MATLAB: Function to decrease image size

image processingImage Processing Toolboximresizeresize image

function [y] = ImageDecrease(i,n)
y=imresize(i,n);
size(y)
end

I need to create a function to decrease the image size. Ex. image size is 512px x 512px and if n=4 the size of image has to be 64×64 (the i parameter is the image)

This function doesnt work bc if scale is >1 it increases the image..

Best Answer

I know it sounds obvious, so you've probably already done it by now, but did you try inverting the number:

function outputImage = ImageDecrease(inputImage, n)
[rows, columns, numberOfColorChannels] = size(inputImage);
fprintf('Input image has %d rows, %d columns, and %d color channels',rows, columns, numberOfColorChannels)
outputImage = imresize(inputImage, 1/n);
[rows, columns, numberOfColorChannels] = size(outputImage);
fprintf('Output image has %d rows, %d columns, and %d color channels',rows, columns, numberOfColorChannels)
end

Related Solutions

MATLAB: How to determine the rows and columns of an image

save your imread data in some variable.

ImageData=imread('car.jpg');

ImageData will be a 3 D array for Colour Image with R, G, B Amplitude Values.

You can do a

[rows columns depth]=size(ImageData );

on it.

MATLAB: How to convert gray or indexed images to color images

That image is a 2D image, an indexed image with a color map. It's not a 3D color RGB image. You need to convert it to an RGB image if you recognize it's an indexed image. Replace your loop with this:

for k = 1:numel(bmpFiles)
  fullInputFileName = fullfile(inputFolder,bmpFiles(k).name)
  [originalImage, colorMap] = imread(fullInputFileName);
  [rows, columns, numberOfColorChannels] = size(originalImage)
  if ~isempty(colorMap) && numberOfColorChannels == 1
    % It's an indexed image with a colormap.
    % Convert it to RGB color
    originalImage = ind2rgb(originalImage, colorMap);
    [rows, columns, numberOfColorChannels] = size(originalImage)
  end
  fullOutputFileName = fullfile(outputFolder, bmpFiles(k).name);
  outputImage = imresize(originalImage, [100,50]);
  [rows columns numberOfColorChannels] = size(outputImage);
  if numberOfColorChannels == 1
    % It's monochrome, so convert to color.
    outputImage = cat(3, outputImage, outputImage, outputImage);
  end
  
  figure,imshow(outputImage);
  imwrite(outputImage, fullOutputFileName);
end

Best Answer

Related Solutions

MATLAB: How to determine the rows and columns of an image

MATLAB: How to convert gray or indexed images to color images

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