Papers by Ulrik Söderström
Distinctive curves : unified scale-invariant detection of edges, corners, lines and curves
This paper aims to broaden the scope of shape related features including edges, corners, lines an... more This paper aims to broaden the scope of shape related features including edges, corners, lines and curves: 1) Edges, corners, lines, curves are all shape related features. In the past, the detectio ...
Comparing Millennials View on Minimalism And Maximalism in Web Design
This study evaluates how Generation Y, also known as millennials, perceive different web design a... more This study evaluates how Generation Y, also known as millennials, perceive different web design approaches. Two web design approaches were compared, using methods in User Experience design. The first approach is minimalism and the second one is maximalism. Minimalism has been a recurring web design trend ever since the end of the twentieth century. Maximalism is claimed to be the most important web design trend of 2018. The interesting question is if millennials who have grown up with minimalism in web design are interested in a new approach – the maximal approach. This study probe the opinions, thoughts and emotions of millennials after they have browsed two websites, one developed with minimalism and one developed with maximalism. The results show that the participants in this study were more exited by the maximal design. However, combining quantitative and qualitative data, the conclusion is that the different design approaches are more or less suitable to use depending on the message that the website is supposed to convey.
With the digitalization and increasing number of Internet users, more and more personal data brea... more With the digitalization and increasing number of Internet users, more and more personal data breaches occur. Many people are not aware of their personal data rights and have not received any instructions on how to act in situations such as when their personal data is abused. This is something that illustrates the flaws of the Internet. A technology that provides solutions to some of these problems, such as trust and transparency, is the blockchain technology. Hence, the objective of this paper is to investigate knowledge about personal data rights and to explore the design of a prototype of a blockchain application for increased security and transparency. User tests were conducted, highlighting the greatest needs for users to feel secure and in control over their personal data. This knowledge provide the foundation for a prototype based on blockchain technology that gives the users increased security and forces those who store personal data to be more transparent with the usage.
The effect of skeleton screens
Progression bars and spinners have long been the norm when providing feedback during wait times o... more Progression bars and spinners have long been the norm when providing feedback during wait times on the web. However, a more recent trend is the use of skeleton screens. This paper aims to evaluate the usefulness of skeleton screens as an alternative to spinners. This is done user testing a fictional news site with two variations, one showing skeleton screens before content is loaded, and another utilizing spinners. Both a questionnaire and measuring timing while finding a specified article when entering a website for the first time was used. The results show that the page using skeleton screens, scored higher on average on both perceived speed and ease of navigation. However, people using the page with spinners were faster at finding the article when entering the site for the first time. The results of this paper cannot show any significant differences in any of the comparisons between the web pages.
The Users' Time Perception
Loading screens are still important in 2018, and there is a reason for that: they provide a great... more Loading screens are still important in 2018, and there is a reason for that: they provide a great way to give feedback to the user in the interface during wait times after a user's action. Previous research shows that it is essential for a well designed interface and it is a well established way to increase and maintain a user's satisfaction. This study specifically examine the looped, passive animation screen with regards to how the animation speed affects the user. Results suggests that with faster animation, perceived wait time gets shorter and the user is more satisfied.
InTech eBooks, Apr 26, 2011
The use of video telephony has not become a big success but it still has potential to become wide... more The use of video telephony has not become a big success but it still has potential to become widespread. Video communication is becoming a well-used application for both personal use and corporations. This kind of communication is used in conversations between people and is essential for saving travel bills for companies. Less traveling also saves the environment and is therefore expected to be an important factor in the future. Even if the available bandwidth will increase it is desirable to use as low bandwidth as possible for communication since less bandwidth means lower cost, more availability in networks and less sensitivity to network delays. As more video is transmitted over networks, lower bandwidth need for video transmission means that more users can make use of video at the same time. Low bandwidth means low power consumption for transmission while low encoding and decoding complexity means low power consumption when the video is encoded and decoded. The impact of power consumption is expected to become much more important in the future as the availability of power is decreased and pollution from energy production needs to be halted. Every human face is contained within a space called the face space. Every face can be recognized, represented or synthesized with this space. Principal component analysis (PCA) [Jolliffe (1986)] can be used to create a compact representation of this space. This enables PCA to be used for highly efficient video coding and other image processing tasks. The faces in the face space all have the same facial expression but PCA can also be used to create a space with different facial expressions for a single person. This is referred to as the personal face space, facial mimic space or personal mimic space [Ohba et al. (1998)]. This space consists of faces for a single person but with several different facial expressions. According to the American psychologist Paul Ekman it is enough to model six basic emotions to actually model all facial expressions [Ekman & Friesen (1975); Ekman (1982)]. The six basic emotions; happiness, sadness, surprise, fear, anger and disgust (Fig. 1), are blended in different ways to create all other possible expressions. The combination of basic emotions is not directly applicable for linear processing with images so more than six dimensions are needed. We have previously evaluated exactly how many dimensions that are needed to reach a certain representation quality [Söderström & Li (2010)]. Efficient use of PCA for modeling of any data requires that the global motion is removed from the data set. For facial video this motion corresponds to motion of the entire head, e.g., positional shift and facial rotation. The motion that is modeled with PCA is the local
Scale-invariant corner keypoints
Effective and efficient generation of keypoints from images is the first step of many computer vi... more Effective and efficient generation of keypoints from images is the first step of many computer vision applications, such as object matching. The last decade presented us with an arms race toward faster and more robust keypoint detection, feature description and matching. This resulted in several new algorithms, for example Scale Invariant Features Transform (SIFT), Speed-up Robust Feature (SURF), Oriented FAST and Rotated BRIEF (ORB) and Binary Robust Invariant Scalable Keypoints (BRISK). The keypoint detection has been improved using various techniques in most of these algorithms. However, in the search for faster computing, the accuracy of the algorithms is decreasing. In this paper, we present SICK (Scale-Invariant Corner Keypoints), which is a novel method for fast keypoint detection. Our experiment results show that SICK is faster to compute and more robust than recent state-of-the-art methods.
Distinctive curves features
Electronics Letters, Feb 1, 2016
Curves and lines are geometrical, abstract features of an image. Whereas interest points are more... more Curves and lines are geometrical, abstract features of an image. Whereas interest points are more limited, curves and lines provide much more information of the image structure. However, the research done in curve and line detection is very fragmented. The concept of scale space is not yet fused very well into curve and line detection. Keypoint (e.g. SIFT, SURF, ORB) is a successful concept which represent features (e.g. blob, corner etc.) in scale space. Stimulated by the keypoint concept, a method which extracts distinctive curves (DICU) in scale space, including lines as a special form of curve features is proposed. A curve feature can be represented by three keypoints (two end points, and one middle point). A good way to test the quality of detected curves is to analyse the repeatability under various image transformations. DICU using the standard Oxford benchmark is evaluated. The overlap error is calculated by averaging the overlap error of three keypoints on the curve. Experiment results show that DICU achieves good repeatability comparing with other state-of-the-art methods. To match curve features, a relatively uncomplicated way is to combine local descriptors of three keypoints on each curve.
Super-resolution Facial Images from Single Input Images Based on Discrete Wavelet Transform
In this work, we are presenting a technique that allows for accurate estimation of frequencies in... more In this work, we are presenting a technique that allows for accurate estimation of frequencies in higher dimensions than the original image content. This technique uses asymmetrical Principal Component Analysis together with Discrete Wavelet Transform (aPCA-DWT). For example, high quality content can be generated from low quality cameras since the necessary frequencies can be estimated through reliable methods. Within our research, we build models for interpreting facial images where super-resolution versions of human faces can be created. We have worked on several different experiments, extracting the frequency content in order to create models with aPCA-DWT. The results are presented along with experiments of deblurring and zooming beyond the original image resolution. For example, when an image is enlarged 16 times in decoding, the proposed technique outperforms interpolation with more than 7 dB on average.
Immersion has become an important factor for video games. This study investigates the effect that... more Immersion has become an important factor for video games. This study investigates the effect that haptic feedback has on the perceived immersion of the player in two different setups; one with haptic feedback in the game controller and one with feedback in a haptic vest. Both experiments consisted of a user test, followed by answering a questionnaire. The results show tendencies of haptic feedback both increasing and inhibiting the ability to feel immersed by certain metrics, even if the statistical analysis shows no significant difference between the groups in any of the sub-scales. The results also show that most of the test subjects thinks that the vest and its' haptic feedback delivers more immersion to the gaming experience. The conclusion that can be drawn from both experiments is that haptic feedback improves the user feeling of immersion, more specifically regarding the players awareness of the surroundings in the game. CCS CONCEPTS • Human-centered computing → Haptic devices; User studies; • Hardware → Haptic devices.
Creative Capabilities of Machine Learning
The concept of creativity is an important part of human society and the continuous evolution of a... more The concept of creativity is an important part of human society and the continuous evolution of artificial minds has raised questions on creativity among machines. This aim of the this study is to explore machine learning algorithms’ ability to be creative. The study reported in this paper uses short samples of music generated by IBM Watson beats that are evaluated using expert assessment of 51 music teachers together with samples generated by humans as control samples. The results show that one of the machine learning generated samples showed the same level of creativity as the human generated samples. Hence, there are indications that today machine learning algorithms can create music that is hard to distinguish from human created music and can be considered creative.
Scale a rotation-invariant matching with curve chain
This paper presents a new methodology that matches image geometry using a curve chain. A curve ch... more This paper presents a new methodology that matches image geometry using a curve chain. A curve chain is defined as a 1-dimensional arrangement of curves. The idea is to match images without using l ...
Eigenspace compression for very low bitrate transmission of facial video
International Conference on Signal Processing, 2007
Principal component video coding for simple decoding on mobile devices
ABSTRACT A problem with watching video on mobile devices is the complexity of the video decoder. ... more ABSTRACT A problem with watching video on mobile devices is the complexity of the video decoder. High complexity requires high energy and the battery-power is often very limited for mobile devices. Simple decoding will save energy but have an even more important feature; a simple decoder enables homogenous implementation. A simple decoder can be im-plemented in Java and thus easily be used on several dif-ferent mobile devices without modifications. We present a video coding scheme based on principal component analysis that only needs matrix multiplication and floating value addi-tion as decoding. The principal components are compressed through integer-JPEG which increases the complexity but is necessary to limit the bitrate needed for the codec.
International Journal of Image and Graphics, Jul 1, 2010
In this paper we introduce an ultra low bitrate video communication scheme, which enables realtim... more In this paper we introduce an ultra low bitrate video communication scheme, which enables realtime video communication at a bitrate of as low as 100 bits/s. The magic behind this scheme is that the receiver will keep a personal facial mimic gallery and the transmitter tells which video frame the receiver should pick out from the gallery and display. Since only the index of video frames is transmitted, ultra-low communication bandwidth is needed. In the paper we describe how the video communication system works and how to handle the jitter problem in playback of reconstructed video with the locally linear embedding tool.
Design Friction
This study evaluates if intentionally added design friction affects users level of satisfaction w... more This study evaluates if intentionally added design friction affects users level of satisfaction when using a mobile application. Today most applications are designed to have as little friction as possible. An interesting question is if a more mindful interaction will lead to more satisfied users. In this study two prototypes inspired by the Headspace application where tested. One prototype had added design friction and the other had none. The participants were asked to rate their experience and to choose which prototype they preferred. The result shows that most participants of the test would choose the mobile application with added design friction and that they felt more satisfied when they had a clear understanding of the goal of the task.
Intressentfokuserade oberoende longitudinella utvärderingar
Utbildningskvalite ar en mycket viktig fraga som diskuteras frekvent inom universitetsvarlden. Sa... more Utbildningskvalite ar en mycket viktig fraga som diskuteras frekvent inom universitetsvarlden. Saval kontroll som forbattring av utbildningskvalite ar i manga lagen starkt kopplat till olika former ...
Re-use of Eigenspaces to encode new facial video sequences
This thesis introduces a coding scheme for very low bitrate video coding through the aid of princ... more This thesis introduces a coding scheme for very low bitrate video coding through the aid of principal component analysis. Principal information of the facial mimic for a person can be extracted and stored in an Eigenspace. Entire video frames of this persons face can then be compressed with the Eigenspace to only a few projection coefficients. Principal component video coding encodes entire frames at once and increased frame size does not increase the necessary bitrate for encoding, as standard coding schemes do. This enables video communication with high frame rate, spatial resolution and visual quality at very low bitrates. No standard video coding technique provides these four features at the same time. Theoretical bounds for using principal components to encode facial video sequences are presented. Two different theoretical bounds are derived. One that describes the minimal distortion when a certain number of Eigenimages are used and one that describes the minimum distortion when a minimum number of bits are used. We investigate how the reconstruction quality for the coding scheme is affected when the Eigenspace, mean image and coefficients are compressed to enable efficient transmission. The Eigenspace and mean image are compressed through JPEG-compression while the while the coefficients are quantized. We show that high compression ratios can be used almost without any decrease in reconstruction quality for the coding scheme. Different ways of re-using the Eigenspace for a person extracted from one video sequence to encode other video sequences are examined. The most important factor is the positioning of the facial features in the video frames. Through a user test we find that it is extremely important to consider secondary workloads and how users make use of video when experimental setups are designed.
Content in digital services is often filtered for users based on individual preferences with the ... more Content in digital services is often filtered for users based on individual preferences with the possible consequence of creating a state referred to as a "filter bubble". The objective of this paper is to examine which of a user's inherent needs that are important to satisfy when a user is consuming personalized content in a digital service. The paper uses a survey to measure the need for autonomy, competence and relatedness of the Self-Determination Theory when users are consuming filtered content in digital services. The results show that the investigated services fail to satisfy all needs. A satisfactory user experience should include the opportunity for the user to satisfy the need for autonomy, competence and relatedness. For autonomy, transparency of filtering and choice about filtering should be offered. For competence, it is essential to offer content that the user can learn from, and also provide the right amount of choice throughout the service. The danger of filter bubbles is not personalization, but to remove choice about personalization.
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Papers by Ulrik Söderström