B4X
B4X
Amazon Rekognition - Detect Text in an Image
See more Amazon Rekognition Examples
Detects text in the input image and converts it into machine-readable text. This example passes theimage as base64-encoded image bytes.Chilkat B4X Downloads
Dim success As Boolean = False
Dim rest As ChilkatRest
rest.Initialize("rest")
Dim authAws As ChilkatAuthAws
authAws.Initialize
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 Int = 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
Log("ConnectFailReason: " & rest.ConnectFailReason)
Log(rest.LastErrorText)
Return
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 ChilkatBinData
bdJpg.Initialize
success = bdJpg.LoadFile("qa_data/jpg/monday_keep_smiling.jpg")
If success <> True Then
Log("Failed to load the input JPG file.")
Return
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:
' (image:https://example-code.com/images/monday_keep_smiling.jpg/endImage)
' 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 ChilkatStringBuilder
sbJpg.Initialize
bdJpg.GetEncodedSb("base64", sbJpg)
Dim json As ChilkatJsonObject
json.Initialize
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 ChilkatStringBuilder
sbRequestBody.Initialize
json.EmitSb(sbRequestBody)
Dim sbResponseBody As ChilkatStringBuilder
sbResponseBody.Initialize
success = rest.FullRequestSb("POST", "/", sbRequestBody, sbResponseBody)
If success <> True Then
Log(rest.LastErrorText)
Return
End If
Dim respStatusCode As Int = rest.ResponseStatusCode
Log("response status code = " & respStatusCode)
If respStatusCode >= 400 Then
Log("Response Status Code = " & respStatusCode)
Log("Response Header:")
Log(rest.ResponseHeader)
Log("Response Body:")
Log(sbResponseBody.GetAsString)
Return
End If
Dim jResp As ChilkatJsonObject
jResp.Initialize
jResp.LoadSb(sbResponseBody)
jResp.EmitCompact = False
Log(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 Int
Dim v_Type As String
Dim ParentId As Int
Dim j As Int
Dim count_j As Int
Dim X As String
Dim Y As String
Dim TextModelVersion As String = jResp.StringOf("TextModelVersion")
Dim i As Int = 0
Dim count_i As Int = jResp.SizeOfArray("TextDetections")
Do 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")
Do 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
Loop
i = i + 1
Loop