2. How does it work?
BY THE END OF THE LESSON: ALL MUST: describe how ultrasound works & state what is meant by a pixel. MOST SHOULD: explain range, resolution and calibration, including systematic zero error and non-linearity & be able to calculate resolution. SOME COULD: Explain glitches and disturbing influences & explain resolution in terms of pixels and the advantages of improved resolution.

3. Chapter 1
Imaging

4. Learning Outcomes ALL MUST: describe how ultrasound works
state what is meant by a pixel
MOST SHOULD:
explain range and resolution.
be able to calculate resolution.
SOME COULD:
explain glitches and disturbing influences.
explain resolution in terms of pixels and the advantages of improved resolution.
Grade E
Grade C
Grade A
Tuesday, 07 May 2019 5

7. BY THE END OF THE LESSON: ALL MUST: describe how ultrasound works & state what is meant by a pixel. MOST SHOULD: explain range, resolution and calibration, including systematic zero error and non-linearity & be able to calculate resolution. SOME COULD: Explain glitches and disturbing influences & explain resolution in terms of pixels and the advantages of improved resolution.

8. Ultrasound Scanning Explain how the images are made and how the
scanner determines distances and dimensions.
The delay times of the reflections tell the scanner where the denser tissue of the baby is.
The strengths of the reflections tell the scanner how dense the various tissues are.
The information from the reflections is assembled to form the image as an array of 256 x 256 pixels each having one of 256 shades of grey: computer tomography (CT)
BY THE END OF THE LESSON: ALL MUST: describe how ultrasound works & state what is meant by a pixel. MOST SHOULD: explain range, resolution and calibration, including systematic zero error and non-linearity & be able to calculate resolution. SOME COULD: Explain glitches and disturbing influences & explain resolution in terms of pixels and the advantages of improved resolution.

10. λ= v/f /1500/2.5 x 106;
6.(0) x 10-4 (m)
at least 3 more wavefronts showing 1
correct direction and an increased
constant spacing judged by eye
accept between 0.9 and 1.5 cm constant to ± 10% NOT gets
reflects/is absorbed/causes heating/is
dissipated/lost as heat

11. Images can be formed by all sorts of signals….
BY THE END OF THE LESSON: ALL MUST: describe how ultrasound works & state what is meant by a pixel. MOST SHOULD: explain range, resolution and calibration, including systematic zero error and non-linearity & be able to calculate resolution. SOME COULD: Explain glitches and disturbing influences & explain resolution in terms of pixels and the advantages of improved resolution.

12. Electronic Image Capture
Why is this now more important?
Images can be enhanced and processed.
Particularly important in astronomy where photographic film can not be used.
BY THE END OF THE LESSON: ALL MUST: describe how ultrasound works & state what is meant by a pixel. MOST SHOULD: explain range, resolution and calibration, including systematic zero error and non-linearity & be able to calculate resolution. SOME COULD: Explain glitches and disturbing influences & explain resolution in terms of pixels and the advantages of improved resolution.

14. Spot the difference?
Why?

15. Spot the difference!
What does this actually mean? You can blow the image up larger. This allows you to have better resolution in your images – you can zoom in more!
BY THE END OF THE LESSON: ALL MUST: describe how ultrasound works & state what is meant by a pixel. MOST SHOULD: explain range, resolution and calibration, including systematic zero error and non-linearity & be able to calculate resolution. SOME COULD: Explain glitches and disturbing influences & explain resolution in terms of pixels and the advantages of improved resolution.

16. A few definitions
Resolution: the smallest size of object that can be distinguished.
Pixels: Discrete picture “elements” that make up an image.
When looking at an image, no object smaller than one pixel can be seen.
Resolution can therefore also be expressed as m/pixel or mm/pixel, since this is the smallest thing that can be distinguished.
BY THE END OF THE LESSON: ALL MUST: describe how ultrasound works & state what is meant by a pixel. MOST SHOULD: explain range, resolution and calibration, including systematic zero error and non-linearity & be able to calculate resolution. SOME COULD: Explain glitches and disturbing influences & explain resolution in terms of pixels and the advantages of improved resolution.

17. Think about….. Why is resolution so important in ultrasound?
BY THE END OF THE LESSON: ALL MUST: describe how ultrasound works & state what is meant by a pixel. MOST SHOULD: explain range, resolution and calibration, including systematic zero error and non-linearity & be able to calculate resolution. SOME COULD: Explain glitches and disturbing influences & explain resolution in terms of pixels and the advantages of improved resolution.

18. The total image when taken contains 12.2 x 106 pixels
12.2 Mega pixel camera
The total image when taken contains 12.2 x 106 pixels
This image is made up of 8 pixels x 10 pixels, therefore the camera would be ….
80 pixel camera
BY THE END OF THE LESSON: ALL MUST: describe how ultrasound works & state what is meant by a pixel. MOST SHOULD: explain range, resolution and calibration, including systematic zero error and non-linearity & be able to calculate resolution. SOME COULD: Explain glitches and disturbing influences & explain resolution in terms of pixels and the advantages of improved resolution.

21. Homework
Complete Q 1-4 on p.10 of text book.