2026-08-09
CCD is the abbreviation of Charge Coupled Device, which is one of the most widely used image sensors. A CCD image sensor has imaging pixels arranged in an XY vertical and horizontal matrix. Each imaging pixel consists of a photodiode and an adjacent charge storage area controlled by it. Photodiodes convert light (photons) into charges (electrons), and the total number of electrons collected in the charge storage area is proportional to the intensity of the light. When reading these charges, the photogenerated electrons collected in each column charge storage area are moved to the charge transfer register in the vertical charge transfer direction, and then the charges in each column charge transfer register are moved row by row to the total row charge transfer register. The charge information of each row in the total row charge transfer register is then continuously read out, and image information is generated through the same charge/voltage converter and amplifier. When the light intensity is not too strong, the response of the CCD sensor is linear. The charge storage area in the CCD pixel can store all the photocharges. This is the linear range. When the light intensity continues to increase, because the charge storage area has stored a lot of photogenerated charges, the electric field generated by the photogenerated charges will prevent the pixel from continuing to accumulate charges linearly, and the CCD enters the saturation region. If the light intensity increases further, the charge storage potential well will fill up with electrons, and the excess electrons will overflow. If there are no special measures, the overflowing electrons will enter adjacent pixels, causing the adjacent pixels that originally work in the linear area to enter the saturation area after collecting the overflowing electrons or also overflowing electrons, causing a halo phenomenon in the image, and the image clarity will be significantly reduced. The principle and structure of the CCD image sensor give it the advantages of high light sensitivity, low noise, and high image quality. Generally, the dynamic range of a CCD industrial camera is about 60dB. However, when there are high-brightness points or areas in the image, the CCD image sensor has "Blooming" and "Smear" effects that seriously degrade the image quality.
CMOS is the abbreviation of Complimentary Metal Oxide Semiconductor. CMOS, like CCD sensors, is made on Si (silicon) semiconductor material. The new generation of CMOS uses an active pixel design. Each pixel consists of a photodiode that converts photons into electrons, a charge/voltage converter, a reset and a selection transistor, and a gain amplifier. The CMOS sensor is structurally arranged like a computer memory DRAM or a flat panel display. The metal grid covering the entire CMOS sensor connects the clock signal, the readout signal and the column output signal to each other. The charge/voltage converter integrated in each pixel of the CMOS image sensor converts the photocharge generated by the pixel and directly outputs a voltage signal. The signal is read out in a manner similar to the simple XY addressing technology of computer memory DRAM. This method allows CMOS to read out the signal from the entire arrangement, part or even a single pixel. This is exactly the same as CCD.
It's completely different, and it's something that CCD can't do. In addition, the built-in charge/voltage converter converts the photocharge generated by the photodiode into a voltage signal in real time, which in principle eliminates the "Blooming" and "Smear" effects and minimizes the interference of strong light on adjacent pixels. In the application of online real-time quality inspection of welding, the light intensity in the observation area of the machine vision system changes very drastically, requiring the dynamic range of the camera to be as large as possible. In this application, CCD cameras are not very suitable because of the "Blooming" and "Smear" effects that lead to image quality degradation and smaller dynamic range.
Photonfocus's CMOS industrial cameras use patented CMOS sensor technology: LinLogTM technology or Linlog2 technology, which completely overcomes the shortcomings of CCD cameras and expands the dynamic range of the camera as much as possible while ensuring image contrast in low-illumination areas. range, with a dynamic range of up to 120dB; the unique global shutter technology ensures that short exposure times (minimum 10 microseconds) are easily achieved; the high-speed ROI technology makes it possible to monitor the welding pool at thousands of Hz in high-speed welding online real-time quality inspection. Photonfocus's CMOS industrial camera is a CMOS camera optimized for online real-time quality inspection applications in welding. It is an important guarantee for obtaining clear images of the welding pool and avoiding welding plasma radiation from obscuring the edges of the welding pool and other detailed information.
Photonfocus's Hurricane-40-U2 camera uses a USB2.0 interface, which is plug-and-play and does not require a special capture card. It is very cost-effective. The full resolution of the MV-D1024 series cameras is 1024*1024, which is suitable for the high-speed requirements of welding inspection applications. The MV-D1024-75-CL has a maximum frame rate of 75 frames per second at full resolution 1024*1024, and the MV-D1024-160-CL has a maximum frame rate of 150 frames per second at full resolution 1024*1024. Currently, all high-speed laser welding machines in Japan use MV-D1024-160-CL for online quality inspection.
