MATLAB Central Newsreader Recent Posts

Re: ? cal the length and area of contours

Cheng Cosine — Sat, 18 May 2013 13:03:26 +0000

Nasser M. Abbasi於 2013年5月18日星期六UTC+8下午6時54分46秒寫道：
> On 5/18/2013 5:36 AM, Cheng Cosine wrote:
>
> > Hi:
>
> >
>
> > One can use contour() to plot contours. But how does one calculate the
>
> > length and area of a contour?
>
> >
>
> > Thanks,
>
> >
>
>
>
>
>
> From help:
>
>
>
> ---------------
>
> load penny;
>
> figure;
>
> contour(flipud(P));
>
> axis square;
>
> ------------------
>
>
>
> So, looking at the above. what length and what area are you
>
> refering to?
>
>
>
> one contour line represent the same value in the data.
>
>
>
> So, I am not even sure what measure of length you
>
> are taking about, and what area you want, since
>
> these lines can all change depending on how many
>
> contour lines you want. If you ask for 2 lines,
>
> you'll get different shapes.
>
>
>
> May be if you explain what is it you are trying to do,
>
> someone might have better suggestion.
>
>
>
> --Nasser

The data file you referred to is too complicated. A single value corresponds
to more than one contours.

Suppose we have a "clean" circular disk and on it we have different contours.

A single value corresponds to a single contour. To be specific, those contours

are closed and concentric circular curves.

If we know the radius of a contour, we can compute its circular length as 2*pi*r and area as pi*( r_outer^2-r_inner^2 ).

What I aksed for were to compute the perimeter and area when the target contour is not a simply cicle or ellipse.

Cocktail Party Problem

Silvia — Sat, 18 May 2013 12:30:10 +0000

Hi Guys,

Any body can tell me where I can find a complete Matlab code that deals with the cocktail party problem using TITO (Two-Inputs Two-Outputs) subband BSS (Blind Source Separation), i.e. using subband filters bank.

Thanks
Silvia

Re: ? cal the length and area of contours

Bruno Luong — Sat, 18 May 2013 12:09:13 +0000

Cheng Cosine <asecant@gmail.com> wrote in message <a100acf9-b4a8-47b8-9b2d-fd49d3f0af2c@googlegroups.com>...
> Hi:
>
> One can use contour() to plot contours. But how does one calculate the
> length and area of a contour?

Use syntax [c h] = contour(...) to retrieve the contour polygons. Then you can compute the length by summing the lengths of the edges, and use polyarea() to compute the surface.

Bruno

set the original phase in Simulink

Mario — Sat, 18 May 2013 11:30:13 +0000

Hi,

I want to know if there is any block or function in simulink with which I can recover the original phase of the signal.

By that I avoid the phase offset before to a QAM demodulator, and get the received constellation has the same phase as the signal sent.

thanks.

Re: Handover simulation in 4G networks

amirjafary@gmail.com — Sat, 18 May 2013 11:18:56 +0000

2LPZhNin2YUgCtix2YjYstiq2YjZhiDYqNiu24zYsQrYqNio2K7YtNuM2K8g2YXbjNiu2YjYp9iz
2KrZhSDYqNio24zZhtmFINio2KfZhNin2K7YsdmHINiq2YjZhtiz2KrbjNivINiq2KfYrtuM2LEg
2Ygg2KfbjNmGINmH2Kcg2LHYpyDYtNio24zZhyDYs9in2LLbjCDaqdmG24zYr9ifINqG2q/ZiNmG
2Ycg2KfbjNmGINqp2KfYsSDYsdinINin2YbYrNin2YUg2K/Yp9iv24zYr9ifCtii2K7ZhyDZhdmG
2YUg2YXZiNi22YjYudmFINiv2LEg2YfZhduM2YYg2LLZhduM2YbZhyDYp9iz2Kog2Ygg2KjZhyDY
tNio24zZhyDYs9in2LLbjCDZhtuM2KfYsiDYr9in2LHZhQ==

Re: EPS bounding box problem

Hermano Cappa — Sat, 18 May 2013 10:56:09 +0000

"Hermano Cappa" wrote in message <kn7lko$22t$1@newscl01ah.mathworks.com>...
> Hi,
>
> When I save a polar plot in Matlab as an EPS file for use in Latex with "Matlabfrag" or "Save as" the bounding box around the outer border (cricle) of my polar plot is partially removed at 0, 90, 180 and 270 degrees.
>
> You can see my polar plot at:
> http://www.xeryon.be/matlab/synchr_vs_asynchr.eps
>
> I think this problem is related with the bounding box of my EPS file. How can I make this bigger?

I was forgot to mention that the polar plot is generated with the "mmpolar" function from the file exchange.

Re: ? cal the length and area of contours

Nasser M. Abbasi — Sat, 18 May 2013 10:54:46 +0000

On 5/18/2013 5:36 AM, Cheng Cosine wrote:
> Hi:
>
> One can use contour() to plot contours. But how does one calculate the
> length and area of a contour?
>
> Thanks,
>

From help:

---------------
load penny;
figure;
contour(flipud(P));
axis square;
------------------

So, looking at the above. what length and what area are you
refering to?

one contour line represent the same value in the data.

So, I am not even sure what measure of length you
are taking about, and what area you want, since
these lines can all change depending on how many
contour lines you want. If you ask for 2 lines,
you'll get different shapes.

May be if you explain what is it you are trying to do,
someone might have better suggestion.

--Nasser

EPS bounding box problem

Hermano Cappa — Sat, 18 May 2013 10:37:12 +0000

Hi,

When I save a polar plot in Matlab as an EPS file for use in Latex with "Matlabfrag" or "Save as" the bounding box around the outer border (cricle) of my polar plot is partially removed at 0, 90, 180 and 270 degrees.

You can see my polar plot at:
http://www.xeryon.be/matlab/synchr_vs_asynchr.eps

I think this problem is related with the bounding box of my EPS file. How can I make this bigger?

? cal the length and area of contours

Cheng Cosine — Sat, 18 May 2013 10:36:24 +0000

Hi:

One can use contour() to plot contours. But how does one calculate the
length and area of a contour?

Thanks,

Re: Face Detection with Adaboost using Matlab

rishabhbansal.2011@gmail.com — Sat, 18 May 2013 07:00:55 +0000

On Monday, January 14, 2008 7:48:36 PM UTC+5:30, nabilah...@gmail.com wrote:
> i need the codes for training in facial detection using adaboost.if
> you can help me,please send them through my email.i have a project
> base on this facial detection using adaboost.please help me.thank you
> very much

for adaboost face detection code contact me @my mail id: rishabhbansal.2011@gmail.com

error message

kavi — Sat, 18 May 2013 06:43:13 +0000

P = '..\file\test24.dat';
R = importdata(P);
S = R.I; %I means a vatiable which stored an images in .dat file
.
.
.
E = importdata(n);
       Y = E.I;

        I3 = imsubtract(S,Y);
        imshow(I3);

IT SHOWS THIS ERROR MESSAGE:

Error in ==> mmm at 17
        I3 = imsubtract(S,E);

??? Attempt to reference field of non-structure array.
How can I solve this problem????
Thank you.
Error in ==> mmm at 14
       Y = E.I;

image subtraction

kavi — Sat, 18 May 2013 05:24:09 +0000

Hi,
I stored images in .dat file and I want to compare those two images.But it; not working properly.
This is my code:

Z = '..\file\test20.dat';
U = '..\file\test21.dat';

E = importdata(Z);
F = importdata(U);

X= E.I; %I is a variable that store image
Y= F.I;

I2 = imsubtract(X,Y);
disp(I2);

It gives these error message:
Error in ==> imlincomb at 87
Z = imlincombc(images, scalars, outputClass);

Error in ==> imsubtract at 63
Z = imlincomb(1.0, X, -1.0, Y, 'double');

Error in ==> diff_img at 96
I2 = imsubtract(X,Y);

Can somebody help me to solve this problem..

Thank you.

image subtraction

kavi — Sat, 18 May 2013 05:15:10 +0000

Hi,
I am doing licence plate recognition system. I stored extracted images in .dat file and I want to compare those stored images by subtracting but those image's matrices are not in same size so it's hard do compare.anyone can help me to solve this problem.....
thank you...

modbus protocol help

BHARAT — Sat, 18 May 2013 04:26:07 +0000

I want to communicate a PLC with a simulation.
I want to send data from simulation via serial port and receive at PLC. And PLC can accept data send on serial port via MODBUS protocol.
I would like to know how can I send data on MODBUS protocol from SIMULINK via serial communication tools?

image compression

sushma sethi — Sat, 18 May 2013 03:34:12 +0000

hi
i need to compress an image using Self organizing map, but i do not know how to input the image in som network and how to train the network for compressing the image.
please help