Information processing apparatus, method of controlling same and computer program

An information processing method of executing compression processing of a multivalued original image, comprising:

• a resolution rising step of obtaining high-resolution multivalued image by subjecting the multivalued original image to interpolation processing;
• a first binarization step of obtaining a first binarized image by applying binarization processing to the high-resolution multivalued image obtained in the resolution rising step, wherein a resolution of the first binarized image is higher than that of the multivalued original image;
• a second binarization step of obtaining a second binarized image by applying binarization processing to the multivalued original image, wherein a resolution of the second binarized image is lower than that of the first binarized image;
• a text-region extraction step of extracting a text region based on the low-resolution binarized image obtained by the second binarization unit, thereby obtaining position information of the extracted text region;
• a text-color extraction step of extracting text colors based on the multivalued original image, the second binarized image and the position information of the extracted text region;
• a partial image generating step of extracting partial images, per each of the text colors, from the first binarized image based on the position information of the extracted text region and the text colors, and obtaining text color information that correlates each of the partial images and the text color;
• a first compression step of generating first compressed data by applying first compression processing to each of the partial images extracted in the partial image generating step;
• a filling step of generating a filled image by filling a text portion of the multivalued original image with a pixel value other than that of the text portion;
• a second compression step of generating second compressed data by applying second compression processing to the filled image generated in the filling step;
• and
• a combined compressed data generating step of generating compressed data by combining the first compressed data, the second compressed data, the position information and the text color information.

A non-transitory computer-readable storage medium storing a computer program for causing a computer to execute the information processing steps comprising:

• a resolution rising step of obtaining high-resolution multivalued image by subjecting a multivalued original image to interpolation processing;
• a first binarization step of obtaining a first binarized image by applying binarization processing to the high-resolution multivalued image obtained in the resolution rising step, wherein a resolution of the first binarized image is higher than that of the multivalued original image;
• a second binarization step of obtaining a second binarized image by applying binarization processing to the multivalued original image, wherein a resolution of the second binarized image is lower than that of the first binarized image;
• a text-region extraction step of extracting a text region based on the low-resolution binarized image obtained by the second binarization unit, thereby obtaining position information of the extracted text region;
• a text-color extraction step of extracting text colors based on the multivalued original image, the second binarized image and the position information of the extracted text region;
• a partial image generating step of extracting partial images, per each of the text colors, from the first binarized image based on the position information of the extracted text region and the text colors, and obtaining text color information that correlates each of the partial images and the text color;
• a first compression step of generating first compressed data by applying first compression processing to each of the partial images extracted in the partial image generating step;
• a filling step of generating a filled image by filling a text portion of the multivalued original image with a pixel value other than that of the text portion;
• a second compression step of generating second compressed data by applying second compression processing to the filled image generated in the filling step;
• and
• a combined compressed data generating step of generating compressed data by combining the first compressed data, the second compressed data, the position information and the text color information.