Added Get-OCR

Runs Windows 10 OCR on an image.

Author: alan-null

media/Get-OCR.ps1

@@ -0,0 +1,104 @@
+# Credits https://github.com/HumanEquivalentUnit/PowerShell-Misc/blob/master/Get-Win10OcrTextFromImage.ps1
+
+function Get-OCR {
+    <#
+.SYNOPSIS
+    Runs Windows 10 OCR on an image.
+
+.DESCRIPTION
+    Takes a path to an image file, with some text on it.
+    Runs Windows 10 OCR against the image.
+    Returns an [OcrResult], hopefully with a .Text property containing the text
+
+.PARAMETER -Path
+    Path to an image file
+
+.EXAMPLE
+    Get-OCR -Path 'c:\test.bmp'
+#>
+    [CmdletBinding()]
+    param(
+        [Parameter(Mandatory = $true,
+            ValueFromPipeline = $true,
+            ValueFromPipelineByPropertyName = $true,
+            Position = 0,
+            HelpMessage = 'Path to an image file, to run OCR on')]
+        [ValidateNotNullOrEmpty()]
+        $Path
+    )
+
+    Begin {
+        # Add the WinRT assembly, and load the appropriate WinRT types
+        Add-Type -AssemblyName System.Runtime.WindowsRuntime
+
+        $null = [Windows.Storage.StorageFile, Windows.Storage, ContentType = WindowsRuntime]
+        $null = [Windows.Media.Ocr.OcrEngine, Windows.Foundation, ContentType = WindowsRuntime]
+        $null = [Windows.Foundation.IAsyncOperation`1, Windows.Foundation, ContentType = WindowsRuntime]
+        $null = [Windows.Graphics.Imaging.SoftwareBitmap, Windows.Foundation, ContentType = WindowsRuntime]
+        $null = [Windows.Storage.Streams.RandomAccessStream, Windows.Storage.Streams, ContentType = WindowsRuntime]
+
+        # [Windows.Media.Ocr.OcrEngine]::AvailableRecognizerLanguages
+        $ocrEngine = [Windows.Media.Ocr.OcrEngine]::TryCreateFromUserProfileLanguages()
+
+        # PowerShell doesn't have built-in support for Async operations,
+        # but all the WinRT methods are Async.
+        # This function wraps a way to call those methods, and wait for their results.
+        $getAwaiterBaseMethod = [WindowsRuntimeSystemExtensions].GetMember('GetAwaiter').
+        Where({
+                $PSItem.GetParameters()[0].ParameterType.Name -eq 'IAsyncOperation`1'
+            }, 'First')[0]
+
+        Function Await {
+            param($AsyncTask, $ResultType)
+
+            $getAwaiterBaseMethod.
+            MakeGenericMethod($ResultType).
+            Invoke($null, @($AsyncTask)).
+            GetResult()
+        }
+    }
+
+    Process {
+        foreach ($p in $Path) {
+            # From MSDN, the necessary steps to load an image are:
+            # Call the OpenAsync method of the StorageFile object to get a random access stream containing the image data.
+            # Call the static method BitmapDecoder.CreateAsync to get an instance of the BitmapDecoder class for the specified stream.
+            # Call GetSoftwareBitmapAsync to get a SoftwareBitmap object containing the image.
+            #
+            # https://docs.microsoft.com/en-us/windows/uwp/audio-video-camera/imaging#save-a-softwarebitmap-to-a-file-with-bitmapencoder
+
+            # .Net method needs a full path, or at least might not have the same relative path root as PowerShell
+            $p = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($p)
+
+            $params = @{
+                AsyncTask  = [Windows.Storage.StorageFile]::GetFileFromPathAsync($p)
+                ResultType = [Windows.Storage.StorageFile]
+            }
+            $storageFile = Await @params
+
+
+            $params = @{
+                AsyncTask  = $storageFile.OpenAsync([Windows.Storage.FileAccessMode]::Read)
+                ResultType = [Windows.Storage.Streams.IRandomAccessStream]
+            }
+            $fileStream = Await @params
+
+
+            $params = @{
+                AsyncTask  = [Windows.Graphics.Imaging.BitmapDecoder]::CreateAsync($fileStream)
+                ResultType = [Windows.Graphics.Imaging.BitmapDecoder]
+            }
+            $bitmapDecoder = Await @params
+
+
+            $params = @{
+                AsyncTask  = $bitmapDecoder.GetSoftwareBitmapAsync()
+                ResultType = [Windows.Graphics.Imaging.SoftwareBitmap]
+            }
+            $softwareBitmap = Await @params
+
+            # Run the OCR
+            Await $ocrEngine.RecognizeAsync($softwareBitmap) ([Windows.Media.Ocr.OcrResult])
+        }
+    }
+}