B = 'Black Threshold\n(drag black text -> white)\n'
W = 'White Threshold\n(drag white bg -> black)\n'
K = 'Dilation/Erosion Kernel Size\n(drag until noise clears)\n'
C = 'Draw Contours'
T = 'Contours Threshold'
I = 'Invert Output'
B = 'Black Threshold\n(drag black text -> white)\n'
W = 'White Threshold\n(drag white bg -> black)\n'
K = 'Dilation/Erosion Kernel Size\n(drag until noise clears)\n'
C = 'Draw Contours'
T = 'Contours Threshold'
I = 'Invert Output'