Abstract: The present disclosure provides a portable apparatus for detecting early crop diseases based on spatial frequency domain imaging. The apparatus includes an end cover, a spatial frequency domain imaging apparatus, a dark box body, a telescopic section, and an opening-and-closing apparatus connected in sequence. The detection method includes: putting a crop sample to be detected into the dark box body from a bottom; projecting structured light of sine grey scale patterns with different spatial frequencies to the crop sample; after the sine gray scale pattern is switched each time, acquiring, by a camera, a diffuse reflection image of a surface of the crop sample once; after capturing all diffuse reflection images, performing uniformity correction on the images, demodulating the images, and extracting an alternating current component; and inputting an alternating current component image to a trained disease detection model, and determining whether the crop sample has a disease.

Abstract: The present disclosure provides a portable apparatus for detecting early crop diseases based on spatial frequency domain imaging. The apparatus includes an end cover, a spatial frequency domain imaging apparatus, a dark box body, a telescopic section, and an opening-and-closing apparatus connected in sequence. The detection method includes: putting a crop sample to be detected into the dark box body from a bottom; projecting structured light of sine grey scale patterns with different spatial frequencies to the crop sample; after the sine gray scale pattern is switched each time, acquiring, by a camera, a diffuse reflection image of a surface of the crop sample once; after capturing all diffuse reflection images, performing uniformity correction on the images, demodulating the images, and extracting an alternating current component; and inputting an alternating current component image to a trained disease detection model, and determining whether the crop sample has a disease.