To eliminate the "hot spot" and reduce 

 scattering many vehicles mount their lights 

 on a boom (Fig. 10.8) or as far out on the 

 brow as possible. In this manner the light 

 has less distance to travel which reduces the 

 amount of scatterers it must confront and 

 permits the lamps to be oriented to provide 

 more uniform lighting over the area of inter- 

 est. 



Television — The television camera has rap- 

 idly become an invaluable tool in virtually all 

 areas of ocean exploration and exploitation. 

 In the early days of deep submergence it 

 played a minor role. Because it was large, it 

 took up valuable space in the pressure hull. 

 It also consumed a significant portion of the 

 limited power, and interfacing it with other 

 electronics was complex. In addition to these 

 problems, relative to the human eye it lacked 

 range, color and depth perception. Subse- 

 quent technological advancements have 

 largely eliminated the volume and interfac- 



n 



Fig, 10,8 Crewman ot ALUMINAUT in the process of lowering a light boom 

 containing four EG&G incandescent lights, (U.S. Navy) 



ing problems, and the latest television cam- 

 eras now provide range of view and details 

 which may exceed the human eye at the 

 viewport. 



The role of TV is quite varied, several 

 submersibles mount a camera on the sail and 

 use it for maneuvering on the surface. In 

 this application, it is not necessary to open 

 the hatch to maneuver, which might well be 

 impossible in certain sea states and, when 

 the vehicle's controls are not portable, might 

 be the only alternative to maneuvering 

 blindly. 



The most general application, however, is 

 as an adjunct to the viewport wherein it 

 allows the operator to maneuver while the 

 observer occupies the viewports. In some 

 instances it is the only means of viewing 

 areas around the vehicle and vehicle compo- 

 nents where there is no direct view availa- 

 ble. On BEN FRANKLIN a television camera 

 was mounted on an external pan and tilt 

 mechanism with two 70 mm cameras and it 

 served as an aiming device for the cameras. 

 One of its increasing roles is that of record- 

 ing bottom features or other objects to pro- 

 vide a permanent video tape record for de- 

 tailed post-dive analysis. 



A variety of TV cameras, monitors and 

 recorders is commercially available {e.g., Hy- 

 dro Products, General Video Corp., Edo West- 

 ern, Ball Brothers Research, Cohu Electron- 

 ics, Thomson-CSF) which can operate to any 

 ocean depth. One commercial camera, the 

 Hydro Products TC150, is shown in Figure 

 10.9. It incorporates automatic light compen- 

 sation, remote focusing from 3 inches to in- 

 finity and is rated to 10,000 feet deep. 



One of the more important technological 

 developments enhancing the role of under- 

 water television is the development of a low 

 light level television camera (LLTV) which 

 extended the viewing distance and reduced 

 illumination requirements. Mr. Arthur Vigil 

 of Hydro Products traced the development of 

 the LLTV for underwater applications and 

 compares its performance advantages 

 against other available television tubes (Vi- 

 dicon. Image Orthicon, Plumbicon, Silicon 

 Target Vidicon). Table 10.4 is taken from 

 Vigil's paper (8) and compares a low light 

 level tube (RCA's Silicon Intensifier Target 

 (SIT) tube) against a conventional Vidicon 



480 



