Effacer les filtres
Effacer les filtres

help with image processing code

3 vues (au cours des 30 derniers jours)
aaa le 11 Juil 2011
Hi, i am new to matlab and need some help with this
i have used imread to read in a jpg image. however the workspace reads this as a 3 dimensional matrix, e.g. 150x100x3 uint8
how can i change this to a 2 dimensional matrix? i believe i have to use a gray scale image to accomplish this, but i cant seem to get it to work.
i have:
a = imread('image.jpg')
b = gray(a);
secondly, how can i read in a bunch of images into matlab for processing? i.e. i want to read in 1.jpg, 2.jpg, 3.jpg into the workspace. I know I need a for loop ,but i can't quite put the code together using the imread syntax.
for i = 1:5
a(i) = imread(xxxxx.jpg);
thank you

Réponse acceptée

Walter Roberson
Walter Roberson le 11 Juil 2011
b = rgb2gray(a);
To read a bunch of images, please see this FAQ
  2 commentaires
aaa le 12 Juil 2011
i just have another question regarding the FAQ you have. it refers to the following code to read a bunch of jpgs in to matlab.
jpegFiles = dir('*.jpg');
numfiles = length(jpegFiles);
mydata = cell(1,numfiles);
%%Processing a sequence of files (matlab doc)
for k = 1:numfiles
mydata(k) = imread(jpegFiles(k).name);
my problem is that i get the error "conversion to cell from uint8 is not possible" however, the imread function makes all images into uint8, and my guess is that the above code wants a "double" format.
However, i cannot do this pre-processing if i don't have the images loaded in the first place, so it seems to be counter-intuitive. What can I do to bypass this?
Walter Roberson
Walter Roberson le 12 Juil 2011
mydata{k} = imread(jpegFiles(k).name);
Notice the {k} instead of (k)

Connectez-vous pour commenter.

Plus de réponses (1)

aaa le 11 Juil 2011
thanks for the quick reply, i read through the faq and tried this but i get the following error
In an assignment A(:) = B, the number of elements in A and B must be the same.
Error in ==> test at 11 b(i) = sprintf('%d.jpg',k(i));
my code looks like
for i = 1:3
b(i) = sprintf('%d.jpg',i);
c(i) = imread(b(i));
thank you
  1 commentaire
Image Analyst
Image Analyst le 11 Juil 2011
Try b{i} instead of b(i).

Connectez-vous pour commenter.


En savoir plus sur Convert Image Type dans Help Center et File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by