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Joseph Cheng


Last seen: 1 dag ago
648 total contributions since 2014

Systems Engineer for Electro-Optical Systems

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Answered
How to make the length/dimension of 6 different 3D vectors the same?
probably the easiest way is to fill a zero array created to be the same max size then populate the indexes with the values: var...

1 dag ago | 1

| accepted

Answered
Extract pixel values inside a Binary Mask
since you already created a binary mask you can just index multiply " .* " the mask with the original image as outside is 0 and...

1 dag ago | 0

Answered
how to color and label only certain histogram bars?
Here is an example for @Adam Danz said with using bar y = randn(100); [N X]=hist(y(:),10); %plot all the data figure,clf,hb...

3 dagen ago | 1

Answered
Looking for a matlab script that extracts data from a plot figure ( here 2D contours from Covariance matrix or Markov chains) and reproduce the original figure
your graph is a bit messy with text and lines that denote items. here is a quick example that may push you along. It'll need a...

3 dagen ago | 0

| accepted

Answered
Scientific notation at y-axis with yticks/yticklabels
from the looks of it the desired state is also plotting in a log10. you can change the current axis by set(gca,'yscale','log'...

4 dagen ago | 0

| accepted

Answered
Find the indices of the imaginary element of the matrix
you can do a comparison to the real(A) like A=[1 2 3; 4+i 5 6-i; 7 8+i 9] [row col]=find(A~=real(A)) ...

4 dagen ago | 0

Answered
How to make the code efficient?
You can do things all at once cine you're not dependent on previous values. n=4 x=[0:n-1]; y=[0:n-1]; k = 0; %%Orig_code ...

4 dagen ago | 0

Answered
Double sigma with exception case
in your nested forloop you can put a check in for if j==i then continue. you do have a check up there with i~=j which should w...

4 dagen ago | 0

| accepted

Answered
Remove shadow and unwanted background
to get your started you can see that the tissue and the shadow area have similar values in all the color channels. you can do a...

5 dagen ago | 0

Answered
How do I plot the upper view of a matrix and represent the intensity color?
Here is an example of what i'm thinking you're doing. Not sure what you're doing with the weighted average but i think i did so...

8 dagen ago | 1

| accepted

Answered
How to vertically and horizontally scan an image to store a coordinates (positions) of the elements having values other than 255.
do you need to "scan" in a for loop or are you just looking for the positions of the colors? if you don't need to scan in a for...

9 dagen ago | 0

Answered
How to plot an equation qith specific data range?
For this you can use the function ylim() clc clear x=0:5:100; y=3*x+10; y1=4*x+5; plot(x,y) hold on plot(x,y1) ylim([25...

10 dagen ago | 0

Answered
How to include function in legend
do you need to use latex as just using the default tex? as latex uses $ for markup of symbols i don't know if it'll take the sy...

10 dagen ago | 1

Answered
Having trouble with looping through fields in a struct
primarily its because of the data.t = zeros(length(list)); data.p = zeros(length(list)); where you've set the t and p to be ...

10 dagen ago | 0

Answered
how to add a label to a contourf plot next to colourbar?
you can set a ylabel by passing the colorbar handles into ylabel [X,Y] = meshgrid(1:12,1:24); Z = sin(X) + cos(Y); figure(1),...

10 dagen ago | 1

| accepted

Answered
Plotting streamlines from a dataset (x,y,u,v)
So, meshgrid generates a grid of x and grid of y values so index wise you get the xy pair-combo. usually very useful when you're...

10 dagen ago | 1

| accepted

Answered
Change variables in for loop
That is because you're evaluating a string in that inpoly and not the variable x_e#... ideally you wouldn't want to do the evalu...

11 dagen ago | 0

| accepted

Answered
hello everyone. How to make the direction of points drawn on Cartesian coordinate system consistent with that drawn on binary image.
in a displayed image (0,0) is top left corner but cartesian is bottem left if in the ++ quadrant. so remedy this you can set th...

11 dagen ago | 0

| accepted

Answered
Help sketching equation into 3d graph
what you'll need to do is use the function meshgrid() which will then create a 2D matrix for both x and y such that you can get ...

11 dagen ago | 1

Answered
Bars disappear with log scale
While not ideal this should get you by since bar tries to plot the bar all the way to 0 which log scales don't show y=randi(100...

11 dagen ago | 0

Answered
pre-define a struct/array of structs in attempt to get rid of out of memory error.
the pre-allocation can be done (though can't really find the right way ultimateR = []; temp = struct('name',[],'size',[],'resu...

11 dagen ago | 0

Solved


Implement simple rotation cypher
If given a letter from the set: [abc...xyz] and a shift, implement a shift cypher. Example: 'abc' with a shi...

8 maanden ago

Answered
Using get and set command to add a title, xlabel, and ylabel?
You can take a look by first extracting out the current axis or assign it to a variable: figure(1),imagesc(randi(10,10,10)) ha...

9 maanden ago | 0

| accepted

Answered
HDFread and hdfinfo on modis data
Answer to this after brute forcing looking at all named values. attributes that should have been pulled from just reading in si...

ongeveer een jaar ago | 0

| accepted

Question


HDFread and hdfinfo on modis data
I appear to be missing some fundamental understanding of hdfread and hdfinfo for MODIS hdf data files (note not hdf5 files). ...

ongeveer een jaar ago | 1 answer | 0

1

answer

Answered
Two-dimensional colormap
I'm puzzeled by your first portion and the need for a for loop. unless you have a hold somewhere the images shouldn't be stackin...

meer dan een jaar ago | 1

| accepted

Answered
how to know if a char vector contains unwanted characters?
check out the function ismember here is snippet of test code x=["0","1","2","3","4","5","6","7","8","9","."]; y = ["3","3","5"...

meer dan een jaar ago | 0

Answered
How can I splitt up a big matrix into smaller matrises, splitting it up by values on the x-axis
so the main question is whether the ranges for the smaller matrixes are known or need to be detectable. then you can use a for ...

meer dan een jaar ago | 0

| accepted

Answered
How can I convert a YCbCr image to 4:2:0
while you're probably not going to implement this in simulink but take a look at https://www.mathworks.com/help/vision/ref/chrom...

meer dan een jaar ago | 0

Answered
How to plot a region in a Matlab plot?
here is quick example of what you can do by putting the regions as an image under the plots: %gen xy spans temps=0:.1:100; ...

meer dan een jaar ago | 0

| accepted

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