# Individualised Halo-Free Gradient-Domain Colour Image Daltonisation

## Abstract

**:**

## 1. Introduction

## 2. Background

## 3. Proposed Method

#### 3.1. The Initial Value

#### 3.2. Local Linear Anisotropic Diffusion

#### 3.3. Further Simplifications

#### 3.4. Implementation

## 4. Results

- the simple daltonisation algorithm proposed in Equation (4),
- the isotropic daltonisation algorithm proposed in Equation (3), which is essentially the same as the one proposed in [17], but with the simplifications described in Section 3.3, and the simple daltonisation as the initial condition, and
- the anisotropic daltonisation algorithm proposed in Equation (5).

## 5. Conclusions

## Funding

## Conflicts of Interest

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**Figure 1.**The image dataset used for testing. Highly saturated images from the web with dominant red–green and blue–yellow contrast. All images are available under the CC0 licence.

**Figure 2.**Sample image for an RG $\alpha =1$ dichromatic observer. (

**Top**to

**bottom**,

**left**hand column): original, simple daltonisation, isotropic daltonisation, and anisotropic daltonisation. Corresponding simulated images for a the RG $\alpha =1$ dichromatic observer in the right hand column.

**Figure 3.**Loss of details in the simple daltonisation algorithm for an RG $\alpha =1$ dichromatic observer.

**Left**to

**right**: original image, simple daltonisation, and anisotropic daltonisation.

**Figure 4.**Box plot of the gamut pixel fraction (GPF) for the original and the simple, isotropic, and anisotropic daltonised images.

**Figure 5.**Halo artefacts in the isotropic daltonisation algorithm for a BY $\alpha =1$ observer. (

**Left**to

**right**): original image, isotropic daltonisation, and anisotropic daltonisation.

**Figure 6.**PSNR (dB) of the daltonised versus the original images for the simple, isotropic, and anisotropic daltonisation algorithms.

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**MDPI and ACS Style**

Farup, I.
Individualised Halo-Free Gradient-Domain Colour Image Daltonisation. *J. Imaging* **2020**, *6*, 116.
https://doi.org/10.3390/jimaging6110116

**AMA Style**

Farup I.
Individualised Halo-Free Gradient-Domain Colour Image Daltonisation. *Journal of Imaging*. 2020; 6(11):116.
https://doi.org/10.3390/jimaging6110116

**Chicago/Turabian Style**

Farup, Ivar.
2020. "Individualised Halo-Free Gradient-Domain Colour Image Daltonisation" *Journal of Imaging* 6, no. 11: 116.
https://doi.org/10.3390/jimaging6110116