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| Stephen Martin, MU, discusses pros and cons of various peripheral devices. |
"Toys of the Trade"
Peripheral Devices and How They Can Be Used for the Farm
Stephen Martin, MU
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| Stephen Martin, MU, discusses pros and cons of various peripheral devices. |
Whether you have purchased a new computer "toy", or are just waiting for the right one to come along, today's computer peripheral "toy box" is overflowing with devices that have practical applications on the farm. From scanners to digital cameras, net cams to CD recordable drives, there are more affordable and useful devices on the market than anyone could possibly sort through. With all of these devices, how can you determine which "toy" you should use on the farm? The purpose of this session is to help answer this question. We will explore some of the ways that computer peripherals are being used by farm operations, and introduce some new devices and their possibilities.
Topics:
If yes, then the scanners speed and it's interface (the way it connects to your computer) should be one of the important factors to consider. All scanners are not created equal in this department and the lack of industry testing standards makes any comparison of manufacturer's specifications virtually meaningless. The best sources of comparative information are comparative product reviews from magazines, television and the web. Also, don't overlook the value of real life experience with a product. Ask family, friends and acquaintances what they use and why they would or would not recommend the product.
Depending on what you will be scanning (Photos, text, slides), you may need special attachments like a multiple document feeder or transparency reader.
How you will use your scanned images will determine the resolution and color depth that your scanner must support. There is a great deal of difference between scanning for computer display (web, photo sharing, optical character recognition) and scanning for printing (newsletters, advertisement, photo reproduction).
For less that $200 you can purchase a scanner that will probably meet your requirements. Even scanners selling for less than $100 will meet the needs of most families and small farms. But if you need professional-level images and speed, you may need to spend $800 or even more.
There are a few different types of scanners on the market. Of these, you will probably choose either a flat bed, hand held, sheet fed, or photo scanner. If all you need to scan are photos, one of the specialty photo scanners may be for you. Short on space? Maybe a sheet feed or hand held would be practical. By far the most popular and versatile is the flat bed scanner. It can be used to scan almost anything, and I do mean anything.
Software can be very expensive. Most scanners come with a mix of software that you might need. The quality and usefulness of this software should be considered in your purchasing decision.
Digital Cameras
Questions to consider before you purchase a digital camera.
How you want to use your digital images will determine the minimal requirements of the camera. The requirements for capturing images for use on a web page are very different than those for printing high quality images on a photo quality printer.
Most quality digital cameras use a charge coupled device (CCD) sensor as part of the process of converting light waves into a digital image. Some lower quality cameras use a CMOS sensor. The images captured by these cameras does not equal the CCD cameras. The sensor also determines the maximum resolution that the camera can capture. The higher the resolution, the higher the price of the sensor required to capture the image. The higher the price of the sensor, the higher the cost of the camera! Resolution refers to the number of pixels or picture elements in a picture. The pixel is the smallest bit of information about a recorded image. When a camera is advertised to have a resolution of 1280x1024 the maximum resolution image captured by that camera will contain 1,310,720 pixels (1280 x 1024 = 1,310,720). This is what is commonly called a 1.3-megapixel camera.
This again depends on how the images are to be used. While a camera capable of capturing images with a resolution of 640x480 may be fine for adding pictures to your web site or sending e-photos of the new baby to family and friends, it will not give you images that equal the quality and size of standard film cameras. The higher the resolution, the more versatile the camera. Most of the consumer oriented higher resolution digital cameras will capture images at several different resolutions. This makes them very versatile. For lower quality images to be used mainly for computer viewing, digital cameras with resolutions of 1.3-megapixels (sensor captures 1280x1024 or less) or less will do the job and are available for under $300. The best of these camera will also allow you to make good quality prints up to around 5x7. You will need to spend $500 for a camera capable of 2-megapixels. A good 2-megapixel camera (sensor captures 1600x1200 or higher) will allow you to produce good quality prints up to 8x10. If your budget goes up to the $800-1000 range, you could purchase a 3-megapixel camera that could print a high quality image up to 11x14. 4-megapixel cameras are on the horizon and when they are available 2 and 3-megapixel cameras will move down in price substantially.
There are a few very inexpensive digital cameras on the market that use plastic lenses. In these cases you get what you pay for in both image quality and durability; beware. Most digital cameras use good quality optical glass. The best of these, and most expensive, use aspherical glass lenses. Aspherical lenses are, as you might guess, not round. It seems that a perfectly round lens can produce a slight distortion to the image. Aspherical lenses can produce better pictures by reducing the distortion. Optical zoom is a very important feature on a digital camera. Zoom lets you adjust how close or far your subject appears in your picture. Optical zoom means that your camera actually moves it's lens in and out to optically change the image. The higher the optical zoom the better. Digital zoom does not move the image closer or farther optically. Instead, digital zoom takes the central part of the image required for the degree of zoom specified and throws away the rest. It then digitally zooms the image (makes it appear closer) by enlarging the remaining pixels (not the whole story, but close). This will always result in a lower quality picture. Avoid cameras that only provide digital zoom. Many cameras provide both optical and digital zoom. On those cameras the optical zoom is the important factor. You can produce the same result as digital zoom with almost any image editing software.
The result of capturing a digital image is a computer file. The size of the file depends on many factors. These factors include, image resolution, file format, and file compression. The higher the image resolution the larger the file, all things being equal. Digital cameras use many different file formats. Many cameras can save images in more than one format depending on their purpose. Some cameras use their own proprietary format to store images. Using a proprietary format will usually require an extra step to convert the image into one of the common formats like JPEG or TIFF before the image can be used. TIFF and JPEG formats are very commonly used in digital cameras. They are both compressed formats. TIFF files are around one-third the size of the uncompressed image. JPEG files can be compressed at varying rates. The common range of compression is from around one-fourth the size for the lowest compression (highest quality image) to one-sixteenth the size for the highest compression (lowest quality image). Many digital cameras will have several compression or quality settings. They may also combine a choice of compression and resolution.
Most digital cameras come with software to edit and manage the image files created by the camera. The quality and usefulness of this software should be one of the factors you consider before making a purchasing decision.
We have only scratched the surface and there are several other factors that should be mentioned. Camera image storage is a major consideration. Digital cameras store their captured images in internal memory or on some type of removable media. If the camera stores it's images internally and the memory becomes full you must either delete some of the images to make room, or connect the camera to a computer and transfer the files. This can be very inconvenient. A camera that stores it's images on some type of removable media can remove the full media and replace it with media that is empty (or has any room available for images). This is very convenient. There are several types of removable media in use today. The most common are Compact Flash cards, SmartMedia cards, Sony's Memory Stick, and standard computer floppy disks (1.44MB).
Most digital cameras have an optical view finder. Most also have a liquid crystal display (LCD). The LCD lets you see how your image if framed before you take the picture. It also allows you to review and manage images stored on the camera. LCDs are often more accurate for framing shots than the optical view finder found on the camera. The main drawback is the power it consumes. You wouldn't want a digital camera without a LCD, but the optical viewfinder can be nearly as important. If the camera allows the LCD to be turned off (a valuable feature), you can frame your shots with the optical viewfinder saving a great deal of battery power.
Speaking of power. That is also an important factor to consider. Most cameras operate on AA batteries. This allows the greatest flexibility in powering your camera. You can use rechargeable batteries (nickel-cadmium (NiCad) or nickel metal hydride (NiMH) ) and recharge them over and over. If you find your batteries depleted and no time to charge them, you can always use single-use alkaline batteries that can be purchased almost anywhere. Some cameras use proprietary batteries packs. The benefit to these proprietary battery packs is that the cameras usually can act as a charger. When the batteries are dead just plug the camera into it's AC adapter and after the required time you've got fresh batteries. On the negative side, when you run short of battery power you can't pop in some AAs from Wal-Mart and keep shooting.
Most digital cameras will include a flash unit. Flash units usually have several operating modes. These will include always on, off, red eye reduction, and others. The more modes probably the better. Some cameras offer special features. These include video recording and audio recording. Video recording quality is generally not very good quality and should not be considered a reason to choose one camera over another. Audio recording is a handy feature that will allow you to add a voice note or other sound to an image. For example you could record the name of the people that were in the image you captured. Or maybe you wanted to capture the sound of the old steam engine you saw powering a sawmill. Other factors you should consider include power-up time and between shot time. You should be aware that some digital cameras can take over ten seconds from the time you turn it on until it is ready to take a picture. You should also be aware that different cameras take different amounts of time to process one image and prepare to capture another. It can be very frustrating waiting for your camera to get ready to take a picture while watching the perfect picture disappear.
Digital Video
Sometimes it is more effective to express an idea through the use of pictures than by using words. If one picture is worth a thousand words then it seems that thirty pictures a second would be worth even more. While capturing, editing, and distributing digital video is becoming easier and more affordable every day, it is still a rather complex topic. There are many ways to get digital video into your computer, but no matter how you capture it, there is a very BIG issue to deal with.
Since digital video is made up of a series of images in sequence, it has many of the same issues as digital cameras. The resolution of the image, the number of images per second (frames per second), and the type and amount of compression applied to the images all affect the size of the computer file that is generated. A relatively small video image of 320x240 pixels captured at 15 frames per second along with audio could require over 200MB of storage per minute of video. The higher the resolution the larger the file size. The more frames per second the larger the file size. The higher the image quality (less compression) the larger the file size. Producing digital video that balances file size with video quality involves finding the right combination of resolution, fps, and compression.
Presented by Stephen Martin during the 2001 Computers on the Farm Conference.
Stephen can be reached by e-mail at martinst@missouri.edu or by telephone at 573-882-4827.