Day 7 – MATLAB Functions

Today I started with the Robotic Vision Project. This project is all about having a worksheet input into MATLAB and make computer identify the colors and shapes of the 2D objects drawn on the worksheet. Hence first of all, the course introduces how to work with functions.

I created a simple function myself to start with. I named it msum.m.

function addition = msum(a,b)
addition = a+b;

What this function does is to add two variables a and b that it takes as arguments.

Then following the course, I created a new function named getColor.m that can be used to identify objects and different colors (Red, Green, Blue) and create binary images.

function color = getColor(im, clr)
Y = sum(im,3);
redChroma = im(:,:,1) ./ Y;
greenChroma = im(:,:,2) ./Y;
blueChroma = im(:,:,3) ./Y;

redBinary = redChroma > 0.4;
greenBinary = greenChroma > 0.4;
blueBinary = blueChroma > 0.4;

case 'red'
color = redBinary;
case 'blue'
color = blueBinary;
case 'green'
color = greenBinary;

fprintf('Invalid color option. Use red, blue or green in single quotes only.');


This function basically takes two arguments im the input image and clr (the binary image having specified color as 1). First of all chromaticity coordinates are calculated and then the separated colors are compared with threshold value of 0.4 which returns the binary image highlighting that only color.

Now I am working on identifying the shape of the objects.


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