What is the principle of the camera's direction selection?
Different types of lenses had different principles for choosing the far and near direction: 1. ** Principle of the object telecentric lens **: The main ray of the object is parallel to the optical axis, and the center of convergence of the main ray is infinitely far away from the image, which is the object telecentric light path. This light path design could eliminate the reading error caused by inaccurate focusing. 2. ** The principle of the lens: Place the aperture stop on the object focal plane of the optical system. The main ray of the image is parallel to the optical axis, and the convergence center of the main ray is located infinitely far away from the object. Its function is to eliminate the measurement error caused by the inaccurate focusing of the image. 3. ** Principle of Dual Telecentric Lenses **: By placing a iris in the middle of the lens, the light entering and exiting the lens is parallel light. Other light is blocked by the iris and cannot reach the imaging chip. On each side, there is a telecentric lens for the image side and a telecentric lens for the object side. The characteristic of the dual monocentric lens was that the distance between the object or the camera did not affect the magnification. It was mainly used in the field of visual measurement. 4. ** The principle of traditional camera lens focusing (involving the choice of far and near direction): For objects at different distances from the lens, focusing is required to clearly image at a fixed position. Most of the lenses in traditional cameras focused by changing the distance between the film surface and the lens (in digital cameras, it was the focal plane of the camera). Intuitionally speaking, when the lens was adjusted, the subject would be particularly clear. 5. ** autofocus principle (involving the choice of the far and near direction)**: The camera autofocus is a complex process of integrating photoelectricity. The basic principle is to let the light reflected by the object be accepted by the photo sensor on the camera. Through the internal smart chip processing, it drives the electric focusing device to focus. At present, most digital cameras used passive autofocus, which directly received and analyzed the reflection from the scene itself and used the phase difference principle to autofocus. This method was good for auto-focusing at different distances (near and far directions) with a certain brightness and contrast. It could also focus well under backlighting and focus through transparent obstacles such as glass. 6. ** Liquid lens principle (involves the choice of far and near direction)**: When the light passes through the water droplet, the device will be converted into a miniature camera lens. When the water droplet passes through the cylindrical hole, the image will enter or leave the focal length range according to the distance of the lens from the object. Read more exciting novels for free
The oldest camera principle
The oldest camera used optical principles to record images. Early cameras required the use of negative film (videotape) to record, and the principle of imaging was the same as that of ordinary cameras. For example, in 1874, France's Jules Jansan invented a camera. He wound the sensitive film on a toothed feeding tray. Under the control of a pendulum mechanism, the feeding tray intermittently fed the film in the circular feeding box. At the same time, the pendulum mechanism drove the shutter to rotate. Whenever the film stopped, the shutter opened for exposure. The invention of this early camera laid the foundation for the later development of camera technology. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The principle of camera formation
The principle of a movie camera is the same as that of a normal camera. Take the camera as an example. It was based on the principle of small hole imaging. According to the straight line transmission property of light, a plate with a small hole was used to block between the object and the screen. An inverted image of the object would be formed on the screen. The camera replaced the screen with a negative film device. A closed black space was formed between the plate and the small hole to block the non-imaging light. The small hole was replaced with a lens, and the zooming lens was used to imitate the plate that could move back and forth to control the image size. The camera was a device that converted the light image of the scene into an electrical signal. Its structure was roughly divided into an optical system (mainly a lens), an optical conversion system (camera tube or solid-state camera device), and a circuit system (Media Processing Service circuit). The light entered the sensor through the lens and was then converted into a digital signal that was pre-processed by the built-in signal processor. The processed digital signal was compressed by the compression chip and finally sent to the network through the network interface for transmission. In the electro-optical conversion system, the object is refracted by the lens of the optical system to form a "focal point" on the imaging surface. The light-sensitive element transforms the optical image outside the "focal point" into an electrical signal carrying a charge, and then it is amplified by the circuit system to form a signal that meets the requirements and is output. The main function of the security lens was to collect the reflected light of the object being photographed and focus it on the CCD. The image projected onto the CCDwas inverted, and the camera circuit had the function of reversing it. The imaging principle was the same as that of the human eye. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The selection principle of the dome light umbrella
There were many factors to consider when choosing a dome light umbrella. In terms of fabric structure and usage, there were white, silver, gold, blue, transparent umbrellas, umbrella boxes, giant parabola umbrellas, and many other types. The white reflective umbrella was softer. Although it was a little harder than a soft box of the same size, it could create a soft light with moderate light ratio, rich shadow tone, and wide light field. It could be used as a more common choice. The light from the silver umbrella was very hard and difficult to control, so it was generally not recommended. Different colors and types of umbrellas had different light effects. It was necessary to choose the appropriate dome light umbrella according to the actual shooting needs, such as the softness of the required light and the difficulty of controlling the light type. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
USB live camera principle
The principle of the old-fashioned camera
The principle of old-fashioned cameras was to convert optical image signals into electrical signals for easy storage or transmission. When shooting an object, the light reflected on the object is collected by the camera lens, so that it is focused on the light receiving surface of the camera device (such as the target surface of the camera tube), and then the light is converted into electrical energy through the camera device, thereby obtaining a "video signal". Since the optical signal was very weak, it needed to be amplified by a pre-amplifier circuit, and then processed and adjusted by various circuits. The final standard signal could be sent to a recording medium such as a video recorder for recording, or transmitted through a transmission system, or sent to a monitor for display. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Realization principle of sdi camera
The principle of the implementation of the camera was as follows: the non-return-to-zero inverted scrambling code (NRZI) was used to replace the early block coding. The standards were SMPTE -259M and EBU-Tech- 3267, which included digital composite and digital component signals including digital audio. Before transmission, the original data stream was scrambled and converted into the NRZI code to ensure that the original data could be restored at the receiver. This could be regarded as a kind of base band signal modification. The SDI-interface could transmit 270Mb/s serial digital component signals, and for 16:9 format images, it could transmit 360Mb/s signals. The NRZI code is a polar sensitive code. It uses "1" and "0" to represent the high and low levels. If there are continuous "1" or continuous "0" for a long time, it will affect the receiver's extraction of the clock from the digital signal.(Because the serial digital signal interface does not transmit the clock signal alone, the receiving end needs to extract the clock signal from the digital signal stream.) Therefore, the NRZI code with "1" and "0" to indicate whether there is a level change. When receiving the NRZI code stream, as long as the level change is detected, the data can be recovered. Even if it is all "1" signals, the resulting signal frequency is only half of the original clock frequency. After scrambling, the chances of continuous "1" are reduced. This further reduced the high-frequency component. At the receiving end of the data stream, the original data stream was recovered from the NRZI stream by the PDI decode. The SDI-interface could not directly transmit compressed digital signals. After the compressed signals recorded by the digital video recorder, hard disk, and other equipment were replayed, they had to be uncompressed and output through the SDI-interface before entering the SDI-system. If it was repeatedly unpacked and compressed, it would inevitably cause the image quality to decline and the delay to increase. For this reason, various digital video recorder and non-linear editing systems of different format had their own interface for directly transmitting compressed digital signals. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The camera's sensor changes direction
Here are some ways to change the direction of the camera sensor: - When adjusting the direction of the camera sensor in the gazebo, you can add it in line 271 of the dofbot.gazebo.urdf.xacro file. If the angle position is not correct after adding the camera to the robotic arm, after the camera is normally written as Link&Jiont and the model position is confirmed, change the angle data<pose>0000300 in</pose>line 40 to adjust the direction of the sensor. - For the security monitoring equipment, an infrared sensor was installed outside the second extension rod. When the infrared sensor sensed people in different directions, the servo-motor inside the shell worked to drive the rotating shaft to rotate the rotating block, thereby adjusting the direction of the camera (including the ordinary camera and the infrared camera) to indirectly change the direction of the sensor. - In the Android system, the camera's sensor direction had a default definition. When the phone was facing the screen horizontally and the camera was close to the top, it was the default direction. When the phone was upright and the front and rear cameras were both above, the front camera's rotation angle was 270 degrees, and the rear camera was 90 degrees. For the camera's previewing direction, you can get the rotation angle through the CameraInfo.orientation parameters, and then use the Camera.setDisplayOrientation(int degree) method to set the previewing angle. For the photo storage direction, you can set the rotation in Camer.parameters. Different phones have different processing of the photo's orientation and the orientation in the EXIF information. You may need to read the EXIF information in the photo (JPEG file) to rotate the Bitmap according to the orientation to achieve the purpose of adjustment. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Wipe the camera direction
When wiping the lens, you can gently wipe it clockwise from the middle of the lens. You can also use the lens paper to wipe the lens surface in a clockwise or counterclockwise direction after taking a breath at the lens. You must not wipe it back and forth. The key to wiping is to gently enter, slightly rub, and then gently start. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The direction of the camera movement is
The direction of the camera's movement included the vertical, horizontal, and vertical directions. In the vertical direction, the lens moves forward along the optical axis to approach the subject, and the lens moves backward along the optical axis to move away from the subject. There was also the movement of the lens on the horizontal plane or in the space, and the movement of the lens in the vertical direction was the upward movement of the lens and the downward movement of the lens in the space. In addition, there was the movement of the lens that quickly changed the angle or position. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Requirements for camera selection
The selection requirements of the camera included the following aspects: the clarity and resolution of the camera, the focal length of the lens, the size of the CCD-shaped target, and the resolution. We can come to the following conclusion: 1. Clarity and resolution: The clarity and image resolution of the camera are important considerations when choosing a camera. Generally speaking, the horizontal resolution of the camera should be greater than 500 lines. The higher the resolution, the better the performance of the camera. 2. Focus of the lens: Choose the lens with the appropriate focal length according to the scope and size of the scene that needs to be monitored. Fixed focus lenses were available in 2.8mm, 3.6mm, 4mm, 6mm, 8mm, 12mm, 16mm, 25mm, etc., while zoom lenses could be adjusted manually or manually. 3. The size of the CCD-target: The size of the CCD-target of the camera determines the choice of the lens. When the size of the CCD-target is 1/3 inch, a 1/3 inch lens should be selected; when the size of the CCD-target is 1/4 inch, a 1/4 inch lens should be selected. 4. Pieces: The camera's resolution determined the clarity of the image. Generally, home surveillance cameras choose 1 million, 1.3 million, or 2 million high-definition graphics, and surveillance cameras with a resolution of 720P, 960P, or 1080P can meet most of the needs. In summary, the selection requirements of the camera included factors such as clarity and resolution, focal length of the lens, size of the CCD-shaped target, and resolution.