The role of filter in digital camera lenses for photography and security
As an optical component, a filter is a tool used to select the desired radiation band. It is made by adding special dyes to plastic or glass sheets, and its main feature is that its size can be made quite large. Thin film filter, usually passing long wavelength light, is commonly used as an infrared high transmittance filter. The latter is a low order, multi-stage series solid interferometer formed by vacuum coating a metal dielectric film with high or low refractive index or a certain thickness of all dielectric film on a certain substrate.
The main functions of camera filters are:
Filter out infrared radiation
Color CCD can also sense infrared because it can sense infrared, which will result in the inability to calculate the correct color. Therefore, you must add a filter to separate the infrared part of the light, so only color CCD needs to install a filter, not black and white.
Adjust the incoming light
Due to the fact that CCD is composed of many photoreceptors (cells), light directly enters, but in order to avoid interfering with adjacent photoreceptors, it is necessary to trim the light. Therefore, the filter is not glass, but quartz. It utilizes the physical polarization properties of quartz to maintain the direct and reflected oblique parts of the incident light, avoiding affecting nearby sensitive points.
What are the functions of the filter used for security monitoring?
Nowadays, cameras all have night vision function. This night vision relies on the ability to see objects in complete darkness, which is achieved by the infrared light emitted by the LED and reflected into the CCD for imaging. This creates a contradiction. In order to filter out the infrared light generated by the sun during the day, we stick blue glass in front of the CCD and cut off the infrared light. The infrared light emitted by the LED at night is filtered out by the blue glass and cannot be imaged. How to resolve this contradiction? Cutting off infrared light during the day makes the image clear and realistic, and at night it allows the infrared light emitted by the LED to fully enter the CCD for night vision function. This is the function of a dual filter. It relies on a mechanical device to place a filter that cuts off infrared light in front of the CCD during the day, and automatically switches to a fully transparent filter at night, thus meeting the requirements of an infrared night vision camera. This mechanical device is called a dual filter switch.
The main functions of camera filters are:
Filter out infrared radiation
Color CCD can also sense infrared because it can sense infrared, which will result in the inability to calculate the correct color. Therefore, you must add a filter to separate the infrared part of the light, so only color CCD needs to install a filter, not black and white.
Adjust the incoming light
Due to the fact that CCD is composed of many photoreceptors (cells), light directly enters, but in order to avoid interfering with adjacent photoreceptors, it is necessary to trim the light. Therefore, the filter is not glass, but quartz. It utilizes the physical polarization properties of quartz to maintain the direct and reflected oblique parts of the incident light, avoiding affecting nearby sensitive points.
What are the functions of the filter used for security monitoring?
Nowadays, cameras all have night vision function. This night vision relies on the ability to see objects in complete darkness, which is achieved by the infrared light emitted by the LED and reflected into the CCD for imaging. This creates a contradiction. In order to filter out the infrared light generated by the sun during the day, we stick blue glass in front of the CCD and cut off the infrared light. The infrared light emitted by the LED at night is filtered out by the blue glass and cannot be imaged. How to resolve this contradiction? Cutting off infrared light during the day makes the image clear and realistic, and at night it allows the infrared light emitted by the LED to fully enter the CCD for night vision function. This is the function of a dual filter. It relies on a mechanical device to place a filter that cuts off infrared light in front of the CCD during the day, and automatically switches to a fully transparent filter at night, thus meeting the requirements of an infrared night vision camera. This mechanical device is called a dual filter switch.