What do the imaging modes on an endoscopy system actually do?
Short answer
Each mode changes how the mucosa is illuminated or processed so different structures stand out. White light (HLI) gives the routine view; TCI emphasises colour differences between tissues; SVI uses narrow-spectrum light to emphasise superficial vessels; DHI uses red-spectrum light for deep vessels and bleeding points; R-TLC digitally enhances texture and luminance detail. Together they follow the examination from observation to treatment.
In detail
Observation starts with white light. HLI — High Color Restored White Light Imaging — is the high colour-restoration white light of the VC-1600 series, and TCI adds emphasis on the colour differences between tissues, which is where the eye needs help when surfaces look similar under plain white light.
Examination goes a layer deeper. SVI uses narrow-spectrum illumination to emphasise superficial vessels. DHI moves to the treatment stage: its narrower green and red illumination raises the contrast of deep vessels and high-concentration blood areas against surrounding mucosa, so bleeding points stand out.
R-TLC is processing rather than illumination. It decomposes the image into frequency bands in the spatial domain and enhances the bands that carry vessel, mucosal and tissue-contour detail, on the basis of a high signal-to-noise ratio. When you compare systems, ask for each mode whether it is produced by the light source, by processing, or by both.
Comparison
| Mode | Mechanism | Stage |
|---|---|---|
| HLI | White light, high colour restoration | Observation |
| TCI | Colour-difference emphasis | Observation |
| SVI | Narrow-spectrum illumination | Examination |
| DHI | Red-spectrum illumination | Treatment |
| R-TLC | Multi-band digital enhancement | Enhancement |
Step by step
- Map your case mix to the stages you use most
- Ask which modes are illumination-based and which are processing-based
- Check which modes are available on which scope
- Confirm the mode set on the processor you are quoted
- Include the mode set in your evaluation sheet alongside scope specifications
Frequently asked questions
Only if the modes map to stages of your actual case mix. A mode you never reach for adds cost, not value.
SVI emphasises superficial vessels with narrow-spectrum light; DHI addresses deep vessels and bleeding points with red-spectrum light. They sit at different stages of the examination.