The Metropolitan Police Photographic Unit
The Photographic Branch of the Metropolitan Police was founded in November 1901 to support the work of the Fingerprint Branch. The same year, the Home Office authorised an experiment involving the purchase of plates, bottles and chemicals. During the experiment, 162 photographs were taken and nearly 100 prints were made. The Home Office deemed the experiment a success and in May 1902 approval was granted to set the operation on a permanent footing. Since 1901, photography in the Metropolitan Police has come a long way, and fingerprint work is now only a small part of the range of photographic techniques undertaken. The Branch is now the largest single Police Photographic Unit in the UK and produces approximately 250,000 Scene of Crime images per year.
The Photographic Unit was until recently producing pictures by conventional methods with the use of film cameras with negatives and prints etc. Scene of Crime Photographers produce a complete proof print of all pictures taken at a crime scene which are then delivered to the Investigating Officers. During the ensuing period when all the evidence is gathered these Officers will select the appropriate images, which will eventually be used in Court. This process is both time consuming and labour intensive, as it involves the manual operation of film storage, print selection and production, together with the logistics of communicating and distributing prints to Officers located around the wide Metropolitan area.
Photography produced by conventional methods is generally accepted as admissible evidence and rarely challenged in Court. However this would not necessarily be the case with photography stored electronically in a computer system. Photographic images stored in computers are often compressed in order to greatly reduce their capacity. For example uncompressed images stored in TIFF file format may have a capacity of around 18MB but when compressed in JPEG file format they are reduced to around 1 MB. It is important that in order to retain total originality that all photography must be stored as uncompressed images. Furthermore even uncompressed images stored in a computer system could still pose a problem since they could be accidentally overwritten or deleted etc. The Photographic Unit is also intending to introduce digital cameras; therefore there would be no film as back up. With all these criteria in mind the Unit set about finding the best way to implement an acceptable digital storage solution.
Kodak introduced the Metropolitan Police Photographic Development Manager to Westpoint, a Data Storage Solution provider with specialist knowledge of Image Storage and Archive Solutions. Westpoint has over the past 10 years been integrating Image Archiving Systems for users such as regional newspapers who were early pioneers of CD-ROM storage techniques.
Westpoint recommended that the solution had to be based on a low cost high capacity media on which data once written could not be changed. The most suitable was DVD-R, which records data using Write Once Read Many - WORM technology. The amount of data the unit was currently creating, around 40GB per week, could be stored on just 5 double sided DVD-R disks at a total media cost of less than £50.
Westpoint, in liaison with the Photographic Development Manager tailored a complete Archive System, which featured the latest hardware and image archiving software. The system comprised of a high performance NT Server with fault tolerant RAID controlling a JVC 8600 series 600 slot
DVD Jukebox fitted with DVD-ROM readers and a DVD-R recorder. The Jukebox Management Software from German developer Point Software included version 4 of Jukebox Manager. This latest release implemented some new features specially requested by the Photographic Unit and was believed to be the first to offer disc spanning and conformity to the UDF standard.
Since the first installation last year two more systems have now been added. The total capacity of these systems is almost 20 Tera bytes - storage for around a million high capacity uncompressed images. These images are easily located by reference to individual case numbers and prints can be produced just as easily as printing hard copies of word processing documents.
The use of DVD-R technology has many advantages for this type of application. Security of data is assured as there is no need to implement back up procedures needed with other storage devices such as hard disks. Duplicate copies of each DVD-R disk can be kept off site for disaster recovery. The Jukebox is lockable providing a secure housing for the stored images.
The emergence of DVD-R standards which include the General Purpose DVD-R standard for computer data together with the UDF standard for recording data, will allow the media to be compatible with future developments. The back up copies stored off site can also be read by desk top DVD-ROM readers conforming to the UDF standard which are now found in the latest Windows and UNIX operating systems.
2012 update to case study
The Metropolitan police have been using the storage solution from Westpoint since the original installation in 2003. The original jukeboxes have been upgraded to support Blu Ray media and currently provide the photographic department with over 120 Terabytes of secure storage.