Portable electronic device with auto-exposure control adaptive to environment brightness and image capturing method using the same

An image capture method with auto exposure control, comprising:

• obtaining a pre-view frame from a camera module;
• dividing the pre-view frame into a plurality of blocks and calculating representative brightness values of the blocks, wherein a representative brightness value of a block is represented by an average of luminance values of all pixels of the block;
• assigning weight values to the blocks according to the representative brightness values, the weight values comprising a first weight value, a second weight value and a third weight value, the first weight value being larger than the second weight value, and the second weight value being larger than the third weight value, so as to emphasize the blocks of higher representative brightness values;
• obtaining a weighted brightness value by performing a weighted calculation on the representative brightness values based on the weight values of the blocks;
• setting at least one auto exposure parameter of the camera module based on the weighted brightness value;
• and
• controlling the camera module to capture images according to the at least one auto exposure parameter,
• wherein the step of assigning weight values to the blocks according to the representative brightness values comprises:
• setting a plurality of brightness threshold values according to a statistical analysis result of the representative brightness values of the blocks and setting a plurality of weight values according the brightness threshold values;
• and
• comparing the representative brightness values of the blocks with the brightness threshold values and assigning corresponding weight values to the blocks according to the comparison result.

An image capture method with auto exposure control, comprising:

• obtaining a pre-view frame from a camera module, wherein the pre-view frame contains a plurality of blocks;
• analyzing the pre-view frame and thereby assigning a plurality of weight values according to representative brightness values of the blocks and setting at least one auto exposure parameter of the camera module according to the representative brightness values and the weight values, wherein a representative brightness value of a block is represented by an average of luminance values of all pixels of the block, the weight values comprises a first weight value, a second weight value and a third weight value, the first weight value is larger than the second weight value, and the second weight value is larger than the third weight value, so as to emphasize the blocks of higher representative brightness values;
• and
• controlling the camera module for capturing images based on the at least one auto exposure control parameter,
• wherein the blocks with higher representative brightness values are assigned with higher weight values, and
• wherein the step of assigning weight values to the blocks according to the representative brightness values comprises:
• setting a plurality of brightness threshold values according to a statistical analysis result of the representative brightness values of the blocks and setting a plurality of weight values according the brightness threshold values;
• and
• comparing the representative brightness values of the blocks with the brightness threshold values and assigning corresponding weight values to the blocks according to the comparison result.