Search Results

You are looking at 1 - 10 of 44 items for :

  • Refine by Access: All x
Clear All
Open access

Dave Hawley, Thomas Graham, Michael Stasiak, and Mike Dixon

., 2017 ; Stasiak et al., 1998 ). The objectives of this study were to evaluate bud yield, and cannabinoid and terpene contents when plants were grown with no SCL (control), Red-Blue SCL, or RGB SCL. Two crop cycles are presented; the results of the first

Free access

Kui Lin, Zhi Huang, and Yong Xu

comprising four layers, each of which was divided into three chambers. The chambers were illuminated from above with model 5050 RGB linear LED light bars (Unihero Corporation, Shenzhen, China). The nutrient film technique was used to cultivate the seedlings

Free access

Keun H. Cho, Veronica Y. Laux, Nathan Wallace-Springer, David G. Clark, Kevin M. Folta, and Thomas A. Colquhoun

:20) and R+G+B (mixture of R, G, and B light, 40:20:40) also were assessed. Fig. 1. Spectroradiometer readings of the light qualities used in these studies. All treatments represent the narrow-bandwidth or combined lights generated at a fluence level at 100

Free access

Hyeon-Hye Kim, Gregory D. Goins, Raymond M. Wheeler, and John C. Sager

Plants will be an important component of future long-term space missions. Lighting systems for growing plants will need to be lightweight, reliable, and durable, and light-emitting diodes (LEDs) have these characteristics. Previous studies demonstrated that the combination of red and blue light was an effective light source for several crops. Yet the appearance of plants under red and blue lighting is purplish gray making visual assessment of any problems difficult. The addition of green light would make the plant leave appear green and normal similar to a natural setting under white light and may also offer a psychological benefit to the crew. Green supplemental lighting could also offer benefits, since green light can better penetrate the plant canopy and potentially increase plant growth by increasing photosynthesis from the leaves in the lower canopy. In this study, four light sources were tested: 1) red and blue LEDs (RB), 2) red and blue LEDs with green fluorescent lamps (RGB), 3) green fluorescent lamps (GF), and 4) cool-white fluorescent lamps (CWF), that provided 0%, 24%, 86%, and 51% of the total PPF in the green region of the spectrum, respectively. The addition of 24% green light (500 to 600 nm) to red and blue LEDs (RGB treatment) enhanced plant growth. The RGB treatment plants produced more biomass than the plants grown under the cool-white fluorescent lamps (CWF treatment), a commonly tested light source used as a broad-spectrum control.

Free access

Sang Yong Nam

Leaf lettuce is a major and widely cultivated vegetable crop. Leaf lettuce is preferred for wrapping food, like rice or meat, and is much more popular than head lettuce in Korea. Color change and water loss condition are most important factor for buying decision as external quality. This paper studied color change during storage at 20 and 4 °C, 60% RH. The color analysis of adaxial surface of leaf lettuce during shelf-life storage condition showed that Hunter L and a value increased slightly after 5 days of harvest, while delta-Eab started increasing after 3 days of postharvest. Chlorophyll content decreased by half during the first 5 days after harvest. These color changes, however, could not explain the changes in leaf chlorophyll content while the color intensity of G (green) component in RGB analysis showed a close relationship with leaf chlorophyll content changes. Visual quality score showed that lettuce may kept its marketability up to 5 days after harvest. But, in refrigerator (4°C, 60% RH, cold chain system) storage condition. Leaf color is about three times longer than shelf-life. Theses results of each evaluation methods consistently demonstrated that leaf lettuce may keep its marketability up to 5 days in a distribution market without color quality damage.

Free access

Steven C. Wiest

A system for the digital analysis of photographic prints of turfgrass plots is being developed. The 3-year-old turfgrass plots included Meyer zoysiagrass, Midlawn bermudagrass, Prairie buffalograss and Mustang tall fescue. The plots were photographed by a camera with a small dual bubble level on the camera back and a 28-mm-wide angle lens. Photographs were digitized with flatbed scanners. The images can then be analyzed in a variety of ways. For example, a series of photographs were taken from mid-Sept. through late Oct 1995 and spectral analysis of the resultant digital images were made. The initial RGB (red-greenblue) format of the images was converted to HSI (hue-saturation-intensity) for analysis. The results indicate, obviously, that hue changed from 104 (i.e., green) to 75.7 degrees (i.e., brownish) between the beginning and end of Oct. 1995. Similarly, intensity changed from ≈0.12 to ≈0.16 during the same time period, indicating that the images became darker over time. These phenomena were observed in all four species examined. However, the saturation value evoked a significant species * date interaction. The three warm-season species showed a decrease in saturation, while Mustang had no significant decrease during Oct. Spectral as well as textural analysis are likely the two most useful techniques in the digital analysis of turfgrass plots. Examples of both will be presented.

Free access

Ignazio Infantino and Riccardo Lo Bianco*

Peel color is a critical index of external fruit quality and consumer appreciation level. Traditional methods for determination of peel color are based on visual analysis or punctual measurements by colorimeter. In this study we present a method based on digital image analysis that integrates the accuracy of an interactive measurement and the efficacy of an image analysis that descibes entire sides of the fruit. A sample of apple, mandarin, grape, and peach fruit was photographed (each fruit on two opposite sides) with a digital camera for determination of peel color. Digital images were converted from RGB to CIE L*a*b* format, and color characteristics were indexed and quantified. The implemented method uses a reference color image cropped from the best fruit (interactively chosen) to calculate a color index for each fruit of the image set. The final index is the weighted sum of the number of pixels of the fruit, where pixels closer to the reference color (distance in the CIE L*a*b space) are considered more relevant. This color index gives integrated information on fruit color quantity (% of cover color) and quality (hue and saturation). The method represents a rapid and efficient way of determining color of the entire fruit surface and overcomes difficulties and approximation of traditional methods. A modification of the same method can be used to determine peel rugosity (mandarin) and average size and number of grape berries per bunch.

Free access

Audrey Darrigues, Jack Hall, Esther van der Knaap, David M. Francis, Nancy Dujmovic, and Simon Gray

because digital devices use a color space that is not standardized, is nonlinear, and may vary between hardware devices and software applications. In the Red Green Blue (RGB) color space, each pixel is represented in the computer or interface hardware as

Free access

Gary W. Stutte, Sharon Edney, and Tony Skerritt

(LEDs; RGB); red and blue LEDs (RB); red LEDs (R); and red and far-red LEDs (RFr). The photosynthetically active radiation ( PAR ) and the photostationary state ( Φ ) for each treatment are shown. The LED treatment matrices used to determine the effect

Free access

Kenneth R. Summy and Christopher R. Little

growth, which consists primarily of Capnodium and related fungal species ( Farr et al., 1989 ; Reynolds, 1999 ). Fig. 1. Examples of color RGB and color infrared photographs (insets) of foliage acquired in a whole plant context and used to