PURPOSE: To quickly decide whether or not a call-originated binary input image is an empty page by deciding whether or not a more than a prescribed number of areas exceed a size threshold value.

CONSTITUTION: An input image is reduced by the low threshold value, linkage configuration elements (eight-linkage or four-linkage) are discriminated, and the threshold value is analyzed. That is, the scanned image is reduced 50 and the ON image elements of the scanning lines (10 scanning lines by 16X reduction) being the 160 high-order ones (optional 160 low-order ones) as an actual size are masked 52 regardless of contents. That is, they are removed. Then, it is supposed that the ON image elements exist or supposed that a step 55 is not executed so that information concerning the number and the size of the linkage configuration elements is collected 57. Moreover, linkage configuration element information is analyzed, various kinds of attributes are compared 60 with one or more threshold values and the page is judged to be null unless the whole respective attributes exceed the threshold values.