DOI Distinctness of Image (Aesthetix)
DOI (Distinctness of Image) is a surface appearance parameter that describes how clearly objects and edges are reflected in a glossy surface.
Parameter description
DOI indicates the sharpness of reflected images: high DOI means crisp, mirror‑like reflections, while low DOI indicates blurred, distorted or surfaces where orange‑peel distorts reflections. It is expressed as a percentage, with 100% representing an ideal mirror and lower values representing increasing loss of image clarity.
How is it measured?
Software analyses the reflected gloss image, a sharp, well‑defined image yields high DOI, a blurred gloss image will return lower values.
Applications
Assessing and optimising the visual quality of automotive bodywork, bumpers and high‑gloss trim where mirror‑like reflections are critical.
Controlling polishing, sanding and coating processes for premium furniture, pianos, consumer electronics and decorative plastics to minimise orange peel and achieve a high‑quality finish.
DOI is a crucial value for polished stone and concrete applications.
DOI values are correlated between Rhopoint Aesthetix and Rhopoint IQ measurement systems.
| Item | Specification / Value |
|---|---|
| Index name | DOI |
| Description | Measures how clearly and sharply images and edges are reflected from a surface |
| Unit | % (0–100%, where 100% represents a perfectly sharp, undistorted reflection) |
| Measurement geometry | Specular reflection geometry (typically 60° or 20°, depending on module/instrument) |
| Measurement principle | Analysis of the spread and distortion of reflected light around the specular angle |
| Field of view (FOV) | 18 Ă— 24 mm (Aesthetix optical head) |
| Standard analysed area | 18 Ă— 9 mm (shared with gloss/DOI measurements) |
| Optional small spot | 4 × 2 mm (small‑area adapter, where available) |
| Other analysed areas | Effect/texture modules up to 10 Ă— 10 mm or 15 Ă— 15 mm, depending on configuration |
| Measurement range | 0–100% |
| Repeatability (typical) | ±0.2% DOI |
| Reproducibility (typical) | ±0.5% DOI |
| Primary use | Quantifying orange peel, surface smoothness and image clarity on high‑gloss finishes |