Subscripted assignment dimension mismatch. Error in computeHOGFeatures

Hello

I want to extract and store HOG features in a matrix but when i run the code i get this error. I know my images are of different sizes and every time the matrix sizes changes that stores the features but i dont know how to resolve this problem.

Subscripted assignment dimension mismatch. Error in computeHOGFeatures

featureRow=1;
HOGfeat=extractHOGFeatures(img);
                       hogFeatures(featureRow,:)=[HOGfeat,lb];
                       featureRow=featureRow+1;