Low-power passive focus measure operator based on the DCT for mobile phones

Abstract

A new focus measure operator applicable in the auto-focus function of a mobile phone has been presented. The proposed operator uses the middle frequency component of a discrete cosine transform to calculate the focus value of an image. Experimental results from various sample images show that the proposed operator requires a minimum number of operations (at least 1/5 for addition and 1/16 for multiplication) and produces reliable focus values with low auto-focusing uncertainty measure as compared to the other operators.

Keywords:

• AUTO-FOCUS
• FOCUS-VALUE
• DCT
• MOBILE PHONE