Image processing apparatus, image processing method, program, recording medium, and image forming apparatus having the same

An image forming apparatus comprising:

• an image processing apparatus including:
• edge determination means for determining whether or not each pixel of an input image is an edge pixel;
• object-image extraction means for extracting an object image section having pixels of a predetermined pixel value or more from the input image;
• first-characteristic-amount calculation means for calculating a first characteristic amount that represents a characteristic of the object image section contained in a first local pixel block containing a prescribed first target pixel on the basis of the result of extraction by the object-image extraction means;
• edge-class determination means for determining which of a plurality of edge classes the first target pixel belongs to, on the basis of the result of determination by the edge determination means and the first characteristic amount calculated by the first-characteristic-amount calculation means;
• second-characteristic-amount calculation means for calculating a second characteristic amount that represents a characteristic of an image of a second local pixel block containing a prescribed second target pixel on the basis of the result of classification by the edge-class determination means;
• and
• image-class determination means for determining which of a plurality of image classes the second target pixel belongs to, on the basis of the second characteristic amount calculated by the second-characteristic-amount calculation means.

An image processing method comprising:

• an edge determination process for determining whether or not each pixel of an input image is an edge pixel;
• an object-image extraction process for extracting an object image section composed of pixels having a predetermined pixel values or more from the input image;
• a first-characteristic-amount calculation process for calculating a first characteristic amount that represents a characteristic of an object image section contained in a first local pixel block containing a predetermined first target pixel on the basis of the result of extraction by the object-image extraction process;
• an edge-class determination process for determining which of a plurality of edge classes the first target pixel belongs to, on the basis of the result of determination by the edge determination process and the first characteristic amount calculated in the first-characteristic-amount calculation process;
• a second-characteristic-amount calculation process for calculating a second characteristic amount that represents a characteristic of an image in the second local pixel block containing a predetermined second target pixel on the basis of the result of classification by the edge-class determination process;
• and
• an image-class determination process for determining which of the plurality of image classes the second target pixel belongs to, on the basis of the second characteristic amount calculated in the second-characteristic-amount calculation process.

A program for causing a computer to execute an image processing method comprising:

• an edge determination process for determining whether or not each pixel of an input image is an edge pixel;
• an object-image extraction process for extracting an object image section composed of pixels having a predetermined pixel values or more from the input image;
• a first-characteristic-amount calculation process for calculating a first characteristic amount that represents a characteristic of an object image section contained in a first local pixel block containing a predetermined first target pixel on the basis of the result of extraction by the object-image extraction process;
• an edge-class determination process for determining which of a plurality of edge classes the first target pixel belongs to, on the basis of the result of determination by the edge determination process and the first characteristic amount calculated in the first-characteristic-amount calculation process;
• a second-characteristic-amount calculation process for calculating a second characteristic amount that represents a characteristic of an image in the second local pixel block containing a predetermined second target pixel on the basis of the result of classification by the edge-class determination process;
• and
• an image-class determination process for determining which of a plurality of image classes the second target pixel belongs to, on the basis of the second characteristic amount calculated in the second-characteristic-amount calculation process.

A computer-readable recording medium which records a program for causing a computer to execute image processing method comprising:

• an edge determination process for determining whether or not each pixel of an input image is an edge pixel;
• an object-image extraction process for extracting an object image section composed of pixels having a predetermined pixel values or more from the input image;
• a first-characteristic-amount calculation process for calculating a first characteristic amount that represents a characteristic of an object image section contained in a first local pixel block containing a predetermined first target pixel on the basis of the result of extraction by the object-image extraction process;
• an edge-class determination process for determining which of a plurality of edge classes the first target pixel belongs to, on the basis of the result of determination by the edge determination process and the first characteristic amount calculated in the first-characteristic-amount calculation process;
• a second-characteristic-amount calculation process for calculating a second characteristic amount that represents a characteristic of an image in the second local pixel block containing a predetermined second target pixel on the basis of the result of classification by the edge-class determination process;
• and
• an image-class determination process for determining which of a plurality of image classes the second target pixel belongs to, on the basis of the second characteristic amount calculated in the second-characteristic-amount calculation process.