Evaluation of graphic effects embedded image compression

A fundamental factor of digital image compression is the conversion processes. The intention of this process is to understand the shape of an image and to modify the digital image to a grayscale configuration where the encoding of the compression technique is operational. This article focuses on an investigation of compression algorithms for images with artistic effects. A key component in image compression is how to effectively preserve the original quality of images. Image compression is to condense by lessening the redundant data of images in order that they are transformed cost-effectively. The common techniques include discrete cosine transform (DCT), fast Fourier transform (FFT), and shifted FFT (SFFT). Experimental results point out compression ratio between original RGB images and grayscale images, as well as comparison. The superior algorithm improving a shape comprehension for images with grahic effect is SFFT technique

Do speakers adapt object descriptions to listeners under load?

For successful communication, it is important that speaker and listener have established a common ground (Clark, 1996). For example, a speaker saying ‘please give me the green chair’ needs to have made sure, among other things, that there is an object near the listener that can be uniquely identified by the referring expression ‘the green chair’. If the listener sees only one chair, mentioning ‘green’ is redundant; if the listener sees more than one green chair, the expression may be underspecified. There is a hot debate as to whether speakers consider the perspective of the listener when making linguistic choices. It is generally accepted that speakers adapt their language to addressees at least at a crude level (e.g. Galati & Brennan, 2010), but it is less clear which cues trigger speakers to explicitly consider the listener’s needs. In this study, we investigated whether speakers adapt descriptions of objects to addressees who are under an increased cognitive load. According to the Uniform Information Density hypothesis (UID; Levy & Jaeger, 2007), speakers strive to produce utterances that minimize peaks in information density, which may lead to processing difficulty for the listener. If speakers are sensitive to the processing capacity of their addressees, they should adjust the overall information density of their utterances to a level that they expect the addressee to be able to process. Hence, we hypothesized that, when the addressee is involved in a difficult task that is noticeably reducing their cognitive capacity, speakers will introduce more redundancy in their descriptions, thereby distributing information over more linguistic units. To test this hypothesis, we conducted a referential communication experiment with pairs of speakers and listeners in a driving simulator. The speaker was in the passenger’s seat and described pieces of furniture (cf. the TUNA corpus; Gatt, et al., 2007) for the listener, who was performing a driving task. Speakers were instructed to describe each object in such a way that the listener could identify it from a set of furniture objects appearing on the driving simulator screen. The objects could be identified by mentioning a particular set of properties (a minimal description) concerning its color, size and/or orientation. Any mentioned property that was not necessary to uniquely identify the referent was considered redundant (cf. Koolen et al., 2013). We manipulated the listener’s cognitive load by varying the difficulty of the driving task in two blocks. In the easy driving block, listeners had to drive down a straight road, while in the difficult driving block, they had to perform a challenging tracking task that has previously been shown to increase cognitive load (Demberg, et al., 2013). The order of the blocks was counterbalanced across participants. After completing the two blocks, speaker and listener switched roles and repeated the experiment with a new set of items. In this way, half of the participants had first-hand experience with the driving task before taking the speaker role. We predicted that speakers would lower the information density of their descriptions, using more redundant attributes and/or producing longer descriptions, when listeners perform a difficult as compared to an easy driving task. In addition, we predicted that adaptation effects would be stronger when speakers had already experienced the driving task before describing. The results showed that in the first block, speakers used more redundant attributes (but not otherwise longer descriptions) when it was a difficult driving block than when it was an easy driving block, but only when the speaker had already been the driver in the first half of the experiment (cumulative link mixed model analysis, β = 0.9368; SE = 0.4497; p < .05). This finding is in line with the view that speakers only take the listener’s perspective into account when there are strong cues that adaptation is necessary (e.g. Pickering & Garrod, 2004). In addition, speakers did not seem to adjust their level of redundancy between the first and the second block, even though the second block had the other driving condition (see Figure 1). This suggests that speakers adapt to their first assessment of listeners' cognitive load, but not when cognitive load changes halfway through the task

Perceptual difficulty differences predict asymmetry in redundant modification with color and material adjectives

When referring to objects, speakers are often more specific than necessary for the purpose of establishing unique reference, e.g., by producing redundant modifiers. A computational model of referring expression production that accounts for many of the key patterns in redundant adjectival modification assumes that adjectives differ in how noisy (reliable), and consequently, how useful they are for reference. Here we investigate one hypothesis about the source of the assumed adjectival noise: that it reflects the perceptual difficulty of establishing whether the property denoted by the adjective holds of the contextually relevant objects. In Exp.1, we collect perceptual difficulty norms for items that vary in color and material. In Exp. 2, we test the highest (material) and lowest (color) perceptual difficulty items in a reference game and find that material is indeed less likely to be mentioned redundantly, replicating previous work. In Exp. 3, we obtain norms for the tested items in a second perceptual difficulty measure with the aim of testing the effect of perceptual difficulty within property type. The overall results provide preliminary support for the hypothesis that the propensity to redundantly use color over material adjectives may be driven by the relative ease of assessing an object’s color, compared to the relative difficulty of assessing its material

Usage context influences the evolution of overspecification in Iterated Learning

This article investigates the influence of contextual pressures on the evolution of overspecification, i.e. the degree to which communicatively irrelevant meaning dimensions are specified, in an iterated learning setup. To this end, we combine two lines of research: In artificial language learning studies, it has been shown that (miniature) languages adapt to their contexts of use. In experimental pragmatics, it has been shown that referential overspecification in natural language is more likely to occur in contexts in which the communicatively relevant feature dimensions are harder to discern. We test whether similar functional pressures can promote the cumulative growth of referential overspecification in iterated artificial language learning. Participants were trained on an artificial language which they then used to refer to objects. The output of each participant was used as input for the next participant. The initial language was designed such that it did not show any overspecification, but it allowed for overspecification to emerge in 16 out of 32 usage contexts. Between conditions, we manipulated the referential context in which the target items appear, so that the relative visuospatial complexity of the scene would make the communicatively relevant feature dimensions more difficult to discern in one of them. The artificial languages became overspecified more quickly and to a significantly higher degree in this condition, indicating that the trend toward overspecification was stronger in these contexts, as suggested by experimental pragmatics research. These results add further support to the hypothesis that linguistic conventions can be partly determined by usage context and shows that experimental pragmatics can be fruitfully combined with artificial language learning to offer valuable insights into the mechanisms involved in the evolution of linguistic phenomena

Ordering adjectives in referential communication

We contrasted two hypotheses concerning how speakers determine adjective order during referential communication. The discriminatory efficiency hypotheses claims that speakers place the most discriminating adjective early to facilitate referent identification. By contrast, the availability-based ordering hypothesis assumes that speakers produce most available adjectives early to ease production. Experiment 1 showed that speakers use more pattern-before-color modifier orders (than the reversed) when pattern, not color, distinguished the referent from alternatives, providing support for the discriminatory efficiency hypothesis. Participants also overspecified color more often than pattern, and they generally favored color-before-pattern orders, in support of the availability-based ordering hypothesis. Experiments 2 and 3 replicated both effects in a dialogue setting, where speakers’ adjective ordering was also primed by their partner’s ordering, using conjoined and non-conjoined constructions. We propose a novel model (PASS) that explains how discriminability and availability simultaneously influence adjective selection and ordering via competition in the speaker’s message representation