Prof. Marina Bloj Profile

Prof. Marina Bloj

Professor of Visual Percpetion at Univ of Bradford

SPIE Involvement:

Author

Publications (2)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 10 February 2009 Paper

Improved colour to greyscale via integrability correction

Mark Drew, David Connah, Graham Finlayson, Marina Bloj

Proceedings Volume 7240, 72401B (2009) https://doi.org/10.1117/12.810290

KEYWORDS: Magnetic resonance imaging, Image compression, Sun, Image analysis, Visualization, Electronic imaging, Image processing, Diffusion, Computer science, Life sciences

Read Abstract +

The classical approach to converting colour to greyscale is to code the luminance signal as a grey value image. However, the problem with this approach is that the detail at equiluminant edges vanishes, and in the worst case the greyscale reproduction of an equiluminant image is a single uniform grey value. The solution to this problem, adopted by all algorithms in the field, is to try to code colour difference (or contrast) in the greyscale image. In this paper we reconsider the Socolinsky and Wolff algorithm for colour to greyscale conversion. This algorithm, which is the most mathematically elegant, often scores well in preference experiments but can introduce artefacts which spoil the appearance of the final image. These artefacts are intrinsic to the method and stem from the underlying approach which computes a greyscale image by a) calculating approximate luminance-type derivatives for the colour image and b) re-integrating these to obtain a greyscale image. Unfortunately, the sign of the derivative vector is sometimes unknown on an equiluminant edge and, in the current theory, is set arbitrarily. However, choosing the wrong sign can lead to unnatural contrast gradients (not apparent in the colour original). Our contribution is to show how this sign problem can be ameliorated using a generalised definition of luminance and a Markov relaxation.

Proceedings Article | 10 February 2009 Paper

Exploring eye movements for tone mapped images

Marina Bloj, Glen Harding, Alan Chalmers

Proceedings Volume 7240, 72400O (2009) https://doi.org/10.1117/12.810497

KEYWORDS: Eye, Computer programming, High dynamic range imaging, Image processing, Calibration, Algorithm development, Visualization, RGB color model, Image compression, Image quality

Read Abstract +

In the real world we can find large intensity ranges: the ratio from the brightest to the darkest part of the scene can be of the order of 10000 to 1. Since most of our electronic displays have a limited range of around 100 to 1, the last 20 years has seen much work done to develop different algorithms that compress the actual dynamic range of an image to that available in the display device. These algorithms, known as tone mappers, attempt to preserve as much of the images characteristics as possible [1]. An increasing amount of research has also been done to try to evaluate the 'best' tone mapper. Approaches have included pair wise comparisons of tone mapped images [2], comparison with real scenes [3] or using images displayed on a High Dynamic Range (HDR) monitor [4]. None of these approaches are entirely satisfactory and all suffer from potential confounding factors due to participant's interpretation of instructions and biases. There is evidence that the spatial and chronological path of fixations made by observers' when viewing an image (i.e. the scanpath) is repeated to some extent when the same image is again presented to the observer (e.g. [5]). In this paper we are the first to investigate the potential of using eye movement recordings, particularly scanpaths, as a discriminatory tool. We propose that if a tone-mapped image gives rise to scanpaths that are different from those obtained when viewing the original image this might be an indication of a poor quality tone mapper since it is eliciting eye movements that are different from those observed when viewing the original image.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years