I try to determine the coordinates of a puzzle piece on the original image using the normxcorr2 function. Then I draw a rectangle on the correspondence of the two elements. Unfortunately, I notice that the coordinates that this match has given me are not good. Could someone have an idea how to improve the use of this feature and get some better results.
The puzzle piece has the name "cpiece" and the original picture has the name "bild"
clear all;
close all;
clc
cpiece = im2gray(imread('cpiece1.jpg'));
bild = im2gray(imread('original.jpg'));
figure(1)
montage({bild,cpiece})
c = normxcorr2(cpiece,bild);
figure(2)
surf(c)
shading flat
[ypeak,xpeak] = find(c==max(c(:)));
yoffSet = ypeak-size(cpiece,1);
xoffSet = xpeak-size(cpiece,2);
figure(3)
imshow(bild)
drawrectangle(gca,'Position',[xoffSet,yoffSet,size(cpiece,2),size(cpiece,1)],'FaceAlpha',0);
It seems, the problem returns back to the quality of your template image, And Check if the scales between original image and the template are exactly the same
Related
I create a polygon on image_area in matlab.
I used impoly.
But after creation polygon.
I need to block possibility to move and drag impoly (ROI is already created).
I don't know how I should do it ?
I would appreciate for any help please.
You can set the makeConstrainToRectFcn such that it is a rectangle encompassing your ROI, then whenever you try to move the latter it won't work. You can also, after creating the ROI, set the setVerticesDraggable method to false in order to prevent vertices from being dragged.
Sample code (adapted from example by the Mathworks):
clc
clear
figure
imshow('gantrycrane.png');
h = impoly(gca, [188,30; 189,142; 93,141; 13,41; 14,29]);
%// Get currentposition
Pos = getPosition(h);
%// Prevent draggable vertices
setVerticesDraggable(h,0);
%// Set up rectangle to prvent movement of ROI
fcn = makeConstrainToRectFcn('impoly', [min(Pos(:,1)) max(Pos(:,1))], [min(Pos(:,2)) max(Pos(:,2))]);
%// Apply function
h.setPositionConstraintFcn(fcn);
which results in this kind of situation (with red rectangle for illustration):
In my image I have 5 Objects in black-white form. Some are respectively small, some are bigger.
So what i am trying to do is drawing a BoundingBox or tag the objects which has less area than others (ex. under 10pixels/area) .
I couldn't make this happen, can anyone help?
That's two separate problems. The first is to select only objects above a certain area. So simply remove all objects below it:
clean = bwareaopen (im, 10); # remove all objects with area below 10
Then for the second problem there are many possibilities. You can get their borders:
borders = bwperim (clean);
imshow (borders);
You can label them:
labeled = bwlabel (clean);
imshow (labeled);
Or you can get their bounding box (which depending on the shape of your objects may overlap):
props = regionprops (clean, 'BoundingBox');
all_bb = props.BoundingBox;
boxes = false (size (clean));
for i = 1:numel (all_bb)
bb = all_bb{i};
bb(round (bb(2):bb(2)+bb(4), bb(1):bb(1)+bb(3))) = true;
end
imshow (boxes);
Note: this was written out of my head, no testing. There may be small oversights, but nothing major.
I want to get only leaf from an image.
The background is a normal white paper(A4) and there is some shadow.
I apply some method (structure element,edge detection using filter) but I cannot find the general way which can apply all the image.
these are examples.
Are there better methods for this problem??
thank you
another example.
and the result I got is
By using
hsv_I = rgb2hsv(I);
Is = hsv_I(:,:,2);
Is_d = imdilate(Is,strel('diamond',4));
Is_e = imerode(Is,strel('diamond',2));
Is_de = imerode(Is_d,strel('disk',2));
Is_def = imfill(Is_de,'holes');
Is_defe = imerode(Is_def,strel('disk',5));
Then Is_defe is a mask to segment
But the method that i did is very specific. I cannot use this in general.
If you have the Image Processing Toolbox, you could do as follows:
The code below first estimates the threshold with the function graythresh, thresholds the image and fills holes with the imfill function. Suppose I is a cell containing your RGB images:
for k=1:length(I)
t=graythresh(rgb2gray(I{k}));
BW{k}=imfill(~im2bw(I{k}, t), 'holes');
subplot(length(I),1,k), imshow(BW{k});
end
I'm using Geometric mean filter to remove noise instead of median filter as image quality goes off in former case. code shown below is a part of m-file to remove noise.
fname = getappdata(0, 'fname');
[a, map] = imread(fname);
x = ind2rgb(a, map);
b = im2double(x);
w=fspecial('gaussian',[3,3]);
geom=exp(imfilter(log(b),ones(3,3),'replicate')).^(1/3/3);
fname=imfilter(b,w,'replicate');
axes(handles.axes1);
imshow(fname);
If i press push button which is named 'Remove Noise' above code get executed irrespective of image quality/property. In the sense even if no noise is present, image will be subjected to filter.
My question, is there any way to detect whether noise is present or not, so that the moment i pressed push button if no Noise in image it should display a message stating 'NO NOISE TO REMOVE' automatically.
There is no direct way to determine whether an image is noisy or not.
However, you can compare resulting image fname with the input image b in such a way that if their difference is lower than a certain threshold, then it can be decided that denoising operation has not changed image effectively and there is not much noise in the original image like:
threshold_ratio = 0.2; % to be decided experimentally
difference_ratio = sum(sum((fname - b).^2)) / sum(sum(b.^2));
if difference_ratio < threshold_ratio
disp('NO NOISE TO REMOVE');
end
Let's say my image is img=zeros(100,100,3), my outputs are several ellipse which i get using a created function [ret]=draw_ellipse(x,y,a,b,angle,color,img), I can display one ellipse using imshow(ret).For the moment, I'm trying to show serval ellipse in the image. But i don't know how to code it. will ‘for loop’ work or I need to hold them?
If this is related to what you were doing in your previous question, then what you need to do is to pass the result of one iteration as input to the next.
So assuming that the function [ret]=draw_ellipse(x,y,a,b,angle,color,img) you mentioned takes as input an image img and returns the same image with an ellipse drawn on it, you could do this:
%# ellipses parameters
%#x = {..}; y = {..};
%#a = {..}; b = {..};
%#angle = {..}; color = {..};
img = zeros(200,100,'uint8'); %# image to start with
for i=1:10
img = draw_ellipse(x{i},y{i}, a{i},b{i}, angle{i}, color{i}, img);
end
imshow(img)
I'm a bit unsure of what you want. You want to show several ellipse in one image, like plotting several graphs with hold on?
There is no equivalent command for images, but a simple solution is to add the ellipses into one image and show that one:
several_ellipse = ellipse1 + ellipse2 + ellipse3;
imshow(several_ellipse)
Presumably you want to pass ret as the final input to the next call to draw_ellipse.