[Retracted] Dictionary Learning-Based Ultrasound Image Combined with Gastroscope for Diagnosis of Helicobacter pylori-Caused Gastrointestinal Bleeding

Figure 4

Noise reduction effects of the three algorithms ((a) noise ρ =10; (b) noise ; (c) noise ; (d) noise ). Note: represents a statistically significant difference compared with N-KSVD ().

(a)

(b)

(c)

(d)