The invention provides a 
color image edge detection method. The method comprises the following steps of 1, inputting a 
color image and carrying out normalization 
processing on the input original image; 2, analyzing the monostable characteristic of the FHN, constructing an adjustment function to optimize a 
diffusion coefficient in a reaction 
diffusion equation according to the 
gray level change of a local region, and calculating a threshold value with 
gray level self-adaption; 3, constructing a 
cellular neural network structure based on a FitzHugh-Nagumo (FHN) reaction 
diffusion equation; 4, performing 
edge detection on a 
gray color image or a 
color image in an HSV 
color space by using the proposed 
cellular neural network model; and 5, outputting an 
edge detection result of the color image. According to the method, the dynamic property of the FHN reaction 
diffusion equation is analyzed, and feasibility of the FHN reaction 
diffusion equation in 
image edge extraction is proved; the CNN based on the FHN reaction 
diffusion equation is applied to edge detection of gray and color images; the diffusion coefficient is optimized by adopting the reaction diffusion equation, so the threshold value is more adaptive, and the adaptive threshold value can be adaptively selected according to brightness of the color image, so the provided color 
image edge detection method is effective.