Fig. 1. Flow chart of proposed method

Fig. 2. Network structure of modified image semantic segmentation model

Fig. 3. Gaussian heat map label generation

Fig. 4. Sematic segmentation results and separated binary images. (a) Semantic segmentation results; (b) binary image of scale lines; (c) binary image of pointer; (d) binary image of scale-range numbers

Fig. 5. Correction for skew and distorted image. (a) Dial ellipse fitting result; (b) schematic graph of perspective transformation

Fig. 6. Image correction and denoising results. (a) Scale line; (b) pointer; (c) scale-range numbers

Fig. 7. Image polar transform. (a) Polar coordinate transform coordinate system; (b) polar coordinate transform result

Fig. 8. Location and repair of scale lines and pointer. (a) Contour refinement result; (b) center line positioning result; (c) scale line repair result

Fig. 9. Comparison of semantic segmentation effects for different lightweight models

Fig. 10. Gray images (left) and binary images (right) of scale-range numbers