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Table 2 Details of data augmentation during training

From: Development and performance evaluation of a deep learning lung nodule detection system

Data augmentation type

Method

Rotation

Randomly rotate around the z-axis in the range of − 10 to 10 degrees

Scale

Randomly change the size by − 15 to 15% in each axis direction

Sharpness

Change the sharpness according to the following formula

\(I_{out} = I_{in} + \alpha \left( {I_{in} - f\left( {I_{in} } \right)} \right)\)

Iin: input image; Iout: output image; f(Iin): image processed with a Gaussian filter with a standard deviation of 3.0; α: parameter (randomly selected within the range of 0.0–5.0

Smoothing

Process with a Gaussian filter that randomly sets the standard deviation in the range of 0.5–2.0

Gaussian Noise

Add Gaussian noise generated in the range of standard deviation 0.0–0.2