Clinical Continued »
and RAM to perform the output to the monitor. This reduces the amount of processing power and RAM available to running programs.
• Graphics cards come equipped with their own processor, a GPU (graphics processing unit), and their own memory, called VRAM (video RAM). This means all graphics and imaging work is performed in one place and not via the main processor and RAM. It also means it will be performed more effi- ciently, an important factor if X-rays are being rendered on the PC.
• Graphics cards can also output at much higher resolutions than integrated graphics. VRAM will enable your computer to load more and higher resolution textures or 3D images onto the GPU, as well as render images at higher resolutions.
• GPU requires enough VRAM to operate smoothly. If not, it will load its resources onto the system RAM instead. However, due to the system RAM’s distance from the GPU, it is a lot slower than VRAM. This is partly the reason why integrated graphics are much slower than dedicated GPUs, since
EXAMPLE OF A MEDICAL GRADE MONITOR
• Panel Technology – IPS TFT with W-LED backlight
• Screen Size [inch/cm] – 61.1 / 24.1
• Screen Aspect Ratio – 16:10
• Pixel Pitch [mm] – 0.270 x 0.270
• Brightness (typ.) [cd/ m2
] – 170, (350 max)
• Contrast Ratio (typ.) – 1000:1
• Optimum Resolution – 1920 x 1200 at 60 Hz
ABOUT THE AUTHOR
Ian Wilson is a director at IW Technology Services
for graphics design and other applications that require colours to be displayed accurately. The response time of the panel allows for smooth playback while watching films and playing games, making the IPS the best all-round technology suitable for both business and home use.
Fig 2 Fig 1
An nVidia GeForce graphics Card
they have no VRAM and thus have to rely on the slower system RAM.
There are many different types of graphics cards and again, checking the minimum requirements of any imaging system will guide you to the best option. There are two main types used – nVidia (
www.nvidia.com) and AMD Radeon (
www.amd.com). Graphics cards come with
different output connectors to suit all types of monitors.
MONITORS A good monitor will provide the best definition and detail of images. It is vital to realise the importance of a monitor display. Buy a cheap one and the detail, colour mix and
EXAMPLE OF A HIGHER-QUALITY PC MONITOR
• Panel – IPS LED • Resolution – 1920 x 1080 Full HD 1080p
• Aspect Ratio –16:9 • Brightness – 250 cd/m2 • Static Contrast – 1000:1 • Advanced Contrast – 5,000,000:1
• Response Time – 5ms • Viewing angle – Horizontal/vertical: 178°/ 178°; right/left: 89°/ 89°; up/down: 89°/ 89°
• Display Colours – 16.7M • Pixel Pitch – 0.265 x 0.265
Three types of monitor connections: VGA – Analogue output (top), HDMI – Digital HD Output (middle) and DVI – Digital Output (bottom)
ability to display true black are pretty poor. This is a vital part of being able to distinguish and display the 256 shades of grey. A cheap monitor results in a low-quality display of images on the screen.
There are different types of monitors available: TN The cheapest monitors are based on twisted nematic (TN). While having a fast response time, they have limited colour reproduction, poor black levels and narrow viewing angles. They are fine for word processing, but not for serious work.
LCD screens use cold cathode fluorescent lamps (CCFLs) to provide backlighting. These fluorescent tubes must light the entire screen evenly. There is no way to vary the back- lighting intensity in different parts of the screen. Even if you want to show a single white pixel on an all-black screen, the light in the back needs to be blazing away at full brightness.
LEDs are LCDs that use LEDs to backlight. This produces better colour. Rather than being on at full brightness all the time, they can be dimmed or turned off entirely. This makes for much better black levels and contrast.
IPS panel technology guarantees consistent colour reproduction with wide viewing angles and high contrast and therefore it is especially recommended
CONSIDERATIONS Contrast ratio The difference in light intensity between white and black on an LCD display is called contrast ratio. The higher the contrast ratio, the easier it is to see details and differences in the shades of grey.
Luminance Also known as brightness, it is the level of light emitted by an LCD display. Luminance is measured in nits or candelas per square meter (cd/m2). One nit is equal to one cd/m2.
Response time The speed at which the monitor’s pixels can change colours is called response time. It is measured in milliseconds (ms).
SUMMARY In conclusion, the investment in a good PC system will provide better results and perform at a higher level. Details in imagery will display in greater detail and let you see far more. Get the best processor within
your budget and consider the amount of RAM in the system. Faster is better when it comes to processors and more RAM is always better in terms of performance. Adding a graphics card
will provide better display results along with better rendering of images. The extra processing power will help with performance, both in the system and in image processing. A good monitor will give the
best output of all the work done on the PC system. The better the monitor, the greater the detail that will be output and seen on the screen. This is important when viewing images and seeing greater detail. Consider an IPS type for best results.
Ireland’s Dental magazine 31
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56