Abstract: Flaws and defects in heat seals formed between sheets of translucent film are identified by optically examining consecutive lateral sections of the seal along the seal length. Each lateral seal section is illuminated and an optical sensor array detects the intensity of light transmitted through the seal section for the purpose of detecting and locating edges in the heat seal. A line profile for each consecutive seal section is derived having an amplitude proportional to the change in light intensity across the seal section. Instances in the derived line profile where the amplitude is greater than a threshold level indicate the detection of a seal edge. The detected edges in each derived line profile are then compared to a preset profile edge standard to identify the existence of a flaw or defect.

Abstract: A high altitude, high pressure balloon comprised of a number of gores. The gores are made from a material and have a size, that are the results of an analysis of the anticipated stresses to which the balloon will be subjected. In particular, the gores are made from nylon and have dimensions that have been determined to result in stable creep characteristics. An alternate embodiment of the balloon uses multiple spheres.

Abstract: A high-altitude balloon having prestrained gores made from an asymmetrical gore pattern. The invention includes the balloon, the method of assembling the balloon, and a table specially designed to implement the method. The method can be used to assemble balloons of varying shapes and sizes, within a determinable range of ratios of gore width to gore length. The method involves cutting and sealing edges of a pair of flexible plastic sheets along a straight edge of a table, then inverting the seam so formed until it is aligned with a curved index line on the surface of the table. The curved index line is longer than the seam created along the straight edge so stretching is required during inverting. Successsively cutting, joining and inverting pairs of sheets in this manner produces a balloon with a plurality of symmetrical gores that give the balloon a predetermined shape when inflated.