Basic Study for Estimation of Nitrogen Content of Rice Plants from Vegetation Cover Rate of Rice obtained by a Simple Image Measurement

Estimating Paddy Rice Leaf Area Index with Fixed Point Continuous Observation of Near Infrared Reflectance Using a Calibrated Digital Camera

“…Recently, the feasibility of using single-lens refl ex digital cameras for mapping was reported (Kunii and Murai, 2008). In fact, several authors have shown favorable results using color video or still digital cameras, or multiband cameras equipped with a near infrared band-pass fi lter for assessing crop coverage or leaf greenness (e.g., Kawashima and Nakatani, 1998;Adamsen et al, 1999;Purcell, 2000;Zhou and Robson, 2001;Matsuda et al, 2003;Jia et al, 2004;Ku et al, 2004;Casadesus et al, 2007;Omine, 2007;Takemine et al, 2007;Crimmins and Crimmins, 2008;Okada and Ikeba, 2008;Takada et al, 2009;Sakamoto et al, 2010).…”

Continuous Monitoring of Visible and Near-Infrared Band Reflectance from a Rice Paddy for Determining Nitrogen Uptake Using Digital Cameras

“…For relatively simple and cost-effective ground observations, a high spatial-and spectral-resolution imaging system using line sensors has been developed for intensive surveys (Kosaka et al, 2007), but it requires a crane for scanning above the targeted object. On the other hand, handy video cameras or digital cameras have been used for assessing crop leaf nitrogen and/or chlorophyll content (Nakatani and Kawashima, 1994;Kawashima and Nakatani, 1998;Matsuda et al, 2003;Jia et al, 2004;Ku et al, 2004;Casadesus et al, 2007;Takemine et al, 2007) and for analyzing plant cover or phenology of vegetation (Purcell, 2000;Zhou and Robson, 2001;Richardson et al, 2007;Ishihara et al, 2008). Cameras with sensitivity in the nearinfrared (NIR) range, which is essential for crops and plant observation due to the characteristic high reflectance from green phytomass have also been used (Omine, 2007).…”

Estimating Rice Leaf Greenness (SPAD) Using Fixed-Point Continuous Observations of Visible Red and Near Infrared Narrow-Band Digital Images

“…Imagery observation may solve the above problem, several papers have described advantages of video or digital cameras in applications for leaf color assessment (e.g., Nakatani and Kawashima, 1994;Kawashima and Nakatani, 1998;Jia et al, 2004;Ku et al, 2004;Casadesus et al, 2007;Takemine et al, 2007). The advantages of image data taken for a certain area in a short time prevail over the other methods.…”

“…Adverse weather during the cropping season frequently disturbs collection of full and timely optical remote sensing data from airplanes and satellites (Akiyama and Kawamura, 2003). Direct reflection of sunlight from leaves may cause problems under sunny and windy conditions because the unified-view sensor of a radiometer cannot separate abnormal targets from correct ones (Takebe et al, 1990).Imagery observation may solve the above problem, several papers have described advantages of video or digital cameras in applications for leaf color assessment (e.g., Nakatani and Kawashima, 1994;Kawashima and Nakatani, 1998;Jia et al, 2004;Ku et al, 2004;Casadesus et al, 2007;Takemine et al, 2007). The advantages of image data taken for a certain area in a short time prevail over the other methods.…”