Pinhole cameras

Fio. 165. The fly s eye method, a. Part of multiple pinhole camera. 6. Arrangement for making repeating patterns by the multiple pinhole camera. Atoms in the unit cell are represented by points of light. 

The basic elements necessary to take a photo are the same for all cameras a dark container, a controlable opening to admit light, and a means for recording the light admitted. A simple camera that is easy for you to construct and that includes these elements is a pinhole camera. 

Compare and contrast the features of a coffee can pinhole camera with the features of a digital camera. Some areas of comparison include resolution, depth of field, use in varied lighting conditions, richness of colors and tone, and convenience. 

ANSWERS TO ACTIVITY QUESTIONS AND CONCLUSIONS Activity 8.1 Making a Pinhole Camera... 

In Activity 1.1 an atomic model kit is constructed, then used in other activities. Atom colors are related to atomic physical and chemical properties. In Activity 8.1 a pinhole camera is constructed and used to photograph model chemical equations. In Activity 9.1a qualitative system for identifying mystery ions in solution is performed and related to detecting these ions in an art forgery. 

The first use of grenades in France, designed by an unknown inventor Crystallo, a clear soda-based glass, is invented by Angelo Barovier The pinhole camera is invented... 

While it may be possible to adapt an ordinary pinhole camera to some microbeam work simply by changing the collimator, better results will be obtained with a specially designed microcamera [6.3, G.39]. Such a camera will usually have a small specimen-to-focal-spot distance (to increase intensity and improve collimation), a small specimen-to-film distance (to reduce exposure time), and some arrangement for accurately positioning the specimen in the beam. Diffraction patterns of specimens amounting to as little as 10 micrograms have been obtained in such cameras. 

The wire is examined in a transmission pinhole camera with filtered radiation and with the wire axis vertical, parallel to one edge of the flat film. The problem of finding the indices uv v of the fiber axis is best approached by considering the diffraction effects associated with an ideal case, for example, that of a wire of a cubic material having a perfect [100] fiber texture. Suppose we consider only the 111 reflection. In Fig. 9-9, the wire specimen is at C with its axis along NS, normal to the incident beam IC. CP is the normal to a set of (111) planes. Diffraction from these planes can occur only when they are inclined to the incident beam at an angle 6 which satisfies the Bragg law, and this requires that the (111) pole lie somewhere... 

Back-reflection pinhole camera. If the incident beam is normal to the sheet specimen and therefore parallel to the fiber axis, and a projection like that shown in Fig. 9-10(b) is made (projection plane parallel to sheet), then both the incident beam and the fiber axis coincide with the center of the projection. If the texture is ideally sharp, the (hkl) pole figure will consist of one or more concentric circles centered on the center of the projection, and the chance that one of these pole circles will coincide with the concentric reflection circle is essentially zero no reflection will occur. But if the texture has enough scatter, one of the pole circles will broaden into a band wide enough to touch the reflection circle at all points a Debye ring of uniform intensity will be formed. See Prob. 9-7. Thus a uniform Debye ring is not always evidence for randomly oriented grains. 

For given values of B and n, which results in a greater effective depth of x-ray penetration, a back-reflection pinhole camera or a diffractometer ... 

An electroplated layer of copper on sheet steel is examined in a back-reflection pinhole camera with Cu Ka radiation incident at right angles to the sheet surface. Assume the copper has a fiber texture with the fiber axis [ww] scattered by an angle p in every direction about the sheet normal. How large must p be for the 420 Debye ring (see Table 4-2) to appear on the film if the fiber axis [//yw] is (a) [110], (b) [100] ... 

The pinhole camera, used in back reflection, is not really an instrument of high precision in the measurement of lattice parameters, but it is mentioned here because of its very great utility in metallurgical work. Since both the film and the specimen... 

In this case it may be shown that the fractional error in d is proportional to sin 4(f) tan = (90° — 0). With either of these extrapolation functions a fairly precise value of the lattice parameter can be obtained in addition, the back-reflection pinhole camera has the particular advantage that mounted metallographic specimens may be examined directly. This means that a parameter determination can be made on the same part of a specimen as that examined under the microscope. A dual examination of this kind is quite valuable in many problems, especially in the determination of phase diagrams. 

The simplest optics making use of the full undulator peak is a pinhole camera without focusing elements. The only optical element necessary is a plane mirror in order to elevate the beam out of the plane of the storage ring, to reduce the background due to Bremsstrahlung and to cut the harmonics (Fig. 10 b). 

The interference filter method was also used by Ruf and Winkler [239] for the detection of oil backstreaming in oil diffusion pumps with a pinhole-camera arrangement. 

The first gamma camera built by Hal Anger used a pinhole collimator (Nature 170, 200,1952). Gamma photons emitted from 1-131 in a patient with metastatic cancer near the skin were the first images with a pinhole collimator that was placed in front of a 2 x 4 in. thallium-activated sodium iodide crystal 5/6 in thick. Another key publication was The Gamma-pinhole Camera and Image Amplifier (UCRL-2524,1954). 

X-Ray Orientation Angle Wide angle X-ray diffraction patterns were obtained with a Warhus pinhole camera and Phillips generating unit No. 12045 having a copper fine focus diffraction tube and a nickel 8 filter. The distance from sample to film was 50 mm. The arc length In degrees between the half-maximum Intensity points of a principal equatorial diffraction spot Is reported as the orientation angle of the sample. 

Rotation Modulation Collimators (RMC s) were originally introduced in X-ray astronomy to provide accurate source localizations over extended fields. This role has since been taken over by the grazing incidence telescope systems. The potential of the RMC s as wide field monitors have recently been demonstrated by the WATCH instruments on GRAN AT and EURECA. It now appears likely, that for use on large, 3-axis stabilized spacecraft, a pinhole camera system may provide better sensitivity than an RMC-system of corresponding physical dimensions. But due to its simplicity, low data rate, and ability to work on spin stabilized (micro)satellites, the RMC wide field monitor may still have a role to play in the X-ray astronomy of the future. 

Tilack-body radiation, in kk Btu/ft hr, from table 8.9. It is rationalized that no emissivity, no absorptivity, or any shape factor need be used here because narrow slots have immense radiating source and receiving areas relative to their slot area (Uke a pinhole camera). 

A camera model transforms the coordinates of a point in space (3D) to the coordinates of a point in an image (2D), i.e., explains the process of forming an image with a camera. In the first instance the Pinhole camera model is used. It is the most simple and specialized camera model, which represents an ideal camera distortion-free as shown by Tsai [1], Weng et al. [2] and Hartley et al. [3]. It will serve to explain other models. Taking into account that the equipment of study has telecentric optics, the affine camera model as shown by Hartley et al. [3] will be employed. In this model, the optical center is a point in the infinity. This camera model can be expressed by the following matrix expression ... 

Gamma-ray pinhole camera (Roscoe Koontz) Working to make nuclear reactors safer, Koontz invents the gamma-ray pinhole camera. The pinhole should act like a lens and form an image of the gamma source. 

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