| FFC
| Flat Field
Correction: a CCD imager is composed of a two dimensional array of light
sensitive detectors or pixels. The CCD array is mechanically quite
stable with the pixels retaining a rigidly fixed geometric relationship.
Each pixel within the array, however, has its own unique light
sensitivity characteristics. As these characteristics affect camera
performance, they must be removed through calibration. The process by
which a CCD camera is calibrated is known as "Flat Fielding" or "Shading
Correction". |
| F-Stop / F# | The f/number is an indication of the
brightness of the lens. It is the measurement of the ratio between the
focal length and the diameter of the entrance pupil (where the light
enters the lens). The f/number is directly proportional to the focal
length and inversely proportional to the effective diameter of the lens.
It determines the amount of light reaching the camera sensor. The
smaller the value, the larger the opening and the brighter the image
produced by the lens. |
| FFT Attenuate | Attenuates the frequencies of a complex image. |
| FFT Filter | Applies a frequency filter to the
image. This function performs three steps. First, it finds the fast
Fourier transform (FFT) of the source image, which is a complex image.
Then the function filters (truncates or attenuates) the complex image. |
FFT High Pass
| Removes low frequencies. |
FFT Low Pass
| Removes high frequencies. |
FFT Mode
| Determines which frequencies to truncate or attenuate. |
FFT Truncate
| Truncates the frequencies of a complex image. |
| FFT Truncation Frequency % | Percentage of the frequencies retained within a Fourier-transformed
image. This percentage is expressed with respect to the length of the
diagonal of the FFT image and the Mode value. |
Field of View
| Field of view (FOV) is the area covered by the lens' angle of view. |
| Filter Size | Sets the size of the filter for the Lowpass and Median functions. Typical made up of kernels. |
| Filters | Prepares an image for processing so you can extract only the information
you need from the image. Most of these filters apply a kernel across
the image. |
| FireWire | FireWire (also known as i.Link or IEEE 1394) is a personal computer (and
digital audio/video) serial bus interface standard, offering high-speed
communications. It is often used as an interface for industrial
cameras. |
| Fixed Focal Length Lens
| Non-zoomed lenses where the distance between the sensor and center of the lens is fixed |
| Fixed pattern noise | abbr. FPN. If the output of an image
sensor under no illumination is viewed at high gain a distinct
non-uniform pattern, or fixed pattern noise, can be seen. This fixed
pattern can be removed from the video by subtracting the dark value of
each pixel from the pixel values read out in all subsequent frames.
Dark fixed pattern noise is usually caused by variations in dark current
across an imager, but can also be caused by input clocking signals
abruptly starting or stopping or if the CCD clocks do not closely match
one another. Mismatched CCD clocks can result in high instantaneous
substrate currents, which, when combined with the fact that the silicon
substrate has some non-zero resistance, can cause in the substrate
potential bouncing. The pattern noise can also be seen when the imager
is under uniform illumination. An imager which exhibits a fixed pattern
noise under uniform illumination and shows no pattern in the dark is
said to have light pattern noise or photosensitivity pattern noise. In
addition to the reasons mentioned above, light pattern noise can be
caused by the imager becoming saturated, the non-uniform clipping effect
of the anti-blooming circuit, and by non-uniform, photosensitive pixel
areas often caused by debris covering portions of some pixels. |
Flat Field Correction
| Flat Field
Correction: (abbr. FFC) a CCD imager is composed of a two dimensional array of light
sensitive detectors or pixels. The CCD array is mechanically quite
stable with the pixels retaining a rigidly fixed geometric relationship.
Each pixel within the array, however, has its own unique light
sensitivity characteristics. As these characteristics affect camera
performance, they must be removed through calibration. The process by
which a CCD camera is calibrated is known as "Flat Fielding" or "Shading
Correction". |
Focal Length
| Focal length is the distance between the camera sensor and the center of
the lens. The greater the focal length, the larger the image will
appear. Therefore, the greater the focal length, the more the lens
becomes telephoto in application. |
| FOV | FOV = field of view. See field of view |
| FPGA
| Field
Programmable Gate Array: a specially made digital semiconductor. With an
FPGA, a design engineer is able to program electrical connections on
site for a specific application. |
| FPN | FPN = fixed pattern noise. Related
with the dark current is its electrical behavior to be regionally
different on the sensor. This introduces a structural spatial noise
component, called fixed pattern noise, although it’s not meant temporal,
visible with low illumination conditions. FPN is typically more
dominant with CMOS sensors than with CCD, where it can be ignored
mostly. This noise nfpn [%] is usually quantified in % of the mean dark
level. |
| Frame | An individual picture image taken by a digital camera. Using an interlaced camera, a frame consists of 2 interlaces fields. |
Frame Grabber
| A device that
interfaces with a camera and, on command, samples the video, converts
the sample to a digital value (if the framegrabber is analog instead of
digital) and stores that in a computer's memory. In contrast to Vision
Processor boards, which have complex image processing capabilities
(usually more than two functions), Frame grabbers have simple image
processing capabilities (usually two or less functions). |
Frame Rate
| Frame rate is the measure of camera speed. The unit of this measurement
is frames per second (fps) and is the number of images a camera can
capture in a second of time. Using area of interest (AOI) readout, the
rate can be increased. |
| Front Illumination |
|
Full Binning
| If horizontal and vertical binning are combined, every 4 pixels are
consolidated into a single pixel. At first, two horizontal pixels are
put together and then combined vertically. This increases light
sensitivity by a total of a factor of 4 and at the same time
signal-to-noise separation is improved by about 6 dB. Resolution is
reduced, depending on the model. See also: horizontal binning and
vertical binning |
