Ideal situation for camera calibration using amateur digital cameras

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

“…Advanced camera calibration techniques for geometric correction (Kunii and Murai, 2008) were not applied in this experiment. For each band and each camera exposure speed, we converted the camera's output digital count (D, 0 − 255) at the center and 24 off-center points of 10 × 10 pixel to a ratio relative to the D value at the center (= 1.0).…”

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

“…Low-cost pocket cameras are designed and manufactured mainly for taking snapshots easily, and manufacturers do not usually recommend them for measurement or survey use that requires a high degree of accuracy and stability. 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).…”