Blinded evaluation of the effects of high definition and magnification on perceived image quality in laryngeal imaging.
ABSTRACT Advances in commercial video technology have improved office-based laryngeal imaging. This study investigates the perceived image quality of a true high-definition (HD) video camera and the effect of magnification on laryngeal videostroboscopy.
We performed a prospective, dual-armed, single-blinded analysis of a standard laryngeal videostroboscopic examination comparing 3 separate add-on camera systems: a 1-chip charge-coupled device (CCD) camera, a 3-chip CCD camera, and a true 720p (progressive scan) HD camera. Displayed images were controlled for magnification and image size (20-inch [50-cm] display, red-green-blue, and S-video cable for 1-chip and 3-chip cameras; digital visual interface cable and HD monitor for HD camera). Ten blinded observers were then asked to rate the following 5 items on a 0-to-100 visual analog scale: resolution, color, ability to see vocal fold vibration, sense of depth perception, and clarity of blood vessels. Eight unblinded observers were then asked to rate the difference in perceived resolution and clarity of laryngeal examination images when displayed on a 10-inch (25-cm) monitor versus a 42-inch (105-cm) monitor. A visual analog scale was used. These monitors were controlled for actual resolution capacity.
For each item evaluated, randomized block design analysis demonstrated that the 3-chip camera scored significantly better than the 1-chip camera (p < .05). For the categories of color and blood vessel discrimination, the 3-chip camera scored significantly better than the HD camera (p < .05). For magnification alone, observers rated the 42-inch monitor statistically better than the 10-inch monitor.
The expense of new medical technology must be judged against its added value. This study suggests that HD laryngeal imaging may not add significant value over currently available video systems, in perceived image quality, when a small monitor is used. Although differences in clarity between standard and HD cameras may not be readily apparent on small displays, a large display size coupled with HD technology may impart improved diagnosis of subtle vocal fold lesions and vibratory anomalies.
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ABSTRACT: Though theoretically superior to standard 2D visualization, 3D video systems have not yet achieved a breakthrough in laparoscopy. The latest 3D monitors, including autostereoscopic displays and high-definition (HD) resolution, are designed to overcome the existing limitations. We performed a randomized study on 48 individuals with different experience levels in laparoscopy. Three different 3D displays (glasses-based 3D monitor, autostereoscopic display, and a mirror-based theoretically ideal 3D display) were compared to a 2D HD display by assessing multiple performance and mental workload parameters and rating the subjects during a laparoscopic suturing task. Electromagnetic tracking provided information on the instruments' pathlength, movement velocity, and economy. The usability, the perception of visual discomfort, and the quality of image transmission of each monitor were subjectively rated. Almost all performance parameters were superior with the conventional glasses-based 3D display compared to the 2D display and the autostereoscopic display, but were often significantly exceeded by the mirror-based 3D display. Subjects performed a task faster and with greater precision when visualization was achieved with the 3D and the mirror-based display. Instrument pathlength was shortened by improved depth perception. Workload parameters (NASA TLX) did not show significant differences. Test persons complained of impaired vision while using the autostereoscopic monitor. The 3D and 2D displays were rated user-friendly and applicable in daily work. Experienced and inexperienced laparoscopists profited equally from using a 3D display, with an improvement in task performance about 20 %. Novel 3D displays improve laparoscopic interventions as a result of faster performance and higher precision without causing a higher mental workload. Therefore, they have the potential to significantly impact the further development of minimally invasive surgery. However, as shown by the custom-built 3D mirror display, this effect can be improved, thus stimulating further research.Surgical Endoscopy 03/2014; 28(8). DOI:10.1007/s00464-014-3487-9 · 3.31 Impact Factor
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ABSTRACT: Laparoscopic surgery requires surgeons to rely on visual clues for discrimination among differing tissues and for depth of field on a two-dimensional screen. High definition (HD) provides a superior image. If there is a measurable advantage with HD television (TV), the increase in the cost of the technology would be justified. A digital three-chip CCD camera with a standard monitor (SD system) and a true HD camera (1,080 pixels) with a 16:9-ratio HD monitor (HD system) were compared in clinical and laboratory settings. Three experiments were performed: (1) subjective visual evaluation of the HD and SD systems during actual surgical cases, (2) subjective visual evaluation in a controlled laboratory surgical setting with simultaneous parallel recording, and (3) three laparoscopic surgical task evaluations in a laboratory setting, namely, task A (metric analysis of participants on the surgical simulator), task B (simple eye-hand coordination performance), and task C (knot tying). All 53 participants subjectively evaluated HD as superior to SD in the laboratory setting and during actual surgery. In task B, there was no significant difference between SD and HD (dominant hand: p = 0.19; nondominant hand: p = 0.07). In task C, the knot-tying time was significantly less when performed with HD (mean, 173 +/- 84 s vs 214 +/- 107 s; p = 0.003). Most importantly, subjects with less skill (more documented time required in the basic module on a surgical simulator) improved significantly in the knot-tying task with the HD system (R = 0.631; p = 0.005). All the participants preferred HD to SD. High definition significantly improved laparoscopic knot tying, which requires precise depth perception, proving that HD is more than just a pretty picture.Surgical Endoscopy 11/2007; 21(10):1849-54. DOI:10.1007/s00464-007-9541-0 · 3.31 Impact Factor
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ABSTRACT: This study aimed to estimate the effectiveness of a full digital, high definition video system for laryngeal observations. A newly available, full digital, high definition video camera and high definition video monitor were used. With an endoscopic adaptor and rigid telescope, laryngoscopy and stroboscopy were performed on patients with various kinds of laryngeal lesions. All laryngeal lesions were observed and recorded by the full digital, high definition video camera without incident. The image quality for laryngoscopy and stroboscopy was far superior to that of a conventional video system, including video-endoscopy. Even tiny structures or lesions could clearly be visualised on the monitor. The still image obtained from the full digital, high definition video camera was 1920 x 1080 pixels and was comparable to that obtained from a still camera. Full digital, high definition video cameras are now commonplace products and can easily be applied to patients with laryngeal disorders. They provide superior laryngeal images, compared with conventional video systems. Furthermore, high definition video systems are cheaper than proprietary medical video systems. We consider our system to represent an accessible technique of gaining superior laryngeal observation in otolaryngological clinics.The Journal of Laryngology & Otology 02/2008; 122(1):78-81. DOI:10.1017/S0022215107000072 · 0.70 Impact Factor