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A Standardized Workflow for Illumination-Invariant Image Extraction

2007· article· en· W2400213164 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueColor and Imaging Conference · 2007
Typearticle
Languageen
FieldPhysics and Astronomy
TopicColor Science and Applications
Canadian institutionsSimon Fraser University
Fundersnot available
KeywordsArtificial intelligenceComputer visionChromaticitySharpeningComputer scienceStandard illuminantInvariant (physics)Mathematics

Abstract

fetched live from OpenAlex

The illumination-invariant image is a useful intrinsic feature latent in colour image data. The idea in forming an illumination invariant is to postprocess input image data by forming a logarithm of a set of chromaticity coordinates, and then project the resulting 2-dimensional data in a direction orthogonal to a special direction, characteristic of each camera, that best describes the effect of lighting change. Lighting change is approximately simply a straight line in the log-chromaticity domain; thus, forming a greyscale projection orthogonal to this line generates an image which is approximately independent of the illuminant, at every pixel. One application has been to effectively remove shadows from images. But a problem, addressed here, is that the direction in which to project is camera-dependent. Moreover, preprocessing with a spectral sharpening transform to linearly transform the sensor curves to more narrowband ones greatly improves shadow attenuation, but sharpening is also camera-dependent and we may not have information on the camera. So here we take a simpler approach and assume that every input image consists of data in the standardized sRGB colour space. Previously, this assumption has led to the suggestion that the built-in mapping of sRGB to XYZ tristimulus values could be used by going on to sharpen the resulting XYZ and then seeking for an invariant. Instead, here we sharpen the sRGB directly and show that performance is substantially improved this way. This approach leads to a standardized sharpening matrix for any input image and a fixed projection angle as well. Results are shown to be satisfactory, without any knowledge of camera characteristics.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Other design · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.867
Threshold uncertainty score0.307

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.013
GPT teacher head0.307
Teacher spread0.293 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it