Colonoscopy is a key technique in the detection and diagnosis of lower gastrointestinal diseases. High quality endoscopy results in better disease outcomes. However, the operant level of different endoscopists is significantly different.This study aims to construct a real-time quality monitoring system based on computer vision, named Endo.Angel, which is used to monitor the velocity of insertion of the endoscope, record the time of insertion and withdrawal of the endoscope, and remind endoscopists of the blind areas caused by intestinal segment slipping.

This study aims to construct a real-time quality monitoring system based on computer vision, named Endo.Angel, which is used to monitor the velocity of insertion of the endoscope, record the time of insertion and withdrawal of the endoscope, and remind endoscopists of the blind areas caused by intestinal segment slipping.Criteria for inclusion and exclusion are determined prior to endoscopic examination. Candidates who meet all inclusion criteria as well as do not meet all exclusion criteria are bring into the study. Participants randomized before the examination, they are divided into the exposed group assisted by Endo.Angel or the non-exposed group without Endo.Angel. Followup are conducted after the examination.Study will be finished when all followup is done,and the examination result collected from participants will send to an independent review data analysis group.

Inclusion criteria:

1. Male or female aged 18 years or above;
2. Colonoscopy is needed to further characterize gastrointestinal diseases;
3. Ability to read, understand and sign informed consent forms;
4. The researchers believe that the subjects can understand the process of the clinical study and are willing and able to complete all the study procedures and follow-up visits to cooperate with the study procedures.

Exclusion criteria:

1. Participated in other clinical trials, signed informed consent forms and followed up in other clinical trials.
2. Participate in a drug clinical trial and during the elution period of the trial or control drug
3. Drug or alcohol abuse or mental disorder in the last 5 years;
4. Pregnant or lactating women;
5. Patients with multiple polyp syndrome;
6. Patients with known space-occupying tumor or intestinal stenosis;
7. Patients with known perforation or colonic obstruction;
8. A history of anaphylaxis with antispasmodic has been documented;
9. The researchers did not consider the subjects suitable for colonoscopy;
10. The researchers determined that the subjects had high-risk diseases or other special conditions that were not appropriate for clinical trials.