The Attical Project

The aim of this project is to develop effective techniques for enhancing colours in images. There are two quite distinct areas of application: aesthetic and interpretive. These are united by common methods and software, but divided by the manner of use. In aesthetic applications the enhancement is subtle and careful. The desire to improve the image is balanced against the need to preserve its qualities. In interpretive applications, often diagnostic and medical, the enhancement is intended to increase the speed and accuracy of interpretation.

NOTE: In the examples that follow, the transformations of the images are (relatively) subtle. You may wonder why a more dramatic demonstration was not chosen. There is an excellent reason: when shown dramatic results, the reaction is often “Great! That's really interesting, but I wouldn't want to do it to my images.”

Samples of aesthetic application in different arrangements: Gradual change | Side-by-side | Colour | Grayscale

Gallery of images

(Click on any image for large version.)

Strength = 0: original	Strength = 4	Strength = 8	Strength = 12


Strength = 0: original	Strength = 4	Strength = 8	Strength = 12

Applications

Aesthetic:

General. When it is desirable to enhance fine detail, lighten dark areas, darken light areas, or expand the contrast within regions.
Visual limitation. The human visual system, especially under ordinary viewing conditions, cannot discern as finer colour differences as can be projected or printed. Enhancement of colour differences prior to output can improve the viewing experience.
Exposure difficulties. The situation and content of scenes often present significant challenges: backlighting, deep shadows, sand, snow, reflective surfaces, dark objects and so on. Often much of the detail is registered in the digital image but is lost in normal viewing. Enhancement is then indicated.
Printing limitations. Detail is often lost in the printing process, even when executed skillfully. Established enhancement techniques are often applied before printing, and colour enhancement could be added to these.

Interpretive:

General. When important information is contained within fine detail, or obscured by low contrast within regions or large contrast differences between regions.
Radiology / diagnosis. Diagnosis of medical conditions is often crucially dependent on radiological examination using a variety of modalities, including X-ray, CAT, PET, MRI, and ultrasound.
Portal imaging. In radiotherapy, positioning the treatment accurately is very important. The accuracy of portal imaging is important in ensuring the best outcome.
Forensic. The interpretation of still or moving images can be important in legal cases.

Current plans and status

For some time software has been released that produces results such as the samples shown here. However, new innovations have been made that permit very high quality processing and these have yet to be implemented. While the old software proved reusable and portable, so many new routines are required that a complete overhaul is sensible.

In addition to the opportunity to revise and expand the software base, we have also taken the opportunity to ‘rebrand’ the project. Past experience has to be faced. These new techniques have been developed from standard and well-known ones. However, such associations have proved to be a drag. The range of effects and applications are fundamentally different, and a fresh perception is needed.

Planned features include:

8-bit, 16-bit and 32-bit versions.
Dramatically improved filtering for spatial estimation.
Improved colourspace transformations.

In the absence of funding, this is a low-priority project. Nevertheless, we hope to see significant progress by the end of 2004.