Method for white balance adjustment of images

A white balance adjustment method of an image capturing device, the method comprising:

• S1:
• capturing a raw image using the image capturing device, wherein an arrangement format of pixels of the raw image is BGb/GrR;
• S2:
• sampling the raw image using a predetermined sampling width, obtaining color scale values of B, Gb, Gr, and R channels;
• S3:
• configuring a first buffer space and a second buffer space of each of the B, Gb, Gr, and R channels, using the first buffer space to store a first color scale value, and using the second buffer space to store a second color scale value that is larger than the first color scale value;
• S4:
• initializing the first and the second buffer spaces, wherein an initial color scale value stored in the first buffer space is 2n-1, an initial color scale value stored in the second buffer space is 0, wherein “n” is a number of bits of the pixel;
• S5:
• determining whether there is a smaller color scale value of each of the B, Gb, Gr, and R channels than the color scale value stored in respective first buffer space;
• in response to the determining that there is the smaller color scale value in the B, Gb, Gr, and R channels, storing the smaller color scale value, the larger color scale value being removed from the first buffer space;
• S6:
• repeating step S5 until a comparison between all of the color scale values in the B, Gb, Gr, and R channels and the corresponding color scale values stored in the first buffer space is complete, and calculating an average value of the color scale values stored in the first buffer spaces, wherein the average value is a reference black;
• S7:
• determining whether there is a larger color scale value of each of the B, Gb, Gr, and R channels than the color scale value stored in respective second buffer space;
• in response to the determining that there is the larger color scale value in the B, Gb, Gr, and R channels, storing the larger color scale value, the smaller color scale value being removed from the second buffer space;
• S8:
• repeating step S7 until a comparison between all of the color scale values in the B, Gb, Gr, and R channels and the corresponding color scale values stored in the second buffer space is completed, and then calculating an average value of the color scale values stored in the second buffer spaces, the average value being a reference white;
• and
• S9:
• adjusting the white balance of the raw image, according to the reference black and the reference white and a color histogram stretching (CHS) method.