An angioscopic system includes image processing so as to determine the dimensions of an unknown dimensional feature within the field of view of the angioscope. The system is calibrated by placing a series of known images at known separation distances from the tip of the angioscope and measuring the size of the image which is produced upon a video monitor. This provides a series of data indicating the relationship between the actual size of the feature, the apparent size in pixels on the image, and the known separation distance from the tip of the scope to the feature plane in which the dimensional feature is disposed. Collection of this data allows one to generate, by curve fitting techniques, a functional relationship such that the size of an unknown dimensional feature may be determined when the angioscope is used upon an actual patient. The coefficients generated by the calibration technique are stored in the computer and called up during the measurement process which involves viewing a scene from several different points and using a Newton-Jordan or other minimization technique in order to generate the actual area or other dimensional aspect of the feature of interest. A modified system uses a stereoscopic angioscope in order to provide depth information with respect to an image without the necessity of moving an angioscope tip. A calibrated guidewire may be used to orient and stabilize the tip of the scope. Markings on the guidewire allow one to determine the amount of change in position of the tip.