To verify the correlation between the proposed artificial intelligence based bowel preparation assessment system and the missed detection rate of adenomas, and to evaluate whether the system can effectively assist doctors in identifying patients who need to be re-examined by colonoscopy due to poor intestinal cleanliness.

Inclusion Criteria:

At least 4 operators were included in this study, and the operating years of colonoscopy were ≥ 5 years, and the number of independent operating cases was ≥ 3000.

Subjects who meet all of the following specific criteria will be considered for participation in the study:

1. Male or female with age ≥ 45 years inclusive;
2. Able to read, understand and sign informed consent;
3. The investigator believes that the subjects can understand the process of the clinical study, are willing and able to complete all study procedures and follow-up visits, and cooperate with the study procedures.

Exclusion Criteria:

Subjects who meet any of the following specific criteria will be refused to participate in the study:

1. have a history of drug or alcohol abuse or psychological disorders within the last 5 years;
2. Pregnant or lactating women;
3. Patients with known multiple polyp syndrome;
4. patients with known inflammatory bowel disease;
5. known intestinal stenosis or space-occupying tumor;
6. known colon obstruction or perforation;
7. patients with a history of colorectal surgery;
8. Patients with previous history of allergy to pre-used spasmolysis;
9. Unable to perform biopsy and polyp removal due to coagulation disorders or oral anticoagulants;
10. High risk diseases or other special conditions that the investigator considers the subject unsuitable for participation in the clinical trial.