Signal processing device, signal processing program and electronic camera

Abstract

The present invention includes a color converting section carrying out color conversion processing and a coefficient correcting section setting a correcting coefficient group to a coefficient group of the color conversion. The coefficient correcting section sets a local area containing a pixel to be processed, and calculates “feature information of the local area” containing at least one of averaged color information, averaged luminance information, and flatness on the basis of the pixel signals of the local area. The coefficient correcting section determines a correcting coefficient group to be used for the pixel to be processed on the basis of the feature information of the local area. With this construction, the present invention suppresses influence of noise when changing the color conversion processing for each pixel.

1 . A signal processing device, comprising: 
 a color converting section multiplying an input color pixel signal by a transformation matrix to execute color conversion processing; and    a coefficient correcting section setting a correcting coefficient group to a coefficient group of the transformation matrix, wherein    the coefficient correcting section includes    an analyzing section setting a local area containing a pixel to be processed and processing plural pixel signals of the local area to calculate average color information (hereinafter referred to as “averaged color information”),    a correspondence setting section in which a correspondence relation between the averaged color information and the correcting coefficient group is preset, and    a coefficient determining section collating the correspondence relation on the basis of the averaged color information calculated in the analyzing section and determining the correcting coefficient group to be used for the pixel to be processed.    
   
   
       2 . The signal processing device according to  claim 1 , wherein the coefficient correcting section adjusts the correcting coefficient group to be used for the pixel to be processed so that saturation of an average hue of the local area containing the pixel to be processed is selectively increased.  
   
   
       3 . A signal processing device, comprising: 
 a color converting section multiplying an input color pixel signal by a transformation matrix to execute color conversion processing; and    a coefficient correcting section setting a correcting coefficient group to a coefficient group of the transformation matrix, wherein    the coefficient correcting section includes    an analyzing section setting a local area containing a pixel to be processed and processing plural pixel signals of the local area to calculate average luminance information (hereinafter referred to as “averaged luminance information”),    a correspondence setting section in which a correspondence relation between the averaged luminance information and the correcting coefficient group is preset, and    a coefficient determining section collating the correspondence relation on the basis of the averaged luminance information calculated in the analyzing section and determining the correcting coefficient group to be used for the pixel to be processed.    
   
   
       4 . The signal processing device according to  claim 3 , wherein the coefficient correcting section adjusts the correcting coefficient group so that saturation is increased when average luminance of the local area containing the pixel to be processed is in a predetermined intermediate gradation range, and in the other cases, adjusts the correcting coefficient group so that saturation is decreased.  
   
   
       5 . A signal processing device, comprising: 
 a color converting section multiplying an input color pixel signal by a transformation matrix to execute color conversion processing; and    a coefficient correcting section setting a correcting coefficient group to a coefficient group of the transformation matrix, wherein    the coefficient correcting section includes    an analyzing section setting a local area containing a pixel to be processed and processing plural pixel signals of the local area to calculate flatness on an image space,    a correspondence setting section in which a correspondence relation between the flatness and the correcting coefficient group is preset, and    a coefficient determining section collating the correspondence relation on the basis of the flatness calculated in the analyzing section and determining the correcting coefficient group to be used for the pixel to be processed.    
   
   
       6 . The signal processing device according to  claim 5 , wherein the coefficient correcting section adjusts the correcting coefficient group so as to increase saturation as flatness of the local area containing the pixel to be processed is higher, and adjusts the correcting coefficient group so as to decrease the saturation as the flatness is lower.  
   
   
       7 . A signal processing device, comprising: 
 a color converting section multiplying an input color pixel signal by a transformation matrix to execute color conversion processing; and    a coefficient correcting section setting a correcting coefficient group to a coefficient group of the transformation matrix, wherein    the coefficient correcting section includes    an analyzing section setting a local area containing a pixel to be processed and calculating averaged color information and flatness on the basis of plural pixel signals of the local area,    an aberration judging section judging whether a condition (1) the averaged color information is in a hue range of any one of green and magenta, and a condition (2) the flatness is lower than a predetermined threshold value and indicates a color boundary or edge portion are satisfied, and    a coefficient determining section setting a correcting coefficient group for decreasing saturation to the coefficient group to be used for the pixel to be processed when the conditions (1) and (2) are satisfied in the aberration judging section.    
   
   
       8 . A signal processing device, comprising: 
 a color converting section multiplying an input color pixel signal by a transformation matrix to execute color conversion processing; and    a coefficient correcting section setting a correcting coefficient group to a coefficient group of the transformation matrix, wherein    the coefficient correcting section includes    an analyzing section setting a local area containing a pixel to be processed and calculating averaged color information, averaged luminance information, and flatness on the basis of plural pixel signals of the local area,    a skin judging section judging whether a condition (1) the averaged color information is in a predetermined hue range of skin tone, a condition (2) the averaged luminance information is in a luminance range of skin, and a condition (3) the flatness is flatter than flatness indicated by a predetermined threshold value and is in a flatness range of skin are satisfied, and    a coefficient determining section setting a correcting coefficient group for enhancing reproducibility of skin tone to the coefficient group to be used for the pixel to be processed when the conditions (1) to (3) are satisfied in the skin judging section.    
   
   
       9 . A signal processing device, comprising: 
 a color converting section multiplying an input color pixel signal by a transformation matrix to execute color conversion processing; and    a coefficient correcting section setting a correcting coefficient group to a coefficient group of the transformation matrix, wherein    the coefficient correcting section includes    an analyzing section setting a local area containing a pixel to be processed and calculating averaged color information, averaged luminance information, and flatness on the basis of plural pixel signals of the local area,    a blue sky judging section judging whether a condition (1) the averaged color information is in a predetermined hue range of blue sky, a condition (2) the averaged luminance information shows a brighter value than luminance indicated by a predetermined threshold value and is in a luminance range of blue sky, and a condition (3) the flatness is flatter than flatness indicated by a predetermined threshold value and is in a flatness range of blue sky are satisfied, and    a coefficient determining section setting a correcting coefficient group for enhancing reproducibility of blue sky to the coefficient group to be used for the pixel to be processed when the conditions (1) to (3) are satisfied in the blue sky judging section.    
   
   
       10 . A signal processing device, comprising: 
 a color converting section multiplying an input color pixel signal by a transformation matrix to execute color conversion processing; and    a coefficient correcting section setting a correcting coefficient group to a coefficient group of the transformation matrix, wherein    the coefficient correcting section includes    an analyzing section setting a local area containing a pixel to be processed and calculating feature information of the local area (hereinafter referred to as “local feature information”) containing at least one of averaged color information, averaged luminance information, and flatness on the basis of plural pixel signals of the local area,    a correspondence setting section in which a correspondence relation between the local feature information and the correcting coefficient group is preset, and    a coefficient determining section collating the correspondence relation on the basis of the local feature information calculated in the analyzing section and determining the correcting coefficient group to be used for the pixel to be processed.    
   
   
       11 . A signal processing program making a computer function as the color converting section and the coefficient correcting section according to  claim 1 .  
   
   
       12 . A signal processing program making a computer function as the color converting section and the coefficient correcting section according to  claim 3 .  
   
   
       13 . A signal processing program making a computer function as the color converting section and the coefficient correcting section according to  claim 5 .  
   
   
       14 . A signal processing program making a computer function as the color converting section and the coefficient correcting section according to  claim 7 .  
   
   
       15 . A signal processing program making a computer function as the color converting section and the coefficient correcting section according to  claim 8 .  
   
   
       16 . A signal processing program making a computer function as the color converting section and the coefficient correcting section according to  claim 9 .  
   
   
       17 . A signal processing program making a computer function as the color converting section and the coefficient correcting section according to  claim 10 .  
   
   
       18 . An electronic camera comprising: 
 a photographing section photographing a subject to generate a color pixel signal; and    the signal processing device according to  claim 1 , wherein    the signal processing device subjects the pixel signal generated by the photographing section to the color conversion processing.    
   
   
       19 . An electronic camera comprising: 
 a photographing section photographing a subject to generate a color pixel signal; and    the signal processing device according to  claim 3 , wherein    the signal processing device subjects the pixel signal generated by the photographing section to the color conversion processing.    
   
   
       20 . An electronic camera comprising: 
 a photographing section photographing a subject to generate a color pixel signal; and    the signal processing device according to  claim 5 , wherein    the signal processing device subjects the pixel signal generated by the photographing section to the color conversion processing.    
   
   
       21 . An electronic camera comprising: 
 a photographing section photographing a subject to generate a color pixel signal; and    the signal processing device according to  claim 7 , wherein    the signal processing device subjects the pixel signal generated by the photographing section to the color conversion processing.    
   
   
       22 . An electronic camera comprising: 
 a photographing section photographing a subject to generate a color pixel signal; and    the signal processing device according to  claim 8 , wherein    the signal processing device subjects the pixel signal generated by the photographing section to the color conversion processing.    
   
   
       23 . An electronic camera comprising: 
 a photographing section photographing a subject to generate a color pixel signal; and    the signal processing device according to  claim 9 , wherein    the signal processing device subjects the pixel signal generated by the photographing section to the color conversion processing.    
   
   
       24 . An electronic camera comprising: 
 a photographing section photographing a subject to generate a color pixel signal; and    the signal processing device according to  claim 10 , wherein    the signal processing device subjects the pixel signal generated by the photographing section to the color conversion processing.