## 1 Introduction  
In the clinical treatment and diagnosis of upper urinary tract lesions, frequent localization and observation of the ureteral orifice are necessary. To assist in diagnosing upper urinary tract diseases, it is common to observe the ureteral orifice, often utilizing urological endoscopes such as cystoscopes, transurethral resection cystoscopes, and ureteroscopes, for visual examination of the appearance and physiological activities (such as peristalsis and efflux) of the ureteral orifice. For example, when a patient experiences ureteral atrophy due to malnutrition, hormonal imbalances, or urinary tract infections, leading to obstruction of normal urine excretion, urologists generally use a rigid retrograde ureteroscope to place a pigtail catheter to facilitate normal urination. This procedure requires the physician to accurately locate the ureteral orifice and advance the ureteroscope at the correct angle. On the other hand, whether in cystoscopic surgery or transurethral prostatectomy, physicians need to observe the position of the ureteral orifice in advance to avoid touching it during the procedure, causing unnecessary damage and complications. Additionally, examining the shape of the ureteral orifice and conducting biopsies can help analyze whether the lesion is a stone, tuberculosis, inflammation, stenosis, or a benign or malignant tumor, providing valuable information for determining the nature and location of upper urinary tract diseases. Therefore, when urologists perform urological endoscopic examinations and surgeries, it is necessary to use urological endoscopes to discover and locate the ureteral orifice. The recognition of the ureteral orifice position is highly significant, yet various practical challenges exist in clinical operations. Despite the anatomical fixation of the ureteral orifice in the posterior-lateral angle of the bladder trigone, several factors make its identification difficult: Figure 1b,c demonstrates variations in the shape of the ureteral orifice due to rhythmic peristaltic contractions. The orifice in (b) has almost closed to a small dot, with reduced discernibility due to interference from vessels on the inner wall. In (c), the overall identification is challenging due to complex background textures and image degradation caused by the endoscope. Similarly, in Figure 1a,d, the angle of entry and corresponding lighting during urological endoscopy can also contribute to difficulties in identifying the ureteral orifice. Particularly in (a), the ureteral orifice's direction is nearly perpendicular to the optical axis, and the flat pale inner wall results in extremely low contrast under lighting, causing significant interference for surgeons to promptly discover the ureteral orifice during clinical procedures. Therefore, the development of an intelligent ureteral orifice detection system is of crucial clinical importance, aiding in the training of urology novices and assisting experienced urologists in managing challenging scenarios with indistinct ureteral orifices. In the clinical process, the identification of features is generally assisted by two methods. One is the exogenous light source identification, which is mostly used for the auxiliary identification of injuries, lesions, and tumors. It involves observing fluorescence or infrared light signals in the field through dyes or the optical properties of the features themselves. On the other hand, it relies on image processing methods, utilizing algorithms in the domains of target detection or segmentation to annotate images directly, assisting doctors in surgery. As a natural bodily feature, the ureteral orifice is challenging to observe through the light source, making the use of target detection algorithms a feasible approach. The task of object detection is a crucial development area in the field of machine vision within the realm of deep learning. Both network structures and functional modules have undergone rich and in-depth research, accumulating a wealth of experience.