Matlab Draw Circle on Image Matrix

Introduction to Matlab Plot Circle

MATLAB can exist used to perform operations involving geometric figures like circles, rectangles, squares etc. In this commodity, we will focus on circles. We will learn how to create various types of circles in MATLAB. Nosotros can create solid or plane circles in MATLAB, which nosotros volition learn equally we go ahead in the commodity. Nosotros will also learn how to create a circle using the rectangle function.

How to Create a circle using Rectangle Function?

Permit usa first acquire syntax to draw a simple circumvolve in MATLAB:

one. Let us starting time declare some points, here we are taking 500 points. The below lawmaking will create these points.

• angles = linspace(0, 2*pi, 500);

2. Let us at present declare the radius and centre of the circle. The centre will be defined past ten and y co-ordinates.

• radius = 20;
• CenterX = 50;
• CenterY = xl;

three. Finally, nosotros will plot our circle.

• ten = radius * cos(angles) + CenterX;
• y = radius * sin(angles) + CenterY;

4. We will also write some code for our output to wait visually better. This is normal formatting and we can adjust it equally per our requirement.

• plot(x, y, 'b-', 'LineWidth', two);
• hold on;
• plot(CenterX, CenterY, 'chiliad+', 'LineWidth', three, 'MarkerSize', fourteen);
• grid on;
• axis equal;
• xlabel('10', 'FontSize', 14);
• ylabel('Y', 'FontSize', 14);

5. This is how our input and output will expect like in MATLAB console:

Code:

angles = linspace(0, two*pi, 500);
radius = 20;
CenterX = 50;
CenterY = 40;
ten = radius * cos(angles) + CenterX;
y = radius * sin(angles) + CenterY;
plot(x, y, 'b-', 'LineWidth', 2);
hold on;
plot(CenterX, CenterY, 'k+', 'LineWidth', iii, 'MarkerSize', xiv);
filigree on;
centrality equal;
xlabel('X', 'FontSize', 14);
ylabel('Y', 'FontSize', fourteen);

Output:

Every bit we can come across in the in a higher place output, the circle is created with a radius xx and centre (fifty, 40) every bit defined by us in the lawmaking.

How to Create a Solid 2D Circle in MATLAB?

Next, allow u.s.a. learn how to create a solid 2nd circle in MATLAB:

one. First, we will be creating logical image of circumvolve. For this, we volition define center, diameter and the image size. Let united states of america first create image.

• imageSizeOfX = 640;
• imageSizeOfY = 480;
• [colInImage rowsInImage] = meshgrid(ane : imageSizeOfX, 1 : imageSizeOfY);

two. Next, we volition exist creating the circle within the image.

• centerOfX = 320;
• centerOfY = 240;
• radius = 80;
• Pixels = (rowsInImage – centerOfY).^2 …
• + (colInImage – centerOfX).^two <= radius.^two;

iii. In the higher up line of code, Pixels is "logical" assortment and is second. Let u.s. at present brandish 'Pixels'.

• image(Pixels);
• colormap([0 0 0; i i 1]);
• title('Image of circle');

4. This is how our input and output will look like in MATLAB console:

Code:

imageSizeOfX = 640;
imageSizeOfY = 480;
[colInImage rowsInImage] = meshgrid(1 : imageSizeOfX, 1 : imageSizeOfY);
centerOfX = 320;
centerOfY = 240;
radius = fourscore;
Pixels = (rowsInImage - centerOfY).^2 ...
+ (colInImage - centerOfX).^2 <= radius.^2;
prototype(Pixels);
colormap([0 0 0; ane 1 ane]);
championship('Prototype of circumvolve');

Output:

How to create a Circumvolve in MATLAB Using Rectangle Role?

Let us now learn how to create a circle in MATLAB using rectangle function: Hither is a unproblematic code to attain this:

i. Like nosotros discussed in in a higher place examples, nosotros will declare the radius and centre co-ordinates of the required circle.

• radius = 6;
• centerX = xxx;
• centerY = 40;
• rectangle('Position',[centerX – radius, centerY – radius, radius*two, radius*two],…
• 'Curvature',[1,1],…
• 'FaceColor','b');
• centrality square;

2. We have passed 'FaceColor' as "b" so our output circle will be of Blue color.

Code:

radius = vi;
centerX = thirty;
centerY = xl;
rectangle('Position',[centerX - radius, centerY - radius, radius*2, radius*2],...
'Curvature',[1,1],...
'FaceColor','b');
axis square;

Output:

How nosotros can Create a Simple arc in MATLAB?

Finally, allow us discuss how we can create a simple arc in MATLAB. As we know that arc is nothing just a small portion of the circle, lawmaking for creating an arc is likewise very similar to that of creating a circle.

1. Commencement we ascertain the parameters of required arc.

• xCenter = i;
• yCenter = 1;
• radius = 4;

2. Next, nosotros define the angle theta as required.

• theta = linspace(20, 100, 50);
• x = radius * cosd(theta) + xCenter;
• y = radius * sind(theta) + yCenter;

3. Finally, nosotros plot our defined points.

• plot(x, y, 'b-', 'LineWidth', 2);
• centrality equal;
• grid on;

Lawmaking:

xCenter = 1;
yCenter = 1;
radius = 4;
theta = linspace(20, 100, l);
x = radius * cosd(theta) + xCenter;
y = radius * sind(theta) + yCenter;
plot(x, y, 'b-', 'LineWidth', ii);
axis equal;
grid on;

Output:

Decision

So, in this commodity, we learnt how to create circles in MATLAB. We can create both plane circles and solid circles in MATLAB. We also learnt how we tin leverage the Rectangle part to plot circles in MATLAB. We can also format our circle as per our requirement.

Recommended Articles

This is a guide to Matlab Plot Circle. Here nosotros discuss an introduction, how to Create a circle using rectangle function, a Solid 2D Circle, a circumvolve in MATLAB and Simple arc. Y'all tin also go through our other related articles to learn more –

1. Intermission in MATLAB
2. Nested Loop in Matlab
3. Matlab pcolor() | Examples
4. Complete Guide to Optimset Matlab
5. Plot Vector Matlab | Functions
6. Matlab Effigy | Examples
7. xlabel Matlab | Examples

maresallove.blogspot.com

Source: https://www.educba.com/matlab-plot-circle/

Share this post