Is it normal for a company such as Demonware to take so long to get in touch with candidates? I'm very unimpressed by the whole process you described... Besides, they created false expectations, telling you they would get in touch soon. Also, why couldn't they simply inform you right away if they didn't want to hire you? Very, very unprofessional and showing a general lack of respect.
Give a two dimentional array of registors that contains intensity value. It is feed to you one registor per cycle. How to design a hardware using FPGA to calculate the average of the 9 registors including 8 that locate right beside the center one.