• A New Descriptive Subjective Video Quality Dataset 

      Alizadeh Mivehforoushi, Asma (Master thesis, 2023)
      During the past few decades, several studies have introduced various Subjective Video Quality Datasets (SVQDs). Most of these datasets are small in size with regard to the number of unique content and consist of relatively ...
    • Analysis of individual quality scores of different image distortions 

      Cherepkova, Olga; Amirshahi, Seyed Ali; Pedersen, Marius (Peer reviewed; Journal article, 2022)
      In this paper, we study individual quality scores given by different observers for various image distortions (saturation, contrast, and color quantization) at different levels. We created a database that contains a total ...
    • Analyzing the Variability of Subjective Image Quality Ratings for Different Distortions 

      Cherepkova, Olga; Amirshahi, Seyed Ali; Pedersen, Marius (Chapter, 2022)
      When it comes to evaluating the quality of images, individual observers show different opinions depending on the type of distortion affecting the quality of the image. While in the opinion of one observer a distortion could ...
    • Assetfront Repair 

      Bako, Abdi; Hamcho, Amr; Abdullah, Mustafa; Khumparov, Shamil Saidovitch (Bachelor thesis, 2021)
      Digitalisering er en viktig prosess for behandling, lagring og utveksling av data, ettersom den gjør det mulig å få tilgang til og overføre data effektivt. Som medfører til å forbedre effektiviteten og konsistensen. ...
    • Colourlab Image Database: Geometric Distortions 

      Pedersen, Marius; Amirshahi, Seyed Ali (Peer reviewed; Journal article, 2021)
      Over the years, a high number of different objective image quality metrics have been proposed. While some image quality metrics show a high correlation with subjective scores provided in different datasets, there still ...
    • Comparing the Chromatic Contrast Sensitivity in Vertical and Oblique Orientations 

      Amirshahi, Seyed Ali; Pedersen, Marius; Beghdadi, Azeddine (Journal article; Peer reviewed, 2019)
      While for many years achromatic contrast sensitivity has been widely studied by different research groups from various fields of work, the same attention has not been paid to chromatic contrast sensitivity. Due to the ...
    • A Critical Analysis on Perceptual Contrast and its Use in Visual Information Analysis and Processing 

      Beghdadi, Azeddine; Qureshi, Muhammad Ali; Amirshahi, Seyed Ali; Chetouani, Aladine; Pedersen, Marius (Peer reviewed; Journal article, 2020)
      Contrast in visible images is one of the most relevant characteristics of visual signals. Since the pioneering works performed in vision psychology and optics, different definitions have been proposed in the literature. ...
    • Deep Learning in Image Quality Assessment: Past, Present, and What Lies Ahead 

      Amirshahi, Seyed Ali (Peer reviewed; Journal article, 2021)
      Quality assessment of images plays an important role in different applications in image processing and computer vision. While subjective quality assessment of images is the most accurate approach due to issues objective ...
    • Do Contrast Measures Correlate? A Pilot Investigation 

      Amirshahi, Seyed Ali; Kadyrova, Altynay; Pedersen, Marius (Journal article, 2019)
    • Explainable Artificial Intelligence for Image Quality Assessment 

      Nguyen, Ha Thu (Master thesis, 2023)
      Image quality assessment has been an active research field for decades because of the high demand for images and video content in daily life. As visual information is processed in various steps from acquisition and storage ...
    • Face Image Quality Assessment 

      Demloj, Walid; Grosberghaugen, Kjetil; Skattum, Julian Nyland; Taralrud, Hans Petter Fauchald (Bachelor thesis, 2021)
      Ytelsen på ansiktgjenkjenningssystmer er avhengig av kvaliteten på bildene for å kunne teste og trene disse systemene. For å automatisk vurdere kvaliteten på ansiktsbilder blir Face Image Quality Metrics (FIQMs) benyttet. ...
    • Future Directions in Image Quality 

      Amirshahi, Seyed Ali; Pedersen, Marius (Journal article; Peer reviewed, 2019)
      With the advancements made in the field of image processing and computer vision, the last few decades have seen an increase in studies focused on image quality assessment. While this has resulted in the introduction of ...
    • How Do Image Quality Metrics Perform on Contrast Enhanced Images? 

      Amirshahi, Seyed Ali; Kadyrova, Altynay; Pedersen, Marius (Journal article, 2019)
    • How Good is Too Good? A Subjective Study on Over Enhancement of Images 

      Azimian, Sahar; Torkamani-Azar, Farah; Amirshahi, Seyed Ali (Peer reviewed; Journal article, 2021)
      For a long time different studies have focused on introducing new image enhancement techniques. While these techniques show a good performance and are able to increase the quality of images, little attention has been paid ...
    • Image Quality Assessment by Comparing CNN Features between Images 

      Amirshahi, Seyed Ali; Pedersen, Marius; Yu, Stella X. (Peer reviewed; Journal article, 2016)
      Finding an objective image quality metric that matches the subjective quality has always been a challenging task. We propose a new full reference image quality metric based on features extracted from Convolutional Neural ...
    • Preventing Over-Enhancement Using Modified ICSO Algorithm 

      Azimian, Sahar; Amirshahi, Seyed Ali; Azar, Farah Torkamani (Peer reviewed; Journal article, 2023)
      This paper proposes an Image Contrast Enhancement (ICE) method based on using an Improved Chicken Swarm Optimization (ICSO) algorithm to enhance images while at the same time preventing over-enhancement. In the optimization ...
    • Quality is in the Salient Region of the Image 

      Jamshidi Seikavandi, Meisam; Amirshahi, Seyed Ali (Peer reviewed; Journal article, 2021)
      The ultimate goal in any proposed Image Quality Metrics (IQMs) is to accurately predict the subjective quality scores given by observers. In the case of most IQMs the quality score is calculated by pooling the quality ...
    • Reviving Traditional Image Quality Metrics Using CNNs 

      Amirshahi, Seyed Ali; Pedersen, Marius; Beghdadi, Azeddine (Journal article; Peer reviewed, 2018)
      Objective Image Quality Metrics (IQMs) are introduced with the goal of modeling the perceptual quality scores given by observers to an image. In this study we use a pre-trained Convolutional Neural Network (CNN) model to ...
    • Towards a perceptual metric for video quality assessment 

      Amirshahi, Seyed Ali (Master thesis, 2010)
      In the last couple of years a huge amount of work has been shifted from works on Image Quality Assessment to Video Quality Assessment. Although some metrics have started to take the temporal aspects of videos into account ...