颜色恒常认知框架模型

颜色恒常认知受到多种因素影响 ,其中包括照明、表面和背景等因素 ,也包括颜色对比、边界检测、颜色适应、模式识别 ,以及根据不同的环境线索采用不同的加工策略等认知影响因素 ,在分析上述因素的基础上尝试性地提出了一个颜色恒常认知框架模型。     

不同时相日光下颜色的恒常性

一、前言 在光源光谱成份改变的条件下,我们周围物体的颜色在眼睛看来保持相对不变,称为颜色恒常性。1807年Thomas Young首先描述了颜色恒常性现象,他指出室内不管是由蜡烛的黄光或火焰的红光来照明的,书页纸仍然看来是白色的。Young认为,外界某一表面的颜色外观,并不完全决定于网膜的红、绿、蓝三种感受器的吸收特性,而也依赖于周围其它物体射入眼睛的光通量。此后,E.Hering对颜色恒常性做了实验表演。一般认为颜色恒常性是对环境照明感受性的降低。视觉通道只传递由物体表面所反射的光谱成     

三种不同人工照明对颜色视觉的影响

不同颜色的照明对颜色视觉具有明显的影响。文献上早已有所报导。其一般规律是:人对客体颜色的知觉,介于客体在有色光照下的客观物理色彩与客体本身固有的颜色之间,这里可能存在颜色恒常性的作用。当照明用的有色光线处于不易被人察觉的情况下,人对客体颜色的知觉接近于客体在有色光照作用下的客观物理色彩,这一事实支持了上述论     

基于计算机仿真的颜色认知实验方法研究

近年来计算机仿真的实验研究方法逐渐成为颜色认知研究的主流方法,该方法克服了传统方法的诸多缺陷。本研究在现有技术的基础上构建了颜色研究仿真系统,并改进了CIE规定的有关CRT显示器颜色标定的方法。笔者通过颜色匹配实验考察了人对CRT显示器上仿真照明体颜色外观的辨别精度,结果表明上述颜色仿真系统在颜色认知实验中具有良好的适用性,并发现被试在计算机模拟颜色刺激的条件下,可进行精确的颜色匹配;不同照明条件下的色差有所不同。这些结果也为建立颜色认知模型提供了人的基准匹配数据。     

颜色知觉恒常理论的回顾

本文对早期颜色恒常理论、系数理论、计算理论和 Octant模型作了简要回顾 ,并结合已有的研究成果进行评述。对影响颜色恒常性机制的主要因素进行了探讨。强调了知觉经验、记忆、认知决策等高级意识活动对颜色恒常知觉的作用 ,并尝试性地提出了描述颜色恒常知觉过程的一般参照框架。     

颜色恒常理论及模型探索

颜色恒常是指外界环境变化时对客观物体颜色知觉保持不变的心理倾向。本文就Von Kries色系数定律、色域映射理论、谱锐化理论、视网膜皮层理论、双线性模型和神经网络模型等现有代表性的颜色恒常理论作了简单的概括与评价。针对目前该类研究的缺陷,尝试性地提出了发展完备的颜色恒常理论(或模型）的研究思路。     

光源显色性对视觉辨认的影响

本实验采用四种不同显色特性的光源分别作为两种类型视标的照明。在同一照度上对各照明条件下的视觉敏度予以测定和计算。结果表明:增加光源显色指数对于颜色背景上黑色视标的辨认能力有所提高;而对于中灰色背景上颜色视标的辨认能力则有所下降。这种效果主要是由于在不同光源照明下,视标与背景的亮度对比变化所致。结果还表明:使用中灰背景颜色视标在辨认效果上优于颜色背景黑视标。对前一类型视标采用高压钠灯照明有助于提高视觉辨别力。这对推广应用这种显色指数较低,但光效率较高的新光源有实际意义。     

立体深度知觉恒常性的研究

本实验研究在六米以内的观察距离上测定了立体深度知觉的恒常性程度,并试用布伦斯维克比率计算了立体常性程度。结果发现,在六米以内不排除辐合、调节为有效的距离线索的条件下,对三种不同的客体深度进行观察其知觉深度保持恒常。立体深度知觉常性也可以用布伦斯维克比率计算其恒常性程度。     

中国人眼对表色色差辨别的实验研究

报导了中国人眼对表色色差辨别的实验研究中彩色类特性实验结果。研究中对颜色所具有的明度、色调、彩度三个属性分别开展了实验研究。研究结果表明了颜色中的色调、明度和彩度的特性变化不影响人眼对表面色色差的识别。中国人眼对彩色系表色色差辨别时,色差识别的量值△Ｅ值仅随感觉等级的不同而产生变化。将彩色类和非彩色类的实验结果进行比较时,发现了彩色类各感觉等级的△Ｅ值均大于非彩色类的△Ｅ值。根据二个类别的实验结果,研究者提出：中国颜色体系中非彩色系样品和彩色系样品色度坐标值的色差宽容度分别为：非彩色系△Ｅ＜１．５;彩色系△Ｅ＜３．０的建议。根据该项技术指标制作的《中国颜色体系样册》中的１３２２个颜色样品,经中国计量科学研究院在国家标准计量装置上测试,将其结果和国际上已有的颜色体系样册中样品的色差比较时,还是让人感到满意的。该项技术指标已作为《中国颜色体系》国家标准中颜色样品色差宽容度的技术参数。     

语境与颜色诊断性对句子理解中物体隐含颜色知觉模拟的影响

具身认知理论的代表知觉符号系统认为知识表征具有知觉特点,并假设语言理解中对于所涉及概念及其隐含属性会即时进行知觉模拟。当前研究采用句图匹配范式,通过三个实验探讨句子理解中是否会对物体隐含颜色属性进行知觉模拟及其具体条件。实验1沿用经典范式验证语言理解中对物体隐含颜色存在知觉模拟过程。实验2通过变化句子前语境考察语境是否支持对于物体隐含颜色知觉模拟的影响。实验3进一步考察当颜色属性与其对应物体存在稳定关联时(即具有高颜色诊断性的物体),在不同语境作用下是否会引起知觉表征的变化。研究结果表明,语言理解中知觉模拟过程是灵活的,语境改变会引起读者所激活的物体颜色知觉表征发生变化,并且对于高颜色诊断物体,即使缺乏支持语境,读者仍然会对句中隐含的物体特定颜色进行知觉模拟。     

A test of color constancy in 4-month-old human infants

Forty-five 4-month-old infants were tested for color constancy using a familiarization, paired-comparison paradigm. Infants were familiarized and tested with colored stimuli under two conditions: (1) no change in the illuminant between familiarization and test and (2) a change in the illuminant between familiarization and test. Infants correctly recognized the familiarization color when tested with no change in the illuminant. Infants tested with a change in the illuminant correctly recognized the familiar color under some conditions yet failed to do so under others. Several explanations are considered for these results and it is concluded that color constancy operates immaturely at 4 months of age.     

Lightness constancy: a direct test of the illumination-estimation hypothesis

Many models of color constancy assume that the visual system estimates the scene illuminant and uses this estimate to determine an object's color appearance. A version of this illumination-estimation hypothesis, in which the illuminant estimate is associated with the explicitly perceived illuminant, was tested. Observers made appearance matches between two experimental chambers. Observers adjusted the illumination in one chamber to match that in the other and then adjusted a test patch in one chamber to match the surface lightness of a patch in the other. The illumination-estimation hypothesis, as formulated here, predicted that after both matches the luminances of the light reflected from the test patches would be identical. The data contradict this prediction. A second experiment showed that manipulating the immediate surround of a test patch can affect perceived lightness without affecting perceived illumination. This finding also falsifies the illumination-estimation hypothesis.     

Surface-illuminant ambiguity and color constancy: effects of scene complexity and depth cues

Two experiments were conducted to study how scene complexity and cues to depth affect human color constancy. Specifically, two levels of scene complexity were compared. The low-complexity scene contained two walls with the same surface reflectance and a test patch which provided no information about the illuminant. In addition to the surfaces visible in the low-complexity scene, the high-complexity scene contained two rectangular solid objects and 24 paper samples with diverse surface reflectances. Observers viewed illuminated objects in an experimental chamber and adjusted the test patch until it appeared achromatic. Achromatic settings made tinder two different illuminants were used to compute an index that quantified the degree of constancy. Two experiments were conducted: one in which observers viewed the stimuli directly, and one in which they viewed the scenes through an optical system that reduced cues to depth. In each experiment, constancy was assessed for two conditions. In the valid-cue condition, many cues provided valid information about the illuminant change. In the invalid-cue condition, some image cues provided invalid information. Four broad conclusions are drawn from the data: (a) constancy is generally better in the valid-cue condition than in the invalid-cue condition: (b) for the stimulus configuration used, increasing image complexity has little effect in the valid-cue condition but leads to increased constancy in the invalid-cue condition; (c) for the stimulus configuration used, reducing cues to depth has little effect for either constancy condition: and (d) there is moderate individual variation in the degree of constancy exhibited, particularly in the degree to which the complexity manipulation affects performance.     

The conscious experience of color constancy and neural responses to subliminal deviations – A behavioral and EEG/ERP oddball study

IntroductionColor constancy, a property of conscious color experience, maintains object color appearance across illuminant changes. We investigated the neural correlates of subliminal vs. conscious stimulus deviations of color constancy manipulations.MethodsBehavioral and Oddball EEG/ERP experiments were conducted (n = 20). Psychophysical illuminant variation discrimination thresholds were first estimated, to establish individual perceptual awareness ranges, allowing for simulation of natural daylight spectral and spatial variations on colored surfaces, at different ambiguity levels.ResultsBehavioral results validated illuminant choice. ERPs showed a significant modulation of posterior P1 component specifically for the subliminal global uniform deviation condition, respecting color constancy. Neural correlates of conscious percepts were identified at posterior N2-P3 latencies, parietal (P3b) and frontal regions.ConclusionsWe identified an early subliminal correlate of low-level illuminant change, which reflects automatic unconscious detection of global color constancy deviations. Its suppression under conscious perception is probably due to top-down suppression according to prediction error models.     

Color constancy: phenomenal or projective?

Naive observers viewed a sequence of colored Mondrian patterns, simulated on a color monitor. Each pattern was presented twice in succession, first under one daylight illuminant with a correlated color temperature of either 16,000 or 4000 K and then under the other, to test for color constancy. The observers compared the central square of the pattern across illuminants, either rating it for sameness of material appearance or sameness of hue and saturation or judging an objective property-that is, whether its change of color originated from a change in material or only from a change in illumination. Average color constancy indices were high for material appearance ratings and binary judgments of origin and low for hue-saturation ratings. Individuals' performance varied, but judgments of material and of hue and saturation remained demarcated. Observers seem able to separate phenomenal percepts from their ontological projections of mental appearance onto physical phenomena; thus, even when a chromatic change alters perceived hue and saturation, observers can reliably infer the cause, the constancy of the underlying surface spectral reflectance.     

The influence of depth segmentation on colour constancy

In real scenes, surfaces in different depth planes often differ in the luminance and chromatic content of their illumination. Scene segmentation is therefore an important issue when considering the compensation of illumination changes in our visual perception (lightness and colour constancy). Chromatic adaptation is an important sensory component of colour constancy and has been shown to be linked to the two-dimensional spatial structure of a scene (Werner, 2003 Vision Research 43 1611 - 1623). Here, the question is posed whether this cooperation also extends to the organisation of a scene in depth. The influence of depth on colour constancy was tested by introducing stereo disparity, whereby the test patch and background were perceived in either the same or one of five different depth planes (1.9-57 min of arc). There were no additional cues to depth such as shadows or specular highlights. For consistent illumination changes, colour constancy was reduced when the test patch and background were separated in depth, indicating a reduction of contextual influences. An interaction was found between the influences of stereo depth and spatial frequency on colour constancy. In the case of an inconsistent illumination change, colour constancy was reduced if the test patch and background were in the same depth plane (2-D condition), but not if they were separated in depth (3-D condition). Furthermore, colour constancy was slightly better in the 3-D inconsistent condition than in the 2-D inconsistent condition. It is concluded that depth segmentation supports colour constancy in scenes with inconsistent illumination changes. Processes of depth segmentation are implemented at an early sensory stage of colour constancy, and they define visual regions within which the effects of illuminant changes are discounted for separately. The results support recent models that posit such implementation of scene segmentation in colour constancy.     

Naming versus matching in color constancy

In this paper, a replication of the color-constancy study of Arend and Reeves (1986) is reported, and an alternative method is presented that can be used for the study of higher order aspects of color constancy, such as memory, familiarity, and perceptual organization. Besides a simultaneous presentation of standard and test illuminants, we also carried out an experiment in which the illuminants were presented successively. The results were similar to Arend and Reeves’s; however, in the object-matching condition of the successive experiment, we found an overestimation, instead of an underestimation, of the illuminant component. Because the results of matching experiments are difficult to interpret, mainly due to their sensitivity to instruction effects, we introduced another type of color-constancy task. In this task, subjects simply named the color of a simulated patch. It was found that, by applying such a task, a reliable measure of the degree of identification of object color can be obtained.     

Naming versus matching in color constancy.

In this paper, a replication of the color-constancy study of Arend and Reeves (1986) is reported, and an alternative method is presented that can be used for the study of higher order aspects of color constancy, such as memory, familiarity, and perceptual organization. Besides a simultaneous presentation of standard and test illuminants, we also carried out an experiment in which the illuminants were presented successively. The results were similar to Arend and Reeves's; however, in the object-matching condition of the successive experiment, we found an overestimation, instead of an underestimation, of the illuminant component. Because the results of matching experiments are difficult to interpret, mainly due to their sensitivity to instruction effects, we introduced another type of color-constancy task. In this task, subjects simply named the color of a simulated patch. It was found that, by applying such a task, a reliable measure of the degree of identification of object color can be obtained.     

The perception of lightness in 3-D curved objects

Lightness constancy in complex scenes requires that the visual system take account of information concerning variations of illumination falling on visible surfaces. Three experiments on the perception of lightness for three-dimensional (3-D) curved objects show that human observers are better able to perform this accounting for certain scenes than for others. The experiments investigate the effect of object curvature, illumination direction, and object shape on lightness perception. Lightness constancy was quite good when a rich local gray-level context was provided. Deviations occurred when both illumination and reflectance changed along the surface of the objects. Does the perception of a 3-D surface and illuminant layout help calibrate lightness judgments? Our results showed a small but consistent improvement between lightness matches on ellipsoid shapes, relative to flat rectangle shapes, under illumination conditions that produce similar image gradients. Illumination change over 3-D forms is therefore taken into account in lightness perception.