image processing - Matlab-how can I use SSIM function using sprintf function -

now i'm researching on image processing interpolation. invented new interpolation algorithms image.

and have check ssim value images interpolated interpolation algorithms.

now i'm using icy tool (on windows, gui environment) tool hard check large amount of images because of gui interface.

so want check image ssim value using matlab ssim function.

but i'm not expert in matlab language, i'm in trouble in dealing import various name ssim function.

this want do:

1. i want checks ssim value large amount of images.
2. so i'm going use sprintf function make valuable image name.
3. the third want import input image name ssim function.

this code used.

for n= 1 : 10 str = sprintf('./x2/cutted/x2_fn%d_4p_3p_cutted.bmp',n); str_ori = sprintf('ori_%d.bmp',n);  img_cutted=imread(str); img_ori=(str_ori);  [ssimval,ssimmap]=ssim(str,str_ori); end 

when use code, error invoked.

error: str must types of uint8, uint16, int16, single, double. used char value.

after got message, write "uint8 str;" still message invoked.

ssim gets 2 images input, not 2 strings. replace code [ssimval,ssimmap]=ssim(img,img_ori);