Development of an image-based measurement instrument for gloss characterization

Abstract

Gloss is one of the main attributes to describe the appearance of surfaces and objects, as it contributes to the general quality perception. Gloss is a multidimensional quantity of which ‘specular gloss’ is the most commonly applied attribute. Specular gloss meters are standardized and widely used in industry. However, their readings correlate only partially to the general visual gloss impression, which also comprises distinctness-of-the-reflected-image (DOI), haze, contrast and surface-uniformity attributes. This study presents a more profound image-based gloss meter (iGM) which incorporates a CMOS camera detector. This concept is not new, but limited research has been conducted on the inclusion of various image processing evaluations for gloss attributes. The designed iGM is compatible to 60° specular gloss meter standards. The CMOS detector captures the reflected source image, which is processed to measure four perceptual attributes of surface gloss. The obtained results validate the 60° specular gloss evaluation and indicate a promising capability in characterizing DOI, haze, and contrast. Contrast is an important attribute that is not available yet in industrial gloss meters. It is measured using a diffuse aspecular light source. Generally, this iGM maintains the hardware principles of specular gloss meters, while evolving toward a representative gloss perception meter.

Effect Of Three Different Whitening Strips On Dental Sensitivity, Oral Tissues, Tooth Color And Luster: A Double-Blinded, Randomized, Controlled Clinical Study

“…Color measurements using the photo-based image analysis approach employed by did not consider tooth luster, nor was luster measured in that study. Thus, the Gurich group may have registered inaccurately lower color readings than the actual in vivo tooth color in the non-peroxide group, because identical colors with higher levels of luster register as a darker shade than those with a lower luster level [25][26][27][28], and this effect is further magnified by the typically higher levels of backscattered light or luster in photographs recorded at 900 such as those used by the industry-recommended angles of 200, 400or 600 [26]. Because the current study demonstrated that tooth luster increased significantly in the teeth treated with the nonperoxide formulations, butit decreased significantly in the teeth treated with the peroxide strips, it seems reasonable to assume that this unmeasured, but essential variable gave rise to misleading conclusions about whitening efficacy in the Gurich study.…”

A Handheld Image-based Gloss Meter for Complete Gloss Characterization

“…It is based on the earlier design from Ref. [6], extended with a 0° camera (item 10) and several light sources at 45° and 10° angles of incidence (items 11 and 12). This extended iGM device complies to the widely known standards for a parallel beam 60° specular gloss meter ( [3], [4]).…”

“…At the same time it captures more advanced measurements relevant to many industrial applications. It is an extension of a previously designed image-based gloss meter (iGM, such as presented in [5] and [6]), which processes the captured reflected light source image to evaluate new metrics for the attributes DOI, haze and contrast. [6] Sample measurements illustrated the versatility and utility of the system for several materials, including anisotropic surfaces.…”

“…It is an extension of a previously designed image-based gloss meter (iGM, such as presented in [5] and [6]), which processes the captured reflected light source image to evaluate new metrics for the attributes DOI, haze and contrast. [6] Sample measurements illustrated the versatility and utility of the system for several materials, including anisotropic surfaces. However, the device did not yet include any surface imaging, making the evaluation of surface-uniformity gloss (fifth gloss attribute) impossible.…”

Specular gloss estimation by measuring the colorimetric data produced by a reflection measurement at 8° of incidence

“…The psychophysical models aim to predict how humans perceive gloss based on visual cues, such as highlights, shading, and contrast. They consider factors like observer angle and lighting conditions to estimate gloss perception [10][11][12][13][14][15][16][17][18]. Ferwerda et al proposed a psychophysically-based model of surface gloss perception, which uses image synthesis techniques to describe and control the appearance of glossy surfaces in synthetic images [11].…”