Sony FCB camera block
Definition
Pixel (also known as pixel point or pixel point) : It is the smallest unit that constitutes a digital image, namely the Picture Element.
In a camera, a pixel is the smallest light-sensitive unit on the camera chip, and each pixel corresponds to one pixel on the image.
The pixel size of a camera refers to the physical dimension of each pixel in a digital imaging system, with the unit usually being micrometers (μm).
The relationship between pixel size and pixels
Pixel size is an important parameter of digital cameras, which determines the actual physical size of each pixel on the camera’s photosensitive chip.
1. Correspondence
The pixel is the basic unit of an image, and the pixel size reflects the physical size of each pixel.
In a camera, each pixel corresponds to one pixel on the image. The photosensitive performance and physical size of pixels directly affect the pixel quality and resolution of the image.
2. Jointly determine the imaging target surface
The pixel size and the number of pixels (i.e., the resolution) jointly determine the size of the imaging target surface of the camera. For example, the SONY 4K/60FPS ultra-high-definition all-in-one camera FCB-ER9500 has a maximum resolution of 3840×2160 and a pixel size of 2.0μm. Then its maximum imaging target surface is 7.68mmx4.32mm.
3. Mutual influence
There is a trade-off relationship between pixel size and the number of pixels. When the sensor size is fixed, a smaller pixel size can increase the number of pixels, thereby improving the resolution and detail resolution of the image.
For example, SONY FCB-ER9500 and FCB-EW9500H have sensors of the same size. The pixel size of FCB-ER9500 is 2.0μm, and that of FCB-EW9500H is 2.9μm. Therefore, relatively speaking, The FCB-ER9500 has higher image resolution and detail resolution than the FCB-EW9500H.
However, too small a pixel size may lead to increased noise and decreased image quality. Therefore, when designing a camera, a trade-off needs to be made between the pixel size and the number of pixels.
The influence of pixel size on image quality
Pixel size affects the quality of the image to a certain extent. At the same pixel density, the larger the sensor size is, the larger the pixel size will be accordingly. This will increase the photosensitive area of each pixel, thereby improving the quality of the image.
For low-light imaging, cameras with larger pixel sizes usually have higher sensitivity and can capture clearer images in low-light conditions.
The smaller the pixel, the better the detail resolution
As the smallest unit of an image, the smaller the size of a pixel, the more pixels can be accommodated within the same sensor area, thereby enhancing the resolution and detail resolution of the image. This is similar to the principle of a microscope. The smaller the pixel, the more details can be observed.
2. The relationship between pixel size and field of view
Under the conditions of the same resolution, constant object distance and consistent lens, the larger the pixel, the larger the field of view for shooting usually is. This is because the larger the pixel, the more photons a single pixel can receive, and thus the more charges are generated under the same lighting conditions and exposure time, enabling the camera to capture a wider field of view.
However, this also means that on the same imaging target surface, an increase in the area occupied by a single pixel may lead to a decrease in detail resolution.
In addition, the pixel size also affects the accuracy of the camera. Precision refers to the size of an actual object represented by one pixel. When the field of view is constant, the higher the resolution of the camera (that is, the relatively smaller the pixel size and the higher the pixel density under the same sensor size), the higher the precision. However, it should be noted that pixel size does not equal precision; they are two different concepts.
Summary
In conclusion, the pixel size of a camera is an important parameter, which determines the size of the imaging target surface, the field of view range, and the image quality of the camera, among other aspects. When choosing a camera, it is necessary to select the appropriate pixel size based on the specific application scenario and requirements.