Auto white balance adjustment system, auto white balance adjustment method, and camera module

An auto white balance adjustment method comprising:

• performing white balance adjustment on an image signal based on a white balance gain;
• performing color judgment targeting the image signal to sort pixel data used for calculating the white balance gain;
• integrating the sorted pixel data through the color judgment and outputting the integration data;
• generating a first color judgment gate to define an entire range of a target color temperature of the white balance adjustment;
• generating a second color judgment gate to define a range of a target color temperature of the white balance adjustment with respect to each light source identified according to the white balance gain;
• outputting a white balance fine adjustment starting signal which makes an instruction to start fine adjustment in white balance in which the second color judgment gate is a reference for color judgment;
• and
• switching the reference for the color judgment from the first color judgment gate to the second color judgment gate according to the white balance fine adjustment starting signal,
• wherein whether to start the fine adjustment is determined depending on a comparison result of the integration data with a first threshold value which is set for the white balance adjustment based on the first color judgment gate, and whether to keep on performing the fine adjustment is determined depending on a comparison result of the integration data with a second threshold value which is set for the fine adjustment based on the second color judgment gate.

A camera module comprising:

• a lens unit which receives light from an object to form an object image;
• an image sensor which captures the object image;
• and
• an auto white balance adjustment system which performs white balance adjustment on an image signal obtained by capturing the image in the image sensor,
• wherein the auto white balance adjustment system includes
• a white balance adjustment unit which performs white balance adjustment on the image signal based on a white balance gain,
• a color judgment unit which performs color judgment targeting the image signal to sort pixel data used for calculating the white balance gain,
• an integration unit which integrates the sorted pixel data by the color judgment unit and outputs the integration data,
• a first color judgment gate generating unit which generates a first color judgment gate to define an entire range of a target color temperature of the white balance adjustment,
• a second color judgment gate generating unit which generates a second color judgment gate to define a range of a target color temperature of the white balance adjustment with respect to each light source identified according to the white balance gain,
• a white balance fine adjustment starting instruction unit which makes an instruction to start fine adjustment in white balance in which the second color judgment gate is a reference for color judgment, and
• a color judgment gate switching unit which performs the switching of the reference for the color judgment in the color judgment unit from the first color judgment gate to the second color judgment gate in response to the instruction caused by the white balance fine adjustment starting instruction unit, and
• wherein the white balance fine adjustment starting instruction unit determines whether to start the fine adjustment depending on a comparison result of the integration data with a first threshold value which is set for the white balance adjustment based on the first color judgment gate, and determines whether to keep on performing the fine adjustment depending on a comparison result of the integration data with a second threshold value which is set for the fine adjustment based on the second color judgment gate.