Automated color detection in orchids using color labels and deep learning

PLoS One. 2021 Oct 27;16(10):e0259036. doi: 10.1371/journal.pone.0259036. eCollection 2021.

Abstract

The color of particular parts of a flower is often employed as one of the features to differentiate between flower types. Thus, color is also used in flower-image classification. Color labels, such as 'green', 'red', and 'yellow', are used by taxonomists and lay people alike to describe the color of plants. Flower image datasets usually only consist of images and do not contain flower descriptions. In this research, we have built a flower-image dataset, especially regarding orchid species, which consists of human-friendly textual descriptions of features of specific flowers, on the one hand, and digital photographs indicating how a flower looks like, on the other hand. Using this dataset, a new automated color detection model was developed. It is the first research of its kind using color labels and deep learning for color detection in flower recognition. As deep learning often excels in pattern recognition in digital images, we applied transfer learning with various amounts of unfreezing of layers with five different neural network architectures (VGG16, Inception, Resnet50, Xception, Nasnet) to determine which architecture and which scheme of transfer learning performs best. In addition, various color scheme scenarios were tested, including the use of primary and secondary color together, and, in addition, the effectiveness of dealing with multi-class classification using multi-class, combined binary, and, finally, ensemble classifiers were studied. The best overall performance was achieved by the ensemble classifier. The results show that the proposed method can detect the color of flower and labellum very well without having to perform image segmentation. The result of this study can act as a foundation for the development of an image-based plant recognition system that is able to offer an explanation of a provided classification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Color*
  • Deep Learning*
  • Flowers*
  • Plants / classification*

Grants and funding

The research described in this paper was funded by Research and Innovation in Science and Technology Project (RISET-Pro) of the Ministry of Research, Technology, and Higher Education of Republic Indonesia (World Bank Loan No.8245-ID) and supported by Indonesian Institute of Sciences (LIPI). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.