Comments on: Indexed Assignment

By: shasrin

shasrin — Thu, 11 Oct 2007 02:39:58 +0000

Hi, I want to know how to perform the arithmetic operation for two image? I have a problem for two image with different size.I really want to know is anyone has a sample coding for that?Plz…help me to find this kind of solution…tq

By: Daniel Armyr

Daniel Armyr — Wed, 12 Sep 2007 14:54:28 +0000

jai: How about you take a look at the Matlab file-exchange. There are loads of files there that do all sorts of things. If someone else has wanted to do that particular thing, there will probably be a script.

On the other hand, maybe you should consider doing your own homework. This sounds very much like you are planning to plagiarize someone else’s work and hand it is as your own.

–DA

By: jai

jai — Sat, 08 Sep 2007 12:18:38 +0000

is there any command to differentiate plastic and paper using the image captured by matlab 7.0 and normal web-camera…plz help

By: jai

jai — Sat, 08 Sep 2007 12:15:56 +0000

Hai guys,
i am currently doing final year project using vision system. my project have to differentiate plastic and paper. I am using normal web-cam to capture the images.The programme that i am using is matlab version 7.0. I am now searching on how to differentiate it. Is there any commands in matlab that can help me in differentiating this two materials. I really want to know if there is any. Please if anyone know do help me.
Thank you

By: Jayathissa K.E.I

Jayathissa K.E.I — Sat, 08 Sep 2007 09:38:48 +0000

we want to more example.

By: Daniel Armyr

Daniel Armyr — Thu, 07 Jun 2007 08:33:46 +0000

I would have to join the group saying Matlab should complain a bit more when it comes to type conversions. Every now and then I have numbers in integer types and I want to keep them that way. However, Matlab tends to like to make them doubles every now and then and tracking down where it happens can be a pain.

However, in the philosophy that Matlab should be math and not programming, I would have to say that warnings are sufficient. Calling it an error would be way overkill.

By: Steve

Steve — Wed, 06 Jun 2007 15:45:03 +0000

Wes,

There’s a page in the MATLAB documentation that discusses concatenation of different data types:

http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/access/helpdesk/help/techdoc/matlab_prog/f1-84864.html

This is from the documentation for MATLAB 7.4 (R2007a) but I don’t believe this behavior has changed recently. The priority list you posted agrees with what’s in the documentation. This page also discusses the integer casting warning.

By: Urs (us) Schwarz

Urs (us) Schwarz — Wed, 06 Jun 2007 12:40:20 +0000

SNIP misunderstanding
x=[false,true,false];
x(1)=2;
% x = 1 1 0
I think Matlab should complain when I run x(1) = 2…

not at all; the help clearly says:
…
Any non-zero real element of input array X is converted to a logical 1 while zeros in X become logical 0.
…
which makes a lot of sense, by the way…
us
sorry, first reply got screwed up

By: Urs (us) Schwarz

Urs (us) Schwarz — Wed, 06 Jun 2007 12:39:13 +0000

Any non-zero real element of input array X is converted to a logical 1 while zeros in X become logical 0.

which makes a lot of sense, by the way…
us

By: Wes Campaigne

Wes Campaigne — Wed, 06 Jun 2007 04:57:12 +0000

How does cat choose the ‘dominant’ class, i.e., the class of its return value?

A quick experiment with the basic types seems to reveal a descending priority of:
char
integer types (if there are multiple different integer-typed operands, the type of the left-most of these is dominant)
single
double
logical

Appropriate warnings are given most of the time, but truncation of floats to char doesn’t throw any. And promotion of one integer type (or logicals) to a bigger integer type DOES throw a warning, even though it’s unnecessary.

Is there a particular reasoning behind all this behaviour? I haven’t noticed it documented anywhere.