Apparatus and a method for image processing

An apparatus for processing an image comprising:

• an analog-to-digital converter for converting an analog image signal with respect to document data which are detected and input by an image reading sensor of an image inputting device into digital data by using a control signal input from a controller of the image inputting device, a changed value of a contrast input from the controller, and a changed value of a brightness;
• an upper limited reference voltage setting means for setting an upper limited reference voltage of the analog-to-digital converter so that the analog-to-digital converter performs a correcting of image distortion and a processing of image;
• a lower limited reference voltage setting means for setting the lower reference voltage of the analog-to-digital converter so that the analog-to-digital converter performs a correcting of image distortion and a processing of image;
• a black correcting memory for storing a black correcting data output after the analog-to-digital converter performs an operation of converting the analog image signal into digital data;
• a white correcting memory for storing a white correcting data output after the analog-to-digital converter performs an operation of converting the analog image signal into the digital data;
• a maximum value detector for detecting a maximum pixel data value from digital data output from the analog-to-digital converter;
• and
• a reference data storing section for storing data output from the maximum value detector.

A method for processing an image by an image inputting apparatus having a preprocessor which includes a white correcting memory, a black correcting memory, and a detector for measuring maximum value, the method comprising the steps of:

• generating reference data so as to correct a distortion of the image;
• determining which operation is selected from operations for respectively controlling a contrast and a brightness, and for removing a background color of the image;
• setting an upper limited reference voltage and a lower limited reference voltage corresponding to the selected operation;
• and
• performing a white correction and a black correction simultaneously of the image by using the reference data while performing the selected operation for the image by using the upper limited reference voltage and the lower limited reference voltage which are set.