Focusing method, suitable for an image capturing apparatus using in an environment of low brightness and image capturing apparatus using the same

An image capturing apparatus suitable for focusing in an environment of low brightness, the image capturing apparatus comprising:

• an image sensing unit, for sensing an object and obtaining a digital image data;
• an image processing unit, for dividing the digital image data into a plurality of regional image data corresponding to a plurality of regions, and summing up the plurality of regional image data for each of the regions using digital image data from its own region, so as to obtain a plurality of sums of data for each of the regions and to calculate a plurality of contrast values with each of the contrast values corresponds to its own region according to the sums of data;
• and
• a focus adjusting module, for performing calculations for the focusing step according to the plurality of contrast values, so as to obtain a focus.

A focusing method suitable for an image capturing apparatus in an environment of low brightness, the focusing method comprising:

• a digital image processor dividing a portion of a digital image data captured by the image capturing apparatus into a plurality of regional digital image data corresponding to a plurality of predefined regions;
• said digital image processor summing up the plurality of the regional digital image data for each of the predefined regions using digital image data from its own region to obtain a plurality of sums of data for each of the predefined regions;
• using the sums of data of each of the regions to calculate a plurality of contrast values with each of the contrast values corresponding to its own predefined regions;
• and using the plurality of contrast values to perform calculations for the focusing step to obtain a focus.