Pixel Interpolation Apparatus, Pixel Interpolation Method and Image Reading Apparatus

An image reading apparatus comprising:

• a reading section having a line image sensor in which a plurality of sensor chips are arranged in series to have a reading area corresponding to a plurality of pixels aligned in one-dimensional prescribed direction, and at a boundary of each one and the another of the plurality of sensor chips a missing pixel is generated, wherein the reading section optically reads a two-dimensional image of an original document by relatively moving the original document and the line image sensor;
• and
• a pixel interpolation apparatus for interpolate a missing pixel in image data obtained through reading the original document by the reading section, the pixel interpolation apparatus comprising, an interpolation section for calculating an estimation density value of the missing pixel from densities of peripheral pixels of the missing pixel, and
• a correction section for calculating a first average value which being an average density value of pixels in a first two-dimensional area containing the missing pixel whose density value is assumed to be the estimation density value calculated by the interpolation section and a second average value which being an average density value of a second two-dimensional area, located in a peripheral of the missing pixel, not containing the missing pixel, and for correcting the estimation density value of the missing pixel in a first two-dimensional area so that a difference between the first average value and the second average value becomes zero or small.

A pixel interpolation method comprising:

• calculating an estimation density value of a missing pixel from densities of peripheral pixels of the missing pixel;
• and
• calculating a first average value which being an average density value of pixels in a first two-dimensional area containing the missing pixel whose density value is assumed to be the estimation density value calculated by the interpolation section, and a second average value which being an average density value of a second two-dimensional area, located in a peripheral of the missing pixel, not containing the missing pixel;
• and
• correcting the estimation density value of the missing pixel in the first two-dimensional area so that a difference between the first average value and the second average value becomes zero or small.