Abstract: A sonde includes an elongate flexible ferromagnetic core and a coil surrounds an intermediate segment of the core. A housing surrounds and supports the coil. An electronic drive circuit is mounted in the housing for supplying the coil with an electric signal that will induce the core to emit electromagnetic signals at a predetermined strength and frequency that can be remotely detected. Self-contained battery powered float-type and pill-type sondes are also disclosed.

Abstract: A video camera head adapted for pipe inspection has thermal feedback control of its scene lighting in order to lower its temperature and reduce unwanted noise in the video output signal. The camera head includes a rugged cylindrical camera housing having a hollow interior. A video camera is mounted inside the housing for generating video signals of an image of an interior of a pipe received through a scratch resistant window in a forward end of the housing. The video camera has a CCD with a predetermined maximum operating temperature. A termination assembly and a socket assembly are provided for operatively coupling a video push cable to the camera housing and the video camera, respectively. A large number of LEDs are mounted in the forward end of the housing surrounding the window for illuminating the interior of the pipe. A drive circuit is connected to the LEDs for driving the LEDs with a predetermined electrical drive signal.