1. Examples In Which Other Imaging
Modalities Are Used
Submitted By:
Mukhtiar Singh
M.Phil 1st
14662

2. INTRODUCTION
 Electron Microscopes are scientific instruments
that use a beam of highly energetic electrons to
examine objects on a very fine scale.
 Transmission Electron Microscope (TEM) -
allows one the study of the inner structures.
 Scanning Electron Microscope (SEM) - used to
visualize the surface of objects.
 Fractals are striking example of Computer
Generated Images.

3. TEM
 A Transmission Electron Microscope(TEM) works
much like a slide projector.
 A projector Shine a beam of light through the slide. As
the light passes through the slide, it is affected by the
contents of slide. This Transmitted beam is then
projected onto the viewing screen , forming an
enlarged image of the slide.

4. CONTINUE…
 TEM work the same way except that they shine beam
of electrons through a specimen . The fraction of the
beam transmitted through the specimen is projected
onto a phosphor screen.
 The interaction of the electrons with the phosphor
produces light and , there fore, a viewable image.
 TEMs require very thin samples.

5. EXAMPLE…

6. ADVANTAGES...
 TEMs offer very powerful magnification and
resolution.
 TEMs have a wide-range of applications and can be
utilized in a variety of different scientific, educational
and industrial fields
 TEMs provide information on element and compound
structure .
 Images are high-quality and detailed.

7. DISADVANTAGES…
 TEMs are large and very expensive.
 Operation and analysis requires special training.
 Samples are limited to those that are electron
transparent.
 Laborious sample preparation.
 TEMs require special housing and maintenance.
 Images are black and white .

8. SEM
 A Scanning Electron Microscope actually scans the
electrons beams and records the interaction of beam
and sample to each location.
 This produces one dot on a phosphor screen. A
complete image is formed by a Raster Scan of the
beam through the sample, much like a TV camera. The
electrons interact with a phosphor screen and produce
light.
 SEM are suitable for “Bulky” samples.

9. EXAMPLE…

10. ADVANTAGES…
 It gives detailed 3D and topographical imaging and
the versatile information garnered from different
detectors.
 This instrument works very fast.
 Modern SEMs allow for the generation of data in
digital form.
 Most SEM samples require minimal preparation
actions.

11. DISADVANTAGES…
 SEMs are expensive and large.
 Special training is required to operate an SEM.
 The preparation of samples can result in artifacts.
 SEMs are limited to solid samples.

12. Differences between SEM and TEM
TEM SEM
Electron beam passes through inside
sample.
Electron beam scans over surface of
sample.
Specially prepared thin samples are
supported on TEM grids
Sample can be any thickness and is
mounted on an aluminum stub.
Specimen stage halfway down column. Specimen stage in the chamber at the
bottom of the column.
Image shown on fluorescent screen. Image shown on TV monitor.
Image is a two dimensional projection of
the sample.
Image is of the surface of the sample

13. FRACTALS
 A Fractals is nothing more than an iterative
reproduction of a basic pattern according to some
mathematical rules. For Instance, Tiling is one of the
simplest ways to generate a fractal image.
 A square can be subdivided into four square
subregions, each of which can be further subdivided
into four square regions , and so on.
 Depending on the complexity of the rules for filling
each subsquares, some beautiful tile images can be
generated using this method.

14. METHOD
 Take a starting image and dividing it into small, non
overlapping, square blocks , typically called “Parents
blocks ”.
 Divide each parents block into 4 blocks , or “child
blocks”.
 Compare each child block against a subset all possible
parent block.
 Determine which larger block has the lowest
difference , according to some measure, between it
and the child block.

15. Method…

16. APPLICATIONS…
 Image Enlargements.
 Automated semiconductor Defect Detection
 Semiconductor devices always follows a definite patter . Fractal
coding can be used to identify any variation from the self similar
part of the Image.
 Image enhancement
 Image have a large amount of affine redundancy
 Any damaged part can be mapped into some other parts of the same
image.
 Texture compression
 Texture are self similar images.
 High Compression can be achieved.