SOLUTIONS MANUAL
,1.1 List four advantages of digital images over analog images.
● They can be easily modified and analyzed
● They can be easily displayed in numerous ways using different LUTs.
● They can be reproduced faithfully an infinite number of times (with the
inclusion of error-checking)
● They can be compressed for ease of storage and transfer.
1.2 What property of the object is exploited in creating the following
images?
• medical ultrasound images
Reflectance and scattering properties of (high-frequency) acoustic
waves.
• CT images
Attenuation of x-rays.
• MRI images
Nuclear spin and nuclear energy levels.
• nuclear medicine images
Concentration of radionuclide.
• impedance tomography images
Electrical impedance.
1.3 To which class of image processing operations do the following
examples belong?
• tomographic reconstruction
Image synthesis
• removing distortion
Image restoration
• pattern recognition
Image analysis
, • edge enhancement
Image enhancement
• noise removal
Image restoration
• brightness adjustment
Image enhancement
1.4 Distinguish between direct and indirect imaging systems, giving
examples to illustrate each system.
Direct imaging systems contain acquired data that is a recognizable
image and includes such examples as the human eye, digital still/motion-
capture cameras and optical telescopes. Indirect imaging systems, on the
other hand, require that the acquired data go through a data
processing/reconstruction step before the resultant image can be
observed. Examples of indirect imaging systems include film cameras, x-
ray computed tomography and holography.
1.5 How many images, each with 512 x 512 pixels and each pixel
requiring one byte of storage, can be stored on: (i) a 3 ½" floppy disk
with a capacity of 1.4 MB (ii) a standard CD ROM with a capacity of
700 MB (iii) a DVD-ROM with a capacity of 4.7 GB?
Assuming that the images are grayscale, an image of 512 x 512 pixels
requires about 262144 bytes (512 * 512 = 262144, plus a small header),
which is 0.25 MB. Hence, the number of images that can be stored on the
following media is: 5 images for a floppy disk, 2800 images for a CD, and
19251 images for a DVD.
1.6 How many different shades of gray can be present in an image that is
(i) 8 bits deep (ii) 12 bits deep (iii) 16 bits deep?
, (i) 256
(ii) 4096
(iii) 65536
1.7 Explain the differences between spatial resolution and brightness
(grayscale) resolution in a digitized image.
Spatial resolution represents that smallest discernible detail of a
given image. The higher the resolution, the more “data” is obtained during
the sampling process which produces a more detailed image. On the
other hand, brightness resolution represents the smallest discernible
change in the grayscale levels. The higher the brightness resolution, the
more ‘continuous’ the changes of shading in an image will appear.