Before the start of first for loop add the following line.
Save image as mat.
Once you have it in matlab as an array you use the save command to save it as mat file as follows.
Saves the specified image acquisition objects obj1 obj2 etc to the mat file filename.
This option is not valid for simulink block diagrams.
Save filename obj1 obj2 is the functional form of the command where the file name and image acquisition objects must be specified as character vectors.
To calculate for all images and save them write your code as follows.
Bitmap image file format specify the format as one of the bitmap image options in the table bitmap image formats.
Also you are also calculating hog feature for the last image.
However when working with actual images use the imwrite function instead.
Use the saveas function to save matlab objects such as plots.
If no objects are specified then all variables existing in the matlab workspace are saved.
You may have to create one or two loops to automate the filename and image name start number creation.
Save filename obj1 obj2.
M or mfig save the figure as a matlab figure file and additionally create a matlab file that opens the figure.
The imwrite function works essentially the same way that saveas does but it works directly with image files.
Filename for mat file save filename img names save to file i tested only the first two lines for img str and img names so i leave the rest for you to experiment with.
In your code the matrix you want to save is x not j.