Development of a Uniform Colour Space for Evaluating Colour Differences Under HDR Viewing Conditions

Colour Image Enhancement using Perceptual Saturation and Vividness

Color and Imaging Conference ◽

10.2352/issn.2169-2629.2019.27.43 ◽

2019 ◽

Vol 2019 (1) ◽

pp. 243-246

Author(s):

Muhammad Safdar ◽

Noémie Pozzera ◽

Jon Yngve Hardeberg

Keyword(s):

Image Quality ◽

Image Enhancement ◽

Test Performance ◽

Appearance Model ◽

Colour Space ◽

Categorical Judgment ◽

Saturation Scale ◽

Colour Image ◽

Colour Appearance ◽

Future Test

A perceptual study was conducted to enhance colour image quality in terms of naturalness and preference using perceptual scales of saturation and vividness. Saturation scale has been extensively used for this purpose while vividness has been little used. We used perceptual scales of a recently developed colour appearance model based on Jzazbz uniform colour space. A two-fold aim of the study was (i) to test performance of recently developed perceptual scales of saturation and vividness compared with previously used hypothetical models and (ii) to compare performance and chose one of saturation and vividness scales for colour image enhancement in future. Test images were first transformed to Jzazbz colour space and their saturation and vividness were then decreased or increased to obtain 6 different variants of the image. Categorical judgment method was used to judge preference and naturalness of different variants of the test images and results are reported.

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Opponent Center-Surround Contrast: Colour to Grey Conversion

London Imaging Meeting ◽

10.2352/issn.2694-118x.2020.lim-18 ◽

2020 ◽

Vol 2020 (1) ◽

pp. 105-108

Author(s):

Ali Alsam

Keyword(s):

Evolutionary Algorithms ◽

Three Dimensional ◽

The State ◽

Colour Space ◽

Vision Science ◽

State Of Art ◽

Over Time

Vision is the science that informs us about the biological and evolutionary algorithms that our eyes, opticnerves and brains have chosen over time to see. This article is an attempt to solve the problem of colour to grey conversion, by borrowing ideas from vision science. We introduce an algorithm that measures contrast along the opponent colour directions and use the results to combine a three dimensional colour space into a grey. The results indicate that the proposed algorithm competes with the state of art algorithms.

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A smoke image segmentation algorithm based on rough set and region growing

Journal of Forest Science ◽

10.17221/34/2019-jfs ◽

2019 ◽

Vol 65 (No. 8) ◽

pp. 321-329

Author(s):

Haitao Wang ◽

Yanli Chen

Keyword(s):

Image Segmentation ◽

Rough Set ◽

Region Growing ◽

Recall Rate ◽

Segmentation Algorithm ◽

Colour Space ◽

Seed Point ◽

Black Smoke ◽

Growth Method ◽

Image Segmentation Algorithm

Because the image fire smoke segmentation algorithm can not extract white, gray and black smoke at the same time, a smoke image segmentation algorithm is proposed by combining rough set and region growth method. The R component of the image is extracted in the RGB colour space, the roughness histogram is constructed according to the statistical histogram of the R component, and the appropriate valley value in the roughness histogram is selected as the segmentation threshold, the image is roughly segmented. Relative to the background image, the smoke belongs to the motion information, and the motion region is extracted by the interframe difference method to eliminate static interference. Smoke has a unique colour feature, a smoke colour model is created in the RGB colour space, the motion disturbances of similar colour are removed and the suspected smoke areas are obtained. The seed point is selected in the region, and the region is grown on the result of rough segmentation, the smoke region is extracted. The experimental results show that the algorithm can segment white, gray and black smoke at the same time, and the irregular information of smoke edges is relatively complete. Compared with the existing algorithms, the average segmentation accuracy, recall rate and F-value are increased by 19%, 21.5% and 20%, respectively.<br /><br />

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EXPLORIA, a New Way to Teach Maths at University Level as Part of Everything

Mathematics ◽

10.3390/math9101082 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1082

Author(s):

Pantaleón D. Romero ◽

Nicolas Montes ◽

Sara Barquero ◽

Paula Aloy ◽

Teresa Ferrer ◽

...

Keyword(s):

Learning Outcomes ◽

Learning Process ◽

Positive Emotions ◽

Ad Hoc ◽

Teaching Methodology ◽

Colour Space ◽

Engineering Degree ◽

Positive Attitudes ◽

University Level ◽

Academic Results

The main objective of this article has been to evaluate the effect that the implementation of the EXPLORIA project has had on the Engineering Degree in Industrial Design and Product Development. The EXPLORIA project aims to develop an integrated competence map of the learning process, where the subjects are no longer considered as isolated contents, by elaborating an integrated learning process where the competences and learning outcomes of the subjects are considered as a whole, global and comprehensive learning. The EXPLORIA project connects the competencies of the different STEAM subjects that make up the degree, designing a learning process as a logical, sequential and incremental itinerary. Through concepts on which the foundations of design are based—shape, volume, colour, space and structure—the competencies of the different subjects are defined in incremental learning levels: understanding, applying, experimenting and developing, all taken from Bloom’s taxonomy. Mathematics is linked to the rest of learning through active learning methodologies that make learning useful. This new methodology changes the student’s affective domain towards mathematics in which positive emotions are transformed into positive attitudes that will improve the learning result and therefore, the students’ academic results. To validate it, at the end of the paper, the academic results compared with previous years are shown, as well as an ad hoc survey of the students’ assessment of the new teaching methodology.

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Linear Uniform Colour Space Composed of Simple Transformations of Tristimulus Values X, Y and Z

Journal of Light & Visual Environment ◽

10.2150/jlve.25.1_49 ◽

2001 ◽

Vol 25 (1) ◽

pp. 49-59 ◽

Cited By ~ 4

Author(s):

Koichi IKEDA ◽

Kiyoshige OBARA

Keyword(s):

Colour Space ◽

Tristimulus Values

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Spectral Sensitivity of Photoreceptors and Colour Vision in the Solitary Bee, Osmia Rufa

Journal of Experimental Biology ◽

10.1242/jeb.136.1.35 ◽

1988 ◽

Vol 136 (1) ◽

pp. 35-52

Author(s):

R. MENZEL ◽

E. STEINMANN ◽

J. DE SOUZA ◽

W. BACKHAUS

Keyword(s):

Spectral Sensitivity ◽

Colour Vision ◽

Three Dimensional ◽

Just Noticeable Difference ◽

Species Discrimination ◽

Colour Space ◽

Absorption Function ◽

Perceptual Distance ◽

Line Elements ◽

Colour Signals

The spectral sensitivity of single photoreceptors of Osmia rufa was determined by a fast voltage-clamp technique. Three receptor types were found whose spectral sensitivity functions followed a rhodopsin-like photopigment absorption function with λmax values at 348nm (ultraviolet receptor), 436nm (blue receptor) and 572nm (green receptor). The λmax of the green receptor in Osmia rufa is shifted to much longer wavelengths compared with other insect species. Discrimination of colour signals was tested after training a bee at the entrance to its nest. The colour signals were filter discs (70 mm in diameter) with a hole (10 mm in diameter) in the centre and the bees quickly learned to use the coloured disc as a marker of the nest entrance. Tests were dual forced-choice tests with two coloured discs closely positioned next to each other. 94 different tests were each repeated 5–15 times and were performed after training to 12 different colour signals. A photoreceptor model was used to calculate the loci of the colour signals in a three-dimensional colour space and in a chromaticity diagram. The perceptual distance between the colour loci was calculated as line elements (minimum number of just noticeable difference, jnd-steps), which were based on the noiseproperties of the photoreceptors. The discrimination determined by the behavioural tests correlated very well with the jnd-steps. The correlation was better for the line elements in the colour plane than in the colour space. Osmia rufa was compared with the honeybee Apis mellifera and the stingless bee Melipona quadrifasciata. There is no difference in colour selection between Osmia and Apis, whereas Melipona discriminates less well in the violet-blue region. The model calculation was used to compare the chromaticity diagrams and the spectral discrimination functions of the three species. It is concluded that the receptor model used in this study predicts the discrimination behaviour of the three bee species very well. Therefore, comparative studies on colour vision in flowervisiting insects may be based on spectral measurements of the photoreceptors, and in many cases this reduces the extent of laborious behavioural studies.

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The Origin of Sand and Its Colour on the South-Eastern Coast of Spain: Implications for Erosion Management

Water ◽

10.3390/w12020377 ◽

2020 ◽

Vol 12 (2) ◽

pp. 377 ◽

Cited By ~ 2

Author(s):

Asensio-Montesinos ◽

Pranzini ◽

Martínez-Martínez ◽

Cinelli ◽

Anfuso ◽

...

Keyword(s):

Western Mediterranean ◽

Mediterranean Coast ◽

Eastern Coast ◽

Storm Events ◽

Colour Space ◽

Source Areas ◽

Beach Width ◽

Severe Erosion ◽

Colour Coordinates ◽

Economic Function

Sand colour can give important information about mineral composition and, consequently, sediment source areas and input systems. Beach appearance, which is mostly linked to sand colour, has a relevant economic function in tourist areas. In this paper, the colour of 66 sand samples, collected along both natural and nourished beaches in the western Mediterranean coast of Spain, were assessed in CIEL*a*b* 1976 colour space. The obtained results showed relevant differences between natural and artificially nourished beaches. The colour of many nourished beaches generally differs from the native one because the origin of the injected sand is different. The native sand colour coordinates’ range is: L* (40.16–63.71); a* (−1.47–6.40); b* (7.48–18.06). On the contrary, for nourished beaches’ the colour range is: L* (47.66–70.75); a*(0.72‒5.16); b* (5.82–18.82). Impacts of beach nourishment on the native sand colour were studied at San Juan beach, the most popular one along the study area. Nourishment works were performed after severe erosion, usually linked to anthropic activities/structures and storm events, but also to increase beach width and hence benefit tourism.

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