What is a Visualiser? Quite simply it is a way to channel the living world into your classroom or training room. Video Visualisers and Document Cameras are electronic imaging tools for displaying 3-D objects. Document Camera is the most commonly used name, however they are much more than that. A Visualiser it is not just a fancy overhead projector, it is a live camera that picks up live images and allows you to view them over any display device. The true beauty of Visualisers can be summed up in one word – flexibility. It can be a piece of paper, a transparency, a 3-dimensional object, a 35mm slide, an x-ray or even a large item or person in a room. You can point, annotate, zoom in and out, and get different views and angles by turning an object. It helps people absorb and retain information by exciting visual technology.

A Visualiser has the ability to connect to virtually any multimedia projector, interactive whiteboard, PC monitor or TV to provide you with a large visual element to lessons and demonstrations. By displaying these documents or objects on a large screen in one central classroom location, your students will not only be able to better understand and visualise content, but it will also inspire interactivity.

Visualizers vs. Overhead Projectors

Unlike overhead projectors, transparencies are not required for Visualizers. Visualizers or document cameras are not restricted to only documents. They can display various 3D objects in which an OHP would only be able to display a shadow rather than a detailed image. Many of the original OHP transparencies can still be used by Visualizers. This function has been further strengthened by the integration with video conferencing, interactive whiteboards, touch screens and telemedicine systems. Display technology paved the way for Visualizers as they depend so heavily on displays to complete their purpose.  As digital display technology developed, so has the connectivity of Visualizers. XGA (1024 x 768) resolution output is used today alongside composite video and s-video.

What makes a Visualiser?

Visualisers are made up of numerous components that vary from model to model. Below is a list of the general components you would likely find on a visualiser followed by a brief description of each.

Arm or Column  

 

There are two types of columns the gooseneck and the rigid arms are generally used in visualisers today.

The Gooseneck column is extremely maneuverable by positioning the camera head over, around and across the subject being viewed. Once the column is in place it will maintain its position. The column attaches to the camera head and to the base accommodating any cables. This type of column is particularly useful for displaying subjects through microscopes as the camera head can be positioned strategically over the eye piece.

Rigid columns are fixed arms which attach the camera head to the base with appropriate cables running through the column. They come in either fixed lengths or telescopic variants.

Rigid columns are fixed at the base usually with a hinge assembly, which allows the camera to be folded down for portability or to be brought down for better viewing of the subject on the base stage.

Base  

The Visualisers base serves two functions. Firstly it creates a firm footing to make the visualiser stable to ensure that it will not topple over. Secondly the base usually houses the base light, main power, control panels, stage, input/output connections and processing circuitry.

Base Lights / Light boxes

Base Lights / Light Boxes For Visualisers

Base lighting, where fitted, is designed to illuminate viewing subjects from behind, such as transparencies and vary in size from 127 x 100mm up to A4 (approx. 297 x 210mm). Normally the light box is constructed out of two Cold Cathode Fluorescent Lamps located either side of the lighting assembly which allows an even spread of light across the entire surface.

Optional accessory light boxes are also offered in a number of cases when they are not integral to the Visualiser.

Camera
 

The main part of any Visualiser is the camera, which will determine what is seen by the Visualiser and the level of image quality. The camera will consist of an image sensor and will usually be either a CCD or CMOS Active Pixel Sensor. Progressive Scan CCD technology is applied in certain models. Important to the quality of the image is the lens array on front of the image sensor and coupled with the resolution of the image sensor. This can make the difference between a good picture and a great picture. The majority of Desktop Visualisers will have a motorised zoom lens which makes it easy to select the correct view of the subject material.

Cameras are commonly located in a housing which will be fixed at a point to permit the camera to move on its axis. The degree to which that movement can be effected depends on the design of the visualiser. With gooseneck types the camera housing is either fixed or limited in movement about its fixing point as manoeuvrability is provided by the gooseneck itself.

Rigid column units commonly have their cameras in a housing attached to an assembly, which provides movement in the vertical axis up to a maximum angle of approximately 90° either side of the down looking position. This allows the camera to look away from the stage both forward and rearward (NB. Unless compensated for, the image will be upside down when looking away from the stage toward the position that the operator would normally stand. Few models provide compensation for this effect. When looking away from the operator the image will be the correct way up).

Depending on the construction and depth of field of the camera lens, Desktop Visualisers will be fitted with a "close-up" lens, which enables the camera to focus and magnify over short distances, i.e. down towards the stage. When viewing away from the stage at distanced objects, when the camera housing is rotated away from the stage, the close-up lens is redundant. Two common types of fixings for these lenses are either screw (similar to SLR camera lens filter fixings), or "flip-up" where the lens is housed in a narrow frame and fixed to the camera head by a hinge arrangement, closing over the main camera lens when close-up viewing is required, and opening or "flipping-up" when distance viewing is in use. Visualisers not fitted with a close-up lens do not require one due either to their design purpose or lens construction.

Camera heads can also contain wireless remote control receivers to maximise the visibility for reception of signals from the handheld transmitter.

Control Panel

Control panels of Visualisers are strategically located for ease of access and use and usually to avoid the camera being obscured by the operator's arm in use.

Desktop Visualisers usually have control panels located at the front of the base stage or on the camera head. Their size and complexity depend on the degree of functionality offered. The majority are push-button and some include "jog shuttle" type controls, all are designed to be intuitive to allow the first-time user to start operation within seconds of introduction to the unit.

Input / Output Panel

 With the exception of USB-only connected units, connector panels are usually located at the rear and/or the side of the visualiser base and their size depends on the functionality and features of the unit. They can be limited to a single connector or provide full connectivity to suit any display type or resolution.

Commonly provided connectivity on Visualisers is: D-sub 15 pin VGA, S-Video (4 pin Mini DIN), Composite Video (RCA/Phono) and BNC. DVI is beginning to appear in some models and offers High-Definition multimedia Interface (HDMI. Audio connectivity is provided by: Mini Jack or RCA/Phono. PC connectivity is provided almost exclusively by USB 1.0/1.1 (12 Mbits/second) or USB 2.0 (up to 480 Mbits/second).

Overhead Lights

Where lights are fitted they can vary in size, type, output and number. Several manufacturers choose LED technology due to intensity, colour temperature, cost and lifespan. Others use CCFL (Cold Cathode Fluorescent), standard Fluorescent or Halogen lamps which are equally as efficient.

Lamps can be mounted on separate smaller columns fixed to the side of the unit's base, at the hinge point of the main column or integral to the camera head itself. Usually lighting is designed to offer directional control which varies the amount of light from the subject reaching the camera. This directional adjustment enables optimum illumination of the subject to be achieved and helps in diminishing the occurrence of "hot spots" or "white outs" and is achieved by gradual rotation of the light unit and the angle of adjustment of the arms they are mounted to.

Special Application Visualisers

Associated Software

Due to increasing technology standards, visualisers are now capable of communicating with laptops, MACs and PCs. Visualiser manufacturers are providing software to boost productivity and provide drivers to ensure faultless image transfer. The images produced by visualisers can now be incorporated into the visualiser's software which is adaptable with one or more imaging standards (.gif, jpg, etc...).

What can this software really do?

Visualiser software can perform numerous functions that are only possible when it is in the digital domain. Software can be an extremely powerful tool, some of the functions that they perform are:

  • image capture
  • image storage
  • movie (AVI) record and store (both real-time and time lapse)
  • image manipulation
  • archiving and retrieval
  • undo and redo functions
  • magnify
  • measurement and logging
  • export data to a Microsoft® spreadsheet
  • inserting text, drawing functions include - arrows, lines, circles, ellipses, pencil tools
  • Image adjustment can include - brightness, contrast, and negative/positive.

Users can share live video across a network, images can be displayed full screen or within a Graphical User Interface. Images can be emailed and screens can be customized.

Available Software

Examples of software are:

  • Elmo's Image Mate

Interactive Whiteboards have software that is equally, if not more powerful than most Visualiser software that can be used in the integration of images from visualisers into a wide range of content software for presentation.

Popular software packages are:

  • SMART Board™ software
  • Promethean's Activprimary
  • Activstudio and PX
  • RM's Easiteach.

 Auto Focus (or AF)

This is a common feature found on most visualisers. The subject being viewed is automatically focused to the correct focus instead of an individually focusing manually. Most systems continuously maintain the focus, adjusting for any difference throughout the presentation

Auto Iris 

This is an automatic process which controls the amount of light being picked up by the image. This feature effects the darkening or lightning of the image which can be useful when environments are either too light or too dark. 

Colour / Black & White Selection
 

 This feature converts a colour picture to a black and white one. "Noise" can often occur in colour pictures and this feature is to help eradicate the "noise" of the picture. When this feature is used, the image is more stable and white and dark are easier to define.

Digital Magnification

This feature provides additional magnification to the optical magnification. Depending on the model, magnification of up to 300 times can be achieved.

Drawing Function

This feature enables the presenter to draw or annotate directly over the document being viewed. The annotation is done using "electronic ink" which can come in many colours for different types of emphasis.

Edge Enhancement

A "halo" effect can sometimes be caused on images such as black text on white; this feature helps to eliminate this from occurring.

External Image Save

Apart from the memory which is provided in the visualiser itself for storing your images, you can use a USB cord to transfer the images to your computer for extra storage or use a SD Card for additional memory.

Gamma Correction

By coding or decoding luminance in video this function helps to optimize the image.

Image Mode

These modes are a set of image enhancement algorithms designed for use depending on the type of subject you are viewing. For example, one of these modes can be used to diminish the "halo" effect created by a high contrast image.

Image Rotation

This is a digital function in which the subject being viewed can be digitally turned 90 degrees at a time without physically moving the subject material.

Internal Image Save

The majority of visualisers have on-board memory to store images. The memory capacity varies from model to model but y ou can store anywhere from 3 up to 80 images for easy retrieval.

Locks the keypad to prevent an undesired selection of a control feature. Usually selected by a combination of buttons.

Negative Positive Conversion

This feature allows colour and black and white images to be converted from positive images to negative images and vice versa. 

Pause / Freeze Mode -This feature allows the presenter to freeze the image last seen on the visualiser allowing the presenter to remove the previous subject with a new one without any disruption in the flow of the presentation.

 Projector control -Functions of the display device can be controlled by the visualiser.This is usually RS232 or USB

Screen split -When comparing images this function can be extremely helpful. The screen is split 50/50 either vertically or horizontally. For example a live image can be displayed with a stored image.

Signal Pass-through -The signal from your computer can pass through the visualiser (even when turned off) to the computer and the image from your computer can be shown on the display device. Slide Show -Displays sequential images from either internal or external memory sources.

Split Display / Slideshow -This feature is associated with image memory, either external or internal. In this feature you can display numerous thumbnail images stored in the memory. The number of images you can display varies from different models, but it can be from 4 to 16 images. 

State Presetting - This feature memories default settings for a particular presenter or function (viewing document, object etc...) It can memorize zoom, image rotation, colour balance, white balance, brightness, lighting, edge enhancement, gamma, positive/negative and B&W selection.

 White Balance -This feature manipulates the colour temperature seen by the camera, thus giving the right colour image on the screen.

 
 
 
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