A new cascade impactor has been designed specifically for pharmaceutical inhaler testing. This impactor, called the Next Generation Pharmaceutical Impactor (NGI), has seven stages and is intended to operate at any inlet flow rate between 30 and 100 L/min. It spans a cut size (D50) range from 0.54-microm to 11.7-microm aerodynamic diameter at 30 L/min and 0.24 microm to 6.12 microm at 100 L/min. The aerodynamics of the impactor follow established scientific principles, giving confident particle size fractionation behavior over the design flow range. The NGI has several features to enhance its utility for inhaler testing. One such feature is that particles are deposited on collection cups that are held in a tray. This tray is removed from the impactor as a single unit, facilitating quick sample turn-around times if multiple trays are used. For accomplishing drug recovery, the user can add up to approximately 40 mL of an appropriate solvent directly to the cups. Another unique feature is a micro-orifice collector (MOC) that captures in a collection cup extremely small particles normally collected on the final filter in other impactors. The particles captured in the MOC cup can be analyzed in the same manner as the particles collected in the other impactor stage cups. The user-friendly features and the aerodynamic design principles together provide an impactor well suited to the needs of the inhaler testing community.

Shifted sinusoidal illumination patterns are useful for appearance capture because they simultaneously separate local and non-local reflections and allow the recovery of surface geometry. Here we show that the same illumination patterns can be used to estimate the local surface reflectance (BRDF) as well, provided that an appropriate correction factor is applied. We derive a closed-form expression for this correction factor, validate it experimentally, and discuss its implications. PreliminariesConsider the system in Fig. 1. A thin-lens camera observes a planar surface patch that is illuminated by a custom light assembly, and this light assembly consists of a planar Lambertian area source placed at the focal plane of another thin lens. The area source in this light assembly produces radiance patterns that are shifted horizontal sinusoids with fixed frequency f , amplitude A, and DC offset G. The shifts are represented by a discrete set of phase values: {φ k } k=1...M , so we can write the radiance at a point p = (p, q) on the focal plane of the source asIllumination from the source is focused at a point x on a planar surface patch, and this patch is observed by a thin-lens camera, which is also focused at x. A pixel (or any square region) on the image plane that is centered at the projection of x and has dimensions w × w measures flux due to the radiance from a neighborhood of the point x on the surface, and assuming that the camera is a linear device, the intensity recorded at the pixel is proportional to this flux. Under the sinusoidal illumination of Eq. 1, the pixel response can be written in the form,where u = Π c (x) is the projection of x (the center of the pixel), and γ = 2πf (t k+1 − t k ), the product of the spatial frequency and the displacement of the sinusoid between consecutive shifts. This relation plays a central role in phase mapping techniques (e.g.[4]), since the apparent phase φ(u) provides information about the depth of the surface along the ray that is back-projected from pixel u.Presently, we are interested in the apparent amplitude α(u) since, as we will show, it provides information about the local surface reflectance (the BRDF at x) and can be used for reflectometry. We show that, in addition to the BRDF, this expression depends on the intrinsic parameters of the lightsource and camera, as well as their positions and orientations relative to the surface.

Shifted sinusoidal illumination patterns are useful for appearance capture because they simultaneously separate local and non-local reflections and allow the recovery of surface geometry. Here we show that the same illumination patterns can be used to estimate the local surface reflectance (BRDF) as well, provided that an appropriate correction factor is applied. We derive a closed-form expression for this correction factor, validate it experimentally, and discuss its implications. PreliminariesConsider the system in Fig. 1. A thin-lens camera observes a planar surface patch that is illuminated by a custom light assembly, and this light assembly consists of a planar Lambertian area source placed at the focal plane of another thin lens. The area source in this light assembly produces radiance patterns that are shifted horizontal sinusoids with fixed frequency f , amplitude A, and DC offset G. The shifts are represented by a discrete set of phase values: {φ k } k=1...M , so we can write the radiance at a point p = (p, q) on the focal plane of the source asIllumination from the source is focused at a point x on a planar surface patch, and this patch is observed by a thin-lens camera, which is also focused at x. A pixel (or any square region) on the image plane that is centered at the projection of x and has dimensions w × w measures flux due to the radiance from a neighborhood of the point x on the surface, and assuming that the camera is a linear device, the intensity recorded at the pixel is proportional to this flux. Under the sinusoidal illumination of Eq. 1, the pixel response can be written in the form,where u = Π c (x) is the projection of x (the center of the pixel), and γ = 2πf (t k+1 − t k ), the product of the spatial frequency and the displacement of the sinusoid between consecutive shifts. This relation plays a central role in phase mapping techniques (e.g.[4]), since the apparent phase φ(u) provides information about the depth of the surface along the ray that is back-projected from pixel u.Presently, we are interested in the apparent amplitude α(u) since, as we will show, it provides information about the local surface reflectance (the BRDF at x) and can be used for reflectometry. We show that, in addition to the BRDF, this expression depends on the intrinsic parameters of the lightsource and camera, as well as their positions and orientations relative to the surface.

This paper presents a technique for acquiring the shape of realworld objects with complex isotropic and anisotropic reflectance. Our method estimates the local normal and tangent vectors at each pixel in a reference view from a sequence of images taken under varying point lighting. We show that for many real-world materials and a restricted set of light positions, the 2D slice of the BRDF obtained by fixing the local view direction is symmetric under reflections of the halfway vector across the normal-tangent and normal-binormal planes. Based on this analysis, we develop an optimization that estimates the local surface frame by identifying these planes of symmetry in the measured BRDF. As with other photometric methods, a key benefit of our approach is that the input is easy to acquire and is less sensitive to calibration errors than stereo or multi-view techniques. Unlike prior work, our approach allows estimating the surface tangent in the case of anisotropic reflectance. We confirm the accuracy and reliability of our approach with analytic and measured data, present several normal and tangent fields acquired with our technique, and demonstrate applications to appearance editing.

The cumulative degree distributions of transport networks, such as air transportation networks and respiratory