Character noise eliminating apparatus, character noise eliminating method, and character noise eliminating program

A character noise eliminating means for eliminating a character noise which is an atypical shaped background noise from a fingerprint or a palm print image, the means comprising:

• a character noise area detecting means for detecting a character noise area, which is an area corresponding to the character noise, from the image;
• a density conversion area layer determining means for setting a plurality of density conversion area layers inside and outside the character noise area;
• a density converting means for, as a reference area of a target pixel, setting a neighboring pixel group within the same density conversion area layer as the density conversion area layer to which the target pixel belongs, and generating a density converted image by applying local image enhancement;
• an image enhancing means for generating an enhanced image by applying a local image enhancement to the image;
• and
• an image synthesizing means for generating a synthetic image by synthesizing the enhanced image and the density converted image taking a smaller density value among two density values of the enhanced image and the density converted image as the density value of a pixel in the density conversion area layer, and taking the density value of the enhanced image as the density value of a pixel outside the density conversion area layer;
• wherein the density converting means and the image enhancing device perform the local image enhancement in a same matter.

A character noise eliminating method for eliminating a character noise which is an atypical shaped background noise from an image of a fingerprint or a palm print, the method comprising:

• detecting a character noise area which is an area corresponding to the character noise, from the image;
• setting a plurality of density conversion area layers inside and outside the character noise area;
• generating a density converted image by setting a neighboring pixel group within the same density conversion area layer as the density conversion area layer to which the target pixel belongs as a reference area of a target pixel, and by applying with local image enhancement;
• generating an enhanced image applying a local image enhancement to the image;
• and
• generating synthetic image by synthesizing the enhanced image and the density converted image taking a smaller density value among density values of two images of the enhanced image and the density converted image as the density value of a pixel in the density conversion area layer, and taking the density value of the enhanced image as the density value of a pixel outside the density conversion area layer;
• wherein the local image enhancement is performed in generating the density converted image and generating the enhanced image in a same manner.

A non transitory computer readable medium having stored thereon a character noise eliminating program for eliminating a character noise which is an atypical shaped background noise from an image of a fingerprint or a palm print, the program makes a computer execute:

• a character noise area detecting processing for detecting a character noise area, which is an area corresponding to the character noise, from the image;
• a density conversion area layer determining processing for setting a plurality of density conversion area layers inside and outside the character noise area;
• a density converting processing for, as a reference area of a target pixel, setting a neighboring pixel group within the same density conversion area layer as the density conversion area layer to which the target pixel belongs, and generating a density converted image by applying local image enhancement;
• an image enhancing processing for generating an enhanced image by applying a local image enhancement to the image;
• and
• an image synthesizing processing for generating a synthetic image by synthesizing the enhanced image and the density converted image taking a smaller density value among density values of two images of the enhanced image and the density converted image as the density value of a pixel in the density conversion area layer, and taking the density value of the enhanced image as density value of a pixel outside the density conversion area layer;
• wherein the local image enhancement is performed in the density converting processing and the image enhancing processing in a same manner.