Does anyone have any sample on MATLAB coding for Number plate recognition?

-Image captured
-RGB to grayscale
-Image filtering (edge detection, sobel, laplacian)
-Morpholgy
-Image treshold
-Convert to black & white
-Extract number plate box from image
-character segmentation
-character recognition (OCR)

Answer 1

[per isakson]

Search the File Exchange for Number plate recognition

Answer 2

[Image Analyst]

See the Computer Vision System Toolbox. It has OCR: http://www.mathworks.com/help/vision/ref/ocr.html#bt548t1-2_1

Find published algorithms here: http://www.visionbib.com/bibliography/motion-f726.html#License%20Plate%20Recognition,%20Extraction,%20Analysis

[Ahmed]

thank you Dr.

[Ahmed]

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
imtool close all;  % Close all imtool figures if you have the Image Processing Toolbox.
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;

% Check that user has the Image Processing Toolbox installed.
hasIPT = license('test', 'image_toolbox');
if ~hasIPT
  % User does not have the toolbox installed.
  message = sprintf('Sorry, but you do not seem to have the Image Processing Toolbox.\nDo you want to try to continue anyway?');
  reply = questdlg(message, 'Toolbox missing', 'Yes', 'No', 'Yes');
  if strcmpi(reply, 'No')
    % User said No, so exit.
    return;
  end
end

% Read in a standard MATLAB gray scale demo image.
folder = fullfile(matlabroot, '\toolbox\images\imdemos');
button = menu('Use which demo image?', 'CameraMan', 'Moon', 'Eight', 'Coins', 'Pout');
if button == 1
  baseFileName = 'cameraman.tif';
elseif button == 2
  baseFileName = 'moon.tif';
elseif button == 3
  baseFileName = 'eight.tif';
elseif button == 4
  baseFileName = 'coins.png';
else
  baseFileName = 'pout.tif';
end

% Read in a standard MATLAB gray scale demo image.
folder = fullfile(matlabroot, '\toolbox\images\imdemos');
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
% Check if file exists.
if ~exist(fullFileName, 'file')
  % File doesn't exist -- didn't find it there.  Check the search path for it.
  fullFileName = baseFileName; % No path this time.
  if ~exist(fullFileName, 'file')
    % Still didn't find it.  Alert user.
    errorMessage = sprintf('Error: %s does not exist in the search path folders.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
grayImage = imread(fullFileName);
% Get the dimensions of the image.  
% numberOfColorBands should be = 1.
[rows, columns, numberOfColorBands] = size(grayImage);
if numberOfColorBands > 1
  % It's not really gray scale like we expected - it's color.
  % Convert it to gray scale by taking only the green channel.
  grayImage = grayImage(:, :, 2); % Take green channel.
end
% Display the original gray scale image.
subplot(2, 2, 1);
imshow(grayImage, []);
title('Original Grayscale Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Give a name to the title bar.
set(gcf,'name','Demo by ImageAnalyst','numbertitle','off') 

% Compute Laplacian
laplacianKernel = [-1,-1,-1;-1,8,-1;-1,-1,-1]/8;
laplacianImage = imfilter(double(grayImage), laplacianKernel);
% Display the image.
subplot(2, 2, 2);
imshow(laplacianImage, []);
title('Laplacian Image', 'FontSize', fontSize);

% Compute the sharpened image when you can get by using imfilter or conv2 and the
% kernel [-1,-1,-1;-1,8,-1;-1,-1,-1], or else if you have the Laplacian already,
% simply add the original image to the laplacianImage.
sharpenedImage = double(grayImage) + laplacianImage;
% Display the image.
subplot(2, 2, 3);
imshow(sharpenedImage, []);
title('Sharpened Image', 'FontSize', fontSize);

% Computer Sobel image
[magnitudeImage, directionImage] = imgradient(grayImage, 'Sobel');
% Display the original gray scale image.
subplot(2, 2, 4);
imshow(magnitudeImage, []);
title('Sobel Image', 'FontSize', fontSize);

p/s : sir, I believe this is your coding. I wonder why the image 'sobel' does not appear when this code is executed?

[Image Analyst]

It does show up. I just copied and pasted and ran, and here is the result:

It's right there in the lower right corner. Why do you say it doesn't show up?

[Ahmed]

Oh, maybe the matlab software i used have some problem or the version is quite old. I just get this result. thank you for your response. It help much

[Image Analyst]

What version of MATLAB do you have? If you have an old version and don't have imgradient(), it should have thrown an exception. Did you see any red error text?

[Ahmed]

MATLAB 7.6.0 (R2008a). yes sir, exactly. when i executed the code, the red error text appeared.

??? Undefined function or method 'imgradient' for input arguments of type 'uint8'.

[Image Analyst]

It's not available in your 6 year old version. Contact the Mathworks about upgrading. Or else write it yourself. You might be able to get by with a DOG filter and I've attached a demo.