how to perform character segmentation in Matlab [closed]

问题

I have license plate image and I want to cut the numbers one by one.

any one have simple idea how to perform it?

after searching the web I found a way by doing the operation of horizontal and vertical smearing, but I really don't know what does it mean.

any explanation would help

Thanks in advance.

回答1:

you can try this code(it's not mine)

% This is a program for extracting objects from an image. Written for vehicle number     plate segmentation and extraction
% Authors : Jeny Rajan, Chandrashekar P S
% U can use attached test image for testing
% input - give the image file name as input. eg :- car3.jpg
clc;
clear all;
k=input('Enter the file name','s'); % input image; color image
im=imread(k);
im1=rgb2gray(im);
im1=medfilt2(im1,[3 3]); %Median filtering the image to remove noise%
BW = edge(im1,'sobel'); %finding edges 
[imx,imy]=size(BW);
msk=[0 0 0 0 0;
 0 1 1 1 0;
 0 1 1 1 0;
 0 1 1 1 0;
 0 0 0 0 0;];
B=conv2(double(BW),double(msk)); %Smoothing  image to reduce the number of connected     components
L = bwlabel(B,8);% Calculating connected components
mx=max(max(L))
% There will be mx connected components.Here U can give a value between 1 and mx for L     or in a loop you can extract all connected components
% If you are using the attached car image, by giving 17,18,19,22,27,28 to L you can     extract the number plate completely.
[r,c] = find(L==17);  
rc = [r c];
[sx sy]=size(rc);
n1=zeros(imx,imy); 
for i=1:sx
x1=rc(i,1);
y1=rc(i,2);
n1(x1,y1)=255;
end % Storing the extracted image in an array
figure,imshow(im);
figure,imshow(im1);
figure,imshow(B);
figure,imshow(n1,[]);

回答2:

regionprops might work for you. If you take this sample license plate.

You could use a little script like this to cut out objects. Sorry, I just typed it together really quickly, but it gives you an idea.

clear all;
close all;
I = imread('plate.jpg');
BW = im2bw(I, 0.9);
BW = ~BW;


stats = regionprops(BW);
for index=1:length(stats)
    if stats(index).Area > 200 && stats(index).BoundingBox(3)*stats(index).BoundingBox(4) < 30000
    x = ceil(stats(index).BoundingBox(1))
    y= ceil(stats(index).BoundingBox(2))
    widthX = floor(stats(index).BoundingBox(3)-1)
    widthY = floor(stats(index).BoundingBox(4)-1)
    subimage(index) = {BW(y:y+widthY,x:x+widthX,:)}; 
    figure, imshow(subimage{index})
    end
end

This will output images like

and this

You still have to decide if it really is a letter. Be careful, the script will output a lot of images (about 30 or 40)

来源：https://stackoverflow.com/questions/5305712/how-to-perform-character-segmentation-in-matlab

标签

matlab

image-segmentation