● Various slides, models, slides, manuscripts and other objects can be clearly and realistically displayed on the projection screen through the camera.
● In traditional work, meetings and teaching activities, people mainly use slide projectors. The appearance of video booth, especially because of its excellent combination with projector, can gradually replace the role of traditional slide projector, and its application scope far exceeds the traditional slide projector.
● At present, video booths are widely used in education, teaching and training, video conferences, seminars and other occasions. They have many functions, such as demonstrating documents, slides, commodities, parts, three-dimensional objects and so on. But their users are mainly in the education industry.
[Edit this paragraph] Type introduction
Double-sided lamp desktop video booth: Double-sided lamp is used to adjust the light intensity required by the video booth, which is convenient for the best demonstration of the displayed items.
Single-sided lamp desktop video booth: Single-sided lamp is used to adjust the light intensity required by the video booth, which is convenient for the best demonstration of the displayed items. Single-sided lights have different positions in different booths, but it does not affect the effect. As an optional part of the video booth, LCD monitor is convenient for the presenter to monitor the position of the items on the booth.
Video booth with separated bottom plate: Because the bottom plate is separated, it enhances the portability of the video booth and is very convenient to move in a small range.
Portable video kiosk: mainly portable.
[Edit this paragraph] Technical indicators
Imaging device CCD (generally1/2; 1/3; 1/4 inches)
The number of lines displayed in a resolution image is generally around 460, and the higher the number of lines, the better the display effect.
The signal-to-noise ratio of scanning system is generally interlaced scanning, and the signal-to-noise ratio of existing video kiosks is mostly 46db.
Zoom refers to the zoom magnification of the lens.
Focus adjustment of the lens of the focused video booth (manual/electric)
Aperture adjustment Aperture adjustment of video room (manual/electric)
Adjustment index of display effect of white balance video kiosk (manual/electric)
Negative films can be shown in the positive and negative screening rooms.
When displaying text in black and white/color, you can adjust to the black and white position.
Lens rotation
Double lights and single side lights of the lighting system; Bottom light source microphone input
Video output mode video; s-video； radio frequency
Various adjustments of the screen menu can be remotely controlled through the menu adjustment of the video booth.
Some video halls are equipped with remote controls.
force
weight
[Edit this paragraph] Maintenance of video display platform
The video display platform is a precision instrument, so attention should be paid to daily maintenance.
1. Do not use or store in high temperature or humid environment.
2. Shock and vibration should be avoided, and disassembly is strictly prohibited.
3. When wiping the car body, do not use strong cleaner, but use soft cloth. When the dirt is not easy to remove, use a special cleaner to wipe it.
4. When there is dust on the lens, gently wipe it with lens paper, deerskin or cotton wool stained with detergent.
5. Do not put heavy objects on the display platform.
6. When not used for a long time, unplug the power plug and put it in a special cabinet.
[Edit this paragraph] Related nouns
1. What is the focal length?
The focal length of the video kiosk refers to the distance from the focal point of the parallel light passing through the lens to the lens. Standard lens: the viewing angle is about 300. When the focal length of the lens is approximately equal to the diagonal length of the camera target, it is the standard lens of the camera. In a 2/3 inch CCD camera, the focal length of the standard lens is16mm, in a 1/2 inch CCD camera, it is12mm, and in a 1/3 inch CCD camera, it is 8mm. ..
Concepts related to rearview mirror clearance:
Wide-angle lens: the viewing angle is above 550, and the focal length can be as small as a few millimeters, which can provide a wider field of vision.
Telephoto lens: The viewing angle is less than 200, and the focal length can reach tens of centimeters and tens of meters. This kind of lens can enlarge the image of the object taken at a long distance, but the observation range will be reduced.
Zoom lens: also known as telescope head, there are two kinds of manual zoom and electric zoom, which can zoom the perspective of monitoring scene and target to capture images, and is suitable for long-distance observation and capture targets.
The characteristic of zoom lens is to change the image size and field of view by changing the focal length of the lens when the image is clear.
2. What is the structure of the aperture?
A: The aperture is a set of metal plates arranged in the lens, designed as an adjustable circular aperture. The aperture can be changed by rotating the adjusting ring on the lens.
Aperture size is indicated by f plus sign, such as f4, f5.6, f8, f 16, f22, etc. The smaller the number, the greater the light transmittance. The larger the number, the smaller the light transmission.
3. What is the relationship between aperture and lens focal length?
The long focal length of the lens means that the aperture is far away from the film, and the travel of light is naturally lengthened, so the amount of light is attenuated. Under the same light source conditions, the aperture required by a short focal length lens is naturally smaller than that of a long focal length lens. Therefore, when using lenses with different focal lengths, we should pay attention to the adjustment of the aperture.
IV. What is the depth of field?
A: The depth of field refers to the clear range in the longitudinal direction of the shot image. For example, the foreground, background and subject are clear, and the depth of field is small. If a part of the subject itself is not clear, the depth of field is too small.
Concepts of zoom and focus
ZOOM is used to enlarge and reduce the theme on the booth, and it is called WIDE/TELE on the booth menu. Zooming is achieved by using a zoom lens. When the image is clear, the size and field of view of the image can be changed by changing the focal length of the lens. In our booth, there is the concept of zoom start/zoom stop in the menu, and its adjustable range is 1- 128.
Focus is used to fine-tune the theme on the booth to achieve the best visual effect. If we set the focus to auto on the menu, the camera will automatically achieve the best effect when we press the zoom or move the subject.
5. Some concepts about camera.
Imaging element: 1/4 inch CCD
CCD is the abbreviation of Charge Couple Device, which can convert incident light into charge, store and transfer it, and convert the imaged optical signal into electrical signal for output, thus completing the photoelectric transfer function, so it is an ideal camera element. CCD camera is a miniature image sensor.
The technical indexes to measure the performance of CCD camera mainly include the following aspects: clarity, sensitivity (also called minimum illumination), signal-to-noise ratio and video output.
1/4 inch CCD represents the size of CCD target surface. At present, the common target surface sizes are: 1 inch-target surface size is 12.7mm× 9.6mm diagonal 16mm, and 2/3 inch-target surface size is 8.8mm× 6.6mm diagonal/kloc-. 2 inches-target size is 6.4 mm× width x 4.8 mm height, diagonal 8 mm, 1/3 inches-target size is 4.8 mm width x 3.6mm height, diagonal 6 mm, 1/4 inches-target size is 3.2 mm× width x 2.4mm height, diagonal 4 mm. The size of the target plane is often the decisive factor to determine the focal length of the lens.
For example, a CCD camera uses a target surface of 1/4 inches to monitor the checkout counter in a shopping mall. The effective range is 2m×2m, and the camera is installed 7m away from the cashier. What focal length lens should the camera be equipped with?
F=v×d/V[ where f is the calculated focal length; V is high field of vision; V is the image field height (that is, the CCD target height); D is the object distance
Therefore, f = v× d/v and f = 2.4 * 7/2 = 8.4 mm
Signal to noise ratio: above 46db
Concept of signal-to-noise ratio
The ratio of the output signal voltage of the amplifier to the noise voltage output at the same time is the signal-to-noise ratio of the amplifier. It is usually represented by English characters S/N, where S represents the image signal value of the camera under the hypothesis of meta-noise, and N represents the noise value (such as thermal noise) generated by the camera itself. The ratio of the two is the signal-to-noise ratio, which is expressed in decibels (dB). The higher the SNR, the better. The greater the signal-to-noise ratio, the less clutter in the signal and the higher the video quality. On the contrary, the worse the situation. The typical value is 46dB.
Electronic shutter:1125-110000
Shutter is used to control the time of light passing, which is divided into two structures: one is focal plane shutter; The other is the blade shutter, which uses a spring to open the "door". Shutter speed is expressed in fractions.
White balance mode: automatic and electric.
What is "white balance"? This must first explain what is white, and the luster color reflected by the object depends on the color of the light source. The human brain can detect and more like this color change, so whether it is in the sun, cloudy days, indoor burning light or fluorescence. People still see the same white objects. But as far as digital cameras are concerned, the "white" produced by different light sources is still different in color, some contain light blue, and some contain yellow or red. In order to get close to human vision, digital cameras must imitate human brains and adjust colors according to light, so as to present the white seen by naked eyes in the final photos. This is called "white balance". Most digital cameras provide the function of "automatic white balance", but under different light sources, this system still can't fully meet people's visual requirements. Therefore, more accurate digital cameras provide users with a series of light source choices, such as: sunlight (color temperature 6000K), cloudy days-(color temperature 3500-3000K), fluorescence-generally used in indoor sunlight environment (fluorescence-color temperature 5500K-4000K), burning light-indoor strong light (incandescence -3500 K).
AGC: adjustable
AGC is automatic gain control, which is used to automatically reduce the gain of the signal source when it is strong. When the signal is weak, its gain will automatically increase, thus ensuring the consistency of the strong and weak signals.
Synchronization mode: internal synchronization
Modern CCD cameras mostly adopt the synchronization mode of phase modulation and line locking, that is, the frequency of AC power supply (50Hz) is taken as the reference value for vertical synchronization, instead of the synchronization generator inside the camera. When switching the camera output, the pixels will scroll, which will not cause picture distortion. In addition, there is an external adjustment phase control (90%), so very accurate synchronization can be obtained. Internal synchronization is adopted to make the image smoother and clearer.
Television system: PAL system
At present, there are three main TV broadcasting systems in the world: PAL, NTSC and SECAM. For example, PAL is used in most parts of China, NTSC is used in southeast areas such as Japan, South Korea and Europe, and SECAM is used in Russia. There are basically two scanning systems, PAL-B and NTSC, and our booth adopts PAL system. There are booths of other manufacturers, all of which are available.
Horizontal definition and vertical definition
Vertical definition is how many horizontal lines an image can be decomposed into, and the maximum vertical definition is determined by the total number of vertical scanning lines. Horizontal sharpness is defined as the number of vertical lines that can be distinguished on an image. The horizontal definition is directly related to the number of pixels of the image sensor and the bandwidth of the video system. The horizontal definition and vertical definition adopt a unified measurement standard, so when the horizontal and vertical line spacing on the screen are the same, the vertical definition and horizontal definition of the image should be the same. The greater the values of horizontal definition and vertical definition, the higher the definition. The horizontal definition of our booth can reach the standard of 470 TV line and the vertical definition can reach the standard of 380 TV line.
Effective pixel: 737 height *535 height
The effective pixels of the booth are directly related to CCD. Most digital cameras and video cameras use CCD as the photosensitive element, and the total number of pixels in them of course refers to the total number of all pixels on the whole CCD, which is also the standard used by most people to draw product grades. In fact, in practice, not all pixels are photosensitive, because the pixels at the edge will be covered to provide a completely pure black signal as the basis for calculating the image, and the rest are.