MATLAB: Colour segmentation on resistor color band and calculate the value

colour segmentationImage Processing Toolboxresistor

I'm a beginner to Matlab. I need to do a color segmentation on a resistor color band, identify the color and do a calculation based on the color. Any guideline for this?

Best Answer

I have color segmentation tutorials here if you're interested: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862. Basically you need to find the regions of interest first - the bands. You might use a variety of techniques depending on how repeatable the lighting and positioning are from image to image. Then you can look at the mean RGB value of each band and see which "master" color it's closest to. If the band is closer red color than any other, then assume it's red.

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MATLAB: How to define the red, green, and blue Threshold value

Use impixelinfo() to have it display the RGB values as you mouse around the image. See updated demo, attached. for the red, green, and blue threshold for the yellow pepper, try these (that I got from the Color Thresholder App):

% Define thresholds for channel 1 (Red) based on histogram settings
channel1Min = 244.000;
channel1Max = 255.000;
% Define thresholds for channel 2 (Green) based on histogram settings
channel2Min = 131.000;
channel2Max = 247.000;
% Define thresholds for channel 3 (Blue) based on histogram settings
channel3Min = 0.000;
channel3Max = 164.000;

MATLAB: How to calculate Black area

No, that's not right. It's as I told you at first.

When you do

binaryImage = grayImage < 128; % Find dark pixels.  Dark = true, 1, white.

you're creating a matrix that is "true" wherever the image is dark . If you sum that, it treats the "true" pixels as 1, and thus, counts them - counts the dark pixels. So you're getting the sum of the "true/1/white" pixels in the binary image which means your getting the count of the dark pixels of the gray scale image. Doing it your complicated way would count the bright pixels. By the way, if you wanted the binary image to be false where the gray scale image was dark, you'd flip the less than sign and then sum the inverse, which is much simpler than doing the multi-step process you did.

binaryImage = grayImage > 128; % Find bright pixels instead of dark pixels.
numDarkPixels = sum(~binaryImage(:)); % Notice I had to invert the image with~.

Best Answer

Related Solutions

MATLAB: How to define the red, green, and blue Threshold value

MATLAB: How to calculate Black area

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