JPS62141283U

JPS62141283U -

Info

Publication number: JPS62141283U
Application number: JP2891286U
Authority: JP
Priority date: 1986-02-27
Filing date: 1986-02-27
Publication date: 1987-09-05
Anticipated expiration: 2001-02-27
Also published as: JP2512665Y2

Description

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本考案の一実施例に係る回路図、第２
図は他の実施例の要部の回路図、第３図は従来例
の回路図、第４図は他の従来例の回路図である。１は入射光、４は撮像素子、５は色分離回路、
６は輝度信号用ローパスフイルタ、７は赤色信号
利得制御回路、８は青色信号利得制御回路、９，
１０は混合回路、１１はカラーエンコーダ、１３
，１５は平均値回路、１４，１６は誤差増幅器、
１７は微分回路、１８は検波回路、１９，２０は
利得制御信号の保持回路、２１は水平方向エツジ
検出回路、２２はエツジ検出信号平均化回路、２
３は直流電圧増幅器、２４は基準電圧発生出力回
路、２５は比較回路。 Fig. 1 is a circuit diagram according to an embodiment of the present invention;
The figures are circuit diagrams of main parts of another embodiment, FIG. 3 is a circuit diagram of a conventional example, and FIG. 4 is a circuit diagram of another conventional example. 1 is incident light, 4 is an image sensor, 5 is a color separation circuit,
6 is a luminance signal low-pass filter, 7 is a red signal gain control circuit, 8 is a blue signal gain control circuit, 9,
10 is a mixing circuit, 11 is a color encoder, 13
, 15 is an average value circuit, 14 and 16 are error amplifiers,
17 is a differentiation circuit, 18 is a detection circuit, 19 and 20 are gain control signal holding circuits, 21 is a horizontal edge detection circuit, 22 is an edge detection signal averaging circuit, 2
3 is a DC voltage amplifier, 24 is a reference voltage generation output circuit, and 25 is a comparison circuit.

Claims

【実用新案登録請求の範囲】赤色信号利得制御回路と、青色信号利得制御回
路と、前記赤色信号利得制御回路からの赤色信号
と輝度信号とを混合して両信号の第１色差信号を
出力する第１混合回路と、前記青色信号利得制御
回路からの青色信号と輝度信号とを混合して両信
号の第２色差信号を出力する第２混合回路と、前
記各色差信号それぞれの平均値を出力する第１、
第２平均値回路と、前記両平均値回路それぞれの
出力を誤差増幅する第１、第２誤差増幅器と、前
記両誤差増幅器それぞれの出力を、対応する前記
赤色信号利得制御回路と青色信号利得制御回路と
に与えてホワイトバランス制御を行うビデオカメ
ラのオートホワイトバランス回路において、被写体が単色体またはこれに近いものであると
きは輝度信号の第１変化成分を検出出力し、また
被写体が非単色体であるときは輝度信号の第２変
化成分を検出出力する検出手段と、前記各誤差増幅器それぞれと前記利得制御回路
それぞれとの間に設けられ、かつ前記検出手段か
ら第１変化成分が与えられるときは前記誤差増幅
器それぞれからの利得制御信号の保持動作を行い
、また前記検出手段から第２変化成分が与えられ
るときは各利得制御信号の保持動作不能となる第
１、第２保持回路とを具備してなるビデオカメラ
のオートホワイトバランス回路。[Claims for Utility Model Registration] A red signal gain control circuit, a blue signal gain control circuit, and a red signal and a luminance signal from the red signal gain control circuit are mixed to output a first color difference signal of both signals. a first mixing circuit; a second mixing circuit that mixes the blue signal and the luminance signal from the blue signal gain control circuit and outputs a second color difference signal of both signals; and outputs an average value of each of the color difference signals. The first thing to do is
A second average value circuit, first and second error amplifiers for error amplifying the respective outputs of the two average value circuits, and the respective outputs of the two error amplifiers are connected to the corresponding red signal gain control circuit and the blue signal gain control circuit. In the auto white balance circuit of a video camera, which performs white balance control based on the circuit, the first change component of the luminance signal is detected and output when the subject is a monochromatic object or something close to this, and when the subject is a non-monochromatic object. When the detection means detects and outputs the second change component of the luminance signal, and is provided between each of the error amplifiers and each of the gain control circuits, and when the first change component is provided from the detection means. comprises first and second holding circuits that hold the gain control signals from each of the error amplifiers, and are incapable of holding each gain control signal when a second change component is applied from the detection means. Auto white balance circuit for video cameras.