Method for detecting blank area of power calibration area

A method for detecting a blank area of a power calibration area, the method comprising:

• selecting a recording test area in the power calibration area of an optical disc;
• applying multiple stages of normal power and multiple stages of detecting power to the recording test area and thus forming a plurality of normal blocks and a plurality of detecting blocks, wherein each detecting block comprises one unit of unrecorded block and one unit of recorded block, and the plurality of normal blocks are formed by applying the multiple stages of normal power having the same recording power and by changing a focus position each time;
• determining whether the unrecorded blocks of the detecting blocks are blank;
• repeating the above steps or entering an error recovery procedure if the unrecorded blocks of the detecting blocks are not totally blank;
• and
• determining the selected recording test area to be blank if the unrecorded blocks of the detecting blocks are totally blank.