make a picture from excel file with MATLAB

hi all, i have excel file which in it, there is a shape of something that specify with numbers, i want to write a code in matlab that make a picture or plot of it , that in it all the cells with same values have a color that i choose, i.e in the picture below , matlab make a picture of a Rectangular, that all cells with value of "nan" be white, and all cells with a value of "20" be red an so on.

thanks so much.

Answer 1

[Joseph Cheng]

I would start by using the function xlsread() to read in the specified excel file and the range of where the image is create. Then using the == comparison you can then create the different color layers. example:

 [num txt raw] = xlsread(____,____)
 raw = cell2mat(raw);
 Img(:,:,1) = 20==raw | isnan(raw);
 Img(:,:,2) = 30==raw | isnan(raw);
 Img(:,:,3) = 40==raw | isnan(raw);

[baran]

thanks, is there any way to specify arbitrary color for each value, i mean all 20 be blue and so on. is the Img(:,:,1) mean specific color?

[baran]

i run this code, but there is something wrong . the error is :

Undefined function 'eq' for input arguments of type 'cell'.

Error in test (line 2)
Img(:,:,1) = {20}==raw | isnan(cell2mat(raw));

what i shoud do ?

[Joseph Cheng]

images are broken into 3 different color layers (RGB). combinations of values between 0 and 1 for each of the layers cause different colors. so i just gave an example of how you'd read it in and shoot it off to a colored image. If you run with it you'd see that all values 40 will be blue, 30's will be green and 20's be red.

[baran]

Excuse me, you mean it produce a image with just 3 colors? if i want to produce a image with so many colors , what should i do ? thanks a lot

[Joseph Cheng]

well what have you tried? you can work with colormaps to define colors like

IMG = raw;
IMG(isnan(IMG))=0;
numcolor = length(unique(IMG(:)));
colors = hsv(numcolor-1);
colors= [1 1 1;colors]; %set value of 0 to be white
imagesc(IMG)
colormap(colors)

[Nurfarrah Syazleen]

what if the image is grayscale ? is the command still the same?

Answer 2

[Shreya Shetty]

Get RGB components from previous excel sheet, display them and retreive original image

[file,Path]=uigetfile('*.xlsx','Select excel file of image matrix '); file=fullfile(Path,file); red=xlsread(file, 'A1:GR200'); green=xlsread(file, 'A201:GR400'); blue=xlsread(file, 'A401:GR600'); figuresubplot(3,2,1); imshow(red,[]); imwrite(uint8(red),'red.jpg'); t1=imread('red.jpg'); title('red channel') subplot(3,2,2); imshow(green,[]); imwrite(uint8(green),'green.jpg'); t2=imread('green.jpg'); title('green channel') subplot(3,2,3); imshow(blue,[]); imwrite(uint8(blue),'blue.jpg'); title('blue channel') t3=imread('blue.jpg'); subplot(3,2,5); im=cat(3, t1, t2, t3); imshow(im) title('retreived image')