After division i am getting 1 as the answer

editor:

f1=input('Enter a image name:','s');
a1=imread(f1);
c1=rgb2gray(imresize(a1,[3,9]))';
N=[208    16   235   255    44   229   236    34   247;...
    245    21   213   254    55   252   215    51   249;...
    248    22   225   252    30   240   242    27   244]';
N=N/256
c2=c1/256

Command window: Enter a image name:51.jpg

N =

    0.8125    0.9570    0.9688
    0.0625    0.0820    0.0859
    0.9180    0.8320    0.8789
    0.9961    0.9922    0.9844
    0.1719    0.2148    0.1172
    0.8945    0.9844    0.9375
    0.9219    0.8398    0.9453
    0.1328    0.1992    0.1055
    0.9648    0.9727    0.9531

c2 =

    1    1    1
    1    1    1
    1    1    1
    1    1    1
    1    1    1
    1    1    1
    1    1    1
    1    1    1
    1    1    1

>>

[Jan]

I've marked the code with the mouse and pressed the "{} Code" button to make the code readable. Please do this by your own in the future. Thanks.

Answer 1

[Image Analyst]

Cast c1 to double so that you're not doing an integer divide, but doing a floating point divide instead:

c2 = double(c1) / 256;

[Udit Jain]

Thanks for your help

Answer 2

[Jan]

What is your question? Does the result differ from your expectation? Then explain, what you expect instead, because the readers cannot guess this detail. Of course the code does exactly what it should.

a1 = imread(f1);
a2 = imresize(a1, [3,9]);
c1 = rgb2gray(a2)';

Check the contents of the variables:

class(a1)
class(a1)
class(c1)
a1(1, 1, :)
a2(1, 1, :)
c1(1)
c1(1) / 256

What do you see?

[Udit Jain]

c1 is a matrix with integers according to the reshape and N is a matrix with some integers. When N is divided by 256 it gives some decimal values while on dividing c1 by 256 it gives 1 as answer for all divisions.

class(a1)

ans =

uint8

>> class(a2)

ans =

uint8

>> class(c2)

ans =

uint8

>> a1(1, 1, :)

ans(:,:,1) =

255

ans(:,:,2) =

255

ans(:,:,3) =

255

>> a2(1, 1, :)

ans(:,:,1) =

254

ans(:,:,2) =

254

ans(:,:,3) =

254

>> c1(1)

ans =

254

>> c1(1) / 256

ans =

    1

>>