In the past, data entry was done manually. Now, in order to save time, we need to scan data tables and automatically identify the content sections that participants entered, such as highlighting the corresponding areas on the form.

We do not know if there is any software that can implement this function.

Our initial idea is to rasterize PDF file and use the axes (X,Y) on PDF document to mark the location of data and use different colors to highlight the modified area. However, no such attempt has been made yet, and no suitable software has been found.

This article on XsPDF.com is what you looking for, check out: import a raster of a PDF file

Answers

Many tools or software does not support directly rasterizing pdf files. They mostly support common raster image files, such as .jpg, bmp, .png, .gif, and so on. So, the best way come to my mind is to convert your PDF to an image format first, and then use rasterizer to process the image.

When you get the converted image file, you can rasterize it and do more processing, like using extract() function to get the brightness value from the image. Also, you can specify which row and column to get pixel values from.