoundingBox": {
' "Height": 0.6399821043014526,
' "Left": 0.219133198261261,
' "Top": 0.08677978068590164,
' "Width": 0.7433173656463623
' },
' "Polygon": [
' {
' "X": 0.219133198261261,
' "Y": 0.3588336706161499
' },
' {
' "X": 0.8984103798866272,
' "Y": 0.08677978068590164
' },
' {
' "X": 0.9624505639076233,
' "Y": 0.4547080099582672
' },
' {
' "X": 0.2831733524799347,
' "Y": 0.7267619371414185
' }
' ]
' },
' "Id": 0,
' "Type": "LINE"
' },
' {
' "Confidence": 99.70352172851562,
' "DetectedText": "but keep",
' "Geometry": {
' "BoundingBox": {
' "Height": 0.09703556448221207,
' "Left": 0.6335319876670837,
' "Top": 0.5153074264526367,
' "Width": 0.21070890128612518
' },
' "Polygon": [
' {
' "X": 0.6355597376823425,
' "Y": 0.5153074264526367
' },
' {
' "X": 0.8442409038543701,
' "Y": 0.5266726613044739
' },
' {
' "X": 0.8422132134437561,
' "Y": 0.6123430132865906
' },
' {
' "X": 0.6335319876670837,
' "Y": 0.6009777784347534
' }
' ]
' },
' "Id": 1,
' "Type": "LINE"
' },
' {
' "Confidence": 99.92333984375,
' "DetectedText": "Smiling",
' "Geometry": {
' "BoundingBox": {
' "Height": 0.31578224897384644,
' "Left": 0.5070608258247375,
' "Top": 0.6086956262588501,
' "Width": 0.4795433282852173
' },
' "Polygon": [
' {
' "X": 0.5070608258247375,
' "Y": 0.6298336386680603
' },
' {
' "X": 0.9808917045593262,
' "Y": 0.6086956262588501
' },
' {
' "X": 0.9866041541099548,
' "Y": 0.9033399224281311
' },
' {
' "X": 0.5127732157707214,
' "Y": 0.9244779348373413
' }
' ]
' },
' "Id": 2,
' "Type": "LINE"
' },
' {
' "Confidence": 99.77294158935547,
' "DetectedText": "IT'S",
' "Geometry": {
' "BoundingBox": {
' "Height": 0.09903381764888763,
' "Left": 0.668789803981781,
' "Top": 0.17874395847320557,
' "Width": 0.1449044644832611
' },
' "Polygon": [
' {
' "X": 0.668789803981781,
' "Y": 0.17874395847320557
' },
' {
' "X": 0.8136942386627197,
' "Y": 0.17874395847320557
' },
' {
' "X": 0.8136942386627197,
' "Y": 0.2777777910232544
' },
' {
' "X": 0.668789803981781,
' "Y": 0.2777777910232544
' }
' ]
' },
' "Id": 5,
' "ParentId": 0,
' "Type": "WORD"
' },
' {
' "Confidence": 98.44307708740234,
' "DetectedText": "MONDAY",
' "Geometry": {
' "BoundingBox": {
' "Height": 0.11112251877784729,
' "Left": 0.5541401505470276,
' "Top": 0.3526569902896881,
' "Width": 0.39013487100601196
' },
' "Polygon": [
' {
' "X": 0.5541401505470276,
' "Y": 0.3526569902896881
' },
' {
' "X": 0.9442675113677979,
' "Y": 0.3502415418624878
' },
' {
' "X": 0.9458598494529724,
' "Y": 0.4613526463508606
' },
' {
' "X": 0.5541401505470276,
' "Y": 0.4637681245803833
' }
' ]
' },
' "Id": 4,
' "ParentId": 0,
' "Type": "WORD"
' },
' {
' "Confidence": 99.61898803710938,
' "DetectedText": "but",
' "Geometry": {
' "BoundingBox": {
' "Height": 0.06521739065647125,
' "Left": 0.6353503465652466,
' "Top": 0.5241546034812927,
' "Width": 0.0843949019908905
' },
' "Polygon": [
' {
' "X": 0.6353503465652466,
' "Y": 0.5241546034812927
' },
' {
' "X": 0.7197452187538147,
' "Y": 0.5241546034812927
' },
' {
' "X": 0.7197452187538147,
' "Y": 0.5893719792366028
' },
' {
' "X": 0.6353503465652466,
' "Y": 0.5893719792366028
' }
' ]
' },
' "Id": 6,
' "ParentId": 1,
' "Type": "WORD"
' },
' {
' "Confidence": 99.78804779052734,
' "DetectedText": "keep",
' "Geometry": {
' "BoundingBox": {
' "Height": 0.07971014827489853,
' "Left": 0.7308917045593262,
' "Top": 0.5265700221061707,
' "Width": 0.1114649698138237
' },
' "Polygon": [
' {
' "X": 0.7308917045593262,
' "Y": 0.5265700221061707
' },
' {
' "X": 0.8423566818237305,
' "Y": 0.5265700221061707
' },
' {
' "X": 0.8423566818237305,
' "Y": 0.6062802076339722
' },
' {
' "X": 0.7308917045593262,
' "Y": 0.6062802076339722
' }
' ]
' },
' "Id": 7,
' "ParentId": 1,
' "Type": "WORD"
' },
' {
' "Confidence": 89.76324462890625,
' "DetectedText": "(",
' "Geometry": {
' "BoundingBox": {
' "Height": 0.16401274502277374,
' "Left": 0.27229300141334534,
' "Top": 0.6642512083053589,
' "Width": 0.2850286066532135
' },
' "Polygon": [
' {
' "X": 0.27229300141334534,
' "Y": 0.6642512083053589
' },
' {
' "X": 0.2707006335258484,
' "Y": 0.37922704219818115
' },
' {
' "X": 0.43471336364746094,
' "Y": 0.37922704219818115
' },
' {
' "X": 0.4363057315349579,
' "Y": 0.6642512083053589
' }
' ]
' },
' "Id": 3,
' "ParentId": 0,
' "Type": "WORD"
' },
' {
' "Confidence": 99.92333984375,
' "DetectedText": "Smiling",
' "Geometry": {
' "BoundingBox": {
' "Height": 0.294724702835083,
' "Left": 0.5079618096351624,
' "Top": 0.6304348111152649,
' "Width": 0.4734293222427368
' },
' "Polygon": [
' {
' "X": 0.5079618096351624,
' "Y": 0.6304348111152649
' },
' {
' "X": 0.9808917045593262,
' "Y": 0.6086956262588501
' },
' {
' "X": 0.9856687784194946,
' "Y": 0.9033816456794739
' },
' {
' "X": 0.512738823890686,
' "Y": 0.9227052927017212
' }
' ]
' },
' "Id": 8,
' "ParentId": 2,
' "Type": "WORD"
' }
' ],
' "TextModelVersion": "3.0"
' }
'
'
' Sample code for parsing the JSON response...
' Use the following online tool to generate parsing code from sample JSON:
' Generate Parsing Code from JSON
Dim Confidence As String
Dim DetectedText As String
Dim GeometryBoundingBoxHeight As String
Dim GeometryBoundingBoxLeft As String
Dim GeometryBoundingBoxTop As String
Dim GeometryBoundingBoxWidth As String
Dim Id As Integer
Dim v_Type As String
Dim ParentId As Integer
Dim j As Integer
Dim count_j As Integer
Dim X As String
Dim Y As String
Dim TextModelVersion As String = jResp.StringOf("TextModelVersion")
Dim i As Integer = 0
Dim count_i As Integer = jResp.SizeOfArray("TextDetections")
While i < count_i
jResp.I = i
Confidence = jResp.StringOf("TextDetections[i].Confidence")
DetectedText = jResp.StringOf("TextDetections[i].DetectedText")
GeometryBoundingBoxHeight = jResp.StringOf("TextDetections[i].Geometry.BoundingBox.Height")
GeometryBoundingBoxLeft = jResp.StringOf("TextDetections[i].Geometry.BoundingBox.Left")
GeometryBoundingBoxTop = jResp.StringOf("TextDetections[i].Geometry.BoundingBox.Top")
GeometryBoundingBoxWidth = jResp.StringOf("TextDetections[i].Geometry.BoundingBox.Width")
Id = jResp.IntOf("TextDetections[i].Id")
v_Type = jResp.StringOf("TextDetections[i].Type")
ParentId = jResp.IntOf("TextDetections[i].ParentId")
j = 0
count_j = jResp.SizeOfArray("TextDetections[i].Geometry.Polygon")
While j < count_j
jResp.J = j
X = jResp.StringOf("TextDetections[i].Geometry.Polygon[j].X")
Y = jResp.StringOf("TextDetections[i].Geometry.Polygon[j].Y")
j = j + 1
End While
i = i + 1
End While
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