You will need
  • program ScanKromsator.
Download and install the program ScanKromsator to remove the grey backgroundand the scans. You can do this by going to the official website of the manufacturer of the program Select an application version and click the link "Download".
Install the software on the computer to remove the grey background with a djvu or pdf file, open it in the program. Go to settings, applications, check the box next to options Enhance image, then click on the button Gray enhance, instead you can also use the grief I feel key B.
Install settings clean backgroundand tab Background cleaner. Set the Cleaner passes equal to one to remove the background of the scan. If the document is very little color contrast between the backgroundω and a text, in this case, the check box must be selected next to the parameter Correct low contrast, it will allow you to choose the sensitivity of the recognition of textual information on the background ofE.
Start with a value of 20-25, and consistently decrease at 5. After Chromator will remove the background from the scanned image, it will check the presence of text, which contrast against the backgroundcolor ovomu greater than or equal to the specified threshold. If such a value is found, the color of this point will not change or will be replaced with pure black.
Navigate to the Quality tab, click Enhance, set the Cleaner passes equal to one. Next, uncheck the option Protect black pixels. Make available to scan the illustrations, filled with gray area Exclude to protect from damage.
Preview of cleaning the grey backgroundand using the Preview button with the resample tab Quality. Adjust the Sensitivity (five to thirty) to achieve the removal of the background. The more contrast between letters and backgroundof om, the more set the value of this parameter. Go to window Protect black and turn it off.