Patent Application
20080048961
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which:
The Figure is a flow chart of a method for improving image quality differences on an LCD due to different viewing modules of the present invention.
Referring to the Figure, the present invention provides a method for improving image quality differences on an LCD due to different viewing modules. In addition, the LCD is a kind of LCD in which the luminance, color and contrast are unable to be adjusted.
The method comprises: firstly, transforming an image data from a spatial domain with a luminance signal and a chrominance signal to a spatial domain with three color signals (S100). In addition, the image is stored in a memory of the LCD, and the spatial domain with the luminance signal and the chrominance signal can be a YUV domain that is called a YCbCr domain. The spatial domain with three color signals can be a RGB domain. The color spatial transforming formula for transforming the YCbCr domain to the RGB domain is as follows:
R=1.164(Y)+1.596(Cb−128)
G=1.164(Y)−0.813(Cr−128)−0.392(Cb−128)
B=1.164(Y)+2.017(Cb−128).
Moreover, the method further comprises: adjusting the LCD's luminance, color and contrast parameters according to luminance, color and contrast displays that the image data need (S102). In addition, the luminance parameter is a green gain (G gain) of a digital gain, the color parameter is a red gain (R gain) and a blue gain (B gain) of a digital gain, and the contrast parameter is a gamma curve.
Furthermore, the method further comprises: transforming the image data from the spatial domain with three color signals to the spatial domain with the luminance signal and the chrominance signal (S104); and then displaying the image data on the adjusted LCD and in playback module (S106). In addition, in the step of S104, if the image data is transformed from the RGB domain to the YCbCr domain, the color spatial transforming formula is as follows:
Y=0.257R+0.504G+0.098B
C
b=−0.148R−0.291G+0.439B
C
r=0.439R−0.368G−0.071B.
In conclusion, the image's spatial domain is a YUV domain (or a YCbCr domain) in playback module. Hence, if a user wants to modify the image's color appearance, the image's spatial domain needs to be transformed from the YUV domain to the RGB domain. Moreover, a digital gain (R gain, G gain and B gain) or a gamma curve (or a gamma table) needs to be adjusted according to a color appearance as desired by a user. Finally, the image is transformed from the RGB domain to the YUV domain via DSP (Digital Signal Process). Hence, the image's brightness and color in the live viewing module are similar to that of the image in the playback module.
Furthermore, the image quality differences on the LCD due to the difference between the preview gamma and the capture gamma are improved via the transformation method between the YUV domain and the RGB domain and the modification method in the RGB domain. Hence, the serious dark angle problems on the LCD of a camera due to the shading of the lens are solved. The image's brightness and color in the live viewing module are similar to that of the image in the playback module.
Although the present invention has been described with reference to the preferred best molds thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.
