16. A method of automatically creating an index in an image forming apparatus, the method comprising: scanning a document with a scan apparatus; separating the scanned document with a text/image separation apparatus into a text area and an image area and separating texts in the text area into symbols based on pixel data of the separated text area by comparing at least one pixel of the pixel data in the separated text area with a plurality of neighboring pixels to determine and separate individual symbols of the text area; extracting one or more properties of the separated symbols and comparing the extracted symbol properties with one or more index thresholds to determine whether the text including the symbols is an index object with an index determination apparatus, where the index thresholds are set as an average value of preset symbol properties calculated based on variation of the preset symbol properties; and creating an index page with an index page creation apparatus including the text determined as the index object and information about a page including the text that corresponds to the index object, wherein the symbols are determined as index-object symbols, the index-object symbols are grouped, and the texts including the groups of the index-object symbols are determined as objects in the index, when the extracted symbol properties are greater than the index thresholds.
16. A method of automatically creating an index in an image forming apparatus, the method comprising: scanning a document with a scan apparatus; separating the scanned document with a text/image separation apparatus into a text area and an image area and separating texts in the text area into symbols based on pixel data of the separated text area by comparing at least one pixel of the pixel data in the separated text area with a plurality of neighboring pixels to determine and separate individual symbols of the text area; extracting one or more properties of the separated symbols and comparing the extracted symbol properties with one or more index thresholds to determine whether the text including the symbols is an index object with an index determination apparatus, where the index thresholds are set as an average value of preset symbol properties calculated based on variation of the preset symbol properties; and creating an index page with an index page creation apparatus including the text determined as the index object and information about a page including the text that corresponds to the index object, wherein the symbols are determined as index-object symbols, the index-object symbols are grouped, and the texts including the groups of the index-object symbols are determined as objects in the index, when the extracted symbol properties are greater than the index thresholds. 18. The method of claim 16 , wherein the index thresholds comprise a reference value for determining an index-object symbol including one or more of a symbol width threshold, a symbol height threshold, and a stroke width threshold, or the index thresholds are set by a user.