In this work, morphological processing is applied to study a bubble, which is crucial factor in laser-induced shock-wave lithotripsy. Erosion, dilation and subtraction are applied for edge detection of a bubble Hence the position and the shape is measured. The image of the bubble is extracted from the actual image of the stone (shadowgram). The image is obtained by fast photography using an N-Dye laser for illumination. A Ho: Yag laser is used for fragmentation ofthe stone. Using a time delay, an oscilloscope and a computer, two laser pulses are synchronized. A microscope and a Kodak-camera are used to photograph the stone and the phenomena around.