Colour Calibration
Definition
The process of correcting a camera's colour rendering to match a known standard, using a colour reference chart captured under the same lighting conditions. Particularly important for face comparison and clothing colour identification.
- Field
- Forensic video and image enhancement
- Method
- Colour reference chart shot under scene lighting
- Key application
- Face comparison and clothing colour identification
- Timing requirement
- Same lighting conditions as the evidence
Common questions
Why must the reference chart be captured under the same lighting as the original footage?+
Colour rendering depends heavily on the spectral composition of the light source, so a chart shot under different lighting would not reveal the correction needed for the actual footage, making the calibration meaningless for that specific recording.
What happens if colour calibration is skipped when comparing clothing colour across cameras?+
Different cameras and lighting can render the same garment as visibly different colours, so without calibration an examiner risks either wrongly excluding a match or wrongly including one based on colour differences that are artefacts of the recording equipment, not the actual item.
Related terms
- De-Interlacing
- The process of reconstructing a full progressive frame from the two interlaced fields captured by analogue video systems. Different algorithms (line doubling,...
- Multi-Frame Averaging
- A noise reduction technique that registers multiple frames of the same scene and averages pixel values. Random noise, which differs between frames,...
- Object Tracking
- Frame-by-frame identification of a target (person, vehicle, or object) across a video sequence, recording its position and trajectory. Used to reconstruct movement...
- Super-Resolution
- Methods that attempt to produce an image with higher pixel density than the source. Interpolation-based SR fills in values by estimation; learning-based...
- Temporal Synchronisation
- The process of aligning the timelines of two or more camera recordings so that events captured from different viewpoints can be placed...