YungKyung Park

The characteristic of image quality perception of elderly group: according to the comparison with adult group

ABSTRACT This study examined the image quality preference of the elderly group. The subjects were divided into adult group and elderly group based on their age, and subjective image quality evaluation was performed. In result, two significant differences were found according to the age group. First, the elderly group evaluates image quality based on sensory stimulation (sharp, clean), which involves less complicated cognitive processes compared with the adult group. Next, the degree of image quality preference of the elderly group was not significantly influenced by decrease and increase of brightness and saturation compared to adult group. Notably, when brightness increased significantly, the tendency of image quality preference of elderly group remained high unlike the adult group. This confirmed that it is necessary to increase the brightness of the image in order to satisfy the elderly groups image quality preference at a high level compared with the adult group.

Human factors of UHD viewing experiences for two different age groups

ABSTRACT In an attempt to contribute to the development of ultra-high-definition (UHD) TV viewing guidelines, the factors that may affect the image quality and visual comfort for both the adult and elderly groups were considered: viewing distance (2H, 4H, and 6H), surrounding environment (illuminance levels 0.6 and 250 lx), video content (day and night, high and low speed), and resolution (UHD and full HD). It was found that the surrounding viewing conditions affected the visual comfort of the adult group more than that of the elderly group. The young adults felt more comfortable visually watching TV in an illuminated room than in a dark room. It was also found that the higher resolution ensures satisfactory visual quality despite the deviations in the viewing distance. With the UHD resolution, the viewing distance was the most significant factor contributing to the image quality and visual comfort for both age groups. Therefore, ‘visual comfort distance’ was recommended considering each human factor variable for the optimal UHD TV viewing experience.

Amendment of CIECAM02 with a technical extension to compensate Helmholtz-Kohlrausch effect for chromatic characterization of display devices

Abstract This paper proposes a method of compensating for the Helmholtz-Kohlrausch (H-K) effect which is a factor not being concerned in CIECAM02. H-K effect refers to the color appearance phenomenon that colored light appears brighter than achromatic light of the same luminance. By the magnitude estimation method, the perceptual lightness of active matrix liquid crystal display (AMLCD) is investigated. The results show that the lightness values predicted by CIECAM02 are lower than perceptual lightness values evaluated by the psychophysical experiments because of the H-K effect. The results on MobileCAM-v2, which is a refined version of CIECAM02, are investigated, as well. Since the color gamut of the display has been widening, the compensation for the H-K effect has also been increasingly important. In this paper, the method to compensate for the H-K effect in CIECAM02 is proposed. By modifying Fairchild’s equation, which is previously announced for CIELAB, CIECAM02 can be developed as a more complete color appearance model that can be universally applied to the display devices having a wide color gamut.

Evaluation for the usage of HUD contents depending on gender while driving

Recently, the attention of the driver to reduce accidents caused by the driver not facing the front of the vehicle accelerates the forward-looking and active research on HUD (Head-Up-Display) that the visual information, such as navigations can be seen on the instrument panel. In addition, HUD has a better response rate to the incident than HDD (head down display driving assistance systems collectively located in the central part of the car control panel) and a faster and has a reliable speed control (Liu and Wen, 2004). When using higher speed limit signs and road conditions the recognition of the HUD was better to follow the traffic sign regulations. According to this study, the HUD can be seen to be more beneficial for safe driving compared to the conventional HDD.