2.2.1 Thresholding

Single Threshold - Pixels values below (or above) threshold, T1, changed to 0; other changed to 255 or left as original value:
   if(pixel<T) pixel=0
   else pixel=255 // or leave pixel unchanged (Transform 2)


Double Threshold - Pixels values between thresholds, T1 & T2, changed to 255; or left as original value, others changed to 0: