Image Compression: Are Our Eyes Deceiving Us?

Digital compression of video images is a common occurrence. There are legitimate and laudatory reasons for such compression. Among those reasons are the fact that more data can be stored in a smaller amount of storage space, data can be easily transmitted electronically, and data can be searched more readily. However, the first casualty of compression is detail and therefore, compression of digital images is a serious concern for anyone interested in obtaining detail from the images.

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Source: Jonothan Hak QC

Source: Jonothan Hak QC

‘False Image’ Helped Clear Cop In Shooting, Expert Says

There’s no question Ronald Johnson was running from Chicago Police in October 2014, before he was shot dead in the back by an officer.

But did Johnson, 25, have a gun?

Three years later, that’s the question still swirling around his death.

Anita Alvarez, the Cook County state’s attorney at the time, declined to criminally charge the officer who shot Johnson.  The reason, she said in a nationally televised press conference in December 2015, was because evidence showed Johnson was armed.

That evidence included grainy police dashboard video, which had been sent to the FBI’s Regional Computer Forensics Laboratory to be enhanced.

Alvarez said the enhanced video appeared to show Johnson holding a gun.

But now, a forensic video analyst tells 2 Investigator Brad Edwards that the video was resized incorrectly, possibly producing a false image.

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Source: Forensic Mag

The CSI Effect – Expectations Vs Limitations

Much has been written about the CSI phenomenon within digital forensics circles, but is there a way we as experts can reduce this effect, maybe not globally but at least amongst our own clients? In just the last couple of weeks, I’ve had requests to enhance a speaker on the other end of the phone, on a recording in which the voice on the other end of the phone sounded like something you would hear on a cartoon. It had the rhythm of somebody speaking but that’s about all it had going for it. Another request asked to enhance a video recording in which the two individuals were seated at a distance, in a dark room, with sunlight streaming through a window across the camera lens and a lamp in front of one of the individuals faces. A third and final example is being asked to enhance the screen of a mobile phone from pictures of said mobile phone. That shouldn’t be a problem you think. Until you consider the pictures were being taken from distances of over a meter of a phone that was turned away from the camera lens.

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Source: Forensic Focus

Source: Forensic Focus