A brief history of document scanning.
- Captain Capture
- Apr 4, 2017
- 5 min read
Scanning a document is now considered a normal productivity task but it wasn’t always as simple as pressing a button and in many respects it can still be quite complex.
In recent years we have seen a huge shift to digitisation. Technological advancements in computing, mobility and cloud services have not only changed our personal relationships but they have totally changed our working practices.
Paper is the oldest form of recording, sharing and transacting our daily lives and whilst there is a significant shift to digitally born information, we will still have to accommodate paper in our processes.
The process of scanning can be described as the procedure of converting hard copy physical media such as paper records and documents into a digital form. Converting hard copy information to digital content allows us to expedite business processes, preserve content digitally, secure archives as well as supporting enhanced collaboration. So who were the first proponents of document scanning and what were the driving forces then?
The Pantelegraph - 1858
The Pantelegraph was developed in the University of Florence by an Italian Giovanni Caselli to help verification of signatures in banking transactions. In November 1860 a telegraph line between Paris and Amiens was allotted to Caselli which enabled a true long-distance experiment, which was a complete success, with the signature of the composer Gioacchino Rossini as the image sent and received, over a distance of 140 km (87 mi). The device used electromagnets to drive and synchronize movement of pendulums at the source and the distant location, to scan and reproduce images. It could transmit handwriting, signatures, or drawings within an area of up to 150 x 100mm. The Pantelegraph is leargely credited with being the first scanner, interestingly the Pantelegraph is also considered as being the forerunner to the facsimile machine.
The Bélinographe - 1907
The French continued to heavily influence image communication and in 1907 Édouard Belin invented a phototelegraphic apparatus called the Bélinographe. Like the Pantelegraph it was used for transmitting information (pictures) long distances over telephone and telegraphic networks. The Bélinographe, device was designed to use an “electric eye” to measure light intensity. The intensity levels then transmit to a receiver, where a source of light can reproduce the intensities that were measured by the transmitter, impressing on photographic paper. Modern photocopiers use a very similar principle, with light captured by a sensor and the impression based on laser technology.
The Drum Scanner -1957
The first image scanner designed for use (or driven by a computer) was the “Drum” Scanner. It was built in 1957 at the US National Bureau of Standards by a team led by Russell A. Kirsch. Drum scanners are rarely used these days, the technology uses photomultiplier tubes, rather than the charge-coupled device (CCD) array that we see in some modern day scanners. Those who are very interested in the fine detail of pictures favour drum scanners because they can extract more detail from the very dark shadow areas of a transparency than flatbed scanners using CCD sensors can.
Technology Jumps.
During the 1960’s and 70’s technological advancements in CCD and CIS as well as light sources made it possible for documents scanners to become a ubiquitous device. In 1974 Ray Kurzweil led the development of the first omni-font Optical Character Recognition (OCR) system which was the process behind recognising text written in multiple font types. During the 70’s two main scanning componets were refined, the Charge Coupled Devive (CCD) and the Contact Image Sensor (CIS) still underpin the scanning operations of all modern day scanners.
Charge Coupled Device (CCD)
The charge-coupled device was invented in 1969 at AT&T Bell Labs. At the time it was thought that CCD could be used for different purposes including imaging. In a CCD for capturing images, there is a photoactive region (an epitaxial layer of silicon), and a transmission region made out of a shift register (the CCD, properly speaking). The CCD is now a major technology component for Digital Imaging and was the breakthrough technology for document scanners.
Contact Image Sensor (CIS)
CIS technology has been enhanced since the sixties and provides a newer technology for capturing images. The advancemenst in LED light sources have allowed CIS technology to become more widely used. A CIS scanning system typically uses light-emitting diodes (LED) to light up the document. The LED light is passed through a light pipe to ensure even distribution of light across the entire scan line. Unlike CCD technology CIS does not use mirrors or lenses and as such takes up a fraction of the space. You will most likely see CIS technology used in smaller mobile scanners that are USB powered.
The quality difference between these two scanning technologies has long been debated. It can be difficult to tell the difference but most commentators would suggest that CCD has bit of an edge in terms of quality. The major disadvantage of CIS is the poor field of focus, this can shows shadows where the document is not absolutely flat. However because the light source, image sensor, and lens assembly are combined into a single scan head, a CIS scanner can be much more compact and requires less power. All mobile powered USB scanners as well as most flatbed scanners have CIS scanner technology whereas most Automatic Document Feeder (ADF) scanners use CCD.
The Flatbed Scanner
The modern day flatbed scanner is now a very consumer oriented device, there has been little technological advancement in recent years apart from reduced manufacturing costs. Flatbed scanners are generally purchased by consumers who wish to scan one or two documents on an ad-hoc basis. The exception to this is where the capture of high resolution images is required.
The ADF Scanner
There have been many advancements in the field of paper handling and image enhancement which has driven the professional document capture industry. These high speed automatic feed scanners are designed to reduce the amount of batch preparation and ensure consistent image quality. These types of devices have interfaces which allow for the capture of images from within an application.
The Mobile Scanner
As our working practices change more and more people use USB powered directly attached scanners to capture content on the go. Typical applications for this are expense management, contract or order confirmation and transactional capture outside of the normal place of work.
The Mobile Phone
There are many scanning APPS available for the modern day smart phone. Like flatbed scanners this is a great solution for the odd document here and there but the lack of consistent ambient light and the difficulty in focus means that it could take more time the necessary if you wanted to scan (or take a picture) of many documents.
There have been and continue to be many developments in the interesting world of document scanning. Thanks to the pioneers of this technology and the companies that continue to develop on these platforms many businesses can offer enhanced customer service to their customers. It may not sound interesting but the scanning industry continues to help document our past and liberate valuable information trapped in hard copy format driving more effective business process. In an age of Artifical Intellignce where we try and predict outcomes and scenarios extracting content from hard copy is now more relevant than ever before.
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