摘要:
The invention relates to an image sensor system which includes an image sensor (CCD). The image from the image sensor is read out as a video signal. In addition to image values, the video signal also contains electrical and optical black noise. Such noises should be removed from the video signal. A value corresponding to the electrical black noise can be obtained from the image sensor by reading out same additional pixel values which does not originate from image pixels. By subtracting this value from the video signal, a clamped video signal is obtained in which the electrical black noise has been reduced or removed. Additionally, by subtracting the electric block noise value, it is achieved that the clamped video signal is not clipped in the analogue-to-digital converter. The optical black noise may be removed from the signal outputted by the ADC.
摘要:
The invention relates to an image sensor system which includes an image sensor (CCD). The image from the image sensor is read out as a video signal. In addition to image values, the video signal also contains electrical and optical black noise. Such noises should be removed from the video signal. A value corresponding to the electrical black noise can be obtained from the image sensor by reading out same additional pixel values which does not originate from image pixels. By subtracting this value from the video signal, a clamped video signal is obtained in which the electrical black noise has been reduced or removed. Additionally, by subtracting the electric block noise value, it is achieved that the clamped video signal is not clipped in the analogue-to-digital converter. The optical black noise may be removed from the signal outputted by the ADC.
摘要:
Etage d'entrée pour un récepteur vidéo comportant un amplificateur à gain variable, un convertisseur analogique-numérique destiné à prélever des échantillons du signal vidéo et une unité de traitement numérique destiné à traiter les échantillons numériques de ce signal vidéo. L'étage d'entrée est caractérisé en ce qu'un circuit de régulation analogique fixe le potentiel d'entrée à l'entrée de l'amplificateur à gain variable. Préférentiellement, on utilise une architecture différentielle pour l'amplificateur à gain variable et pour le convertisseur analogique numérique. On intercale à cet effet, entre le condensateur de liaison et l'amplificateur à gain variable, un circuit de conversion permettant de générer le signal vidéo sur deux voies en opposition de phase, lesquelles sont centrées sur le potentiel de mode commun. L'architecture différentielle permet de réduire la course des signaux analogiques, se qui se révèle particulièrement avantageux dans le cas d'une tension d'alimentation basse de quelques volts. De surcroît, on améliore alors la linéarité du traitement du signal vidéo.
摘要:
A digital control technique for automatically obtaining lock on an analog video signal, and identifying the sync tip and back porch levels, by adjusting gain and offset. Pixel samples for each scan line are obtained from the output of an analog-to-digital converter (112) and fed back to a microprocessor (120) running a control program which provides digital control of gain and offset. After gain and offset are adjusted to obtain lock, a fine adjustment mode is entered during which gain and offset are adjusted to obtain the desired sync tip height and back porch levels.
摘要:
La présente invention concerne un dispositif (AAM) d'acquisition et d'amplification de signaux électroniques, comprenant :
. un module d'acquisition (T/H) recevant un signal d'entrée (ES) à mémoriser, . un amplificateur (A1) pour amplifier le signal mémorisé, et ayant un gain variant en fonction d'un signal de contrôle de gain (GC).
Selon l'invention, deux boucles de régulation distinctes (A2, CMP1, OM1) et (CMP2, OM2) permettent de compenser des composantes continues parasites introduites par le module d'acquisition (T/H), d'une part, et par l'amplificateur (A1), d'autre part. Applications : acquisition et amplification de signaux dans une caméra CCD.
摘要:
An apparatus having a selectable first mode of operation for clamping an input signal to a first reference level and a selectable second mode of operation for clamping a signal derived from said input signal to a second reference level.
摘要:
In a video sync tip clamp circuit having a section (A) defining an input voltage and a section (B) defining a reference voltage there is provided a feedback section (C) interconnecting the input and reference sections and operating to maintain the input voltage at substantially the same level as the reference voltage.
摘要:
A video signal clamp involves evaluating (310) the difference between the signal level (VIDEO_IN) and the desired clamp level (CLAMP LEVEL) during the back porch interval. A correction signal (CHARGE_x) indicates whether the signal level must be increased or decreased to establish the desired clamp level. Generation of the correction signal involves a median filter algorithm (330-350). Any required increase or decrease of the signal level occurs continuously throughout each horizontal line interval.