After I did a 'imclearborder', there are still a bit of unwanted object around the barcode. How can I remove those objects to isolate the barcode? I have pasted my code for your reference.
rgb = imread('barcode2.jpg');
% Resize Image
rgb = imresize(rgb,0.33);
figure(),imshow(rgb);
% Convert from RGB to Gray
Igray = double(rgb2gray(rgb));
% Calculate the Gradients
[dIx, dIy] = gradient(Igray);
B = abs(dIx) - abs(dIy);
% Low-Pass Filtering
H = fspecial('gaussian', 20, 10);
C = imfilter(B, H);
C = imclearborder(C);
figure(),imagesc(C);colorbar;
Well, i have already explained it in your previous question How to find the location of red region in an image using MATLAB? , but with a opencv code and output images.
Instead of asking for code, try to implement it yourself.
Below is what to do next.
1) convert image 'C' in your code to binary.
2) Apply some erosion to remove small noises.( this time, barcode region also shrinks)
3) Apply dilation to compensate previous erosion.(most of noise will have removed in previous erosion. So they won't come back)
4) Find contours in the image.
5) Find their area. Most probably, contour which has maximum area will be the barcode, because other things like letters, words etc will be small ( you can understand it in the grayscale image you have provided)
6) Select contour with max. area. Draw a bounding rectangle for it.
Its result is already provided in your previous question. It works very nice. Try to implement it yourself with help of MATLAB documentation. Come here only when you get an error which you don't understand.
%%hi, i am ading my code to yours at the end of your code%%%%
clear all;
rgb = imread('barcode.jpeg');
% Resize Image
rgb = imresize(rgb,0.33);
figure(),imshow(rgb);
% Convert from RGB to Gray
Igray = double(rgb2gray(rgb));
Igrayc = Igray;
% Calculate the Gradients
[dIx, dIy] = gradient(Igray);
B = abs(dIx) - abs(dIy);
% Low-Pass Filtering
H = fspecial('gaussian', 10, 5);
C = imfilter(B, H);
C = imclearborder(C);
imshow(Igray,[]);
figure(),imagesc(C);colorbar;
%%%%%%%%%%%%%%%%%%%%%%%%from here my code starts%%%%%%%%%%%%%%%%
bw = im2bw(C);%%%binarising the image
% imshow(bw);
%%%%if there are letters or any other noise is present around the barcode
%%Note: the size of the noise and letters should be smaller than the
%%barcode size
labelImage = bwlabel(bw,8);
len=0;labe=0;
for i=1:max(max(labelImage))
a = find(labelImage==i);
if(len<length(a))
len=length(a);
labe=i;
end
end
imag = zeros(size(l));
imag(find(labelImage==labe))=255;
% imtool(imag);
%%%if Necessary do errossion
% se2 = strel('line',10,0);
% imag= imerode(imag,se2);
% imag= imerode(imag,se2);
[r c]= find(imag==255);
minr = min(r);
maxc = max(c);
minc = min(c);
maxr = max(r);
imag1 = zeros(size(l));
for i=minr:maxr
for j=minc:maxc
imag1(i,j)=255;
end
end
% figure,imtool(imag1);
varit = find(imag1==0);
Igrayc(varit)=0;
%%%%%result image having only barcode
imshow(Igrayc,[]);
%%%%%original image
figure(),imshow(Igray,[]);
Hope it is useful
Related
I have an image (white background with 1-5 black dots) that is called main.jpg (main image).
I am trying to place another image (secondary.jpg) in every black dot that is found in main image.
In order to do that:
I found the black pixels in main image
resize the secondary image to specific size that I want
plot the image in every coordinate that I found in step one. (the black pixel should be the center coordinates of the secondary image)
Unfortunately, I don't know how to do the third step.
for example:
main image is:
secondary image is:
output:
(The dots are behind the chairs. They are the image center points)
This is my code:
mainImage=imread('main.jpg')
secondaryImage=imread('secondary.jpg')
secondaryImageResized = resizeImage(secondaryImage)
[m n]=size(mainImage)
for i=1:n
for j=1:m
% if it's black pixel
if (mainImage(i,j)==1)
outputImage = plotImageInCoordinates(secondaryImageResized, i, j)
% save this image
imwrite(outputImage,map,'clown.bmp')
end
end
end
% resize the image to (250,350) width, height
function [ Image ] = resizeImage(img)
image = imresize(img, [250 350]);
end
function [outputImage] = plotImageInCoordinates(image, x, y)
% Do something
end
Any help appreciated!
Here's an alternative without convolution. One intricacy that you must take into account is that if you want to place each image at the centre of each dot, you must determine where the top left corner is and index into your output image so that you draw the desired object from the top left corner to the bottom right corner. You can do this by taking each black dot location and subtracting by half the width horizontally and half the height vertically.
Now onto your actual problem. It's much more efficient if you loop through the set of points that are black, not the entire image. You can do this by using the find command to determine the row and column locations that are 0. Once you do this, loop through each pair of row and column coordinates, do the subtraction of the coordinates and then place it on the output image.
I will impose an additional requirement where the objects may overlap. To accommodate for this, I will accumulate pixels, then find the average of the non-zero locations.
Your code modified to accommodate for this is as follows. Take note that because you are using JPEG compression, you will have compression artifacts so regions that are 0 may not necessarily be 0. I will threshold with an intensity of 128 to ensure that zero regions are actually zero. You will also have the situation where objects may go outside the boundaries of the image. Therefore to accommodate for this, pad the image sufficiently with twice of half the width horizontally and twice of half the height vertically then crop it after you're done placing the objects.
mainImage=imread('https://i.stack.imgur.com/gbhWJ.png');
secondaryImage=imread('https://i.stack.imgur.com/P0meM.png');
secondaryImageResized = imresize(secondaryImage, [250 300]);
% Find half height and width
rows = size(secondaryImageResized, 1);
cols = size(secondaryImageResized, 2);
halfHeight = floor(rows / 2);
halfWidth = floor(cols / 2);
% Create a padded image that contains our main image. Pad with white
% pixels.
rowsMain = size(mainImage, 1);
colsMain = size(mainImage, 2);
outputImage = 255*ones([2*halfHeight + rowsMain, 2*halfWidth + colsMain, size(mainImage, 3)], class(mainImage));
outputImage(halfHeight + 1 : halfHeight + rowsMain, ...
halfWidth + 1 : halfWidth + colsMain, :) = mainImage;
% Find a mask of the black pixels
mask = outputImage(:,:,1) < 128;
% Obtain black pixel locations
[row, col] = find(mask);
% Reset the output image so that they're all zeros now. We use this
% to output our final image. Also cast to ensure accumulation is proper.
outputImage(:) = 0;
outputImage = double(outputImage);
% Keeps track of how many times each pixel was hit by the object
% This is so that we can find the average at each location.
counts = zeros([size(mask), size(mainImage, 3)]);
% For each row and column location in the image
for i = 1 : numel(row)
% Get the row and column locations
r = row(i); c = col(i);
% Offset to get the top left corner
r = r - halfHeight;
c = c - halfWidth;
% Place onto final image
outputImage(r:r+rows-1, c:c+cols-1, :) = outputImage(r:r+rows-1, c:c+cols-1, :) + double(secondaryImageResized);
% Accumulate the counts
counts(r:r+rows-1,c:c+cols-1,:) = counts(r:r+rows-1,c:c+cols-1,:) + 1;
end
% Find average - Any values that were not hit, change to white
outputImage = outputImage ./ counts;
outputImage(counts == 0) = 255;
outputImage = uint8(outputImage);
% Now crop and show
outputImage = outputImage(halfHeight + 1 : halfHeight + rowsMain, ...
halfWidth + 1 : halfWidth + colsMain, :);
close all; imshow(outputImage);
% Write the final output
imwrite(outputImage, 'finalimage.jpg', 'Quality', 100);
We get:
Edit
I wasn't told that your images had transparency. Therefore what you need to do is use imread but ensure that you read in the alpha channel. We then check to see if one exists and if one does, we will ensure that the background of any values with no transparency are set to white. You can do that with the following code. Ensure this gets placed at the very top of your code, replacing the images being loaded in:
mainImage=imread('https://i.stack.imgur.com/gbhWJ.png');
% Change - to accommodate for transparency
[secondaryImage, ~, alpha] = imread('https://i.imgur.com/qYJSzEZ.png');
if ~isempty(alpha)
m = alpha == 0;
for i = 1 : size(secondaryImage,3)
m2 = secondaryImage(:,:,i);
m2(m) = 255;
secondaryImage(:,:,i) = m2;
end
end
secondaryImageResized = imresize(secondaryImage, [250 300]);
% Rest of your code follows...
% ...
The code above has been modified to read in the basketball image. The rest of the code remains the same and we thus get:
You can use convolution to achieve the desired effect. This will place a copy of im everywhere there is a black dot in imz.
% load secondary image
im = double(imread('secondary.jpg'))/255.0;
% create some artificial image with black indicators
imz = ones(500,500,3);
imz(50,50,:) = 0;
imz(400,200,:) = 0;
imz(200,400,:) = 0;
% create output image
imout = zeros(size(imz));
imout(:,:,1) = conv2(1-imz(:,:,1),1-im(:,:,1),'same');
imout(:,:,2) = conv2(1-imz(:,:,2),1-im(:,:,2),'same');
imout(:,:,3) = conv2(1-imz(:,:,3),1-im(:,:,3),'same');
imout = 1-imout;
% output
imshow(imout);
Also, you probably want to avoid saving main.jpg as a .jpg since it results in lossy compression and will likely cause issues with any method that relies on exact pixel values. I would recommend using .png which is lossless and will also likely compress better than .jpg for synthetic images where the same colors repeat many times.
I have a matlab image from a matrix named Two_dim as shown in the figure below.
I would like to remove all 3 of the bottom straight horizontal lines from the image. I looked up on Stackoverflow to use regionprops to eliminate horizontal lines and obtained this code. But that doesn't seem to remove the lines.
rp = regionprops(Two_dim, 'PixelIdxList', 'Eccentricity', 'Orientation');
rp = rp([rp.Eccentricity]>0.95 & (abs([rp.Orientation])<2 | abs([rp.Orientation])>89));
Two_dim(vertcat(rp.PixelIdxList)) = false;
Here is an answer using Hough transform approach. I will add some more explanations to the code below later:
% I crop only the intresting part for illustration:
BW = edge(Two_dim(1:1000,:),'canny');
subplot 131
imagesc(Two_dim(1:1000,:))
title('Original image')
axis xy
[H,theta,rho] = hough(BW); % preform Hough transform
subplot 132
P = houghpeaks(H,10,'NHoodSize',[1 1]); % find the peaks in the transformation
lines_found = houghlines(BW,theta,rho,P,...
'FillGap',50,'MinLength',1); % convert the peaks to line objects
imagesc(Two_dim(1:1000,:)), hold on
result = Two_dim(1:1000,:);
for k = 1:length(lines_found)
% extract one line:
xy = [lines_found(k).point1; lines_found(k).point2];
% Plot the detected lines:
plot(xy(:,1),xy(:,2),'LineWidth',1,'Color','green');
% remove the lines from the image:
% note that I take a buffer of 3 to the 'width' of the line
result(xy(1,2):xy(1,2)+3,xy(1,1):xy(2,1)) = 0;
end
title('Detected lines')
axis xy
subplot 133
imagesc(result)
title('Corrected image')
axis xy
The output:
You could look at the row intensity sums. They will stand out as long as the lines stay horizontal.
grayI = rgb2gray(I);
rowSums = sum(grayI,2);
plot(rowSums);
filterRows = rowSums > 1*10^5
I(filterRows,:,:) = 255;
regionprops needs a binary image with each pixel being one of two values.
You can do e.g.
Two_dim(Two_dim<0.5) = 0;
Two_dim(Two_dim>=0.5) = 1; # the actual value doesn't matter
or
Two_dim = logical(Two_dim);
I have 2 images ("before" and "after"). I would like to show a final image where the left half is taken from the before image and the right half is taken from the after image.
The images should be separated by a white diagonal line of predefined width (2 or 3 pixels), where the diagonal is specified either by a certain angle or by 2 start and end coordinates. The diagonal should overwrite a part of the final image such that the size is the same as the sources'.
Example:
I know it can be done by looping over all pixels to recombine and create the final image, but is there an efficient way, or better yet, a built-in function that can do this?
Unfortunately I don't believe there is a built-in solution to your problem, but I've developed some code to help you do this but it will unfortunately require the image processing toolbox to play nicely with the code. As mentioned in your comments, you have this already so we should be fine.
The logic behind this is relatively simple. We will assume that your before and after pictures are the same size and also share the same number of channels. The first part is to declare a blank image and we draw a straight line down the middle of a certain thickness. The intricacy behind this is to declare an image that is slightly bigger than the original size of the image. The reason why is because I'm going to draw a line down the middle, then rotate this blank image by a certain angle to achieve the first part of what you desire. I'll be using imrotate to rotate an image by any angle you desire. The first instinct is to declare an image that's the same size as either the originals, draw a line down the middle and rotate it. However, if you do this you'll end up with the line being disconnected and not draw from the top to the bottom of the image. That makes sense because the line being drawn on an angle covers more pixels than if you were to draw this vertically.
Using Pythagorean's theorem, we know that the longest line that can ever be drawn on your image is the diagonal. Therefore we declare an image that is sqrt(rows*rows + cols*cols) in both the rows and columns where rows and cols are the rows and columns of the original image. After, we'll take the ceiling to make sure we've covered as much as possible and we add a bit of extra room to accommodate for the width of the line. We draw a line on this image, rotate it then we'll crop the image after so that it's the same size as the input images. This ensures that the line drawn at whatever angle you wish is fully drawn from top to bottom.
That logic is the hardest part. Once you do that, you declare two logical masks where you use imfill to fill the left side of the mask as one mask and we'll invert the mask to find the other mask. You will also need to use the line image that we created earlier with imrotate to index into the masks and set the values to false so that we ignore these pixels that are on the line.
Finally, you take each mask, index into your image and copy over each portion of the image you desire. You finally use the line image to index into the output and set the values to white.
Without further ado, here's the code:
% Load some example data
load mandrill;
% im is the image before
% im2 is the image after
% Before image is a colour image
im = im2uint8(ind2rgb(X, map));
% After image is a grayscale image
im2 = rgb2gray(im);
im2 = cat(3, im2, im2, im2);
% Declare line image
rows = size(im, 1); cols = size(im, 2);
width = 5;
m = ceil(sqrt(rows*rows + cols*cols + width*width));
ln = false([m m]);
mhalf = floor(m / 2); % Find halfway point width wise and draw the line
ln(:,mhalf - floor(width/2) : mhalf + floor(width/2)) = true;
% Rotate the line image
ang = 20; % 20 degrees
lnrotate = imrotate(ln, ang, 'crop');
% Crop the image so that it's the same dimensions as the originals
mrowstart = mhalf - floor(rows/2);
mcolstart = mhalf - floor(cols/2);
lnfinal = lnrotate(mrowstart : mrowstart + rows - 1, mcolstart : mcolstart + cols - 1);
% Make the masks
mask1 = imfill(lnfinal, [1 1]);
mask2 = ~mask1;
mask1(lnfinal) = false;
mask2(lnfinal) = false;
% Make sure the masks have as many channels as the original
mask1 = repmat(mask1, [1 1 size(im,3)]);
mask2 = repmat(mask2, [1 1 size(im,3)]);
% Do the same for the line
lnfinal = repmat(lnfinal, [1 1 size(im, 3)]);
% Specify output image
out = zeros(size(im), class(im));
out(mask1) = im(mask1);
out(mask2) = im2(mask2);
out(lnfinal) = 255;
% Show the image
figure;
imshow(out);
We get:
If you want the line to go in the other direction, simply make the angle ang negative. In the example script above, I've made the angle 20 degrees counter-clockwise (i.e. positive). To reproduce the example you gave, specify -20 degrees instead. I now get this image:
Here's a solution using polygons:
function q44310306
% Load some image:
I = imread('peppers.png');
B = rgb2gray(I);
lt = I; rt = B;
% Specify the boundaries of the white line:
width = 2; % [px]
offset = 13; % [px]
sz = size(I);
wlb = [floor(sz(2)/2)-offset+[0,width]; ceil(sz(2)/2)+offset-[width,0]];
% [top-left, top-right; bottom-left, bottom-right]
% Configure two polygons:
leftPoly = struct('x',[1 wlb(1,2) wlb(2,2) 1], 'y',[1 1 sz(1) sz(1)]);
rightPoly = struct('x',[sz(2) wlb(1,1) wlb(2,1) sz(2)],'y',[1 1 sz(1) sz(1)]);
% Define a helper grid:
[XX,YY] = meshgrid(1:sz(2),1:sz(1));
rt(inpolygon(XX,YY,leftPoly.x,leftPoly.y)) = intmin('uint8');
lt(repmat(inpolygon(XX,YY,rightPoly.x,rightPoly.y),1,1,3)) = intmin('uint8');
rt(inpolygon(XX,YY,leftPoly.x,leftPoly.y) & ...
inpolygon(XX,YY,rightPoly.x,rightPoly.y)) = intmax('uint8');
final = bsxfun(#plus,lt,rt);
% Plot:
figure(); imshow(final);
The result:
One solution:
im1 = imread('peppers.png');
im2 = repmat(rgb2gray(im1),1,1,3);
imgsplitter(im1,im2,80) %imgsplitter(image1,image2,angle [0-100])
function imgsplitter(im1,im2,p)
s1 = size(im1,1); s2 = size(im1,2);
pix = floor(p*size(im1,2)/100);
val = abs(pix -(s2-pix));
dia = imresize(tril(ones(s1)),[s1 val]);
len = min(abs([0-pix,s2-pix]));
if p>50
ind = [ones(s1,len) fliplr(~dia) zeros(s1,len)];
else
ind = [ones(s1,len) dia zeros(s1,len)];
end
ind = uint8(ind);
imshow(ind.*im1+uint8(~ind).*im2)
hold on
plot([pix,s2-pix],[0,s1],'w','LineWidth',1)
end
OUTPUT:
In the implementation of downsampling by a factor of 2 to the image, the downsampled image is gray. What should I do in order to add all of the color components to the downsampling implementation so that it will be a color image?
I = imread('lena.gif','gif');
[j k] = size(I)
x_new = j./2;
y_new = k./2;
x_scale = j./x_new;
y_scale = k./y_new;
M = zeros(x_new,y_new);
for count1 = 1:x_new
for count2 = 1:y_new
M(count1,count2) = I(count1.*x_scale,count2.*y_scale);
end
end
figure,imshow(I);
title('Original Image');
M = uint8(M);
figure,imshow(M);
title('Downsample');
GIF images are what are known as indexed images. This means that what you read in with imread are values that are indices to a colour map. Each index generates a unique colour for you, and that's how GIF images are stored. They choose from a predefined set of colours, and each pixel in the GIF image comes from one of the colours in the colour map.
You first need to convert the image into RGB, and you do that with ind2rgb. However, you need to read in the colour map first with the two-output version of imread. You also will want to convert the images to uint8 as good practice with im2uint8:
[X,map] = imread('lena.gif');
I = im2uint8(ind2rgb(X,map));
What you need to do next is what #NKN suggested. You must apply the algorithm to all channels.
As such, simply make an output matrix that has three channels, and apply the algorithm to each plane independently. If I can make a suggestion, when accessing pixels this way after you downsample, make sure you floor or round the image coordinates so you're not inadvertently specifying locations that aren't defined - things like (13.8, 25.5) for example. Image pixel locations are integer, so you need to make sure the coordinates are integer too.
[X,map] = imread('lena.gif');
I = im2uint8(ind2rgb(X,map));
j = size(I,1); %// Change
k = size(I,2);
x_new = j./2;
y_new = k./2;
x_scale = j./x_new;
y_scale = k./y_new;
M = zeros(x_new,y_new,size(I,3)); %// Change
for jj = 1 : size(I,3) %// Change
for count1 = 1:x_new
for count2 = 1:y_new
M(count1,count2,jj) = I(floor(count1.*x_scale),floor(count2.*y_scale),jj); %// Change
end
end
end
figure,imshow(I);
title('Original Image');
M = uint8(M);
figure,imshow(M);
title('Downsample');
To test this, I'm using the mandrill dataset that's part of MATLAB. It is an indexed image with an associated colour map. These are coincidentally stored in X and map respectfully:
load mandrill;
I = im2uint8(ind2rgb(X,map));
Running the modified code, I get these two figures:
When you read the original image it contains 3 layers, R-G-B (as suggested by #rayryeng:
[X,map] = imread('lena.gif');
I = ind2rgb(X,map);
size(I)
ans =
768 1024 3
You should perform the down-sampling process on all the layers:
The code you provided does not down-sample. A simple downsampling example is as follows:
imshow(I(1:2:end,1:2:end,:))
I have an image with a white background and trying to extract the object within it using MATLAB. I tried different techniques (bounded box) but I am not getting desired results. I have tried this StackOverflow post but it isn't quite working: MATLAB Auto Crop
How I can extract the object? Any idea which technique is suitable?
The image is shown below:
I propose the following workflow:
Binarize the image
Get the centroid and orientation of the main object
Crop the image to set the center of the object at the center of the image
Rotate the object with respect to the center to compensate for the tilt
Crop again to get the object
In practice, step 1 turned out to be rather complicated to perform because of the shadow and of the not-so-well-defined boundaries between the white part of the object and the background. The trick I used relies on the fact that, because of the many details inside the object (and the jpg compression) there is a lot of "noise" all over it. So looking for edges combined with a BW-dilation produced a very decent binarized image. I then used regioprops to filter the small outliers and get the properties of the object.
Here is the code:
% --- Load image
Img = imread('Tilted.jpg');
% --- Binarisation
% Find edges and dilate to get a bloc
BW = edge(mean(Img,3),'sobel');
BW = imdilate(BW, strel('disk',5));
% Get BW image
RP = regionprops(BW, 'Area', 'PixelIdxList', 'Centroid', 'Orientation');
[~, i] = max([RP(:).Area]);
BW = Img(:,:,1)*0;
BW(RP(i).PixelIdxList) = 1;
x = RP(i).Centroid(1);
y = RP(i).Centroid(2);
theta = -RP(i).Orientation;
% imshow(BW)
% plot(x+[0 500*cos(theta*pi/180)], y+[0 500*sin(theta*pi/180)]);
% return
% --- First crop
w = min(x-1, size(Img,2)-x);
h = min(y-1, size(Img,1)-y);
C = Img(ceil(y-h):floor(y+h), ceil(x-w):floor(x+w),:);
% --- Rotate image
R = imrotate(C, theta);
R(R==0) = 255;
% --- Second crop
% Parameters (to adjust)
th = 70;
margin = 25;
% Remove grey levels
Rwg = std(double(R),0,3).^2;
% Get x-bounds
sx = sum(Rwg,1);
x1 = max(find(sx>prctile(sx,th), 1, 'first')-margin, 1);
x2 = min(find(sx>prctile(sx,30), 1, 'last')+margin, size(Rwg,1));
% Get y-bounds
sy = sum(Rwg,2);
y1 = max(find(sy>prctile(sy,th), 1, 'first')-margin, 1);
y2 = min(find(sy>prctile(sy,th), 1, 'last')+margin, size(Rwg,1));
Res = R(y1:y2, x1:x2, :);
% --- Display
imshow(Res)
Of course, if you have many different images to process this may not work every time. This code is only a starting point and you now have to modify it to meet your precise needs.
Best,