*3.3. Correlation Analysis of the Chlorophyll Content and Spect*/*ral Reflectance*

3.3.1. Characteristic Wavelength Selection Based on the Maximum Correlation Coefficient Method

The correlation curve of the chlorophyll content and spectral reflectance is shown in Figure 5. The chlorophyll content was positively correlated with spectral reflectance in the blue (450–500 nm) and red (620–780 nm) regions, and negatively correlated in the green region. This result is consistent with the absorption characteristics of chlorophyll in visible light. The absolute value of the correlation coefficient between the chlorophyll content and the spectral reflectance was higher than 0.5 in the five bands, namely, 376–504, 518–596, 671–681, 698–746, and 880–913 nm. The correlation coefficient gradually decreased.

**Figure 5.** Correlation curve between the spectral reflectance and the chlorophyll content.

The top 15 wavelengths with the maximum correlations were selected as the chlorophyll-sensitive wavelengths (denoted as CA bands). The results were concentrated in the green light region of 529–543 nm. The CA bands were only divided into narrow bands. Accordingly, information redundancy may occur due to autocorrelation of information caused by adjacent narrow-band wavelengths.
