PSImaging - A PowerShell module for comparing and extracting text from images

[Arthur]

Website / Download (or follow the instructions below)

 

Installing the PSImaging module

You can download and install the latest versions of PSImaging using any of the following methods:

 

To install from PowerShell 3.0 or later, open a native PowerShell console (not ISE, unless you want it to take longer), and invoke one of the following commands:

 

# [b]If you want to install PSImaging for all users or update a version already installed[/b]
# (recommended, requires elevation for new install for all users)
& ([scriptblock]::Create((iwr -uri http://tinyurl.com/Install-GitHubHostedModule).Content)) `
 -GitHubUserName Positronic-IO -ModuleName PSImaging -Branch 'master'

 

# [b]If you want to install PSImaging for the current user[/b]
& ([scriptblock]::Create((iwr -uri http://tinyurl.com/Install-GitHubHostedModule).Content)) `
 -GitHubUserName Positronic-IO -ModuleName PSImaging -Branch 'master' -Scope CurrentUser

 

Using the PSImaging module

The Get-ImageHash Cmdlet uses a signature schema developed by H. Chi Wong, Marshall Bern, and David Goldberg of Xerox, published in 2002, An image signature for any kind of image. The algorithm compares relative brightness levels of regions within the image. This method is resilient to some resizing, cropping, and compression. Here's an example:

 

PS C:\> Get-ImageHash .\Quick-Brown-Fox.png -Level 4
000000000000000000005210004240808004525256738080008052104673808000805210425280800000525
63567777777734000880000800880908EB50CF3908B50567356735677356300000000000000008080800080
800080D00A94E0D200EB0856735252946F356300000042142100008080080800800880D20CB561F300F7085
6731042946B1463000000421421000000000000000000008008808080808008D4F18A40DA4A1CA1

The Export-Text Cmdlet in this module uses Tesseract by Google (https://code.google.com/p/tesseract-ocr/), the most accurate open-source OCR engine available. The Tesseract dependencies are bundled into the module. No additional files are required to use this Cmdlet. Here an exmaple:

 

PS C:\> Export-ImageText .\Quick-Brown-Fox.png
The quick brown fox jumps right
over the lazy dog. the quick brown
fox jumps right over the lazy dog.

The Group-ImageFile Cmdlet utilizes the Get-ImageHash function to generate signatures for all of the image files in a collection, then compares them to one another for similarity, grouping those that it has a degree of confidence are similar. Here's an example:

 

PS C:\> $groups = dir | Group-ImageFile
PS C:\> $groups

               Confidence                      Count Files
               ----------                      ----- -----
                     High                          5 {C:\Users\ben_000\Test...
                   Medium                          5 {C:\Users\ben_000\Test...
                   Medium                          3 {C:\Users\ben_000\Test...
                   Medium                          3 {C:\Users\ben_000\Test...

PS C:\> $groups | ? Confidence -eq High | select -ExpandProperty Files

Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---         10/4/2014  10:20 AM    2816872 1.tiff
-a---         2/16/2015   9:34 PM    2736074 10.tiff
-a---         2/16/2015   9:34 PM    2753074 17.tiff
-a---         1/18/2015   2:02 PM    2753074 4.tiff
-a---         1/18/2015   2:02 PM    2753074 7.tiff

 

http://a.pomf.se/ymgkdx.png

Edited March 21, 2015 by Arthur