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Page 18 of 28 Zhang et al. J Mater Inf 2024;4:34 https://dx.doi.org/10.20517/jmi.2024.64
Figure 15. The grayscale distribution of pulsed TIG welding images. (A) At peak current; (B) at base current (i-iii) HDR images,
three-dimensional grayscale distribution, grayscale variation along the direction of maximum arc length. TIG: Tungsten inert gas; HDR:
High dynamic range.
Figure 16. Extraction of ROI from melting pool images. ROI: Region of interest.
conditions in the image, the technique can retain more detailed information. As shown in Figure 17C,
gamma correction adjusts the brightness of the image by applying a power law transformation, and the
degree of adjustment is determined by the gamma (γ) value. A γ value less than 1 will increase the contrast
of the darker areas of the image, while a value greater than 1 will increase the contrast of the brighter areas.
Applying gamma correction can adjust the overall contrast of the image. The texture information of the
weld seam outside the molten pool in the original image is weak. Adjusting the Gamma value to 2.5 can
