Abstract: A probe system for use in carrying out inspections in an enclosed, non-conducting environment, such as an endoscope for use in carrying out internal inspections of a human or animal patient, comprises sensing coils (7) mounted at spaced positions along the probe (6) for movement with the latter and a planar grid array (1) of antennas (2) which is disposed adjacent the environment. AC electrical signals are supplied to the antennas, either simultaneously or sequentially, by an electrical source (4,5) so as to induce corresponding voltage signals in the sensing coils (7). When the probe (6) is introduced into the environment, the induced signals, converted to a digital format, are processed by a microprocessor (12) to produce a visual indication of the three dimensional location of the probe (6) with respect to the antenna array (1).

Abstract: The method of detecting the direction of insertion of an endoscope includes the steps of a) forming a system of images made of a plurality of picture images which have a different number of pixels from the same endoscope image, and b) extracting a spatially largest region including an average gray level and variance of gray level within predetermined ranges by examining the average gray level and variance of the gray level of respective pixels in a plurality of picture images formed by the forming step. The region extracted by the extracting step is considered to be an endoscope insertion direction.

Abstract: The endoscope insertion direction detecting method is to extract the form of a fold existing on the inside wall of an observed part from an endoscope picture image and to judge the direction of inserting the endoscope on the basis of the form of this fold and comprises, for example, a step of extracting discontinuous points in the endoscope picture image, a step of extracting line segments based on the above mentioned discontinuous points from respective divided picture images obtained by dividing into a plurality of picture images the picture image obtained by the step of extracting the discontinuous points, a step of connecting the line segments obtained by the step of extracting the line segments and a step of considering the line connected by the connecting step to be the form of a fold existing on the inside wall of the observed part and judging the endoscope insertion direction on the basis of this form of the fold.

Abstract: This endoscope insertion direction detection method comprises the steps of forming from the same endoscope image a plurality of picture images different in the number of pixels (or picture elements) and extracting a dark region in the picture image of a predetermined number of pixels by inspecting in the order of the picture images of less pixels the gray levels of the respective pixels in the plurality of picture images formed by the above mentioned forming step, the above mentioned dark region extracted by the above mentioned extracting step being considered to be the endoscope insertion direction. Preferably, the forming step includes gradually forming picture images of less pixels while reducing the number of pixels to 1/4 so that, in the case where the number of pixels is reduced to 1/4, the gray level of one pixel in the picture image of less pixels wil be of an average value of the gray levels of the four son pixels in the 2.times.