topic 3 - photo forgery

Question 1

what is politically motivated photo forgery?

Answer 1

when a person or a thing is removed in a later version of a photo to avoid controversy

Question 2

what is the aim of photo forensics?

Answer 2

to find the source of camera identification

to check the image intergrity - is it real?

Question 3

what are the methods of detecting photo forgeries?

Answer 3

Many methods including:

Reverse image search

EXIF data check

Specular reflections (eyes)

Photogrammetry

Inconsistencies in shadows/reflections

Grey level resampling

JPEG signatures.

Question 4

what does a reverse image search do?

Answer 4

By performing a reverse image search we can sometimes determine if the image already existed online before it was edited.

e.g. images.google.com or Tineye.com

Question 5

what does an Exif data check do? (exchangeable image file)

Answer 5

Is the image consistent with the camera settings in the EXIF metadata?

Camera make and model provided.

Could also contain time and date and GPS coordinates.

Downside, can be removed intentionally or unintentionally.