A method of determining slope of pixel intensities in an image includes the following steps: receiving, from an imaging device, input pixel samples of a region of interest; forming an impulse response function for use in resampling the input pixel samples into output pixel intensities; and calculating a derivative of the IPR. Magnesium and calcium basic inorganic salt stabilizing agents are particularly useful. Such compositions may be used as refrigerants, cleaning agents, expansion agents for polyolefins and polyurethanes, aerosol propellants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents. The lens portion has appropriate optical power to improve a user’s visual acuity of near objects when the user looks through the lens portion. The strain capacitor may then be mounted to the circuit board and monitored for failure. The honeycomb structure 1 comprises a cell structure portion 20 constituted of partition walls 2 arranged so as to form a plurality of cells 3 extending through an axial direction, and an outer peripheral wall 7 disposed in an outer periphery of the cell structure portion 20.