Which product best suits your needs depends, of course, on your organization. The first three products (professional, corporate, FineReader online) are targeted towards end users and smaller organizations; we can omit them from further discussion because the XML output formats most suitable in a digital library context are not supported. The other three options (recognition server, cloud SDK and engine SDK) may be used for digitization workflows in a digital library context.
Engine vs. Recognition Server
The recognition server manages aspects like distributed processing and job scheduling; the engine allows full control over all configurable processing options, but using it requires software development. Development of custom applications involving OCR requires the use of the engine SDK. It seems hard to give a general rule for use in digitization workflows, but, for instance, service providers or libraries targeted on running high-volume standardized processes might well use the recognition server, whereas organizations with skilled technical staff and specific requirements might favour the engine.
In terms of technical staff competence, deployment of the recognition server leans on systems administration, whereas the engine SDK leans more heavily on software developers.
Cloud SDK vs. Engine SDK
For a comparison between the FineReader Engine SDK and the cloud SDK, cf. www.abbyy-developers.eu/en:onlineocrsdk:comp_onlinesdk-fre. Cf. alsoforum.ocrsdk.com/questions/133/ocr-sdk-versus-finereader-engine:
FineReader Engine has a bigger set of tuning options compared to Cloud SDK. For example, using Engine you can specify your own dictionaries for recognition, you can get detailed information about recognition variants, you can setup advanced export parameters like encryption for created PDFs and so on. Engine has dozens of options, Cloud SDK provides access only to most useful of them.
Cloud SDK is already using the best Engine’s settings for general images, but in some cases it is possible to achieve better recognition results using FineReader Engine by tuning it according to you image source. For example you may set up а specific dictionary, or apply image preprocessing filters, or tell recognizer that there is no italic. This is not a simple task and requires a lot of testing.
For which Tasks do we need the Engine SDK?
The engine SDK is the only product allowing for full control over a number of features, for instance
1. Use of custom dictionaries
2. Accessing recognition variants
3. We want to do medium to large scale in-house processing; we have our own workflow requirements or other reasons not the use the recognition server.