Sunday, April 10, 2011

Book Scanner Improvements

The book scanner continues to evolve with passage of time.
Last week's work has been a great success.
The three improvement areas are:

  • Camera
  • Switched from regular camera to five year old Nikon D50 SLR.
  • This camera allows remote controlled operation. The remote allows a single operator to scan books. The operator does not have to physically touch any buttons on the camera to take a picture, the relative location of the camera to the page remains constant even after multiple shots.
  • The picture taken by the SLR camera is exactly the same as seen from the view finder. There is no offset and there is no need for guessing.
  • This camera allows fine control over shutter speed, aperture and ISO in the manual mode. It is possible to fine tune these parameters to get an awesome picture in normal room lighting conditions. Thus eliminating the need for any additional lighting.
  • Aperture - Lower aperture (high F stops) as the image does not have depth. This leads to a sharper image (F11)
  • Shutter speed - Lower shutter speed to compensate for poor room lighting conditions (1/2.5 seconds)
  • The lowest ISO number for the camera is 200.
  • Book Stop
  • The book stop prevents the book from sliding. This allows a fixed location of the camera to the book as the successive pages are flipped.
  • Software
  • Wrote an auto-numbering script last year in python. This script auto-numbers successive even/odd pages to the actual number of the page.
  • Photoshop allows batch operation. Once a picture is cropped, then the same cropping settings can be used for multiple images in an automated manner.
  • OCR software was able to convert image to text with a 6 Mega Pixel image resolution images.

It is now possible to get good quality images with minimal room lighting conditions.

No comments: