# Single dielectric cylinder (obstacle to Fresnel in 2D: dielTM_dec8f.exp)

For reference see incontrastsRef.html.

## Contents

- Position of obstacle
- Other parameters of the obstacle
- References

## Position of obstacle

- Theoretical, see [1], position should be left from origin, but Fresnel data are rotated 270 degrees mathematical positive.
- Note: rotation seems to be 90 degrees, but take care of y-axis, because it is top negative, when you plot with imagesc

    imagesc(...);

- Solution: Corrected when plotting with:

    axis xy;

## Other parameters of the obstacle

Fresnel, op. 1: Section 4.2 dielectric targets, see [1]:

- Radius a = 15 mm
- Real part of relative permittivity .
- Relative permeability not given, so guess .
- Cylinders are "dielectric", this means imaginary part of contrast is 0.

## References

- [1] Kamal Belkebir and Marc Saillard. Special section on testing inversion algorithms against experimental data. Inverse Problems, 17(6):1565-1571, 2001. URL: https://doi.org/10.1088/0266-5611/17/6/301.

    function q = fresnel_op1_dielTM(X1,X2,varargin)

    finecorrection = 1; % manually correction of obstacles position

    qBall = 2 + 1i*0; % dielectricum, so imaginary part is 0 (in theory)

    rBall = 15E-3; % 15 mm
    dist = 30E-3; % 30 mm distance from origin
    r = hypot(X1,X2-dist); % 30 mm top of origin

    if finecorrection == 1
        xshift = 1E-3;
        yshift = -3E-3;
        r = hypot(X1-xshift,X2-dist-yshift);
    end

    q = qBall*( r < rBall );
    q = double(q);

    end