Managing bandwidth utilisation for image transmission

Few networks offer sufficient bandwidth for the transmission of high resolution 2-D and 3-D medical image sets without incurring significant latency. Traditional compression methods do not resolve this problem because, in most cases, the latency in decoding compressed data is similar to, or greater than, the reduction in transmission latency achieved by compression. We describe an approach to managing image transmission in which spatial regions are selected and prioritised for transmission so that data is received in a timely manner. This is a lossless form of progressive image transmission in which we first transmit an approximate, iconic form of the image. Then each part of the iconic image is progressively updated. The order in which the subparts are updated is determined using a simple set of rules. This progressive image transmission scheme takes into account the behavioural requirements of the user to make good use of the bandwidth available. This strategy addresses the need to minimise effective latency and network loading. Initial results indicate that with this scheme of bandwidth management, a valuable transmitted image is received with a latency that is about 1/10th that of other progressive image transmission schemes and that the dedicated bandwidth required to achieve this is much reduced. Frequently, the necessary regions of the image are transmitted in about half the time taken to transmit the full image.