TELEBIZ
The brand of perfect camera
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WHO WE ARE
Telebiz is your number one source for affordable high-quality full HD and 4K Ultra HD PTZ cameras. We are dedicated to providing you the very best cameras with stunning image quality for effective video collaboration, such as video conferencing, distance learning solutions, tele-medicine, broadcasting and live event solutions.
Telebiz platform combines Image Signal Processor (ISP) and core algorithms based on Ambarella’s HD and 4K solutions. Telebiz portfolio includes various products such as Broadcast HD PTZ video cameras and USB based video conferencing cameras for various applications.
With all solutions provided by Telebiz, the emphasis is always on quality of experience and highest level of service. We are serving thousands of customers, including hi-tech companies, finance institutes and education, banks, law offices, public and government agencies.
Top 3 characteristics essential for getting superb Image Quality on PTZ Cameras
Video conferencing system is not just a buzzword, it become an essential way of doing business. As users, we require a crystal clear, realistic, and high definition image. In order to support a reasonable decision making when procuring a PTZ camera, we are providing some high-level details about four top characteristics that should be considered when choosing a camera.
As a best practice, do not assume the camera resolution is everything regarding image quality. While image quality is influenced by the resolution configured on the camera, the quality of the lens, sharpness of focus, and lighting conditions also come into play. For example, harshly lit areas may not offer a well-defined image, even if the resolution is very high. Bright areas may be washed out and shadows may offer little detail. Cameras that offer wide dynamic range processing, an algorithm that samples the image several times with different exposure settings and provides more detail to the very bright and dark areas, can offer a more detailed image.
The optical signal pass through a lens to a sensor which transforms it into electrical signal, and then processed by Image Signal Processor (ISP) embedded some complex algorithms that would provide the final image. Therefore, it is important to consider at least three elements which affecting the image quality before making up our mind to purchase a video camera.
- Image Signal Processor (ISP) and Algorithms
ISP is a processing block that converts a raw digital image into a usable image for a given application (typically a color image for viewing). This conversion is quite complex and includes a number of discrete processing blocks that can be arranged in a different order depending on the ISP. An example image processing block is shown in Figure 1. Each ISP has its own unique features, but almost all ISPs have the same basic blocks and processing pipeline. The following is a brief description of each of the functional blocks identified in Figure 1.
Lens shading correction–corrects for brightness and color non-uniformity towards the image periphery
Auto white balance–corrects for the color temperature of the ambient lighting conditions, to preserve color constancy (i.e., that a gray object appears gray regardless of the spectrum of light illuminating the scene)
AEC/AGC–Auto Exposure Control, Auto Gain Control
Defect pixel correction–corrects for defective pixels on the image sensor
Denoise–reduces the appearance of noise in the image
Color interpolation–converts a sensor’s raw color data, typically captured using a Bayer Color Filter Array (CFA) into a color RGB image
Edge enhancement–processing block which enhances edges, normally to make an image appear sharper to a human observer
Color correction matrix–corrects for crosstalk between adjacent sensor pixels
Brightness/contrast adjustment–the implementation details of this block vary significantly, but the key goal is to enhance image contrast and digitally adjust image brightness
Gamma–gamma correction block adjusts the contrast associated with differently light levels differently, to increase the salience of features
Each vendor has its own software algorithm ability; therefore, the final imaging results and perceived image quality is not the same. Only with excellent software algorithm capability, the image optimization can result in superb images that fits to different applications and use cases.
- Image sensor
- An image sensor or imaging sensor (also: imager) is a sensor that detects and conveys the information that constitutes an image. It does so by converting the variable attenuation of light waves (as they pass through or reflect off objects) into signals, small bursts of current that convey the information. Image sensors are fundamental component in any digital imaging camera.
Most modern cameras use image sensors based on semiconductor charge-coupled devices (CCD) or active pixel sensors in complementary metal–oxide–semiconductor (CMOS) or N-type metal-oxide-semiconductor (NMOS, Live MOS) technologies. Digital sensors include flat panel detectors.
CMOS sensors are characterized by low power consumption, competitive price and excellent image quality, and therefore are adopted in video cameras mostly. When considering a CMOS based camera, the following parameters are most important:
- Pixel sensor size
The size of the pixel sensor is often given in height and width. Common dimensions include 14um, 10um, 9um, 7um, 6.45um, 3.75um, and so on. The pixel size reflects the response capability to light in a certain extent. The larger the pixel size, the more the number of photons that can be received, and the more amount of charge generated in the same lighting condition and exposure time. For low light imaging, pixel size is a representation of chip sensitivity. - Sensitivity
Sensitivity is one of the important parameters of the sensor’s chip, it has two physical meaning. One is photoelectric conversion capability of a pointing device, which is the same as the response rate. The other means that the device can sense (the minimum illumination) to ground radiation power (or illumination).
- Dead pixels
Due to the limitations of the manufacturing process, it is almost impossible for all the pixels in a sensor to be good (considering a sensor with a few million pixels). The number of dead pixels is an important measure of the quality of the chip parameters.
- Dead pixels
- Spectral response
Spectral response refers to light response capacity of the chip for different wavelengths, usually given by the spectral response curve.
Relatively speaking, considering a given resolution, the larger the sensor size is the better the photographic performance; the more graphics signal captured, the higher the signal to noise ratio, which result in better imaging results.
- Lens
- The lens zoom is one of the more important specifications for PTZ cameras. The lens is measured in focal length (mm or angle). The maximum zoom (or smallest angle) defines how far away we can see an object, while the minimum zoom (wide angle) determines how wide the field of view will be, as shown in Figure 2
- A camera with a variable focal length can be adjusted to optically magnify (or zoom) to enhance details of distance objects. A key characteristic is depth of field, which refers to the range of distance where objects appear acceptably sharp in an image. It varies depending on camera type, aperture and focusing distance. Camera that are placed to cover near and distant objects must reduce the apertures, softening the image due diffraction. The aperture describes the iris or hole that lets light into the camera’s sensor. The larger the hole, the more light can enter the camera. The more light that can enter the camera, the better it can see in poor light and the brighter the picture will be. The higher the aperture (less light) means an increase in depth of field. The lower the aperture (more light) means a decrease in the depth of field. The value of the aperture is usually expressed in F / 2.2, F / 2.4, the smaller the number, the greater the aperture.
