Martin Tall - Academia.edu (original) (raw)
Papers by Martin Tall
Proceedings of the 2010 Symposium on Eye-Tracking Research & Applications - ETRA '10, 2010
ABSTRACT CONCLUSION Our approach offers insight into the relationship between recorded gaze data ... more ABSTRACT CONCLUSION Our approach offers insight into the relationship between recorded gaze data and the volumetric space of the viewed medical images. It has specifically been developed for gaze tracking data acquisition within the field of medical imaging and will be employed to facilitate studies across a wide variety of 3D modalities. BACKGROUND Previous studies investigating eye movements of radiologist during their image analysis have recorded gaze data on single images containing one or more objects, e.g., nodules in a radiograph. Typically the images are displayed for a fixed duration and the results are illustrated through aggregated visualizations e.g., fixation plotting, scan paths or heat maps. However, when analyzing search patterns while performing standard interpretation of volumetric chest CT data, paging through a stack of transverse sections warrants three-dimensional analysis of eye movements. EVALUATION Measurements among four individuals reveals an in-plane (x/y) accuracy between 0.4-1° visual angle while being absolutely accurate on the through-plane axis at a 50 Hz sampling rate. The remote corneal reflection system employed is tolerant against 100 mm/sec. head movements within a 300x300 mm area at 600 mm distance from the display. Our platform offers real-time interaction with CT data while simultaneously recording gaze data and includes algorithms for classification of eye movements such as fixations and saccades. Novel volumetric visualizations, such as time-stamped 3D gaze paths and 3D heat maps, offer direct insight to foveal dwell time per voxel and the platform is capable of fusing the gaze data with the acquired volume data. DISCUSSION The platform we have developed enables a real-time mapping between on-screen fixations and the 3D DICOM coordinates of the viewed images, thereby linking our eye tracker data and the physical space in which the 3D image data were obtained. Further research aims at illuminating specific aspects of volumetric inspection that can be used for training and diagnostic support.
The purpose of this study is to explore the area surrounding computer energy consumption. After r... more The purpose of this study is to explore the area surrounding computer energy consumption. After reviewing general background on related fields we measured energy consumption among different computers and monitors. Based on the results we constructed a survey aimed at Swedish schools. Using a quantitative approach we draw some conclusions, a majority of the respondents lacked someone responsible of shutting down computers after hours; even more lacked a tool to do so. With the help of our survey result we demonstrate how organization could reduce energy waste and receive financial benefits, with a minimal effort. To enhance the power management in an environment with computer networks we introduced related techniques and describe how they operate. We then suggest a centralized solution based on open source. Our intention is to provide references and discuss several of the open source implementations that freely exist.
CONCLUSION Our approach offers insight into the relationship between recorded gaze data and the v... more CONCLUSION Our approach offers insight into the relationship between recorded gaze data and the volumetric space of the viewed medical images. It has specifically been developed for gaze tracking data acquisition within the field of medical imaging and will be employed to facilitate studies across a wide variety of 3D modalities. BACKGROUND Previous studies investigating eye movements of radiologist during their image analysis have recorded gaze data on single images containing one or more objects, e.g., nodules in a radiograph. Typically the images are displayed for a fixed duration and the results are illustrated through aggregated visualizations e.g., fixation plotting, scan paths or heat maps. However, when analyzing search patterns while performing standard interpretation of volumetric chest CT data, paging through a stack of transverse sections warrants three-dimensional analysis of eye movements. EVALUATION Measurements among four individuals reveals an in-plane (x/y) accurac...
PURPOSE Detecting lung nodules in volumetric CT data is daunting because a large volume of comple... more PURPOSE Detecting lung nodules in volumetric CT data is daunting because a large volume of complex anatomy must be exhaustively searched for the presence of small objects. We have developed a volumetric gaze tracking technique that records the gaze path as subjects page through CT lung volumes (LV). We analyze the gaze data to understand the process of detection and to identify influences on accuracy of detection in trainees. METHOD AND MATERIALS Three 1st year radiology residents (R) and two fellows (F) each studied a set of 40 LVs. For each study, one of 3 patient CT scans (2 M, 1 F; 120 kVp, 350-460 mA, 1-1.3 mm slice thickness) was chosen and 3 to 6 simulated nodules 4-6 mm in diameter were digitally embedded at various locations in the LV. In addition to the gaze path, recorded unobtrusively, subjects gave a location and confidence level from 1 to 5 for all detected nodules. The nearest distance (ND) from the gaze path to each nodule location was calculated for each study. For ...
This thesis investigates suitable interaction methods for gaze driven computer interfaces. The la... more This thesis investigates suitable interaction methods for gaze driven computer interfaces. The lack of input devices requires interface components that are especially designed to be driven by gaze input. A set of reusable and configurable interface components were developed to support various interaction styles. The components were then used to build a prototype application containing a game, a photo viewer and a music player. An evaluation of the interface components as we! as the prototype application was performed. The use of dynamically appearing target areas for saccadic selection was found to be a suitable interaction method for gaze driven interfaces. The interaction methods helps to alleviate the previously found stress associated with gaze driven interfaces (the Midas touch problem). Overall the prototype application received a positive response from the evaluation participants with appreciation for being intuitive to use.
Radiology, 2015
To determine the effectiveness of radiologists&am... more To determine the effectiveness of radiologists' search, recognition, and acceptance of lung nodules on computed tomographic (CT) images by using eye tracking. This study was performed with a protocol approved by the institutional review board. All study subjects provided informed consent, and all private health information was protected in accordance with HIPAA. A remote eye tracker was used to record time-varying gaze paths while 13 radiologists interpreted 40 lung CT images with an average of 3.9 synthetic nodules (5-mm diameter) embedded randomly in the lung parenchyma. The radiologists' gaze volumes ( GV gaze volume s) were defined as the portion of the lung parenchyma within 50 pixels (approximately 3 cm) of all gaze points. The fraction of the total lung volume encompassed within the GV gaze volume s, the fraction of lung nodules encompassed within each GV gaze volume (search effectiveness), the fraction of lung nodules within the GV gaze volume detected by the reader (recognition-acceptance effectiveness), and overall sensitivity of lung nodule detection were measured. Detected nodules were within 50 pixels of the nearest gaze point for 990 of 992 correct detections. On average, radiologists searched 26.7% of the lung parenchyma in 3 minutes and 16 seconds and encompassed between 86 and 143 of 157 nodules within their GV gaze volume s. Once encompassed within their GV gaze volume , the average sensitivity of nodule recognition and acceptance ranged from 47 of 100 nodules to 103 of 124 nodules (sensitivity, 0.47-0.82). Overall sensitivity ranged from 47 to 114 of 157 nodules (sensitivity, 0.30-0.73) and showed moderate correlation (r = 0.62, P = .02) with the fraction of lung volume searched. Relationships between reader search, recognition and acceptance, and overall lung nodule detection rate can be studied with eye tracking. Radiologists appear to actively search less than half of the lung parenchyma, with substantial interreader variation in volume searched, fraction of nodules included within the search volume, sensitivity for nodules within the search volume, and overall detection rate.
Advances in Assistive Technologies, 2012
Proceedings of the 2011 annual conference extended abstracts on Human factors in computing systems - CHI EA '11, 2011
Accuracy of an open source remote eye tracking system and a state-of-the-art commercial eye track... more Accuracy of an open source remote eye tracking system and a state-of-the-art commercial eye tracker was measured 4 times during a usability test. Results from 9 participants showed both devices to be fairly stable over time, but the commercial tracker was more accurate with a mean error of 31 pixels against 59 pixels using the low cost system. This suggests that low cost eye tracking can become a viable alternative, when usability studies need not to distinguish between, for instance, particular words or menu items that participants are looking at, but only between larger areas-of-interest they pay attention to.
Proceedings of the 1st Conference on Novel Gaze-Controlled Applications - NGCA '11, 2011
In this paper we assess the performance of an open-source gaze tracker in a remote (ie table-moun... more In this paper we assess the performance of an open-source gaze tracker in a remote (ie table-mounted) setup, and compare it with two other commercial eye trackers. An experiment with 5 subjects showed the open-source eye tracker to have a significantly higher level of ...
Proceedings of the 12th ACM international conference adjunct papers on Ubiquitous computing - Ubicomp '10, 2010
Eye gaze can be used to interact with high-density information presented on large displays. We ha... more Eye gaze can be used to interact with high-density information presented on large displays. We have built a system employing off-the-shelf hardware components and open-source gaze tracking software that enables users to interact with an interface displayed on a 55" screen using their eye movements. The system works at a viewing distance of 1 to 1.5 meters and requires a 30 second calibration procedure for every user. We demonstrate how it can be used to navigate a digital bulletin board display with several notes on top of each other. There are some technical challenges detecting the eyes when people are wearing glasses and when external light sources are present.
Academic Radiology, 2012
To determine the accuracy and reproducibility of a remote eye-tracking system for studies of obse... more To determine the accuracy and reproducibility of a remote eye-tracking system for studies of observer gaze while displaying volumetric chest computed tomography (CT) images.
Proceedings of the 2010 Symposium on Eye-Tracking Research & Applications - ETRA '10, 2010
ABSTRACT CONCLUSION Our approach offers insight into the relationship between recorded gaze data ... more ABSTRACT CONCLUSION Our approach offers insight into the relationship between recorded gaze data and the volumetric space of the viewed medical images. It has specifically been developed for gaze tracking data acquisition within the field of medical imaging and will be employed to facilitate studies across a wide variety of 3D modalities. BACKGROUND Previous studies investigating eye movements of radiologist during their image analysis have recorded gaze data on single images containing one or more objects, e.g., nodules in a radiograph. Typically the images are displayed for a fixed duration and the results are illustrated through aggregated visualizations e.g., fixation plotting, scan paths or heat maps. However, when analyzing search patterns while performing standard interpretation of volumetric chest CT data, paging through a stack of transverse sections warrants three-dimensional analysis of eye movements. EVALUATION Measurements among four individuals reveals an in-plane (x/y) accuracy between 0.4-1° visual angle while being absolutely accurate on the through-plane axis at a 50 Hz sampling rate. The remote corneal reflection system employed is tolerant against 100 mm/sec. head movements within a 300x300 mm area at 600 mm distance from the display. Our platform offers real-time interaction with CT data while simultaneously recording gaze data and includes algorithms for classification of eye movements such as fixations and saccades. Novel volumetric visualizations, such as time-stamped 3D gaze paths and 3D heat maps, offer direct insight to foveal dwell time per voxel and the platform is capable of fusing the gaze data with the acquired volume data. DISCUSSION The platform we have developed enables a real-time mapping between on-screen fixations and the 3D DICOM coordinates of the viewed images, thereby linking our eye tracker data and the physical space in which the 3D image data were obtained. Further research aims at illuminating specific aspects of volumetric inspection that can be used for training and diagnostic support.
The purpose of this study is to explore the area surrounding computer energy consumption. After r... more The purpose of this study is to explore the area surrounding computer energy consumption. After reviewing general background on related fields we measured energy consumption among different computers and monitors. Based on the results we constructed a survey aimed at Swedish schools. Using a quantitative approach we draw some conclusions, a majority of the respondents lacked someone responsible of shutting down computers after hours; even more lacked a tool to do so. With the help of our survey result we demonstrate how organization could reduce energy waste and receive financial benefits, with a minimal effort. To enhance the power management in an environment with computer networks we introduced related techniques and describe how they operate. We then suggest a centralized solution based on open source. Our intention is to provide references and discuss several of the open source implementations that freely exist.
CONCLUSION Our approach offers insight into the relationship between recorded gaze data and the v... more CONCLUSION Our approach offers insight into the relationship between recorded gaze data and the volumetric space of the viewed medical images. It has specifically been developed for gaze tracking data acquisition within the field of medical imaging and will be employed to facilitate studies across a wide variety of 3D modalities. BACKGROUND Previous studies investigating eye movements of radiologist during their image analysis have recorded gaze data on single images containing one or more objects, e.g., nodules in a radiograph. Typically the images are displayed for a fixed duration and the results are illustrated through aggregated visualizations e.g., fixation plotting, scan paths or heat maps. However, when analyzing search patterns while performing standard interpretation of volumetric chest CT data, paging through a stack of transverse sections warrants three-dimensional analysis of eye movements. EVALUATION Measurements among four individuals reveals an in-plane (x/y) accurac...
PURPOSE Detecting lung nodules in volumetric CT data is daunting because a large volume of comple... more PURPOSE Detecting lung nodules in volumetric CT data is daunting because a large volume of complex anatomy must be exhaustively searched for the presence of small objects. We have developed a volumetric gaze tracking technique that records the gaze path as subjects page through CT lung volumes (LV). We analyze the gaze data to understand the process of detection and to identify influences on accuracy of detection in trainees. METHOD AND MATERIALS Three 1st year radiology residents (R) and two fellows (F) each studied a set of 40 LVs. For each study, one of 3 patient CT scans (2 M, 1 F; 120 kVp, 350-460 mA, 1-1.3 mm slice thickness) was chosen and 3 to 6 simulated nodules 4-6 mm in diameter were digitally embedded at various locations in the LV. In addition to the gaze path, recorded unobtrusively, subjects gave a location and confidence level from 1 to 5 for all detected nodules. The nearest distance (ND) from the gaze path to each nodule location was calculated for each study. For ...
This thesis investigates suitable interaction methods for gaze driven computer interfaces. The la... more This thesis investigates suitable interaction methods for gaze driven computer interfaces. The lack of input devices requires interface components that are especially designed to be driven by gaze input. A set of reusable and configurable interface components were developed to support various interaction styles. The components were then used to build a prototype application containing a game, a photo viewer and a music player. An evaluation of the interface components as we! as the prototype application was performed. The use of dynamically appearing target areas for saccadic selection was found to be a suitable interaction method for gaze driven interfaces. The interaction methods helps to alleviate the previously found stress associated with gaze driven interfaces (the Midas touch problem). Overall the prototype application received a positive response from the evaluation participants with appreciation for being intuitive to use.
Radiology, 2015
To determine the effectiveness of radiologists&am... more To determine the effectiveness of radiologists' search, recognition, and acceptance of lung nodules on computed tomographic (CT) images by using eye tracking. This study was performed with a protocol approved by the institutional review board. All study subjects provided informed consent, and all private health information was protected in accordance with HIPAA. A remote eye tracker was used to record time-varying gaze paths while 13 radiologists interpreted 40 lung CT images with an average of 3.9 synthetic nodules (5-mm diameter) embedded randomly in the lung parenchyma. The radiologists' gaze volumes ( GV gaze volume s) were defined as the portion of the lung parenchyma within 50 pixels (approximately 3 cm) of all gaze points. The fraction of the total lung volume encompassed within the GV gaze volume s, the fraction of lung nodules encompassed within each GV gaze volume (search effectiveness), the fraction of lung nodules within the GV gaze volume detected by the reader (recognition-acceptance effectiveness), and overall sensitivity of lung nodule detection were measured. Detected nodules were within 50 pixels of the nearest gaze point for 990 of 992 correct detections. On average, radiologists searched 26.7% of the lung parenchyma in 3 minutes and 16 seconds and encompassed between 86 and 143 of 157 nodules within their GV gaze volume s. Once encompassed within their GV gaze volume , the average sensitivity of nodule recognition and acceptance ranged from 47 of 100 nodules to 103 of 124 nodules (sensitivity, 0.47-0.82). Overall sensitivity ranged from 47 to 114 of 157 nodules (sensitivity, 0.30-0.73) and showed moderate correlation (r = 0.62, P = .02) with the fraction of lung volume searched. Relationships between reader search, recognition and acceptance, and overall lung nodule detection rate can be studied with eye tracking. Radiologists appear to actively search less than half of the lung parenchyma, with substantial interreader variation in volume searched, fraction of nodules included within the search volume, sensitivity for nodules within the search volume, and overall detection rate.
Advances in Assistive Technologies, 2012
Proceedings of the 2011 annual conference extended abstracts on Human factors in computing systems - CHI EA '11, 2011
Accuracy of an open source remote eye tracking system and a state-of-the-art commercial eye track... more Accuracy of an open source remote eye tracking system and a state-of-the-art commercial eye tracker was measured 4 times during a usability test. Results from 9 participants showed both devices to be fairly stable over time, but the commercial tracker was more accurate with a mean error of 31 pixels against 59 pixels using the low cost system. This suggests that low cost eye tracking can become a viable alternative, when usability studies need not to distinguish between, for instance, particular words or menu items that participants are looking at, but only between larger areas-of-interest they pay attention to.
Proceedings of the 1st Conference on Novel Gaze-Controlled Applications - NGCA '11, 2011
In this paper we assess the performance of an open-source gaze tracker in a remote (ie table-moun... more In this paper we assess the performance of an open-source gaze tracker in a remote (ie table-mounted) setup, and compare it with two other commercial eye trackers. An experiment with 5 subjects showed the open-source eye tracker to have a significantly higher level of ...
Proceedings of the 12th ACM international conference adjunct papers on Ubiquitous computing - Ubicomp '10, 2010
Eye gaze can be used to interact with high-density information presented on large displays. We ha... more Eye gaze can be used to interact with high-density information presented on large displays. We have built a system employing off-the-shelf hardware components and open-source gaze tracking software that enables users to interact with an interface displayed on a 55" screen using their eye movements. The system works at a viewing distance of 1 to 1.5 meters and requires a 30 second calibration procedure for every user. We demonstrate how it can be used to navigate a digital bulletin board display with several notes on top of each other. There are some technical challenges detecting the eyes when people are wearing glasses and when external light sources are present.
Academic Radiology, 2012
To determine the accuracy and reproducibility of a remote eye-tracking system for studies of obse... more To determine the accuracy and reproducibility of a remote eye-tracking system for studies of observer gaze while displaying volumetric chest computed tomography (CT) images.