Line Matrix code in Matlab - matlab

function [fl re]=lines(im_text)
%# Divide text in lines
im_text=clip(im_text);
num_filas=size(im_text,1);
for s=1:num_filas
if sum(im_text(s,:))==0
nm=im_text(1:s-1, :); %# First line matrix
rm=im_text(s:end, :);%# Remain line matrix
fl = clip(nm);
re=clip(rm);
%#result
break
else
fl=im_text;%#Only one line.
re=[ ];
end
end
function img_out=clip(img_in)
[f c]=find(img_in);
img_out=img_in(min(f):max(f),min(c):max(c));%#Crops image
Can anyone please provide with an explanantion of this code and how i can summarise it
and simplify it without changing the function its performs? How i can implement same algorithm without making it a function on its own. adding this to another code.
thanks

The function takes a binary image, then looks for a row in the image with no object (i.e. only black pixels), and splits the image along this line. In addition, it crops off all the empty (i.e. black) area around the objects in the subfunction clip.
You can simplify it to
cutRowIdx = find(all(~im_text,2),1,'first');
topPart = clip(im_text(1:cutRowIdx-1,:));
bottomPart = clip(im_text(cutRowIdx:end,:));
Put clip as a subfunction into your function, or make it into a standalone function and put it into your path.

Related

Matlab: Color of legend doesn't fit plot

I am writing a script, which imports several sample files. Afterwards it calculates ratios of different elements and save them in a double-array. I am plotting the first column of this file for all the sample files into one plot. Which is working well. But the legends causes trouble. I want, that it includes the filenames of the sample files. But the color of the legend doesnt fit. I give you here parts of my code. Because I think the calculations are not interesting for you.
directory_name=uigetdir('','Ordner mit Messungen auswählen');
[nur_file_name,pfad]=uigetfile({'*.csv','csv-files (*.csv)';'*.*','all Files'},...
'Die csv-Files der Proben oeffnen (probe_001.csv=',[directory_name '/'], 'Multiselect', 'on');
nur_file_name=cellstr(nur_file_name);
nur_file_name=sort(nur_file_name);
filename=strcat(pfad,nur_file_name);
anzahl_files=size(filename,2);
for xy=1:anzahl_files
fid_in=fopen(char(filename(xy)),'r');
This part above import several files and saves the filename. To handle the filename easier, I changed it to a string array (1 x number of files) with the name filename_s.
Now I do some calculations (shown below). In the end I have for all measurement files a double array called "Ratio". I try to plot it with the legend includig the filenames:
tmpImport = importdata(filename{xy},',');
element_RL = tmpImport.colheaders;
element_RL=string(element_RL);
intens_RL=tmpImport.data;
[anzahl_runs,anzahl_elemente]=size(intens_RL);
for k=1:anzahl_elemente
Background(k)=mean(intens_RL(:,k)); %
Sigma(k)=std(intens_RL(:,k));
end
SP_limit=Background+(4*Sigma);
[~, PosSr87] = ismember('87Sr+', element_RL);
SpalteSr87(:,1)=intens_RL(:,PosSr87);
[~, PosSr86] = ismember('86Sr+', element_RL);
SpalteSr86(:,1)=intens_RL(:,PosSr86);
is_SP = intens_RL > SP_limit;
intens_RL(is_SP)=1;
intens_RL(~is_SP)=0;
anzahl_runs1=size(intens_RL,1);
id = true(anzahl_runs1,1) ;
for k=1:anzahl_runs1
if any (intens_RL(k,:)==1)
Ratio(k,1)=SpalteSr87(k,:)/SpalteSr86(k,:);
id(k) = 0 ;
end
end
filename_s = matlab.lang.makeValidName(nur_file_name);
filename_s=string(nur_file_name);
%Plot:
[NumRows1 NumCols1]=size(Ratio);
figure(1)
title('Proben 87Sr/86Sr');
xlabel('Partikel');
ylabel('87Sr/86Sr');
for p=1:anzahl_files
h(p)= scatter(1:NumRows1, Ratio(:,1));
legendtext{p} = filename_s(1,p);
hold on
end
legend(h, legendtext)
end
Plot works, filenames in the legend works but the colours are not fitting. Please be aware that i delete some parts of the code, so some for loops makes sense if there is more ;-). I appreciate any help. Thank you really much. And please forgive if something is not the right term, I dont work with matlab so long.

Matlab draw line with plot and dynamic values

I am trying to draw line with plot in matlab app designer. But i dont know how to create line. I am just redrawing point on new coordinates.
This is my code (functions runs each second) (format of plot is plot(PlotUI,X,Y))
function function2(app)
app.timeCounter = app.timeCounter + 1;
plot(app.UIAxes,app.timeCounter,app.newValDblPublic);
end
I will be thankful for any help.
At the moment you are just plotting the current set of values, if you want to plot the historic values too, you need to keep them in an array and plot the entire array.
%When the GUI is first created, start with one value in the array
app.time_values = [0];
app.y_values = [0];
%Inside your function
function function2(app)
app.time_values(end+1) = app.time_values(end)+1; % Add a new value to the array, 1 greater than the last value
app.y_values(end+1) = app.newValDblPublic;
plot(app.UIAxes,app.time_values,app.y_values);
end

Plotting brownian motion matlab

First of all, I just want to say that I'm not that used to using matlab, but I need for an assignment, I'm supposed to create a "brownian movement". My code is currently looking like this:
clf
hold on
prompt = 'Ge ett input';
size = input(prompt) ;
numParticles = input('Ange antal partiklar');
axis([-size size -size size]);
Part = [];
color = 'brkgmyco';
for i = drange(1:numParticles)
Part = [Part [0;0]];
end
for i = drange(1:200)
dxdy = randn(2,numParticles);
k = Part
Part = Part + dxdy;
My concern is how to print, I would even want like a small delay on every print, so you really can see what's happening for the assignment, is this possible to achieve from the code I've written for now or should anything be changed? Thanks in advance!
Here are some basic problems with your code, regardless of what you are trying to do:
You use size as a variable name. Doing so overrides MATLAB's function size.
The function zeros creates an array initialized by zeros, no need for a loop for that.
Instead of calculating randn for 200 times in a loop, you can do it once, with dxdy = randn(2,numParticles,200) and then simply refer to dxdy(:,:,i) within the loop.
The same holds for summation. Instead of summing within a loop to get the cumulative sum, use cumsum like Part = cumsum(randn(2,numParticles,200),3); and then refer to Part(:,:,i), within the loop.
Now to your task. You said you want to know how to print, but I believe you want to plot because you use some commands like axis, clf and hold, that refer to graphic objects. However, you never really do plot anything.
The basic and general function for plotting in 2D is plot, but there are many other more specific functions. One of them is scatter, and it has a sister function gscatter, that takes triples of x, y and groupand plot each (x(k),y(k)) colored by their group(k).
This code plots the particles on an axes, and animate their movement:
prompt = 'Ge ett input';
scope = input(prompt) ;
numParticles = input('Ange antal partiklar');
N = 500;
Part = cumsum(randn(2,numParticles,N)*scope/100,3);
h = gscatter(Part(1,:,1),Part(2,:,1),1:numParticles);
axis([-scope scope -scope scope]);
legend off
for k = 2:N
for p = 1:numParticles
h(p).XData = Part(1,p,k);
h(p).YData = Part(2,p,k);
end
drawnow
end
Is this what you look for?

Directional Derivatives of a Matrix

I have 40 structures in my Workspace. I Need to write a script to calculate the directional derivatives of all the elements. Here is the code :
[dx,dy] = gradient(Structure_element_1.value);
dxlb = min(min(dx));
dxub = max(max(dx));
dylb = min(min(dy));
dyub = max(max(dy));
[ddx,ddy] = gradient(gradient(Structure_element_1.value));
ddxlb = min(min(ddx));
ddxub = max(max(ddx));
ddylb = min(min(ddy));
ddyub = max(max(ddy));
This is the code for one element. I Need to find out the same for all the 40 elements and then use it later. Can anyone help with this.
To answer your literal question, you should store the variables in a structure array or at least a cell array. If all of your structures have the same fields, you can access all of them by indexing a single array variable, say Structure_element:
for i = 1:numel(Structure_element)
field = Structure_element(i).value
% compute gradients of field
end
Now to address the issue of the actual gradient computation. The gradient function computes an approximation for , where is your matrix of data. Normally, a MATLAB function is aware of how many output arguments are requested. When you call gradient(gradient(F)), the outer gradient is called on the first output of the inner gradient call. This means that you are currently getting an approximation for .
I suspect that you are really trying to get . To do this, you have to get both outputs from the inner call to gradient, pass them separately to the
outer call, and choose the correct output:
[dx,dy] = gradient(F);
[ddx, ~] = gradient(dx);
[~, ddy] = gradient(dy);
Note the separated calls. The tilde was introduced as a way to ignore function arguments in MATLAB Release 2009b. If you have an older version, just use an actual variable named junk or something like that.

Repeating trials in MatLab

i'm am very new to Matlab but really want improve. For my experiment i want to show a picture which the participant response yes/no to, using two different keys (f&g) and then the next picture is presented and it repeats so onward.
Presenting the picture, using the keys works for far, but i can't get it to repeat the trial. Thus my question is how can i get the program to repeat/loop my trial?
Is there something wrong in my code so far or is there additional coding i should use?
this is my code so far
function try1_6()
cleanupObj= onCleanup(#() myCleanupFxn);
% PRETEST
% Initialize screen with black background
winID = Screen('openWindow',0, [0 0 0]);
%Parameter
backcol=255;
textcol=0;
% Load image file(s)
structimages= [];
TheImagesdir = dir('theImagesdir/*.jpg');
for i=1: length(TheImagesdir);
TheImages = imread(['theImagesdir/' TheImagesdir(i).name], 'JPEG');
% Get width and height
imageX = size(TheImages,2);
imageY = size(TheImages,1);
% Convert to texture
myTexture = Screen('MakeTexture', winID, TheImages);
% Set destination rectangle
destRect = [50 100 50+imageX 100+imageY];
%save to structure
structimages(end+1).filename=TheImagesdir(i).name;
structimages(end).destRect= destRect;
structimages(end).texture= myTexture;
end
%Make triallist
numberOfItems= [5]; %list of all possible items
Nrepeats=4;
Response=0;
TrialList=HH_mkTrialList({numberOfItems Response},Nrepeats);
%PRESENTATION
for trialnum=1:size(TrialList,1)
nitems = TrialList(trialnum,1);
Screen('FillRect', winID,backcol); % makes the screen blank
%displays text
DrawFormattedText(winID,'dkjfghaslkdfglksdjgfh','center','center',textcol);
Screen('Flip', winID)
HH_waitForKeyPress({'space'}); % waits for spacebar to be pressed
Screen('FillRect',winID,backcol);
Screen('Flip',winID);
WaitSecs(1);
%display picture
whichTheImages= randi(length(TheImagesdir)); % randomly selects image for directory
Screen('FillRect',winID,backcol);
Screen('DrawTexture', winID, myTexture, [], destRect);
Screen('Flip', winID);
HH_waitForKeyPress({'f','j'},5)
if resp==-1
break
end
TrialList(trialnum,4)= response; %records response
end
end
function myCleanupFxn()
Screen('CloseAll')
end
There are a number of problems with you code that you need to address. First of all, TrialList is used before it is declared/initialized. The Make triallist block of code seems out of place in the body of the for loop, and should probably be placed before you loop TrialList.
Your second problem is the inner for loop that loads images. Right now, it loads every image found in the directory, on every trial! There is no reason for you to be doing this, and you should be placing this for loop outside the trial loop as well. Furthermore, your original code never worked as intended, because you never save the loaded texture anywhere; myTexture is overwritten by the last image in your folder and that's the only texture you're ever gonna get. So in addition to pre-loading the images before the loop, you need to save them in a data structure so that you can use them later in your trial loop. A simple struct will work nicely here:
structImages = [];
TheImagesdir = dir('theImagesdir/*.jpg');
for i = 1:length(TheImagesdir);
TheImages = imread(['theImagesdir/' TheImagesdir(i).name], 'JPEG');
% Get width and height
imageX = size(TheImages,2);
imageY = size(TheImages,1);
% Convert to texture
myTexture = Screen('MakeTexture', winID, TheImages);
% Set destination rectangle
destRect = [50 100 50+imageX 100+imageY];
%save to structure
structImages(end+1).filename = TheImagesdir(i).name;
structImages(end).destRect = destRect;
structImages(end).texture = myTexture;
end
There are other inconsistencies in your code:
whichTheIamges is defined but not used
resp is used in the comparison if resp==-1 but is not defined
response is saved into TrialList before it is defined
Finally, the biggest problem is Screen('CloseAll', winID); is inside the trial loop, so you tear down your whole presentation platform after the first trial.
FYI, as noted in my comment wrapping your entire script in a try block is really poor practice. I suspect you do this because you want to be able to Ctrl+C mid-task, but there's a better way to do this. If you make your entire script a function then you can use the onCleanup method to execute code whenever your function exits (whether normally, by error, or by interruption). The method goes like this:
function myScript()
%//make your script a function. There is an additional advantages to doing this:
%//function performance is better than script performance.
%//blah-blah-blah
%//setup the cleanup object before opening screen
cleanupObj = onCleanup(#() myCleanupFxn);
%//open the screen
winID = Screen('openWindow',0, [0 0 0]);
%//blah-blah-blah
end
function myCleanupFxn()
%//local function, not visible outside of this file
Screen('CloseAll');
end