A 2.5 dimensional vein imaging system for venipuncture

Imaging of subcutaneous veins is important in many applications, such as gaining venous access, vascular surgery and venipuncture. Traditional vein imaging system can only obtain the two dimensional information of the vein which loses the depth information of the vein. It may cause the errors of judgment and increase the venipuncture failure. On the basis of previous research, a new system was proposed to acquire the three dimensional of the vein. In this paper, the infrared absorption characteristics of the vein and the principle of binocular vision were combined to obtain infrared images of subcutaneous veins and recovery the three dimensional information. The binocular vision system was consists of several 850 nm near-infrared LEDs to illuminate the back of the hand and two near-infrared CCD devices to obtain the transmission of IR image. The couple of CCDs will get IR images of the hand which contain the disparity information. The principle of stereo vision was used to recover the three dimensional structure. The algorithm processes includes camera calibration, image preprocessing, epipolar rectification, stereo correspondence and three dimensional reconstructions. Experimental result shows that it can acquire a good three dimensional structure. Since the new system can recover the depth of the vein, it can be applied as the venipuncture auxiliary equipment to improve the success rate of venipuncture.