Automatic focusing method and automatic focusing system

1. An automatic focusing method comprising:

acquiring an image data in a focus area;

calculating the image data to get a contrast value curve by a contrast value algorithm;

acquiring a contrast weight of each contrast value, wherein acquiring a contrast weight of each contrast value comprising:

determining whether the focus area is a skin area;

decreasing contrast weight corresponding to the non-skin area;

determining whether the skin area is integrated;

increasing contrast weight corresponding to the integrated skin area;

determining whether the non-integrated skin area accords with human feature;

increasing the corresponding contrast weight when the non-integrated skin area accords with human feature;

decreasing the corresponding contrast weight when the non-integrated skin area does not accord with human feature;

calculating an adapted contrast value by multiplying the contrast value to the contrast weight; and

adapting the focus according to the adapted contrast value curve.

2. The automatic focusing method of claim 1 , wherein determining whether the focus area is a skin area comprising:

setting a determining area;

converting each pixel in the focus area to the HIS model, getting a hue angle of each pixel;

comparing each hue angle located in the determining area;

confirming the focus area a skin area when the hue angle is located in the determining area; and

confirming the focus area a non-skin area when the hue angle is not located in the determining area.

3. The automatic focusing method of claim 1 , wherein determining whether the skin area is integrated comprising:

building a scan area in a center coordinates of a center of the skin area;

determining whether there is one or two arm areas in the scan area;

confirming the scan area is a skin area when there is one or two arm areas in the scan area; and

confirming the scan area is a non-skin area when there is no arm area in the scan area.

4. The automatic focusing method of claim 3 , wherein building a scan area in a center coordinates of a center of the skin area further comprising: finding out the center of the skin area to be the center coordinates (xc, yc); extending a preset length downwards; respectively extending left and right a preset shoulder length to get two preset shoulder coordinates (xl, yl) and (xr, yr); respectively drawing a circle in a center of circle of (xl, yl) and (xr, yr) and a radius of a preset arm length; and confirming the set of the two circles to the scan area.

5. The automatic focusing method of claim 4 , wherein determining whether the skin area is integrated further comprising: adjusting the scan area by adjusting the preset length, the preset shoulder length, or/and the preset arm length when there is more than two arm areas.

6. The automatic focusing method of claim 1 , wherein determining whether the non-integrated skin area accords with human feature comprising:

determining whether the skin area is shining;

decreasing the corresponding contrast weights when the skin area is shining;

determining whether the non-shining area is moving;

increasing the corresponding contrast weights when the non-shining area is moving; and

decreasing the corresponding contrast weights when the non-shining area is not moving.

7. An automatic focusing system comprising:

an image acquiring module, configured to acquire an image data in a focus area; and

a processor comprising:

a calculating module, configured to calculate the image data to get a contrast value curve by a contrast value algorithm;

a weight acquiring module, configured to acquire a contrast weight of each contrast value, wherein the weight acquiring module comprising:

a skin area confirming module, configured to determine whether the focus area is a skin area;

a weight adjusting module, configured to decrease contrast weights corresponding to the non-skin area;

a skin integrity confirming module, configured to determine whether the skin area is integrated;

a human feature confirming module, configured to determining whether the non-integrated skin area accords with human feature, wherein the weight adjusting module is further configured to increase contrast weights corresponding to the integrated skin area; increase the corresponding contrast weights when the non-integrated skin area accords with human feature; and decrease the corresponding contrast weights when the non-integrated skin area does not accord with human feature;

a revising module, configured to calculate an adapted contrast value by multiplying the contrast value to the contrast weight; and

an adjusting module, configured to adapt the focus according to the adapted contrast value curve.

8. The automatic focusing system of claim 7 , wherein the skin area confirming module comprising:

a setting module, configured to set a determining area;

a converting module, configured to convert each pixel in the focus area to the HIS model, getting a hue angle of each pixel;

a comparison module, configured to compare whether each hue angle is located in the determining area; and

an angle determining module, configured to confirm the focus area a skin area when the hue angle is located in the determining area, and confirm the focus area a non-skin area when the hue angle is not located in the determining area.