High speed cameras are designed for very fast image acquisition. They are used in scientific and industrial applications in which a process or inspection function is changing or moving rapidly. High speed cameras can operate in monochrome or color. Monochrome is black and white, or grayscale; the image is presented in black, white, and grayscale. The range of colors is generated with varying combinations of different discrete colors. One common technique is sensing the red, green, and blue components (RGB) and combining them to create a wide spectrum of colors.
Important performance specifications to consider for high speed cameras include maximum frame rate, horizontal resolution, and shutter speed. The maximum frame rate is the frames that can be captured per unit time, typically frames per second. Horizontal resolution is the maximum number of individual picture elements that can be distinguished in a single scanning line. It is most common to characterize horizontal video resolution corrected for the image aspect ratio, or specify the resolution in the largest circle than can fit in a rectangular image. Thus, for example a 640 x 480 image would be specified as 480 horizontal lines. Shutter speed is the time of exposure or light collection, typically may be set across a wide range.
High speed cameras are designed for very fast image acquisition. They are used in scientific and industrial applications in which a process or inspection function is changing or moving rapidly. High speed cameras can operate in monochrome or color. Monochrome is black and white, or grayscale; the image is presented in black, white, and grayscale. The range of colors is generated with varying combinations of different discrete colors. One common technique is sensing the red, green, and blue components (RGB) and combining them to create a wide spectrum of colors.
Important performance specifications to consider for high speed cameras include maximum frame rate, horizontal resolution, and shutter speed. The maximum frame rate is the frames that can be captured per unit time, typically frames per second. Horizontal resolution is the maximum number of individual picture elements that can be distinguished in a single scanning line. It is most common to characterize horizontal video resolution corrected for the image aspect ratio, or specify the resolution in the largest circle than can fit in a rectangular image. Thus, for example a 640 x 480 image would be specified as 480 horizontal lines. Shutter speed is the time of exposure or light collection, typically may be set across a wide range.
Choices for imaging technology for high speed cameras include CCD, CMOS, tube, and film. Charge Coupled Devices (CCD) use a light-sensitive material on a silicon chip to detect electrons excited by incoming light. They also contain integrated microcircuitry required to transfer the detected signal along a row of discrete picture elements (or pixels) and thereby scan an image very rapidly. CCD cameras use two-dimensional CCD arrays with many thousands of pixels. CMOS image sensors operate at lower voltages than CCDs, reducing power consumption for portable applications. Analog and digital processing functions can be integrated readily onto the CMOS chip, reducing system package size and overall cost. In a tube camera, the image is formed on a fluorescent screen. It is then read by an electron beam in a raster scan pattern and converted to a voltage proportional to the image light intensity. In film high speed cameras, the image is exposed onto photosensitive film, which is then developed to be played or stored. The shutter, a manual door that admits light to the film, typically controls exposure.
Choices for analog video format for high speed cameras include NTSC, PAL, SECAM, RS170, RS330, and CCCIR. The digital output interface can be RS232, RS422, RS485, parallel, Ethernet, DeviceNet, ARCNET, PROFIBUS, CANbus, Foundation Fieldbus, IEEE-1394, modem, SCSI, TTL, USB, and radio or wireless. Choices for number of bits or pixels include 8 bits, 10 bits, 12 bits, 14 bits, and 16 bits. The color output can be RGB, Y PbPr, Y/C (S-Video), and composite. Physical features for high speed cameras include outdoor rated, underwater rated, radiation hardened, pan or tilt, dome, gooseneck, remote head, and board mount.
