Method for developing and using high quality reference images to evaluate tone mapping operators

Abstract

With the advancement of imaging technology, high dynamic range (HDR) images can now be captured and displayed to produce realistic effects. Tone mapping operators (TMOs) are used to map HDR radiance to the displayable range. A reliable TMO would play a significant role in the accurate reproduction of HDR scenes. The present study aimed to establish an image quality metric based on external references to evaluate various TMOs. Two psychophysical experiments were conducted to develop reference images and to investigate the performance of TMOs. In experiment 1, a set of high quality reference images was developed by rendering image features in terms of contrast, sharpness, and colorfulness, to achieve good rendering for each image. The images were used as reference in experiment 2 to evaluate the performance of 14 TMOs using a six-point categorical judgment method. The TMOs were evaluated using four scales, i.e., contrast, sharpness, colorfulness, and overall performance. The hierarchical relationship among TMOs was established. The results were further compared with previous studies, and high correlation was found between the current experiments and previous studies.

Generic Color Correction for Tone Mapping Operators in High Dynamic Range Imaging

“…The other useful assessment scale could be the assessment of the overall preference of the images. Studies have shown that the subjects may prefer images with more colorfulness rather than the original colors of the scenes [24]. Therefore, in our psychophysical experiment, the naturalness of the colors was used as an assessment scale.…”

“…The images contained a wide variety of colors, including night and natural scenes. The images were tone mapped using 6 TMOs including 3 recent TMOs, i.e., Hui [21], Liang [23] and Khan [9]; one TMO that reproduces low saturation images i.e., Meylan [22]; one commonly used TMO named Reinhard [8]; and a TMO that typically produces high contrast images i.e., Schlick [11,24]. Although Hui's TMO processes the color however it results in over saturated images.…”

Generic Color Correction for Tone Mapping Operators in High Dynamic Range Imaging

“…The other useful assessment scale could be the assessment of the overall preference of the images. Studies have shown that the subjects may prefer images with more colorfulness rather than the original colors of the scenes [24]. Therefore, in our psychophysical experiment, the naturalness of the colors was used as an assessment scale.…”

“…The images contained a wide variety of colors, including night and natural scenes. The images were tone mapped using 6 TMOs including 3 recent TMOs, i.e., Hui [21], Liang [23] and Khan [9]; one TMO that reproduces low saturation images i.e., Meylan [22]; one commonly used TMO named Reinhard [8]; and a TMO that typically produces high contrast images i.e., Schlick [11,24]. Although Hui's TMO processes the color however it results in over saturated images.…”

CIECAM16-based Tone Mapping of High Dynamic Range Images

“…The performance of the TMOz was compared with state-ofthe-art TMOs. The TMOs include three recent TMOs named Hui [16], Liang [4] and Khan [5]; four widespread TMOs [17], iCAM06 [8], Schlick [2] and Reinhard [3] and one TMO from 2006 named Meylan TMO [18]. Since the TMOz was fully adaptive, the default parameters (as suggested in the original papers) were used for other TMOs.…”