int* somme = new int[dmin-dmax];
int dispe[imax][jmax];

for (int i = 0; i < imax; ++i) {
    for (int j = 0; j < jmax; ++j) {
        for (int d = dmin; d < dmax; ++d) {
            int sum = 0;
            for (int wi = -3; wi <= 3; ++wi) {
                for (int wj = -3; wj <= 3; ++wj) {
                    sum += roba(mat1[i+wi][j+wj], mat2[i+wi][j+wj+d]);
                }
            }
            somme[d] = sum;
        }
        dispe[i][j] = min(somme);
    }
}