Photographic method and apparatus for producing polychromatic echograms

Claim 1

In apparatus for surveying and graphically charting the contours of interfaces between water-covered strata, which includes: means for generating, in the water, substantially nondirectional elastic wave pulses, of short duration, at a uniform rate of repetition from a source substantially at the water surface while moving the source horizontally at constant velocity, each pulse having a broad frequency content including frequencies high enough and low enough, respectively, to produce appreciable reflections from the bottom and the most remote interface of interest; means for receiving at a position constantly maintained in spaced relationship to said source, those pulse waves that have been reflected from the interfaces; the improvement comprising: said receiving means including means amplifying the received pulse waves and passing three selected bandwidths of frequencies thereof; and sensing means including: first means for sensing a first independent spatial variable of said signal, second means for sensing a second independent spatial variable of said signal, and third means for sensing a third independent spatial variable of said signal; first, second and third light sources, respectively, actuated by each signal variable; filter means effective to pass only one of three selected primary colors From each of said light sources; means for recording the summation of said colors; means for focusing each said color on an identical region of said recording means; said filter means comprising a first dichroic mirror capable of reflecting only blue light; a second dischroic mirror capable of reflecting only red light; said light sources and said mirrors being so arranged that light from said first source is intercepted by said mirrors so as to pass only a green component; light from said second source is intercepted by said mirrors so as to pass only a red component; light from said third source is reflected by said mirror reflecting only a blue component; said recording means including: revolvable drum means carrying a sheet of color sensitive photographic film, and means for rotating said drum and moving said focusing means along a path parallel to said drum in synchronism with said signal so that a three color multihued photograph is obtained which is representative of the spatial components of the signal.