Chromatic Components Research Articles

Differential Coding Using Enhanced Inter-Layer Reference Picture for the Scalable Extension of H.265/HEVC Video Codec

Differential coding methods improve coding efficiency of scalable video codecs by adding the high-frequency component present in the previously coded enhancement layer (EL) pictures to the base layer (BL) picture. This paper proposes a method to enable differential coding in a scalable codec design without affecting the core coding tools, thus allowing a practical implementation to reuse single-layer hardware or software components. This is achieved by creating an additional reference picture called enhanced inter-layer reference (EILR) and inserting it to the EL decoded picture buffer and reference picture lists. An EILR picture is generated by adding differential information to the current inter-layer reference picture. The differential information is calculated using the previously decoded pictures of the BL and EL and the motion information of the BL picture. The proposed method reduces luma total bitrate on average by 2.2% and 2.8% for random access and low-delay test cases, respectively. The improvements are more significant for chroma components with the average bitrate reduction of 6.5%. The measured decoding time increase for a reference software implementation is 16% with negligible overhead on encoding time.

In situ observations on behaviour of the ommastrephid squid genus Illex (Cephalopoda: Ommastrephidae) in the northwestern Atlantic

We compiled observations of ommastrephid squid of the genus Illex, primarily Illex illecebrosus from archived submarine video footage recorded during dives off Cape Hatteras and New England, and in the Gulf of Mexico. Based on the behaviour observed, we derived a partial in situ ethogram, or catalogue of the body patterns and behaviour. In total, 36 components were observed: 16 chromatic components (5 light and 11 dark), 10 postural components and 10 locomotor components. Co-occurrence analyses were used to show that specific sets of components occurred together either more or less often than they would if chosen at random. In addition, some of the components were observed occurring during specific behaviours, such as bottom sitting, hunting, or schooling. Such observations by submersibles also provide very precise, although incomplete, records of depth distribution. We summarize the depths and altitudes above bottom of these observations by time of day. Most of the squid were observed near bottom at depths of about 200–900 m. The deepest depths observed were during daytime and the shallowest during the evening. However, individuals were observed as much as 1000 m above the bottom during daytime whereas others were on or near the bottom in deep water during the evening.

An improved universal subsampling strategy for compressing mosaic videos with arbitrary RGB color filter arrays in H.264/AVC

This work proposes an improved version of Yang et al.’s universal subsampling strategy for compressing mosaic videos with arbitrary red–green–blue (RGB) color filter arrays in H.264/AVC. For the subsampled images with 4:2:0 format, Yang et al.’s work retains the original Y luma component, but samples the proper U and V chroma components according to the corresponding mosaic structure for better reconstructing R and B pixels. However, Yang et al.’s strategy suffers from the RGB color deviations due to the U and V chroma subsampling, which results in the quality degradation of the reconstructed mosaic videos. We propose a novel modification for the Y luma component instead of only retaining the Y luma component such that the RGB color deviation problem can be resolved. Experimental results demonstrate that the proposed improved universal subsampling strategy delivers better quality of the reconstructed mosaic and full-color videos, when compared with Yang et al.’s one.

Calculation reduction method for color digital holography and computer-generated hologram using color space conversion

A calculation reduction method for color digital holography (DH) and computer-generated holograms (CGHs) using color space conversion is reported. Color DH and color CGHs are generally calculated on RGB space. We calculate color DH and CGHs in other color spaces for accelerating the calculation (e.g., YCbCr color space). In YCbCr color space, a RGB image or RGB hologram is converted to the luminance component (Y), blue-difference chroma (Cb), and red-difference chroma (Cr) components. In terms of the human eye, although the negligible difference of the luminance component is well recognized, the difference of the other components is not. In this method, the luminance component is normal sampled and the chroma components are down-sampled. The down-sampling allows us to accelerate the calculation of the color DH and CGHs. We compute diffraction calculations from the components, and then we convert the diffracted results in YCbCr color space to RGB color space. The proposed method, which is possible to accelerate the calculations up to a factor of 3 in theory, accelerates the calculation over two times faster than the ones in RGB color space.

Influence of local scene color on fixation position in visual search

Where observers concentrate their gaze during visual search depends on several factors. The aim here was to determine how much of the variance in observers' fixations in natural scenes can be explained by local scene color and how that variance is related to viewing bias. Fixation data were taken from an experiment in which observers searched images of 20 natural rural and urban scenes for a small target. The proportion R2 of the variance explained in a regression on local color properties (lightness and the red-green and yellow-blue chromatic components) ranged from 1% to 85%, depending mainly on how well those properties were consistent with observers' viewing bias. When viewing bias was included in the regression, values of R2 increased, ranging from 62% to 96%. By comparison, local lightness and local lightness contrast, edge density, and entropy each explained less variance than local color properties. Local scene color may have a much stronger influence on gaze position than is generally recognized, capturing significant aspects of scene structure on target search behavior.

Chromatic analysis of blue ballpoint pen inks and related dyes

AbstractAnalysis of ballpoint pen inks on questioned documents is often required in the field of forensic analysis to identify the writing implement used in the commitment of a crime. In forensic work, it is thus necessary to identify the manufacturer of the pen or the specific ink product.In this article, a forensic analysis is documented for discrimination of a series of ballpoint pastes to identify the chromatic components used for blue ballpoint pen inks and thus to establish the writing instrument used in a questioned document. To achieve this, data of various adequate techniques have been corroborated: X‐ray fluorescence spectroscopy, ultraviolet–visible–near‐infrared spectrophotometry, in diffuse reflection and transmission modes, completed by trichromatic analyses, and thin layer chromatography. A protocol consisting of four steps has been proposed, in which various components provided by a database of reference dyes are removed, selected, and combined to assess the possible identity of an unknown pen ink paste among a set belonging to the same color pallet. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 169–177, 2015

Deploying Wide Color Gamut and High Dynamic Range in HD and UHD

This is an extended version of the paper with the same title that has been presented at IBC 2014. 1 Twenty years ago, Poynton presented a paper at IBC 1994 entitled “Wide gamut device-independent color image interchange.” The CCIR 709 standard had just been adopted (in 1990), and, by 1994, sRGB deployment in desktop computing was well under way. That paper anticipated commercial interest in exchange for wide-gamut imagery. As it turned out, wide gamut was not imminent: We’ve had 20 years of very stable color encoding for video in the form of BT.709 for HD (augmented recently by BT.1886, which finally standardizes gamma), and the 709-derivative sRGB that remains ubiquitous in the computer domain. Now, however, dramatic changes are under way. Wide color gamut (WCG), enabled mainly by RGB LED backlights for liquid crystal display (LCD) displays, has already seen initial deployment in consumer television. High dynamic range (HDR) cameras are commercially available; and HDR displays, mainly enabled by spatially modulated LED backlights, are on the verge of commercialization. Many industry experts agree that consumers will experience WCG and HDR as more significant than increasing spatial resolution from HD (“2K”) to “4K.” This paper revisits the topic of the 1994 paper, but now with some urgency, to address the question: How should wide color gamut and high dynamic range video imagery be encoded? The main conclusion is that the Y’CBCR technique and its variants are perfectly adequate for moderate dynamic range, but yield less than optimum performance when combined with HDR. New encoding techniques are needed. We conclude that: ▪A new high dynamic range opto-electronic conversion function (HDR OECF) (perceptual quantizer) should replace the conventional gamma function to enable HDR. ▪HDR should be encoded with at least 10 bits per component, to suppress “banding.” 10 bits Y”C B C R 4:2:0 is at this moment the accepted standard for encoding HDR, and Philips will support the developments deriving from that choice. ▪Going to 12 bits Y”C B C R 4:2:0 will bring too little perceived improvement on natural content; further improvement must come from other changes. ▪C B C R (chroma) subsampling performs worse in combination with the HDR OECF; we propose encoding and decoding constant luminance, with modified u'v' chromaticity components instead of C B C R . ▪Therefore, for the future, we propose going to 10 bits Y”u”v” 4:2:0.

On the purposes of color for living beings: toward a theory of color organization

Phylogenetic and paleontological evidence indicates that in the animal kingdom the ability to perceive colors evolved independently several times over the course of millennia. This implies a high evolutionary neural investment and suggests that color vision provides some fundamental biological benefits. What are these benefits? Why are some animals so colorful? What are the adaptive and perceptual meanings of polychromatism? We suggest that in addition to the discrimination of light and surface chromaticity, sensitivity to color contributes to the whole, the parts and the fragments of perceptual organization. New versions of neon color spreading and the watercolor illusion indicate that the visual purpose of color in humans is threefold: to inter-relate each chromatic component of an object, thus favoring the emergence of the whole; to support a part-whole organization in which components reciprocally enhance each other by amodal completion; and, paradoxically, to reveal fragments and hide the whole-that is, there is a chromatic parceling-out process of separation, division, and fragmentation of the whole. The evolution of these contributions of color to organization needs to be established, but traces of it can be found in Harlequin camouflage by animals and in the coloration of flowers.

Color Selectivity of the Spatial Congruency Effect: Evidence from the Focused Attention Paradigm

ABSTRACT The multisensory response enhancement (MRE), occurring when the response to a visual target integrated with a spatially congruent sound is stronger than the response to the visual target alone, is believed to be mediated by the superior colliculus (SC) (Stein & Meredith, 1993). Here, we used a focused attention paradigm to show that the spatial congruency effect occurs with red (SC-effective) but not blue (SC-ineffective) visual stimuli, when presented with spatially congruent sounds. To isolate the chromatic component of SC-ineffective targets and to demonstrate the selectivity of the spatial congruency effect we used the random luminance modulation technique (Experiment 1) and the tritanopic technique (Experiment 2). Our results indicate that the spatial congruency effect does not require the distribution of attention over different sensory modalities and provide correlational evidence that the SC mediates the effect.

Motion Compensated Prediction and Interpolation Filter Design in H.265/HEVC

Coding efficiency gains in the new High Efficiency Video Coding (H.265/HEVC) video coding standard are achieved by improving many aspects of the traditional hybrid coding framework. Motion compensated prediction, and in particular the interpolation filter, is one area that was improved significantly over H.264/AVC. This paper presents the details of the interpolation filter design of the H.265/HEVC standard. First, the improvements of H.265/HEVC interpolation filtering over H.264/AVC are presented. These improvements include novel filter coefficient design with an increased number of taps and utilizing higher precision operations in interpolation filter computations. Then, the computational complexity is analyzed, both from theoretical and practical perspectives. Theoretical complexity analysis is done by studying the worst-case complexity analytically, whereas practical analysis is done by profiling an optimized decoder implementation. Coding efficiency improvements over the H.264/AVC interpolation filter are studied and experimental results are presented. They show a 4.0% average bitrate reduction for the luma component and 11.3% average bitrate reduction for the chroma components. The coding efficiency gains are significant for some video sequences and can reach up to 21.7%.

A Segmentation-Based Chroma Intra Prediction Coding Scheme for H.264/AVC

In this paper, we propose a novel segmentation-based intra prediction coding scheme for low-bitrate video coding. Different coding schemes are separately designed for the luma and chroma components in our proposed method. The traditional block-based coding scheme is still used for the luma components, and the segmentation-based coding scheme is developed for the chroma components. The segmentation operation is used for the reconstructed luma components, which groups similar pixels together and produces a set of homogenous regions. Here, these local and homogenous regions are referred to superpixels. By utilizing the spatial correlation between the luma and chroma planes, we transfer the segmentation result of the luma components to the chroma components, which will not induce any side information in the chroma intra prediction coding. Instead of using the macroblock (MB) as the coding unit, the proposed method implements the chroma intra prediction in each superpixel, and the original pixels in each superpixel are employed to substitute the neighboring reconstructed samples in the prediction process. The experimental results show that the proposed method can achieve an average 0.20 dB and up to 0.63 dB coding gains in comparison to the directional intra prediction scheme for H.264/AVC low-bitrate video coding.

Salient Motion Detection in Compressed Domain

We propose a novel motion saliency framework using DCT coefficients and motion vectors as features from MPEG-2 videos. The DCT coefficients of the luma and chroma components are used to calculate the spatial saliency of a frame while the motion vectors are utilized to refine it. Spatio-temporal similarity maps are calculated separately in order to cater to tracking shots. Results show that the proposed motion saliency framework is computationally nearly an 8-fold improvement over the best performing state-of-the-art method while nearly equalling its performance in identifying salient regions.

Selection on quantitative colour variation inCentaurea cyanus: the role of the pollinator's visual system

Even though the importance of selection for trait evolution is well established, we still lack a functional understanding of the mechanisms underlying phenotypic selection. Because animals necessarily use their sensory system to perceive phenotypic traits, the model of sensory bias assumes that sensory systems are the main determinant of signal evolution. Yet, it has remained poorly known how sensory systems contribute to shaping the fitness surface of selected individuals. In a greenhouse experiment, we quantified the strength and direction of selection on floral coloration in a population of cornflowers exposed to bumblebees as unique pollinators during 4days. We detected significant selection on the chromatic and achromatic (brightness) components of floral coloration. We then studied whether these patterns of selection are explicable by accounting for the visual system of the pollinators. Using data on bumblebee colour vision, we first showed that bumblebees should discriminate among quantitative colour variants. The observed selection was then compared to the selection predicted by psychophysical models of bumblebee colour vision. The achromatic but not the chromatic channel of the bumblebee's visual system could explain the observed pattern of selection. These results highlight that (i) pollinators can select quantitative variation in floral coloration and could thus account for a gradual evolution of flower coloration, and (ii) stimulation of the visual system represents, at least partly, a functional mechanism potentially explaining pollinators' selection on floral colour variants.

Comparison of water and infrared blanching methods for processing performance and final product quality of French fries

The main objective of this work was to compare infrared blanching (IRB) with water blanching (WB) as a pretreatment method for producing lower calorie French fries. It was observed that complete inactivation of polyphenol oxidase enzyme for 9.43mm potato strips could be achieved in 200s and 16min by using IRB and WB, respectively. Following the blanching, the samples were deep-fat par-fried at 174°C for 1min and were then deep-fat finish-fried at 146, 160, and 174°C for 2, 3, 4 and 5min. At all frying times and temperatures infrared blanched samples had less oil content than water blanched ones. The energy analysis of both blanching operations showed that energy expenditure-wise the operation cost for pre-treating French fries with IRB would be head-to-head with WB. The final moisture contents of infrared and water blanched samples were between 40% and 50% after 5min of finish-frying. The chromatic color components of infrared and water blanched samples were significantly (P<0.05) affected by finish-frying time and temperature and the a* and b* values for infrared blanched samples developed faster than water blanched samples during deep-fat finish frying.

P.34: A Video Signal Coding Method Based on an Absolute Color Space for Saving Bit Depth

AbstractA coding method based on CIE u'v' is proposed for saving bit depth. The signal format comprises a luminance component and a chromaticity component. An example shows that 27 bits are required so that a display following UHDTV could be able to reproduce color‐banding free picture under any luminance adaptation.

The Effect of Chromatic and Lightness Components for Preferred Skin Color Reproduction on a Display

It is essential to understand preferred skin colors for color reproduction in the display industry. This article presents three psychophysical experiments that were conducted to determine the preferred skin color ranges of East Asian women by East Asian observers on the chromatic and lightness components of CIELAB color space displayed on a standard sRGB-gamut display. In the first experiment, the preferred skin color was searched using various settings of correlated color temperatures (CCTs) and luminance levels on the screen. The results indicate that the most preferred skin color on a display had small differences between various images varying in CCT and luminance level. In the second experiment, a more precise preferred skin color center was produced. The preference scores were analyzed, and the preference map of skin colors was presented on the CIELAB a&#x2217; b&#x2217; plane. The final experiment examined the relationship between the lightness of facial skin color and the perceived preference on a display. It was conducted to examine the effect of the lightness component on the preference of facial skin color. It was found that the &lt;mml:math overflow="scroll"&gt; &lt;mml:mrow&gt; &lt;mml:mo&gt;(&lt;/mml:mo&gt; &lt;mml:msubsup&gt; &lt;mml:mrow&gt; &lt;mml:mi&gt;C&lt;/mml:mi&gt; &lt;/mml:mrow&gt; &lt;mml:mrow&gt; &lt;mml:mi&gt;a&lt;/mml:mi&gt; &lt;mml:mi&gt;b&lt;/mml:mi&gt; &lt;/mml:mrow&gt; &lt;mml:mrow&gt; &lt;mml:mo&gt;&#x2217;&lt;/mml:mo&gt; &lt;/mml:mrow&gt; &lt;/mml:msubsup&gt; &lt;mml:mo&gt;,&lt;/mml:mo&gt; &lt;mml:msub&gt; &lt;mml:mrow&gt; &lt;mml:mi&gt;h&lt;/mml:mi&gt; &lt;/mml:mrow&gt; &lt;mml:mrow&gt; &lt;mml:mi&gt;a&lt;/mml:mi&gt; &lt;mml:mi&gt;b&lt;/mml:mi&gt; &lt;/mml:mrow&gt; &lt;/mml:msub&gt; &lt;mml:mo&gt;)&lt;/mml:mo&gt; &lt;/mml:mrow&gt; &lt;/mml:math&gt; value of the most preferred skin colors of East Asian women is (25.4, 50.5), with an L&#x2217; value of 65.

Universal Chroma Subsampling Strategy for Compressing Mosaic Video Sequences With Arbitrary RGB Color Filter Arrays in H.264/AVC

In this paper, we propose a universal chroma subsampling strategy for compressing mosaic video sequences with arbitrary red-green-blue (RGB) color filter arrays (CFAs), which are widely used in the single sensor imaging pipeline, in H.264/AVC. We first develop a modified universal demosaicing scheme, which specifically recovers the G component in the color difference domain, to recover the missing color components in the input mosaic image frames. Then, based on the transform between the RGB and the YUV color spaces, the proposed universal subsampling strategy automatically samples, by considering the significance of the U and V components for reconstructing R and B pixels, the proper U and V chroma components according to the corresponding mosaic structure. To the best of our knowledge, this is the first universal chroma subsampling strategy designed specifically for mosaic video sequences with arbitrary RGB-CFAs. Experimental results on mosaic video sequences with seven common types of the RGB-CFAs demonstrate that the proposed universal chroma subsampling strategy is superior to the conventional strategy of H.264/AVC. Moreover, integrating the proposed universal demosaicing scheme and the chroma subsampling strategy can deliver better video sequence quality.

Characterisation of flavonoids in anthurium spathes and their contribution to spathe colouration

SummaryAnthurium cultivars are popular worldwide, with flowers having red, pink, coral, white, green, or brown spathes. Anthocyanins are important pigments in the anthurium spathe; however, the presence of other flavonoids has not yet been clarified. Three anthocyanins, seven flavone glycosides, and four flavonol glycosides were characterised using high–performance liquid chromatography–electrospray ionisation–mass spectrometry (HPLC–ESI–MS) in the spathe of 25 anthurium cultivars. Correlation analyses and multivariate analyses were then used to explore the relationships between flavonoid composition and spathe colour. The content of anthocyanin cyanidin 3-rutinoside (Cy3R), and the ratio of Cy3R content to pelargonidin 3-rutinoside (Pg3R) content were negatively correlated with spathe lightness (L*), and positively correlated with the chromatic component a*. The value of the chromatic component b* was positively correlated with the contents of several flavonols. This indicated that the anthocyanins Cy3R and Pg3R were the key factors responsible for the red, pink, and purple spathe colours. Flavonols and flavones accounted for the yellow hue of the spathe. This is the first report on flavonoid characterisation in the genus Anthurium using HPLC–ESI–MS. This work will be valuable for elucidating the flavonoid compositions of other anthurium spathes and their effects on the colouration of the spathe.

Enhancement of Color Images by Scaling the DCT Coefficients and Interpolation

This paper presents the enhancement of color images in the frequency domain with interpolation. The novelty in our approach is the treatment of the chromatic components, while previous techniques treated only the luminance components and the enhanced image is interpolated with bicubic interpolation. After interpolation, the interpolated surface is smoother than corresponding surface obtained by the enhancement. The treatment of chromatic components improves the visual quality of the images to a great extent. The proposed technique, is more efficient than the spatial domain method. This paper investigate how we can increase the number of pixels and there by smoothening the enhanced surface. General Terms Image processing, Digital camera application, Scaling coefficients, Algorithms.

On the colours dichromats see

Dichromatic colour vision is commonly believed to be a reduced form of trichromatic colour vision (referred to as the reductionist principle). In particular, the colour palette of the dichromats is believed to be a part of the colour palette of the trichromats. As the light‐colour palette differs from the object‐colour palette, the dichromatic colour palettes have been derived separately for light‐colours and object‐colours in this report. As to light‐colours, the results are in line with the widely accepted view that the dichromatic colour palettes contain only two hues. However, the dichromatic object‐colour palettes have proved to contain the same six component colours which constitute the trichromatic object‐colour palette (yellow, blue, red, green, black and white). Moreover, all the binary and tertiary combinations of the six component colours present in the trichromatic object‐colour palette also occur in the dichromatic object‐colour palettes. Yet, only five of the six component colours are experienced by dichromats as unitary (unique) object‐colours. The green unitary colour is absent in the dichromatic object‐colour palettes. The difference between the dichromatic and trichromatic object‐colour palettes arises from the fact that not every combination of the component‐colour magnitudes occurs in the dichromatic object‐colour palettes. For instance, in the dichromatic object‐colour palettes there is no colour with the strong green component colour. Furthermore, each achromatic (black or white) component colour of a particular magnitude is combined with the only combination of the chromatic components. In other words, the achromatic component colours are bound with the chromatic component combinations in dichromats. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 112–124, 2014