Starry sky distortion correction of fish-eye lens
The core of the fisheye lens 'distortion correction was to solve a "good" remap matrix, which rearranged some of the original image's pixel-points (or intervening points) and "pieced" them into a rectangular image. Different tasks often used different correction/transformation plans. For the star distortion correction of the fisheye lens, the camera's correction parameters could be used to correct the distortion in the image. This could be achieved by re-projecting each of the elements, making the lines and shapes of the image more straight and natural. After distortion correction, the image would usually become circular or hemisphere, and it might need to be perspective transformed to return to a standard rectangular or square shape. However, there were also some problems in the correction. For example, the distortion correction based on digital images needed to reorganize the arrangement of the elements. For fisheye lenses that had problems with the edge image quality, it might cause the edge image quality to be worse. Moreover, different lenses might need to adapt to different correction codes and could not be used universally. Read more exciting novels for free
Distortion correction of fish-eye lens
Fish-eye lens distortion correction aims to reduce or eliminate the image distortion effect caused by fish-eye lenses. When correcting the distortion of the fisheye lens, the core was to solve a "good" remap matrix, which rearranged some of the original image's pixel-points (or intervening points) and "pieced" them into a rectangular image."Good" was linked to the final requirement, and different tasks often used different correction/distortion solutions. For example, in the smart security industry, whether it was a monocular camera or a monocular camera, the images captured would have distortions, which was the same as the distortion correction principle of a fisheye camera. For monocular cameras, in order to obtain the corresponding relationship between the camera's coordinate system and the three-dimensional world coordinate system, the barrel distortion and pillow distortion of the camera needed to be corrected. For binocular cameras, in order to do epipolar line alignment and realize depth estimation, the output of the two cameras needed to be transformed into the same coordinate system. Teacher Zhang Zhengyou's chessboard correction method estimated the internal and external parameters and distortion coefficient of the camera through the position coordinates of the marker, and then calculated the remap matrix. This method had a good correction effect for monocular and binocular cameras. In terms of practical operations, fisheye correction can also be performed using python language (only relying on the opencv-python package and numpy package), and fisheye distortion correction can also be performed from code examples such as PILimport Image. In addition, the distortion correction function based on digital image processing was also applied to the fisheye lens correction. This solution required rearranging the arrangement of the elements, but for the ultra-wide system where the edge image quality itself was a big problem, it might lead to the image quality of the most edge area being worse. Some equipment would use the image field redundant design and the sensor to perform the redundant matching of the elements to reduce the side effects of the digital correction. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Fish-eye lens is
A fisheye lens was a lens with a focal length of about 6 - 16mm and a viewing angle close to or equal to 180°. It was a type of ultra-wide-angle lens. Its front lens was shaped like a parabola and protruded to the front of the lens, which was similar to the eyes of a fish, hence its name. The concept was proposed and developed in 1906. In the 1920s, it was used for the study of cloud formation in meteorology. Robin Hill was the first person to truly create a fisheye lens and use it for commercial use. Mass production began in the 1960s. It was usually composed of a front group of imaging lenses and a rear group of correction lenses. It was divided into half-frame fisheye lenses and full-frame fisheye lenses. It was first used in photography to create artistic photos with a large field of view and large distortion. It was also widely used in fields that required wide-angle imaging, such as surveillance, dome imaging, aerospace cameras, and other industrial, medical, and scientific research fields. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Fish-eye lens imaging theory
The imaging theory of the fisheye lens was based on its special optical structure design. The fisheye lens had a large spherical curvature, similar to the spherical crystal of a fisheye, and the imaging plane was closer to the lens. The visual effect was similar to a fish observing things on the surface of the water. When the fish was close to the surface of the water, the angle of view could reach a wide angle of nearly 180°. This phenomenon was based on the principle of total reflection and optical reversibility. In terms of structure, the front lens of the fish-eye lens protruded from the front in a parabolic shape in order to maximize the camera angle. It was generally believed that lenses with a focal length of 16mm or shorter were fisheye lenses. However, in engineering, lenses with a viewing angle of more than 140 degrees were collectively referred to as fisheye lenses. In fact, there were also lenses with a viewing angle of more than 270 degrees. In terms of imaging mode, the M12 fisheye lens (180°) generally used vertical or horizontal in-cut imaging mode (mode 1 Circular Fisheye, mode 3 Full Horizontal). At the same time, fisheye lens imaging relied on artificially introducing a large number of barrel distortions to obtain a large field of view, so that it could obtain image information with a large field of view. However, except for the shape of the object in the center of the image, the other parts that should be straight lines had a certain degree of distortion. When matching an image sensor with a fisheye lens, a 1:1 or 4:3 image sensor was generally selected to maximize the use of effective pixelation. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Fish-eye lens for piano teaching
Using a fish-eye lens in piano teaching has certain advantages. The fish-eye lens had a large angle of view and could accommodate more scenes. It could adapt to the needs of shooting in a small space. In a piano teaching scene, such as an online piano lesson, the fish-eye lens could be used to let students see more details of the teaching environment, such as the teacher's overall performance posture, the piano's overall appearance, and so on. However, there were some problems with using a fisheye lens. Due to the distortion of the image, the straight lines around the screen would be bent. When shooting piano teaching content, if you need to show some flat music score or the straight arrangement of the keys, there may be distortion. Therefore, when using it, one had to pay attention to the selection of the shooting angle and content. For example, the subject that needed to be highlighted (such as the teacher's hand movements, etc.) could be placed in the center of the lens because the straight line in the center of the lens could maintain its original state. This was also the brightest and clearest part of the photo to reduce the impact of distortion on the teaching content. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The perspective distortion of the camera lens
The perspective distortion referred to the change in relative size and position between objects in the shot. Its main characteristic was "near big, far small". For example, when shooting a road, the distant road would get closer and closer to finally converge into a point. Similarly, the closer the lens was to the subject, the larger the subject appeared. The further away from the subject, the smaller the size change in the appearance of the subject. For example, train windows, the change between the windows closer to the lens was obviously larger than the change between the windows far from the lens. The change in size between the windows was smaller the further back. The perspective distortion was only related to the shooting distance and had nothing to do with the focal length. However, in actual shooting, in order to maintain the same size of the subject, different focal length lenses needed to adjust the shooting distance, which would cause differences in perspective distortion. Generally speaking, a wide-angle lens needed to be shot close to the subject, so the perspective distortion was large. A telephoto lens needed to be shot far away from the subject, so the perspective distortion was small. A short focal length (such as 18mm) would produce a wide perspective, and the objects in the picture would appear to be far away, resulting in strong perspective distortion. This distortion was more obvious when shooting buildings with straight lines; a long focal length (such as 200mm) could eliminate or reduce perspective distortion, making the objects in the picture more realistic. In addition, different shooting methods and equipment would also affect the perspective distortion. For example, using a large frame shiftable camera and shiftable lens to shoot could effectively prevent perspective distortion; finding a suitable height to shoot to ensure that the camera lens was parallel to the vertical line of the building to avoid building distortion; post-adjustment could also deal with perspective distortion. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What are the characteristics of fish eye lens in cartoon?
Fish eye lens in cartoons often creates a distorted and wide-angle view. It can make objects appear curved and give a unique perspective that adds a sense of exaggeration or fantasy.
A phone app with a fish-eye lens effect
There were two mobile phone applications that had a fisheye lens effect. One was Fisheye Cameras.(English name: Fisheye Plus Pro). It allowed the iPhone to have a digital simulation of a 170-degree wide-angle and an amazing fisheye lens. It also had a real-time fisheye viewfinder, simulated film replacement, lens, and ring flash. It supported five lenses, seven color ring flashes, and 22 effects. It gave a deeper three-dimensional sense and presented a completely different field of view. However, before using it, one had to go to the App Store to review it to fully unlock it. It was easy to flash back when using it. Especially when choosing the mode, color, and filter, the photos imported from the album couldn't be saved directly. Only the photos taken by the camera could be saved with one click. The other was the Fisheye lens app. The user could change the lens they liked during the shooting process. It was simple to operate. With just one click, they could take a funny photo with a big eye effect. It was powerful and had a delay function. It was very convenient to cut, add text or filter when editing photos. There was also a rich material library with many filter effects. When shooting, you could choose beauty effects. The modes were diverse. You could change the lens according to different scenes and needs. You could also adjust the photo parameters online at any time. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Which software has a fish-eye lens?
The POCO camera had a built-in fish-eye lens. In addition, there was a special fisheye lens app that allowed users to use a fisheye filter to take photos with a fisheye effect. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Single-lens reflex parameters starry sky
When shooting stars with a DSLR, the following are some key parameters: - Aperture: Can be opened to the maximum, such as F2.8 or F4. - [Shutter Speed: Can be set to 20 seconds or 30 seconds.] - [Light sensitivity: This is the key to controlling the exposure. It can be adjusted from 1600 to 6400 depending on the light in the shooting environment.] In addition, shooting the starry sky also required the following attention: - In terms of equipment, he needed a good single-lens reflex camera with a good wide-angle lens. A tripod and shutter release were also essential. Because shooting the starry sky required a long exposure time, using a tripod and pressing the shutter with a shutter release could ensure that the photo would not be blurred. - The shooting location should be chosen to be unobstructed, with a wide field of vision and avoid light pollution. Only then would the photos be clean and beautiful. - In terms of composition, whether it was shooting the Milky Way or the orbit of the stars, there had to be a good composition. Close-up with buildings or trees would make the photo more perfect. If you were shooting the Milky Way, you had to set the USB to 1600 or higher, and you had to prepare a backup battery. When shooting the star orbit, don't expose it for a long time. It was essential to have objects in the background. When shooting, try to aim at the position of the North Star. This way, hundreds of photos could be taken to get a beautiful circular star orbit photo through post-synthesis technology. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Starry sky time-lapse camera lens
When taking time-lapse shots of the starry sky, you can choose a wide-angle lens with a large aperture. A wide-angle lens could obtain a wider field of view, and a large aperture could obtain a higher amount of light. For example, the Nikon Nikkor 14 - 24mm F.8G ED was an excellent wide-angle lens. The focal length of 14mm could capture images of the starry sky with a view angle of more than 110 degrees. At the same time, the constant maximum f/2.8 aperture could also ensure enough light. With a 14 - 24mm zoom range, it could cope with more scenery photography scenes and provide more rich scenery. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>