Effects of surface color on the estimated freshness of vegetables

Luminance distribution information is a critical cue for estimating visual freshness of vegetables, such as strawberries 1 and cabbages 2. However, it remains unclear how color affects the freshness estimation of vegetables. Therefore, we conducted two kinds of experiment. They were designed to investigate the effect of the color of vegetables on our visual estimation of fresh vegetables by controlling the image color information. We took calibrated pictures of fresh vegetables: cabbage, carrot and komatsuna (Japanese Mustard Spinach) that gradually degraded in a controlled environment. In Experiment 1, we created gray- scale stimuli of the vegetable surface with the same luminance values as the original color images and derived results of freshness estimation using monochromatic and chromatic stimuli. We found no difference between the results, suggesting that the color does not add critical information for the visual freshness estimation. Moreover, in Experiment 2, we created strange color stimuli of the vegetable surface (e.g. yellow cabbage) with the same luminance values as the original color images. The freshness estimation results showed that visual freshness estimation does not depend on the color of the vegetable surface even when the color does not exist in nature. In spite that color information is an important cue for identifying the type of vegetable and for estimating the ripeness of vegetables, our results suggest that visual freshness estimation is quite robust against color modification.

Okajima, K., Sakurai, Y., Arce-Lopera, C. A. (2014). In AIC 2014 Interim Meeting “Color, culture and identity: past, present and future”. (Ed.), Effects of surface color on the estimated freshness of vegetables (pp. 622-625). Oaxaca: www.aic-color.org/congr.htm

Check out the Conference Proceedings