Metrology And Measurements Set 4

Answer: number of pixels alone

Explaination:
some of the measures which are used to describe a region are mean and median of grey values, minimum and maximum of grey values and number of pixels above and below mean. the area of the region, i.e., the total number of pixels in the region cannot alone describe the region.

Answer: false

Explaination:
one of the regional descriptor is normalized area. it can be quite useful to extract information from the image. in satellite images of earth, the data can be refined by normalized it with respect to land mass per region.

Answer: topology

Explaination:
we can define topology as the study of properties of a figure that are unaffected by any deformation, as long as there is no joining or tearing of the figure. we use topological properties in the region description.

Answer: folding

Explaination:
if a topological descriptor is defined by the number of holes in an image, then the number of holes will not vary if the

Answer: true

Explaination:
we know that, as stretching affects distance, topological properties do not depend on the notion of distance or any properties implicitly based on the concept of distance measures.

Answer: -1

Explaination:
the image shown in the question has two holes and one connected components. so, the euler number e is given as 1-2=-1.

Answer: v-q+f

Explaination:
it is very important to classify the polygonal network. let v,q and f denote

Answer: -2

Explaination:
the polygonal network given in the figure has 7 vertices, 11 edges and 2 faces. thus the euler number is given by the formula,

Answer: smoothness, coarseness and regularity

Explaination:
one of the important approach to region description is texture content. this helps to provide the measure of some of the important properties of an image like smoothness, coarseness and regularity of the region.

Answer: true

Explaination:
structural techniques deal with the arrangement of image primitives, such as the description of the texture based on the regularly spaced parallel lines.

Answer: spectral

Explaination:
spectral techniques are based on properties of the fourier spectrum and are used primarily to detect global periodicity in an image by identifying high energy, narrow peaks in the image.

Answer: bryan

Explaination:
fundamental principle of measurement of straightness is given by bryan. according to this principle, “a straightness measurement system should be in

Answer: straight edge

Explaination:
at many places, it is necessary that the surface must be straight e.g. in lathe machine it is required that the tool must move in straight path. straight line is the basis of most methods of measurements.

Answer: maximum deviation from the straight line joining two extremities

Explaination:
the tolerance on the straightness of a line can be defined as the maximum deviation in

Answer: winding sticks

Explaination:
straight edge is a measuring tool consist of a steel and is used to check the straightness. straight edges are used in machining industry and automotive service. winding stick is a pair of straight edges which are used in woodwork.

Answer: between laser head and straightness reflector

Explaination:
straightness interferometer is placed between laser head and reflector.

Answer: ±2.5 mm

Explaination:
to measure straightness errors in a linear axis, straightness measurement optics are used. for both short range and long range measurement, length of straightness measurement is ±2.5 mm.

Answer: optics fixed rigidly

Explaination:
factors affecting the accuracy of straightness measurement by optics are air turbulence, mechanical vibrations, optic errors, slope errors, optics not fixed in the correct position, optics not fixed rigidly, localised heat sources etc.

Answer: edges only

Explaination:
straight edges are extremely useful for setting up machines such as planers. precision straight edges are hardened and lapped on the edges by a small radius, which makes a blunt knife edge straight to a few thousands of an mm.

Answer: internal thread

Explaination:
an internal thread is that which formed on the inside of a workpiece e.g. on female screw gauge or a nut. an external thread is that which formed on the outside of a workpiece e.g on bolts or studs.

Answer: thread can be tranculated at crest and root both

Explaination:
a thread is truncated sometimes at the crest or at the root or at both root and crest and root. the radial distance from the crest to the nearest apex of the fundamental triangle is truncation at the crest is and at the root it is the radial distance from the root to the nearest apex.

Answer: radial distance between pitch and minor cylinder

Explaination:
addendum for an external thread is defined as the radial distance between the major cylinder and pitch cylinder and for internal addendum is the radial distance between the minor cylinder and pitch cylinder. dedendum for external thread is the radial distance between the pitch cylinder and minor cylinder and this is the radial distance between the major and pitch cylinders for internal thread.

Answer: cone diameter

Explaination:
for a straight thread, major diameter is the diameter of the major cylinder. it is also known to as the outside diameter or full diameter for external threads. sometimes it is also called crest diameter.

Answer: measured in direction perpendicular to the axis of thread

Explaination:
in a screw thread axial thickness is the distance between the opposite faces of the same thread. it is measured on the pitch cylinder and in a direction parallel to the thread axis.

Answer: virtual diameter

Explaination:
functional diameter is also known as virtual diameter. for an internal or external thread, this is the pitch diameter of the enveloping thread, lead and flank angles having the full depth of engagement but not at roots and crests.