Computers require a digital image to display photographs on PC monitors (or laptops).
On a microscope digital images can be produced by digital SLR and compact cameras,
digital USB streaming cameras and microscopes that have a digital USB streaming camera
built in. Analogue image has to be converted to digital before it can be seen with
a computer. For PC’s this requires the addition of a PCI card in one of the card
bays, and for laptops an external USB video encoder is required. -
Digital images can of course be manipulated and measuring software is often included with the package for the more expensive digital CCTV cameras. Choose from the topics listed for more information.
Digital image capture
For still images the technology is well established and digital cameras download images very easily to computers. CCTV cameras on the other hand have no internal memory system and traditionally provide a live image to TV or TV monitor that requires an analogue (non digital) image. Digital CCTV cameras on the other hand connect to computers via USB 2.0 or USB 3.0 ports. The speed of the download of these cameras requires a very fast assimilation of the images, this can cause a ‘bottleneck’ resulting in a forced reduction in frame rate which produces a very ‘jerky’ image. USB’s built for fast processing and a quality graphics card help improve these issues.
Analogue CCTV cameras produce an output suitable for TV’s and their resolution is measured (as for TV monitors) in lines. These days high resolution colour cameras (approx 540 lines) can be obtained for under £200. Some of these analogue CCTV cameras are actually marked ‘digital’ however this does not apply to the output which is analogue. These units produce images through AVI, Svideo, VGA and HDMI, To obtain an image from these cameras on a PC or laptop, the analogue image has to be converted to digital. For PC’s this can be done by using an internal PCI card that can be added to one of the vacant card bays. Alternatively an external conversion unit can be used to relay a digital image into a USB port. An internal PC card is of course not an option for laptops that must rely either on the external conversion unit allows image grabbing. All PCI, and external conversion units come complete with the necessary software. MAC have their own conversion encoders. Our video encoders are MAC and Windows compatible.
There are a number of medium priced PCI cards suitable for microscopy. Brunel Microscopes recommends the Meiji or Eurosys internal card which supports high resolution images. It is easy to install and comes complete with the necessary software. For less difficult resolution requirements, for laptops or for those not wishing to insert internal cards into their computers, we recommend the Hauppage or Grand external capture card systems, which connect to a PC or laptop via the USB port and directly to the CCTV camera. No internal PCI card is needed, and the CD ROM software and all connectors are included at a very reasonable price. We also have an external encoder compatible with Windows and Mac OS.
The relatively fast download speeds of USB 2.0 and 3.0 ports has allowed the production of a number of digital cameras that are more realistically priced. They are particularly effective for laptop computers and give good resolution video clips and grabbed still images. Computer images are defined by pixels, with the concentration of pixels dictating the maximum size of the image. At Brunel we now offer a range of these cameras at 2M, 3M, 5M and 10M