1. Field of the Invention
The present invention relates to a color matching method and an image capturing device using the color matching method or an electronic apparatus provided with such image capturing device. More particularly, the present invention relates to a color matching method for handling an electronic digital image and an image capturing device using the color matching method or an electronic apparatus provided with such image capturing device.
2. Description of the Related Art
Recently, electronic apparatuses provided with a color image capturing device are widely used, for example, a digital camera, an electronic type video recorder, or a mobile phone. Generally, a semiconductor image sensor is provided in these electronic apparatuses for converting a captured image into an electrical signal. Due to the inherent limitations of the image sensor with respect to the color sensing performance, the color of an image outputted under such limitations is usually required to be adjusted. In addition, the color of the image is different depending on the light illumination conditions. For example, the perception of color for the human visual system is quite different in the moonlight and in the daylight outdoors. Therefore, it is important that the obtained electronic image is required to meet the perception of the human's visual sense in color processing.
In these electronic apparatuses, an image signal outputted from the image sensor will be subjected to a series of signal processing procedures in which the color of the obtained image will be corrected by performing a color matching process so as to output an image with a natural color.
Regarding the color correction process, a number of conventional techniques that adopt a correction matrix to correct the color of an image are known. For example, U.S. Pat. No. 7,053,935 has disclosed one advantage over current electronic capture systems that the accuracy of color capture, which is a result of the match between the human visual system and the unique set of spectral response curves and the correction matrix used in the invention. However, the color correction result cannot be dynamically adjusted since the matrix is predefined, and thus a quick, accurate color correction result is difficult to be achieved, and a high-quality image cannot be offered.
As a result, in the conventional technique described above, since a fixed correction matrix is used to correct the color of the image, the color difference is large and cannot be rapidly converged to a predetermined value.
Therefore, a color matching method capable of dynamically adjusting the color difference and rapidly converging the color difference to the predetermined value is required for achieving a color demonstration with high color accuracy.