How to Detect Image Manipulations Part III: The Office of Reseach Integrity's Forensic Tools
A Column by Thorsten Beck
The US Office of Research Integrity (ORI) in the United States has been occupied with research integrity related issues for well over two decades. The office was established in 1992 by consolidating the „Office of Scientific Integrity“ and the „Office of Scientific Integrity Review.“ Today the Office of Research Integrity oversees many of the „Public Health Service (PHS) research integrity activities on behalf of the Secretary of Health and Human Services.“
For more information on the history and agenda of ORI, please visit: https://ori.hhs.gov/
Among its many aims are the development of “policies, procedures and regulations related to the detection, investigation, and prevention of research misconduct and the responsible conduct of research.” Over the years the office developed a wide spectrum of activities and services, like interactive videos, case studies, web modules, and many other forms of outreach and tools.
One of the resources the office provides for the wider academic audience are the so-called “Forensic Tools” for image analysis and manipulation detection, which provide customized standard operations and recordings of standard routines in Adobe Photoshop.
Forensic Droplets and Actions
ORI started with the development of such tools for Photoshop CS2-CS3, which leads to the fact that many of these routines can not be assessed with later versions of Photoshop. The office offers droplets and actions: droplets are „small desktop applications (…) that automatically process image files that are dragged onto their icon” whereas an action “is the sequence of steps that was pre-recorded in Photoshop” and is started from inside the program.
The “Forensic Tools” package comprises routines for the enhancement of certain image qualities and features, like droplets for the lighting up of areas or the adjustment of gradients. Other droplets allow for the comparing of two images, or provide overlays for images with dark or light backgrounds. Basically, the aim is to enhance features to support visibility, so that hidden details in an image (like obscured background information, artifacts or edges from copy-paste operations) may be revealed.
Other than the droplets the actions for Photoshop are claimed to be compatible with later versions of the program. However, the office provides many operations – too many to deal with all of them in detail in this blog post – therefore I am first going to first focus on the “Advanced Gradient Map” and thereby demonstrate some of the underlying logics of working with such actions.
For the purpose of testing I composed two different forms of manipulations of an image of a wallpaper to demonstrate the capacities or limitations of such standard operations.
Fig. 1: The original image: Wallpaper with decorative floral design. Photo was taken at Mirow Castle, Mecklenburg, Western Pomerania with a Sony Alpha 6000 ILS Camera.
Manipulation 1: Copy-Move Forgery
Fig. 2: Image detail of the original image without manipulation.
Fig. 3: Details obscured through background cloning.
Fig. 4: Copying and moving floral element with magic wand tool.
Fig. 5: Resulting manipulated image with copied floral elements (highlighted).
Manipulation 2: Cut & Paste Manipulation
The second manipulation is less subtle and easier to spot even with the naked eye.
Fig. 6: Copied and pasted area (highlighted).
Fig. 7: Detail of copied and pasted area. The cutting edge is clearly visible even without further enhancements.
Image Analysis with Forensic Photoshop Action: Advanced Gradient Map
Processing an image with the Advanced Gradient Map action simply requires to drag and drop the image onto the action item. This automatically initiates a number of steps: first the color image is reduced to grey scales, then the user is free to manually adjust curves and finally the action offers a set of color tables that may be helpful for further enhancing contrasts.
Analysis: Manipulation 1
Here are some screenshots I took while executing the action:
Fig. 8: Adjusting curves.
Fig. 9: Choosing a suitable color scheme for contrast enhancement
This is how the resulting image looks like:
Fig. 10: Result of Analysis
The Advanced Gradient Map action allows for new perspectives when analyzing image content. Still, the action did not help to reveal the subtle changes that were carried out with the clone stamp and the magic wand – they simply remain invisible. Note: the result could have looked completely different with another color scheme. There is not just one option.
Fig. 11: Detail from resulting image: No clear evidence of a manipulation.
Analysis: Manipulation 2
Now let’s have a look at the second manipulated image in which the pasted region appears to be easier detectable. Again, the analysis is carried out applying the automatized steps of the action, but with different curve adjustments and color scheme. This is how the resulting image looks like:
Fig. 12: Advanced Gradient Map action: result with cut and paste manipulation
Clearly in this case the Advanced Gradient Map supports the identification of the manipulation. The edges around the pasted area are enhanced through the “light rainbow” effect and thus clearly visible.
Fig. 13: Detail from Advanced Gradient Map action
As has been shown in this quick evaluation the ORI action palette opens up a wide range of opportunities when it comes to image manipulation detection – respectively the visual examination of images or the visualization of hidden features. However, it should be mentioned that the ORI customized the action palette for analyzing specific images, especially for Western blots and other images from the field of biomedicine. Nevertheless, the manipulations carried out on the wallpaper images above are in some way comparable to manipulations of blot images. Duplicating image areas or obscuring certain aspects are a serious concern in many biomedicine research integrity cases.
Other than the “Forensically” tools that we have discussed earlier on this blog Photoshop actions support the enhancement of certain features within an image, but can not be understood as a way of automatically detecting image manipulations. On the contrary, applying the actions requires a “trial and error”-attitude and the user has to invest time and effort to produce satisfying results. As it seems there are manipulations that cannot easily be traced with the Advanced Gradient Map action tool, but which require other tools.