Nick LaVassar

Introduction

Color vision deficiency (often called "colorblindness") affects hundreds of millions of people around the world. The deficiency is sex linked: approximately 8% of men have a CVD versus only 0.5% of females. This project aims to simulate the most common types of CVDs for people with normal color perception.

Background

Color vision deficiencies are characterized by reduced sensitivity to color as a result of anomalies in the eye's color receptors (called cones). In extremely rare cases, the cones in the eye are either completely absent or totally dysfunctional which results in monochromacy (no color perception). When only one cone is missing a person is said to be dichromatic. The most common CVDs are caused by a shift in the sensitivity of one of the types of cone in the eye and is known as anomalous trichromacy.

CVDs are classified according to which cone type is affected:

• Protanomaly - L cone sensitivity is defective.
• Deuteranomaly - M cone sensitivity is defective.
• Tritanomaly - S cone sensitivity is defective.

Likewise, someone with dichromatic vision is completely missing either their L, M or S cones, and is called either a protanope, deuteranope, or tritanope, respectively.

Protanopia and deuteranopia reduce senstivity to red-green colors, while tritanopia reduces sensitivity to blue-yellow colors.

Methods

Overview

Anomalous trichromacy can be simulated by shifting the sensitivity of the L, M, and S cones in the following ways1:

• Protanomaly - Shift L cone toward M cone (L(/lambda)_a = L(/lambda +\delta \lambda))
• Deuteranomaly - Shift M cone toward L cone
• Trianomaly - Shift S cone

Results - What you found

Retinotopic models in native space

Some text. Some analysis. Some figures.

Retinotopic models in individual subjects transformed into MNI space

Some text. Some analysis. Some figures.

Retinotopic models in group-averaged data on the MNI template brain

Some text. Some analysis. Some figures. Maybe some equations.

Equations

If you want to use equations, you can use the same formats that are use on wikipedia.
See wikimedia help on formulas for help.
This example of equation use is copied and pasted from wikipedia's article on the DFT.

The sequence of N complex numbers x₀, ..., x_N−1 is transformed into the sequence of N complex numbers X₀, ..., X_N−1 by the DFT according to the formula:

$X_{k}=\sum _{n=0}^{N-1}x_{n}e^{-{\frac {2\pi i}{N}}kn}\quad \quad k=0,\dots ,N-1$

where i is the imaginary unit and $e^{\frac {2\pi i}{N}}$ is a primitive N'th root of unity. (This expression can also be written in terms of a DFT matrix; when scaled appropriately it becomes a unitary matrix and the X_k can thus be viewed as coefficients of x in an orthonormal basis.)

The transform is sometimes denoted by the symbol ${\mathcal {F}}$, as in $\mathbf {X} ={\mathcal {F}}\left\{\mathbf {x} \right\}$ or ${\mathcal {F}}\left(\mathbf {x} \right)$ or ${\mathcal {F}}\mathbf {x}$.

The inverse discrete Fourier transform (IDFT) is given by

$x_{n}={\frac {1}{N}}\sum _{k=0}^{N-1}X_{k}e^{{\frac {2\pi i}{N}}kn}\quad \quad n=0,\dots ,N-1.$

Retinotopic models in group-averaged data projected back into native space

Some text. Some analysis. Some figures.

Conclusions

Here is where you say what your results mean.

References

[1]Gustavo M. Machado, Manuel M. Oliveira, and Leandro A. F. Fernandes "A Physiologically-based Model for Simulation of Color Vision Deficiency". IEEE Transactions on Visualization and Computer Graphics. Volume 15 (2009), Number 6, November/December 2009. pp. 1291-1298.

Software

Appendix I - Code and Data

Code

File:CodeFile.zip

Data

zip file with my data

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