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Stuart West2001751

westsb@lsbu.ac.uk

Content-Based Information Content-Based Information Retrieval (CBIR) in ImagesRetrieval (CBIR) in Images

The Applications and the RealThe Applications and the RealWorld UsesWorld Uses

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What is CBIR?What is CBIR?

Content-Based Information Retrieval is the retrieval of images based on the visual features of an image such as colour, texture, and shape.

CBIR came about due to the large volumes of images being stored in databases with only name association, which made searching for specific images inefficient and labour intensive.

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Basics of CBIRBasics of CBIR

There are two basic steps to the process of CBIR and they are: -

•Extract features of the image to a distinguishable extent.•Match these features to yield a result.

For example if you placed a query where you were looking for blue at the top of an image then you would likely get results where the top of the image was of sky.

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The ApplicationsThe Applications

I will now give a brief overview of three image retrieval systems which are available now.

– Blobworld– SQUID– PicToSeek

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BlobworldBlobworld

Blobworld is an image retrieval system which automatically segments an image into regions which, roughly represent objects or parts of an object.

As you can see from the image above the image has been segmented into the wolf and the background.

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Blobworld (continued)Blobworld (continued)

As could be seen the image was segmented. Then using this system you can then select an area of the image to query.

Here the wolf is selected and this can be searched for in the database. The database is searched by colour and the texture of the selected area.

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SQUID (Shape Queries Using SQUID (Shape Queries Using Image Databases)Image Databases)

SQUID is the only internet image retrieval system where you can submit shapes as queries.

SQUID works by processing each image so that a boundary contour can be recovered.

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SQUID (continued)SQUID (continued)

As could be seen from the previous images the contour had been processed. This can then be queried and the contour is manipulated using very complex formulae. Then the results are returned.

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PicToSeekPicToSeek

PicToSeek is a java based image retrieval system that can retrieve images not only from a database but it also uses WebCrawler's so you cans input the URL of an image and the system will retrieve it.

This system uses colour histograms to retrieve its results

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PicToSeek (continued)PicToSeek (continued)

Colour histograms show the distribution of the tones by way of a histogram. This means that a graph shows how many of each colour there is in an image.

An example of a colour histogram

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PicToSeek (continued)PicToSeek (continued)

In order for this system to return results, the histogram for the query image is compared to the histograms of the images in the database.

Then the images that closely match the histogram of the query are returned.

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PicToSeek (continued)PicToSeek (continued)

Original state of the system

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PicToSeek (continued)PicToSeek (continued)

State of the system after query

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Real World ApplicationsReal World Applications

I will now give a brief overview of what kind of real world applications that CBIR could be used for.

• Medical Diagnoses• Forensic Investigations• The Military

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Medical DiagnosisMedical Diagnosis

The main requirement for image retrieval in medicine is retrieving images for a specific patient.

However there is now an interest in using CBIR to aid in diagnosis.

For example an x-ray of a patient can be used as a query, and matching x-rays from other patients can be retrieved with their diagnosis.

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Forensic InvestigationsForensic Investigations

Law enforcement agencies store a huge amount of images ranging from mug shots, crime scene photos to tyre treads and shoe prints.

CBIR has been used in forensic investigations for many years with fingerprint matching.

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Forensic Investigations (continued)Forensic Investigations (continued)

However fingerprint recognition is still not perfect, sometimes they still have to be checked manually.

Although this technique is still not perfected there are other areas that other law enforcement agencies are interested in such as face recognition, and iris scans.

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MilitaryMilitary

These CBIR systems are probably the best developed but they are not well publicised for obvious reasons.

The military use these systems for things such as the identification of targets from satellite photography or the recognition of enemy aircraft from radar screens.

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Other ApplicationsOther Applications

There are also many more real world applications that CBIR can be used for: -

– Journalism– Geographical Information– Web Searching– Education– And various others

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ConclusionConclusion

CBIR is still a relatively young technology but advances are being made at a steady rate.

It is a very important tool in the military and law enforcement agencies. I believe it could become extremely useful in the commercial sector.

However before this can happen further advances must be made.