In　order　to　overcome　the　shortages　of　current　checking　methods　based　on　optical　eyes　or　analog　video,　a　novel　intelligent　page　checking　system　based　on　image　sensors　with　complementary　metal-oxide-semiconductor　(CMOS)　is　designed.　In　this　system,　CMOS　sensor,　chip　of　digital　signal　processor　and　chip　of　complex　programmable　logic　device　are　integrated　as　a　core　unit　for　gathering　and　processing　images.　And　this　system　also　includes　auxiliary　circuits　of　USB　communication,　serial　communication　and　memory.　A　new　algorithm　for　page　checking　is　also　developed　on　the　basis　of　back　propagation　neural　network　and　geometric　invariant　moments,　and　this　algorithm　is　embeded　in　DSP　chip.　Experiments　of　parameter　estimation　indicate　that　this　new　algorithm　is　suitable　for　recognizing　different　pages,　such　as　word　pages,　graphic-word　pages　and　graphic　pages.　Experiments　show　that　recognition　precision　is　about　98%　when　relative　rotation　angle　is　±7.　©2009　Journal　of　Mechanical　Engineering.