In forensic field Video image analysis is a new scientific technique for crime scene investigation.
With the help of Videos we can see real time incident. Video recordings can provide a real time eye witness of a crime which make investigation little bit easy for crime scene investigators.
For example- CCTV footage, hidden camera , etc.
In Parties, Riots, Fairs, Agitation, etc. video recordings are very common by people and media which help investigators to identifying the suspect of the crime etc.
Now a days almost every house, mall, shop have a cctv camera which can have footage of that particular place which also helps in investigations .
Video analysis can be performed on recovered recording to answer the questions of “who” “what” “ when”, “where” and “How” in order to reconstruct an event.
Uses of Video Recordings or Video Image Analysis
1.Compare objects in different videos, or compare them with objects to determine similarity, differences or alterations.
2. Reconstruct incidents to understand the events preceding , during and after an incident.
3. Perform speed calculations to ascertain whether a vehicle was travelling below or above the road speed limit.
4. Present the findings and opinions clearly and effectively in an expert report that is admissible in the courts.
5. Sift out the details in the recording.
6. Fame-by-frame analysis.
Factors Affecting Forensic Video Analysis
1- Quality of video,
2- Distance of the object form the camera,
3- Its angle with respect to the camera,
5- Other environmental factors.
Techniques Used In Video Image Analysis
Repair and Recovery Of Evidence
Forensic experts are also able for repairing video evidence and can also recover the evidence like- CD’s, DVD’s , Cell phone, Video Cameras are Commonly used.
By video analysis the images can be enhanced, slow down, enlarge to give a clear view of the recorded image and to track the CCTV footage.
Digital video recorder (DVR) and the deleted retains can be analyzed and recovered.
The facial comparison of two or more images to provide a clear view of the criminal or victim is given by the forensic expert.
Height Calculation And Comparison
By video image analysis we can compare the height of unknown person recorded in CCTV footage can be determined.
This technique helps to see CCTV footage more clearly in digital form.
it is possible to cover the face of some areas of the videos to protect the witness, victim or the police officers.
Reduces the amount of disturbances in the video producing the smoothness.
Sharpening makes images in the recording more clear.
To Corroborate Statements
In many cases video evidences can be used to corroborate statements.
Forensic experts can enhanced a video recording, filters can be used to adjust the brightness of the image to correct to color etc. the speed of playback can be adjusted.
Unwanted noise can be removed.
The technique of combining to TV field to in order to provide a full frame of video.
A process called de-interlacing may be used to retrieve the information in both fields of video.
In CCTV system a device called multiplexer is used to combined multiple video signals into single signals or separate a combined signals.