Fig. 1. Image of pyramid

Fig. 2. Physical drawing of experimental workpiece

Fig. 3. Trans-illumination images under different tube voltages. (a) 50 kV; (b) 70 kV; (c) 90 kV;(d) 100 kV; (e) 120 kV; (f) 140 kV

Fig. 4. Different color gradation map processing results of variable energy fusion image. (a) Display result of grayscale linear mapping; (b) display result of grayscale logarithmic mapping; (c) display result of grayscale gamma correction; (d) display result of partition grayscale mapping

Fig. 5. Enhancement display processing results of high dynamic range image. (a) Original horizontal gradient diagram; (b) enhanced horizontal gradient diagram; (c) original vertical gradient diagram; (d) enhanced vertical gradient diagram

Fig. 6. Enhanced image obtained by proposed method

Fig. 7. Schematic of local trans-illumination partition of target