Along with the rapid development of wearable computer and multi-medium technology, many units need to be mounted on the helmet such as micro display, camera, voice input and output components, even some devices for safety and security purpose. If these units and components are controlled by the wearable computer directly, it would make the interface between helmet and wearable computer complicated. The better way is to add a controller to the helmet, then the wearable computer only need to interface with the controller. The helmet controller controls all of the functional components of helmet. Of cause, it should be noticed that the dimensions of the components must be small since the volume of helmet for the controller is very limited. The core of the helmet controller we designed is composed of a digital signal processor (DSP) and field programmable logical array (FPGA). The DSP carries out the function of encoding, decoding, compression, encryption, synthesis, and filtering of image and voice signals. FPGA drives and controls a micro display, controls the functional components, as well. All of these reduced the amount of elements, enlarged the integration level, which realized the helmet controller microminiaturization.
This paper focuses mainly on DMT transmission technology applying to downhole image transmission to extend bandwidth, also considers the details about using digital signal processor (DSP) to compress, process and reconfigure the image taken from infrared CCD camera and to process signals from multi-parameter sensors. The system is composed of multi-parameter sensors, infrared camera, TMS320c6x DSP for image compression and reconfiguration, ADSL modem chipset, ground computer, etc., which extends the bandwidth, decreases signal attenuation and abates the noise. Therefore system implements real time downhole imaging, multi-parameter monitoring and inspection by two-wire transmission over 7000 feet no repeaters.