A study on the integration and synchronization of video image using H.261 in polysomnography

The importance of the video monitoring during polysomnographic recording is increasing, but the analog-taped storage method currently in use has difficulties in random access and synchronization with the polysomnographic data. To overcome these limits we need to develop the digitalized integration and synchronization method. The digitization of the moving image during sleep requires at least the quality of detecting the relatively fast movement. It also requires the minimal volume of data for the storage and communication. We analyzed the two standards of digital moving image compression to find the optimal storing format for the video image during sleep. Based on this analysis, we developed the integration method using the format H.261, which has better performance than MPEG-1 in low bit rate of 128 kbps. We also used the QCIF format in H.261 to increase the frame rate, and added the time index to H.261 format to support random access. We synchronized these video images with the polysomnographic data.