Physics 2 (HQ 8 Scan Converter/ Digital + Analog / Pixels/ Bits/ Contrast Resolution/ Spatial Resolution)

How many bits are needed to represent 16 shades of gray? 1. 4 2. 3 3. 6 4. 5 5. 2

1. 4 - Level of shade of gray = 2n(# of layered of matrix) = 24 = 16

The binary number 1001001 is equivalent to which decimal number below? 1. 73 2. 146 3. 219 4. 35

1. 73

Which information is LEAST relevant to determining an echo's pixel address on the matrix of a scan converter: 1. echo amplitude 2. echo arrival time 3. sound propagation speed 4. beam orientation

1. echo amplitude - Echo amplitude has no relationship to an address of an echo.

The computer parameter that limits the number of brightness levels available for display of the image matrix is the: 1. number of bits per pixel 2. number of pixels in the matrix 3. memory speed 4. clock speed in megahertz 5. memory capacity in megabytes

1. number of bits per pixel - The more bits per pixel → the more shades of gray → provides superior contrast resolution.

What is the smallest part of a digital picture called? 1. pixel 2. bit 3. fractal 4. byte

1. pixel

The actual device on a real-time imaging system that enables the rapid manipulation of digitized data is called the: 1. scan converter 2. high frequency generator 3. cathode ray modulator 4. multiphase transformer

1. scan converter

Which of the following u/s system components is responsible for the allocation of displayed gray scale? 1. scan converter 2. system receiver 3. transducer 4. the display monitor 5. none of the above

1. scan converter - The scan converter is responsible for allocating the information acquired by the xdcr in a form that eventually results in a TV image.

The spatial resolution of a system is affected by all of the following EXCEPT: 1. pulse length 2. depth calibration 3. beam width 4. pixel size

2. depth calibration

Which of the following adjustments would improve contrast resolution? 1. increasing the number of scan lines 2. increasing the number of bits 3. increasing the number of raster lines 4. increasing the number of pixels 5. decreasing the size of the scan converter matrix

2. increasing the number of bits - As the # of bits per pixel increases, the # of shades of gray that can be displayed by the u/s system increases. Contrast resolution is improved by increasing the # of shades of gray.

Differentiation between two very similar reflected signal strength is most closely associated with: 1. number of pixels in the scan converter matrix 2. number of bits per pixel in the scan converter matrix 3. dimension of the scan converter matrix 4. number of raster lines in the scan converter matrix 5. Interpolation scheme

2. number of bits per pixel in the scan converter matrix - The # of bits per pixel determines the # of shades of gray that can be demonstrated. As the # of bits increases, the # of possible shades of gray increases. The ability to differentiate between two echoes with very similar amplitudes is termed contrast resolution. This capability is partially determined by the # of shades of gray that can be used to create the image.

The scan converter: 1. converts echo frequency to Doppler signals 2. stores digital data 3. carries out beam formation during echo reception 4. converts digital data to analog data

2. stores digital data - It is the component that stores echo data during scan build-up.

Analog scan converters store electric charges. How does this affect echo amplitude? 1. the greater the binary number the lower the electrical amplitude 2. the greater the electrical charges the greater the amplitude of the echo 3. the greater the electrical charge the lower the amplitude of the echo 4. the lower the electrical charge the smaller the digital memory

2. the greater the electrical charges the greater the amplitude of the echo - The stronger electrical charges the greater strength of the echo amplitude.

How many levels of information can a single bit represent? 1. four 2. two 3. one 4. sixteen 5. eight

2. two - A single bit can represent only two values, on and off. The earliest u/s system only showed 1 bit of information. They were referred to as bistable. Images were displayed with only two shades-black or white. Obviously, the amount of information that could be obtained with such systems was quite limited compared to today's instruments.

How many bits are required to display 10 different shades of gray? 14 shades? 15 shades? 1. 4 bits, 5 bits, 6 bits 2. 4 bits, 4 bits, 2 bits 3. 4 bits, 4 bits, 4 bits 4. 10 bits, 14 bits, 15 bits

3. 4 bits, 4 bits, 4 bits - 4 bits depth can store as many as 16 shade of gray.

Which of the following digital scan converters would demonstrate the best contrast resolution? 1. 5 bit 2. 6 bit 3. 8 bit 4. 7 bit 5. 4 bit

3. 8 bit - The larger number of bits provides the greater the number of shades of gray, the better the contrast resolution. Contrast resolution is the ability to visually differentiate small amplitude differences between adjacent tissues.

The system that will have the BEST contrast resolution is the one with: 1. 5 bit deep memory 2. 7 bit deep memory 3. 8 bit deep memory 4. 6 bit deep memory

3. 8 bit deep memory - Bits per pixel responsible for allocation of gray scale contrast resolution—the more bits per pixel, the more shades of gray, the best contrast resolution.

The most important benefit of analog scan conversion is: 1. advanced image processing capabilities 2. a flicker-free storage tube 3. an infinitely variable gray scale range 4. a drift free storage tube 5. none of the above

3. an infinitely variable gray scale range

The spatial resolution of an u/s imaging system is LEAST likely to be limited by: 1. pixel density 2. beam frequency 3. bits/pixel in the memory 4. beam line density 5. all of the above affect spatial resolution

3. bits/pixel in the memory - Spatial (relating to, occupying, or having the character of space) resolution of an imaging system is not affected by bits in memory. Bits in the memory effect echo amplitude resolution.

In an analog scan converter, what component stores the image data? 1. computer memory 2. video tape recorder 3. dielectric matrix 4. none of the above

3. dielectric matrix

Which one of the following is the principal benefit of digital scan conversion over analog scan conversion? 1. increased signal penetration is made possible 2. computer circuitry can acquire and display information at faster rates than other forms of scan conversion 3. it is more stable and more flexible than analog scan conversion 4. there is no need for multiple transmit focal zones 5. an infinitely variable gray-scale range is capable (within the limits of video display technology)

3. it is more stable and more flexible than analog scan conversion

The component of an u/s machine that serves as the primary site for storing echo information is the: 1. echo modulator 2. display monitor 3. scan converter 4. receiver 5. transducer

3. scan converter - After the echo signals are processed in the receiver, they are stored in the scan converter

In the digital storage and processing of u/s images, pixels stand for: 1. peak echo amplitude 2. post-processing programs 3. small picture cells 4. pick-up tubes 5. none of the above

3. small picture cells - Pixel is a small picture cell—" " smallest building block or smallest storage part of digital picture.

Analog scan converters: 1. function perfectly as peak deflectors 2. have greater image sharpness than digital scan converters 3. store any increment of signal amplitude 4. have better image uniformity than digital scan converters

3. store any increment of signal amplitude - Scan converters come in two types; analogue and digital. Analog scan converters store any increment of signal amplitude, whereas digital scan converters store the signal amplitude in discrete steps.

The number of bits per pixel in the scan converter memory is most closely related to: 1. scan converter spatial resolution 2. lateral resolution capabilities 3. the number of amplitude levels stored 4. axial resolution capabilities

3. the number of amplitude levels stored - Number of bits per pixel is responsible for the allocation of displayed gray scale.

Digital scan converters are: 1. stable and extremely fast 2. ideal for dynamic imaging 3. prone to thermal drift 4. 1 and 2 5. 1, 2, and 3

4. 1 and 2

The binary number system: 1. is a computer version of the decimal system 2. has only two digits 3. is a convenient system for computer operation 4. 2 and 3 5. all of the above

4. 2 and 3 - Digital scan converters use a special number system called binary numbers, has two digits, 0 and 1-- converts increment of signal amplitude form analog format into a discrete signal amplitude format.

A digital memory with 5 bits available for quantifying echo amplitude would be limited to _______ levels: 1. 25 2. 16 3. 5 4. 32 5. 10

4. 32 = 32 levels are found by multiplying 2 × 2 × 2 × 2 ×2.

The binary number 100100 is equivalent to which decimal number below? 1. 64 2. 84 3. 72 4. 36 5. 32

4. 36

A digital scan converter is another name for what system component? 1. beam former 2. pulser 3. receiver 4. image memory 5. analog to digital converter

4. image memory - Scan converter is the memory component of the u/s system. The analog to digital converter is a converter that convert analog format into digital format.

The spatial resolution of the scan converter is determined by: 1. interpolation scheme 2. total number of bytes available in memory 3. brightness and contrast setting of the monitor 4. number of pixels in the scan converter matrix 5. number of bits per pixel

4. number of pixels in the scan converter matrix - A matrix of 512 × 512 pixels is capable of much better spatial resolution than a similarly sized matrix containing only 64 × 64 pixels. In the latter example, the image would appear blocky with discrete square-shaped segments. Overall image resolution would therefore be degraded.

The number 36 in binary notation is: 1. 101011 2. 110011 3. 111 4. 111110 5. 100100

5. 100100

Gray scale display of ultrasonic images is made possible by: 1. receiver 2. cathode ray storage tubes 3. linear array transducers 4. TV monitors 5. scan converters

5. scan converters - Scan converter or image processor is the memory component of the u/s system. Scan converter makes gray scale display possible by receive echo information from receiver, storing (write) the data, manipulate the information, and read them for display on the monitor.

The digital scan converter has a number of pixels assigned to each bit. True False

False

Both digital and analog scan converter use computer technology to process electronic data into images. True False

False - Digital scan converters use a computer technology to process and store the signal amplitude in discrete steps, whereas analog scan converters store electrical increment of signal amplitude.