Backlight image determining apparatus, backlight image determining method, backlight image correction apparatus, and backlight image correction method

A backlight image determining method comprising:

• using a processor to perform the steps of:
• generating, based on data of pixels constituting an image to be determined, data of histograms for respective colors, the histograms representing a distribution of the number of pixels in respect to density values of the respective colors of those pixels;
• partitioning regions given by the histograms for the respective colors into at least three small regions according to the magnitude of the density values, based on the data of the histograms for the respective colors generated by the histogram data generation section;
• selecting for each color at least one small region from the at least three small regions as a first small region, and selecting, from the at least three small regions, for each color at least one small region whose density values are larger than those of the first small region and which is not adjacent to the first small region, as a second small region;
• obtaining, for each color, attribute information relating to the first small region and the second small region;
• and
• determining whether an image to be determined is a backlight image, based on the attribute information relating to the first small region obtained for each color and the attribute information relating to the second small region obtained for each color.

A non-transitory computer readable medium storing thereon a program for backlight image enhancement, the program comprising:

• a histogram data generation section that, based on data of pixels constituting an image, generates data of histograms for respective colors, the histograms representing a distribution of the number of pixels in respect to density values for the respective colors of those pixels;
• an attribute information obtaining section that obtains, for each color, attribute information for a relevant small region by partitioning, based on the histogram data for the respective colors generated with the histogram data generation section, the regions given by the histograms for the respective colors into at least two small regions according to the magnitude of the density values and selecting at least one small region from the at least two small regions;
• an enhancement information generation section that generates enhancement information for performing a backlight enhancement process on the image based on the attribute information for each color obtained with the attribute information obtaining section;
• and
• a backlight enhancement processing section that performs a backlight enhancement process on the image, based on the enhancement information generated with the enhancement information generation section.

A method for backlight image enhancement, comprising:

• using a processor to perform the steps of:
• generating, based on data of pixels constituting an image, data of histograms for respective colors, the histograms representing a distribution of the number of pixels in respect to density values of the respective colors of those pixels;
• partitioning regions given by the histograms for the various colors into at least two small regions according to the magnitude of the density values, based on the data of the histograms for each color generated with the histogram data generation section;
• obtaining, for each color, attribute information for that small region by selecting at least one small region from the at least two small regions;
• generating enhancement information for performing a backlight enhancement process on the image based on the obtained attribute information for each color;
• and
• performing a backlight enhancement process on the image, based on the generated enhancement information.

A backlight image determining apparatus comprising:

• a memory that stores a program;
• and
• a processor that executes the program;
• wherein the program comprises:
• a histogram data generation section that, based on data of pixels constituting an image to be determined, generates data of histograms for respective colors, the histograms representing a distribution of the number of pixels in respect to density values of the respective colors of those pixels;
• an attribute information obtaining section that obtains, for each color, attribute information relating to a first small region and a second small region by partitioning regions given by the histograms for the respective colors into at least three small regions according to the magnitude of the density values, based on the data of the histograms for the respective colors generated by the histogram data generation section, selecting for each color at least one small region from the at least three small regions as the first small region, and selecting, from the at least three small regions, for each color at least one small region whose density values are larger than those of the first small region and which is not adjacent to the first small region, as the second small region;
• and
• a determination section that determines whether the image to be determined is a backlight image, based on the attribute information relating to the first small region for each color and the attribute information relating to the second small region for each color, which is obtained with the attribute information obtaining section.

A backlight image enhancement apparatus comprising:

• a memory that stores a program;
• and
• a processor that executes the program;
• wherein the program comprises:
• a histogram data generation section that, based on data of pixels constituting an image, generates data of histograms for respective colors, the histograms representing a distribution of the number of pixels in respect to density values for the respective colors of those pixels;
• an attribute information obtaining section that obtains, for each color, attribute information for a relevant small region by partitioning, based on the histogram data for the respective colors generated with the histogram data generation section, the regions given by the histograms for the respective colors into at least two small regions according to the magnitude of the density values and selecting at least one small region from the at least two small regions;
• an enhancement information generation section that generates enhancement information for performing a backlight enhancement process on the image based on the attribute information for each color obtained with the attribute information obtaining section;
• and
• a backlight enhancement processing section that performs a backlight enhancement process on the image, based on the enhancement information generated with the enhancement information generation section.