Objective Based on the general belief that the tongue characteristics of blood stasis constitution is"purple tongue,tortuous sublingual vessels",this study systematically summarized blood stasis tongue characteristics using artificial intelligence image processing combined with expert evaluation.Methods A physical questionnaire survey was conducted on 1275 college students,and 100 cases were randomly selected from the blood stasis constitution group and the mild constitution group.After collecting the tongue images,Unet,OpenCV,YOLOv5 and YOLOv8 algorithms combined with expert evaluation method were used to extract and analyze the tongue features of the two groups.By comparing the differences of tongue image characteristics between the blood stasis constitution group and the mild constitution group,the tongue characteristics of blood stasis constitution were systematically summarized.Results Compared with the mild constitution group,the proportion of light dark tongue and light purple tongue in the blood stasis constitution group was significantly higher(P＜0.05).The I value,L value and a value of the tongue area 1 in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05).The S value and a value of area 2 and area 3 were significantly larger(P＜0.05),and the I value,L value,a value and b value of area 5 were significantly smaller(P＜0.01,P＜0.05).Compared with the mild constitution group,the proportion of tooth marks tongue in the blood stasis constitution group was significantly higher(P＜0.01),the proportion of cracked tongue in the blood stasis constitution group was significantly larger(P＜0.05),and the number of tooth marks,crack area,relative height of crack and relative width of crack in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05).Compared with the mild constitution group,the I value,L value,a value and b value of tongue coating area 1 in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05),the I value,L value,S value,a value and b value of tongue coating area 2 were significantly larger(P＜0.01,P＜0.05),the I value,S value,a value and b value of tongue coating area 3 were significantly larger(P＜0.01,P＜0.05),the b value of tongue coating area 4 was significantly larger(P＜0.05),the S value,a value and b value of tongue coating area 5 were significantly larger(P＜0.01,P＜0.05).The proportion of thick tongue coating and greasy tongue coating in the blood stasis group was significantly higher than that in the gentleness group(P＜0.05).Compared with the mild constitution group,the proportion of tortuous,thickened and nodular sublingual collaterals in the blood stasis constitution group was significantly larger(P＜0.01,P＜0.05).The a value,I value,S value,b value and relative width of sublingual collaterals in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05).Conclusion On the basis of the general belief that the characteristics of blood stasis constitution tongue are dark purple tongue and dark purple sublingual collaterals/varicose veins/thickening,blood stasis constitution people also have new tongue characteristics,such as redder tips and edges,more teeth marks and fissures,thicker and greasier coatings,and yellow fur.These findings offer new insights for"to identify the constitution of traditional Chinese medicine and prevent diseases by observing the tongue manifestation".

Objective Based on the general belief that the tongue characteristics of blood stasis constitution is"purple tongue,tortuous sublingual vessels",this study systematically summarized blood stasis tongue characteristics using artificial intelligence image processing combined with expert evaluation.Methods A physical questionnaire survey was conducted on 1275 college students,and 100 cases were randomly selected from the blood stasis constitution group and the mild constitution group.After collecting the tongue images,Unet,OpenCV,YOLOv5 and YOLOv8 algorithms combined with expert evaluation method were used to extract and analyze the tongue features of the two groups.By comparing the differences of tongue image characteristics between the blood stasis constitution group and the mild constitution group,the tongue characteristics of blood stasis constitution were systematically summarized.Results Compared with the mild constitution group,the proportion of light dark tongue and light purple tongue in the blood stasis constitution group was significantly higher(P＜0.05).The I value,L value and a value of the tongue area 1 in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05).The S value and a value of area 2 and area 3 were significantly larger(P＜0.05),and the I value,L value,a value and b value of area 5 were significantly smaller(P＜0.01,P＜0.05).Compared with the mild constitution group,the proportion of tooth marks tongue in the blood stasis constitution group was significantly higher(P＜0.01),the proportion of cracked tongue in the blood stasis constitution group was significantly larger(P＜0.05),and the number of tooth marks,crack area,relative height of crack and relative width of crack in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05).Compared with the mild constitution group,the I value,L value,a value and b value of tongue coating area 1 in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05),the I value,L value,S value,a value and b value of tongue coating area 2 were significantly larger(P＜0.01,P＜0.05),the I value,S value,a value and b value of tongue coating area 3 were significantly larger(P＜0.01,P＜0.05),the b value of tongue coating area 4 was significantly larger(P＜0.05),the S value,a value and b value of tongue coating area 5 were significantly larger(P＜0.01,P＜0.05).The proportion of thick tongue coating and greasy tongue coating in the blood stasis group was significantly higher than that in the gentleness group(P＜0.05).Compared with the mild constitution group,the proportion of tortuous,thickened and nodular sublingual collaterals in the blood stasis constitution group was significantly larger(P＜0.01,P＜0.05).The a value,I value,S value,b value and relative width of sublingual collaterals in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05).Conclusion On the basis of the general belief that the characteristics of blood stasis constitution tongue are dark purple tongue and dark purple sublingual collaterals/varicose veins/thickening,blood stasis constitution people also have new tongue characteristics,such as redder tips and edges,more teeth marks and fissures,thicker and greasier coatings,and yellow fur.These findings offer new insights for"to identify the constitution of traditional Chinese medicine and prevent diseases by observing the tongue manifestation".