Study On The Infrared Imaging Contrast Enhancement For Subcutaneous Veins

Venipuncture is a common skill used in medical treatment, but its failure rate is high. Especially for newborn babies, children and patients with obesity and others whose veins are not obvious, the failure rate is higher. Therefore enhancing venous contrast can effectively improve the success rate of venipuncture. It will not only lessen the workload of medical workers, but also reduce pain of patients due to the puncture failure. And then this technique has a very important practical significance.Enhancing venous contrast is based on the different absorption coefficient to near-infrared between the veins and the surrounding tissues. Under the irradiation of near-infrared LED with a center wavelength of850nm,the infrared images of subcutaneous veins are acquired by CCD. Then the acquired images are processed by Matlab software with denoising, enhancement and character extraction to enhance the contrast of venous images. Next the processed images are projected to their sources though the projecton path, so as to make venous information more obvious and effectively enhance the contrast.Near infrared image processing had used Matlab software, which reduced the complexity of the program and the run time. With the help of dichroscope, the collecting and projection paths are transmitted to the same path, which will guarantee effectively that the enhanced images are covered exactly to the collecting places. The covering precision of processed images is an important factor for the whole system, and marking the collecting site could make the images covering more effective and accurate.Finally we have carried on the comprehensive test to the performance of the system. By comparing the effects of enhanced venous images under different irradiation intensity and their histogram, we determined the power of LED arrays, under which the enhancing effect is best. And though comparing the venous entrancement under the irradiation of845nm laser, we confirmed the rationality of adopting the LED arrays. At last we collected different people’s venous images to enhance the contrast and found the enhancement was effective, especially to those people whose veins is not obvious, so this system has achieved our purpose.