Activity 3 Scilab Basics

So our activity for today was to get familiar with the programming language that is Scilab. The objective was to create synthetic images out of test algorithms. 

Centered Square Aperture

Code Snippet in Scienotes:

nx = 100; ny = 100; //defines the the number of elements along x and y

x = linspace(-1,1,nx); //defines the range

y = linspace(-1,1,ny);

[X,Y] = ndgrid(x,y); //creates two 2D arrays with x and y coordinatesnx = 100;

l = abs(X); //length

w = abs(Y); //width

A = zeros (nx,ny);

A (find(l<0.5 & w<0.5) ) = 1;

f = scf();

grayplot(x,y,A);

f.color_map = graycolormap(32);

As one can see I could have made a rectangle just by simply editing the length and width. It can be edited on lines 5 and 6.

Sinusoid along the x-direction (corrugated roof)

nx = 100; ny = 100; //defines the the number of elements along x and y

x = linspace(-1,1,nx); //defines the range

y = linspace(-1,1,ny);

[X,Y] = ndgrid(x,y); //creates two 2D arrays with x and y coordinatesnx = 100;

A = zeros(nx,ny);

A = 10*sin(20*X); //defines the sinusoid with frequency and amplitude

f = scf();

grayplot(x,y,A);

f.color_map = graycolormap(32);

This was achieved by simply letting the matrix (A) have the assigned values of sine with varying frequency on line 6 of the code snippet. The frequency is 20 while the amplitude is 10.

Grating along the x-direction

nx = 100; ny = 100; //defines the the number of elements along x and y

x = linspace(-1,1,nx); //defines the range

y = linspace(-1,1,ny);

[X,Y] = ndgrid(x,y); //creates two 2D arrays with x and y coordinatesnx = 100;

A = zeros (nx,ny);

g = 10*sin(20*X);

A (find(g<0)) = 1;

f = scf();

grayplot(x,y,A);

f.color_map = graycolormap(32);

  

Annulus

nx = 100; ny = 100; //defines the number ofelements along x and y

x = linspace(-1,1,nx); //defines the range

y = linspace(-1,1,ny);

[X,Y] = ndgrid(x,y); //creates two 2-D arrays of xand y coordinates

r= sqrt(X.^2 + Y.^2); //note element-per-element squaring of X and Y

A = zeros (nx,ny);

A (find(r<0.7 & r>0.3) )= 1;

f = scf();

grayplot(x,y,A);

f.color_map = graycolormap(32);

Circular Aperture with graded transparency (Gaussian transparency)

nx = 100; ny = 100; //defines the number ofelements along x and y

x = linspace(-1,1,nx); //defines the range

y = linspace(-1,1,ny);

[X,Y] = ndgrid(x,y); //creates two 2-D arrays of xand y coordinates

Z = exp(-X.^2 -Y.^2);

f = scf();

grayplot(x,y,Z);

f.color_map = graycolormap(32);

 Here is a product of the Sine function and Gaussian function.

Code Snippet:

nx = 100; ny = 100; //defines the the number of elements along x and y

x = linspace(-1,1,nx); //defines the range

y = linspace(-1,1,ny);

[X,Y] = ndgrid(x,y); //creates two 2D arrays with x and y coordinatesnx = 100;

G = sin(10*X)*exp(-X.^2 - Y.^2);

f = scf();

plot3d(x,y,G);

f.color_map = graycolormap(32);

Pretty cool huh?