Image with Box and X

$$xbox(i,j) = I_{[i=n/4,\;3n/4,\;j;~ n/4 \leq j \leq 3n/4]} + I_{[n/4 \leq i \leq 3n/4;~ j=n/4,\;3n/4,\;i]}$$

data(xbox)

Format

A 128 \(\times\) 128 matrix.

Source

S+WAVELETS.

References

Bruce, A., and H.-Y. Gao (1996) Applied Wavelet Analysis with S-PLUS, Springer: New York.