What is a characteristic curve definition?

What is a characteristic curve definition?

A curve plotted on a graph from two axes, exposure and density, used to describe the characteristics and performance of sensitive emulsions. A characteristic curve is a graph of the relationship between the amount of exposure given a film and it’s corresponding density after processing.

What is the purpose of Sensitometry?

In radiation therapy, a sensitometric technique can be used for the determination of the proper characteristic curve for a film which can be placed beneath the patient before radiation treatment and removed afterwards so that an image of the anatomy actually irradiated is obtained.

What does the toe of the characteristic curve represent?

The “toe” region of the curve indicates very low exposures. The center or “straight line” region is the approximate linear response range, where OD is proportional to the log of the exposure. The “shoulder” region represents higher exposures and is relatively flat.

What is characteristic curve in PDE?

A characteristic curve of PDE (1a) is a curve in the (x,t)-plane given by x = x(t), where x(t)

What is film gamma?

In film, gamma is defined as the slope of the characteristic curve – that is, the graph of Density versus logE (the scene brightness). Essentially that defines the contrast of the image as compared with the original. A lower gamma will give a lower contrast image.

Who are the pioneers of Sensitometry?

Sensitometry is the scientific study of light-sensitive materials, especially photographic film. The study has its origins in the work by Ferdinand Hurter and Vero Charles Driffield (circa 1876) with early black-and-white emulsions.

What happens when two characteristic curves intersect?

For larger t, after characteristics have intersected, the PDE will fail to have a classical solution — that is, a single-valued solution or a function — as the information obtained by following the characteristics will produce a multivalued solution or, possibly, no solution at all.

What are solid characteristics?

Solids are defined by the following characteristics: Definite shape (rigid) Definite volume. Particles vibrate around fixed axes.

What is sensitometry in radiology?

In radiology, the procedure of measuring film response to radiation. sen·si·tom·e·try. sensitometry. In radiography, the use of densities on an exposed and processed film to evaluate, monitor, and maintain processors, intensifying screens, film types, and exposure systems.

What is a film characteristic curve?

The plot is called a film characteristic curve, sensitometric Sensitometric – The process or technique of producing images of an opaque object on photographic film or on a fluorescent screen by means of radiation. Density – The mass of a substance per unit volume. curve, or H and D curve (named for developers Hurter and Driffield).

Which characteristic curve can be used to adjust the exposure?

Film characteristic curves can be used to adjust the exposure Radiograph – a photographic recording produced by the passage of radiation through a subject onto a film. Density – The mass of a substance per unit volume. Radiograph – a photographic recording produced by the passage of radiation through a subject onto a film.

How can sensitometry be used to improve exposure control?

With controlled development, we can use sensitometry to optimize exposures, set up or change techniques, troubleshoot and control quality.