I have a cell with 3 synchronized signals in each column. I want to extract specific segments into my seg cell. How do I get rid of the loop here?
data = cell(1, 3);
data{1,1} = [ones(30, 1)];
data{1,2} = [1:30]';
data{1,3} = 2*[1:30]';
ind1 = [1; 11; 17];
ind2 = [10; 16; 30];
for i = 1:3
seg{i, 1} = [data{:,1}(ind1(i):ind2(i)) data{:,2}(ind1(i):ind2(i)) data{:,3}(ind1(i):ind2(i))];
end
You mean like this?
data = cell(1, 3);
data{1,1} = ones(30, 1);
data{1,2} = (1:30)';
data{1,3} = 2*(1:30)';
D = cell2mat(data);
Cel = mat2cell(D,[10 6 14],3);
Related
The picture with noise is like this.
Noised picture: Image3.bmp
I was doing image processing in MatLab with some built-in and self-implemented filters.
I have already tried a combination of bilateral, median and gaussian. bilateral and gaussian code are at the end of this post.
img3 = double(imread('Image3.bmp')); % this is the noised image
lena = double(imread('lena_gray.jpg')); % this is the original one
img3_com = bilateral(img3, 3, 2, 80);
img3_com = medfilt2(img3_com, [3 3], 'symmetric');
img3_com = gaussian(img3_com, 3, 0.5);
img3_com = bilateral(double(img3_com), 6, 100, 13);
SNR3_com = snr(img3_com,img3_com - lena); % 17.1107
However, the result is not promising with SNR of only 17.11.
Filtered image: img3_com
The original picture is like this.
Clean original image: lena_gray.jpg
Could you please give me any possible ideas about how to process it? Like what noise generators generated the noised image and what filtering methods or image processing method I can use to deal with it. Appreciate!!!
My bilateral function bilateral.m
function img_new = bilateral(img_gray, window, sigmaS, sigmaI)
imgSize = size(img_gray);
img_new = zeros(imgSize);
for i = 1:imgSize(1)
for j = 1:imgSize(2)
sum = 0;
simiSum = 0;
for a = -window:window
for b = -window:window
x = i + a;
y = j + b;
p = img_gray(i,j);
q = 0;
if x < 1 || y < 1 || x > imgSize(1) || y > imgSize(2)
% q=0;
continue;
else
q = img_gray(x,y);
end
gaussianFilter = exp( - double((a)^2 + (b)^2)/ (2 * sigmaS^2 ) - (double(p-q)^2)/ (2 * sigmaI^2 ));
% gaussianFilter = gaussian((a^2 + b^2)^(1/2), sigma) * gaussian(abs(p-q), sigma);
sum = sum + gaussianFilter * q;
simiSum = simiSum + gaussianFilter;
end
end
img_new(i,j) = sum/simiSum;
end
end
% disp SNR
lena = double(imread('lena_gray.jpg'));
SNR1_4_ = snr(img_new,img_new - lena);
disp(SNR1_4_);
My gaussian implementation gaussian.m
function img_gau = gaussian(img, hsize, sigma)
h = fspecial('gaussian', hsize, sigma);
img_gau = conv2(img,h,'same');
% disp SNR
lena = double(imread('lena_gray.jpg'));
SNR1_4_ = snr(img_gau,img_gau - lena);
disp(SNR1_4_);
I'm using the next code to plot in a pie chart the percentage of values in a matrix that are greater/smaller than 1. The thing is that when I want to put the title above the graph, it overlaps with the label of one of the groups.
I tried replacing it with text() but it didn't worked, and Documentation on pie say nothing to this. How can I avoid this overlap?
eigen = []; % Modes array
c2 = 170; % Sound speed divided by 2
%% Room dimensions
lx = 5.74;
ly = 8.1;
lz = 4.66;
i = 1; % Index for modes array
for nz = 0:50
for ny = 0:50
for nx = 0:50
aux = c2 * sqrt((nx/lx)^2+(ny/ly)^2+(nz/lz)^2);
if aux < 400 %% If value is into our range of interest
eigen(i) = aux;
i=i+1;
end
end
end
end
eigen = round(sort(eigen'),1);
eigen
% dif = eigen(2:end)-eigen(1:end-1); % Distance between modes
x = 0; %% dif >= 1
y = 0; %% dif <= 1
dif = [];
for i=2:length(eigen)
if eigen(i)-eigen(i-1) >= 1
x = x+1;
else
y = y+1;
end
end
figure
dif = [x,y];
explode = [1 1];
graf = pie(dif,explode);
hText = findobj(graf,'Type','text');
percentValues = get(hText,'String');
txt = {'Smaller than 1 Hz: ';'Greater than 1 Hz: '};
combinedtxt = strcat(txt,percentValues);
oldExtents_cell = get(hText,'Extent');
oldExtents = cell2mat(oldExtents_cell);
hText(1).String = combinedtxt(1);
hText(2).String = combinedtxt(2);
title('Distance between modes')
You can rotate the pie chart so that the figure look better. Further, you can use position to allocate your text as follows,
figure
dif = [x,y];
explode = [1 1];
graf = pie(dif,explode);
hText = findobj(graf,'Type','text');
percentValues = get(hText,'String');
txt = {'Smaller than 1 Hz: ';'Greater than 1 Hz: '};
combinedtxt = strcat(txt,percentValues);
oldExtents_cell = get(hText,'Extent');
oldExtents = cell2mat(oldExtents_cell);
hText(1).String = combinedtxt(1);
hText(2).String = combinedtxt(2);
view([90 90]) % this is to rotate the chart
textPositions_cell = get(hText,{'Position'});
textPositions = cell2mat(textPositions_cell);
textPositions(:,1) = textPositions(:,1) + 0.2; % replace 0.2 with any offset value you want
hText(1).Position = textPositions(1,:);
hText(2).Position = textPositions(2,:);
title('Distance between modes')
You can change only the text position (without rotation) by deleting view command.
I have written a code that reads an image and does scaling of 2 units in x-axis direction. Scaling matrix is filled by values that are read from a text file.
Scaling Matrix looks like
2 0 0
0 1 0
0 0 1
Original Image
Transformed Image (Scaling of 2 units in X-direction)
Code
file = importdata('transform_c.txt');
fileData = file.data;
image = imread('mecca06.pgm');
[row, col] = size(image);
scalingMatrix = zeros(3,3);
scalingMatrix(1,1) = fileData(2);
scalingMatrix(1,2) = fileData(3);
scalingMatrix(1,3) = fileData(4);
scalingMatrix(2,1) = fileData(5);
scalingMatrix(2,2) = fileData(6);
scalingMatrix(2,3) = fileData(7);
scalingMatrix(3,1) = fileData(8);
scalingMatrix(3,2) = fileData(9);
scalingMatrix(3,3) = fileData(10);
m1Inverse = inv(scalingMatrix);
outputImage = applyTransformation(image, row, col, m1Inverse);
figure
imshow(outputImage);
function outImage = applyTransformation(image, row, col, m1Inverse)
points = zeros(3,1);
for i=1:row
for j=1:col
points(1,1) = i;
points(2,1) = j;
points(3,1) = 1;
m2 = m1Inverse * points;
x = m2(1,1);
y = m2(2,1);
xlb = floor(x);
ylb = floor(y);
if(xlb <= 0)
xlb = 1;
end
if(xlb > row)
xlb = row;
end
if(ylb <= 0)
ylb = 1;
end
if(ylb > col)
ylb = col;
end
xub = xlb+1;
yub = ylb+1;
if(xub <= 0)
xub = 1;
end
if(xub > row)
xub = row;
end
if(yub <= 0)
yub = 1;
end
if(yub > col)
yub = col;
end
exub = xub-x;
eyub = yub-y;
exlb = x-xlb;
eylb = y-ylb;
outImage(i,j) = (exub*eyub*image(xlb,ylb))+(exlb*eyub*image(xub,ylb))+(exub*eylb*image(xlb,yub))+(exlb*eylb*image(xub,yub));
end
end
end
My question is how can i modify the above code to get uncropped image ?
I want to get following image
Try to see if this code produces the result you need:
img = imread('aSxLS.png');
scale = [
2 0 0
0 1 0
0 0 1
];
tform = maketform('affine',inv(scale));
img_tform = imtransform(img,tform,'bilinear');
figure();
imshow(img);
figure();
imshow(img_tform);
To calculate an enhancement function for an input image I have written the following piece of code:
Ig = rgb2gray(imread('test.png'));
N = numel(Ig);
meanTotal = mean2(Ig);
[row,cal] = size(Ig);
IgTransformed = Ig;
n = 3;
a = 1;
b = 1;
c = 1;
k = 1;
for ii=2:row-1
for jj=2:cal-1
window = Ig(ii-1:ii+1,jj-1:jj+1);
IgTransformed(ii,jj) = ((k*meanTotal)/(std2(window) + b))*abs(Ig(ii,jj)-c*mean2(window)) + mean2(window).^a;
end
end
How can I reduce the calculation time?
Obviously, one of the factors is the small window (3x3) that should be made in the loop each time.
Here you go -
Igd = double(Ig);
std2v = colfilt(Igd, [3 3], 'sliding', #std);
mean2v = conv2(Igd,ones(3),'same')/9;
Ig_out = uint8((k*meanTotal)./(std2v + b).*abs(Igd-cal*mean2v) + mean2v.^a);
This will change the boundary elements too, which if not desired could be set back to the original ones with few additional steps, like so -
Ig_out(:,[1 end]) = Ig(:,[1 end])
Ig_out([1 end],:) = Ig([1 end],:)
I have a problem that I can't seem to solve. I want a query to determine whether a given value lies within a predefined range, but my loop is very slow for big datasets. Is there a more efficient way?
clear all
close all
Regression(1,1) = 1.001415645694801;
Regression(1,2) = 0.043822386790753;
FF_Value(:,1) = [24.24 30.77 31.37 29.05 29.20 29.53 29.67 27.78];
FF_Value(:,2) = [24.16 30.54 31.15 29.53 29.39 29.34 29.53 28.17];
FF_Distance = FF_Value(:,2)-(Regression(1,2)+Regression(1,1)*FF_Value(:,1));
FF_Distance_Positiv = sort(FF_Distance(FF_Distance > 0));
FF_Distance_Positiv(FF_Distance_Positiv == 0) = [];
FF_Distance_Negativ = sort(FF_Distance(FF_Distance < 0),'descend');
FF_Distance_Negativ(FF_Distance_Negativ == 0) = [];
A = repmat(FF_Distance_Positiv,length(FF_Distance_Negativ),1);
B = repmat(FF_Distance_Negativ',length(FF_Distance_Positiv),1);
C = reshape(B,[length(FF_Distance_Positiv)*length(FF_Distance_Negativ),1]);
Recognition(:,1) = A;
Recognition(:,2) = C;
FF_Recognition = zeros(length(FF_Value),1);
for i = 1:length(Recognition)
for j = 1:length(FF_Value)
if (Regression(1,2)+Recognition(i,1))+Regression(1,1)*FF_Value(j,1) >= FF_Value(j,2) &&...
(Regression(1,2)+Recognition(i,2))+Regression(1,1)*FF_Value(j,1) <= FF_Value(j,2)
FF_Recognition(j,1) = 1;
end
end
end
Welcome to the world of bsxfun's replacing your world of repmats -
%------------ Original code -----------------------------------------
FF_Distance = FF_Value(:,2)-(Regression(1,2)+Regression(1,1)*FF_Value(:,1));
FF_Distance_Positiv = sort(FF_Distance(FF_Distance > 0));
FF_Distance_Positiv(FF_Distance_Positiv == 0) = [];
%// Note for Performance: If number of elements satisfying `FF_Distance_Positiv == 0`
%// is a lot, consider doing this instead -
%// `FF_Distance_Positiv = FF_Distance_Positiv(FF_Distance_Positiv~=0)`.
%// Follow this strategy for `FF_Distance_Negativ` too.
FF_Distance_Negativ = sort(FF_Distance(FF_Distance < 0),'descend');
FF_Distance_Negativ(FF_Distance_Negativ == 0) = [];
%------- Added vectorization replacing `repmats` and nested loops ------------
mult = Regression(1,1)*FF_Value(:,1);
y1 = bsxfun(#plus,Regression(1,2),FF_Distance_Positiv);
y2 = bsxfun(#plus,y1.',mult); %//'
mc1 = bsxfun(#ge,y2,FF_Value(:,2));
z1 = bsxfun(#plus,Regression(1,2),FF_Distance_Negativ);
z2 = bsxfun(#plus,z1.',mult); %//'
mc2 = bsxfun(#le,z2,FF_Value(:,2));
FF_Recognition = all([any(mc1,2) any(mc2,2)],2);