I am playing OBV now. The original OBV is only calculate CLOSE. I got an idea about XOBV with HLOC. A bar has 5 periods: - Open--Low--Open--Close--High--Close or - Open--High--Open--Close--Low--Close
Assume that volume will evenly distributed on these 5 periods. Only Open--Close period has effective changed volume.
So XOBV = OBV * abs(close-open)/(2*(high-low)-abs(close-open)))
Better use XOBV and OBV both. Divergence and same price comparison are worth to watching.