JP3542383B2

JP3542383B2 - Image reading device, image reading method, and imaging device

Info

Publication number: JP3542383B2
Application number: JP19707594A
Authority: JP
Inventors: 浩佐藤; 川井　　隆; 一仁大橋
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 1994-08-22
Filing date: 1994-08-22
Publication date: 2004-07-14
Anticipated expiration: 2019-07-14
Also published as: JPH0865455A

Description

【０００１】
【産業上の利用分野】
本発明は画像読み取り装置及び画像読み取り方法及び撮像装置に関し、特に画素内転送読み出し動作を行なうリニアイメージセンサを用いた画像読み取り装置及び画像読み取り方法に関するものである。
【０００２】
【従来の技術】
従来より、リニアイメージセンサを用いたカラー画像読み取り装置として、図５に示す構成のものが提案されている。
図５のカラー画像読み取り装置は、原稿台ガラス２１１上の原稿２１２を照明用光源２１０及び、反射笠２０９で照明し、原稿からの反射光を第１ミラー２０８、第２ミラー２０５、第３ミラー２０６及びレンズ２０２によりＣＣＤ（カラーリニアイメージセンサ）２０１の受光面上に結像させる構成となっている。また、図２において破線２０７で示される部分を図中矢印方向に速度Ｖで移動させ、破線２０３で示される部分を図中矢印方向に速度Ｖ／２で移動させることにより、原稿２１２全体の画像を、ＣＣＤ２０１に読み取らせるができる。
【０００３】
図６は、従来のカラー画像読み取り装置に使用されるＣＣＤリニアイメージセンサ２０１の構成例を示した図である。
図６において、３０１，３０２，３０３はそれぞれＲ，Ｇ，Ｂ各カラーフィルタを有する受光部である。この受光部には、光子を電荷（エレクトロン）に変換するためのダイオードが各画素ごとに配置されている。所定時間の受光およびそれにより生じた電荷はそれぞれＯＤＤ画素用のＣＣＤ転送部（電荷転送部）３０４,３０６,３０８およびＥＶＥＮ画素用のＣＣＤ転送部（電荷転送部）３０５,３０７,３０９に転送（シフト）される。ＣＣＤ転送部へ転送（シフト）された電荷は、受光部が次のラインの受光・蓄積を行なっている間に、ＣＣＤ転送部内で順次一定方向に向って転送され、アンプ３１０〜３１６により順次、電圧信号に変換されて出力される。
【０００４】
【発明が解決しようとする課題】
しかしながら、図６に示した様に、従来より使用されているカラーリニアイメージセンサは、Ｒ，Ｇ，Ｂ各受光部の間に電荷転送のためのＣＣＤ転送部を設けているため、図６に示す様にＲとＧの受光部の間隔及びＧとＢの受光部の間隔を大きく設定する必要があった。
【０００５】
受光部と受光部の間隔が広がると、読み取ったＲ，Ｇ，Ｂ信号に対しマスキング演算等の信号処理を行なう場合、Ｒ，Ｇ，Ｂの読み取り位置を補正するメモリが必要となるが、Ｒ，Ｇ，Ｂの間隔が大きい程必要となるメモリ容量も増えてしまうという問題点がある。
ところが最近、ＣＣＤ転送部を受光部に隣接させるのではなく、異なる色の受光部をはさんで配置させる構造が提案されている。
【０００６】
この場合、各色の受光部の間にＣＣＤ転送部を配置させる必要がないため、従来のセンサに比べ大幅にＲ，Ｇ，Ｂの受光部の間隔を小さくする事が可能になる。
しかし、その反面、受光・蓄積した電荷をＣＣＤ転送部へ転送（シフト）させるために、異なる色の受光部（画素）を経由する必要がある。いわゆる、この画素内転送を行なう場合、異なる色の受光部を通過する際にも、光が照射されているため、転送（シフト）時に、わずかではあるが、混色を引き起こすという問題点がある。
【０００７】
従って、本発明は上述した課題に鑑見てなされたものであり、その目的とするところは、電荷転送部を異なる色の受光部を挟んで配置したリニアイメージセンサを使用した場合でも、混色が生じにくい画像読み取り装置及び画像読み取り方法を提供することにある。
【０００８】
【課題を解決するための手段】
上述した課題を解決し、目的を達成するために、本発明に係わる画像読み取り装置は、被写体からの反射光を受光し電荷信号を生成する赤、緑、青のうちのそれぞれ異なる色に対応して順番に配列された第１、第２、第３の受光部と前記電荷信号を転送し出力する信号転送部とを有する撮像手段を備え、前記撮像手段と前記被写体とが相対的に移動されることによって前記第１、第２、第３の受光部の順に前記被写体からの反射光が結像され、前記第１の受光部に蓄積された電荷信号は前記第２、第３の受光部を経由して前記信号転送部へシフトされ、前記第２の受光部に蓄積された電荷信号は前記第３の受光部を経由して前記信号転送部へシフトされるとともに、前記第３の受光部に蓄積された電荷信号は前記第１、第２の受光部を経由せずに前記信号転送部へシフトされることを特徴としている。
【０００９】
また、本発明に係わる画像読み取り方法は、被写体からの反射光を受光し電荷信号を生成する赤、緑、青のうちのそれぞれ異なる色に対応して順番に配列された第１、第２、第３の受光部と前記電荷信号を転送し出力する信号転送部とを有する撮像手段により前記被写体画像を読み取る画像読み取り方法において、前記撮像手段と前記被写体とを相対的に移動させることによって前記第１、第２、第３の受光部の順に前記被写体からの反射光を結像させ、前記第１の受光部に蓄積された電荷信号を前記第２、第３の受光部を経由して前記信号転送部へシフトさせ、前記第２の受光部に蓄積された電荷信号を前記第３の受光部を経由して前記信号転送部へシフトさせるとともに前記第３の受光部に蓄積された電荷信号を前記第１、第２の受光部を経由せずに前記信号転送部へシフトさせることを特徴としている。
【００１０】
また、本発明に係わる撮像装置は、被写体からの反射光を受光し電荷信号を生成する赤、緑、青のうちのそれぞれ異なる色に対応して順番に配列された第１、第２、第３の受光部と前記電荷信号を転送し出力する信号転送部とを有する撮像装置であって、前記撮像手段と前記被写体とが相対的に移動されることによって前記第１、第２、第３の受光部の順に前記被写体からの反射光が結像され、前記第１の受光部に蓄積された電荷信号が前記第２、第３の受光部を経由して前記信号転送部へシフトされ、前記第２の受光部に蓄積された電荷信号が前記第３の受光部を経由して前記信号転送部へシフトされるとともに前記第３の受光部に蓄積された電荷信号が前記第１、第２の受光部を経由せずに前記信号転送部へシフトされることを特徴としている。
【００１２】
【作用】
以上のようにこの発明に係わる画像読み取り装置及び画像読み取り方法及び撮像装置は構成されているので、受光部で受光，蓄積された電荷信号を異なる色の受光部を経由して転送する場合に、電荷を転送する方向をリニアイメージセンサ上を画像情報が走査される副走査方向に一致させることにより、電荷を副走査方向と逆方向に転送する場合に比較して、混色する画像情報の位置が各色について接近することとなり、混色が画質の劣化に及ぼす影響を少なく抑えることができる。
【００１３】
【実施例】
以下、本発明の好適な実施例について、添付図面を参照して詳細に説明する。
（第１の実施例）
図１は、本発明の第１の実施例のカラー画像読み取り装置に使用されるＣＣＤリニアイメージセンサ２０１の構成例を示した図である。同図において、１０１，１０２，１０３はそれぞれＲ（赤），Ｇ（緑），Ｂ（青）の各カラーフィルタを有する受光部である。この受光部には、光子を電荷（エレクトロン）に変換するためのダイオードが各画素ごとに配置されている。このリニアイメージセンサは、従来のリニアイメージセンサと異なり、ＣＣＤ転送部を各受光部の間に配置していない為、受光部の間隔を狭くする事が可能である。図中、ＧとＲの受光部の間隔，ＲとＢの受光部の間隔は、受光系の画素の１辺の大きさをＡとしたとき、約２倍の２Ａの距離まで小さくすることが十分に実現可能である。従って、従来の様に各受光部間にＣＣＤ転送部を配置してリニアイメージセンサを構成した場合に比べて、受光部の間隔を狭く設定する事が可能であり、受光部の間隔に応じて必要となる読み取り位置補正用メモリ容量を減少させる事ができる。
【００１４】
さらに、第１の実施例の構成においては、受光部で受光、蓄積された電荷を異なる色の受光部を経由して転送する場合に、副走査方向に電荷を転送する方向を、リニアイメージセンサ上を画像情報が走査される方向に一致する様に設定している。図１においては、Ｒの受光部１０２で受光、蓄積された電荷は、Ｂの受光部１０３を経由してＣＣＤ転送部１０６，１０７に転送される。さらに転送された電荷はアンプ１１２，１１３を介して、Ｒ−ＯＤＤ出力，Ｒ−ＥＶＥＮ出力として出力される。この様に、この実施例においては、電荷の副走査方向への転送方向を図中上方から下方に、すなわちリニアイメージセンサ上を画像情報が走査されている方向Ｓに一致する様に設定している。
【００１５】
次に、異なる色の受光部を経由して電荷を転送する場合に、転送時にも光が照射されていることにより生ずる混色の影響が、画像走査方向と電荷転送方向により、どの様に表われるかを以下に説明する。
図２において、（ａ）に示す画像情報が副走査方向４０１に時間的に移動した場合を考える。画像情報は（ｂ）に示す受光部４０３，４０４，４０５の受光面に結合された状態で、副走査方向４０１に走査される。ここで紙面に垂直な方向が受光部（画素）の並び方向である主走査方向である。画像情報の先端４０９が時間的に副走査方向４０１に沿って移動した場合に、各受光部４０３，４０４，４０５に発生する電荷量の変化を（ｃ），（ｄ），（ｅ）に示す。画像情報がＲの受光部４０４上を走査したとき、斜線部４０７で示す部分の電荷が積分され蓄積されたとする。このとき、異なる色の受光部を経由して電荷を転送する方向を副走査方向４０１と逆方向である矢印４０２で示す方向に転送した場合を考える。Ｒの受光部４０４に蓄積された電荷は、Ｇの受光部４０３を経由して転送される。この時、Ｒの受光部４０４で一定期間の蓄積が終了した直後に転送が行なわれるから、Ｒの受光部４０４で蓄積された電荷がＧの受光部４０３を経由して転送される時に、混色される電荷は、斜線部４０６に示す電荷量の一部と考えられる。斜線部４０６の情報は、Ｒの受光部４０４に時間的に発生する電荷について考えると、斜線部４０８に相当するから、副走査方向４０１と転送方向４０２が逆の場合には、受光部Ｒ４０４に混色する情報は、時間的にＬ１だけ遅れた位置の画像情報である斜線部４０８に相当するＧの受光部４０２の電荷量の一部であることがわかる。
【００１６】
さらに、図３に示す様に、本実施例の場合である副走査方向５０１と転送方向５０２が同一の方向である場合について同様に考える。Ｒの受光部５０７に発生した電荷が、斜線部５０７の期間蓄積され転送されたとすると、混色される電荷は、Ｂの受光部５０５で発生する斜線部５０６の電荷である。斜線部５０６の情報は、Ｒの受光部５０４に時間的に発生する電荷について考えると、斜線部５０８に相当するから、受光部Ｒ５０４に混色する情報は、時間的にＬ２だけ進んだ位置の画像情報であることがわかる。ここで重要なのは、混色によって影響を受ける画像情報が、自らの受光部で読み取った画像情報に対して、どれだけ離れた位置の情報であるかということである。細線パターンの様に画像情報のコントラストの変化量が大きく、周期が短い場合には、特に混色の影響を受ける画像情報が自らの受光部で読み取った画像情報に近い位置の情報である程、電荷の混色の影響が少ない事は明白である。今、受光部の一辺の大きさをＡとし、受光部の副走査方向のピッチを２Ａとすると、先に述べた転送方向と副走査方向の違いによる混色する画像情報の位置は、
Ｌ１＝２．５Ａ
Ｌ２＝１．５Ａ
となる。
【００１７】
上記の値より明白な様に、画像情報がイメージセンサ上を副走査する方向は、異なる色を経由して電荷を転送する方向に一致している事が非常に有効である。（実施例２）
図４に示す様に、各色の受光部の間にＣＣＤ転送部を配置せず受光蓄積した電荷をＣＣＤ転送部へ転送（シフト）させるために異なる色の受光部（画素）を経由する場合に、ＣＣＤ転送部の位置が受光部に対して副走査方向の一方にまとまって配置している場合においても、電荷を転送する方向をリニアイメージセンサ上を画像情報が走査される方向に一致する様に設定することにより、実施例１と同様に電荷の混色の影響を低減化する事が可能である。
【００１８】
以上説明したように、上記の実施例によれば、受光部で受光、蓄積された電荷を異なる色の受光部を経由して転送する場合に、副走査方向に電荷を転送する方向をリニアイメージセンサ上を画像情報が走査される方向に一致する様な構成とすることにより、混色の影響を受ける画像情報が自らの受光部で読み取った画像情報に位置的に近い情報となり、混色の影響を低減化する事が可能である。
【００１９】
なお、本発明はその趣旨を逸脱しない範囲で、上記実施例を修正又は変形したものに適用可能である。
【００２０】
【発明の効果】
以上説明したように、本発明の画像読み取り装置及び画像読み取り方法及び撮像装置によれば、受光部で受光，蓄積された電荷信号を異なる色の受光部を経由して転送する場合に、電荷を転送する方向をリニアイメージセンサ上を画像情報が走査される副走査方向に一致させることにより、電荷を副走査方向と逆方向に転送する場合に比較して、混色する画像情報の位置が各色について接近することとなり、混色が画質の劣化に及ぼす影響を少なく抑えることができる。
【図面の簡単な説明】
【図１】本発明の第１の実施例のリニアイメージセンサの構成図である。
【図２】走査方向と転送方向が逆の場合の電荷の蓄積と混色を示す図である。
【図３】走査方向と転送方向が同じ場合の電荷の蓄積と混色を示す図である。
【図４】ＣＣＤ転送部を受光部に対して副走査方向の一方に配置したイメージセンサの構成図である。
【図５】リニアイメージセンサを用いたカラー画像読み取り装置を説明する図である。
【図６】従来のリニアイメージセンサの構成図である。
【符号の説明】
１０１Ｇの受光部
１０２Ｒの受光部
１０３Ｂの受光部
１０４，１０５，１０６，１０７，１０８，１０９ＣＣＤ転送部
１１０，１１１，１１２，１１３，１１４，１１５アンプ
Ａ画素の一辺
２０１ＣＣＤ
２０２レンズ
２０３破線部
２０５第２ミラー
２０６第３ミラー
２０７破線部
２０８第１ミラー
２０９反射笠
２１０光源
２１１原稿台ガラス
２１２原稿
３０１Ｒの受光部
３０２Ｇの受光部
３０３Ｂの受光部
３０４，３０５，３０６，３０７，３０８，３０９ＣＣＤ転送部
３１０，３１２，３１３，３１４，３１５，３１６アンプ
４０１，５０１副走査方向
４０２，５０２転送方向
４０３，５０３Ｇの受光部
４０４，５０４Ｒの受光部
４０５，５０５Ｂの受光部
４０６，５０６混色する電荷
４０７，５０７蓄積される電荷
４０８，５０８混色する電荷の位置
４０９，５０９画像情報の先端[0001]
[Industrial applications]
The present invention relates to an image reading device, an image reading method, and an imaging device, and more particularly to an image reading device and an image reading method using a linear image sensor that performs an intra-pixel transfer reading operation.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a color image reading apparatus using a linear image sensor, one having the configuration shown in FIG. 5 has been proposed.
5 illuminates a document 212 on a platen glass 211 with an illumination light source 210 and a reflection shade 209, and reflects light reflected from the document on a first mirror 208, a second mirror 205, and a third mirror. An image is formed on a light receiving surface of a CCD (color linear image sensor) 201 by a lens 206 and a lens 202. 2 is moved at a speed V in a direction indicated by an arrow in the figure, and a portion indicated by a broken line 203 is moved at a speed V / 2 in the direction indicated by an arrow in the figure. Can be read by the CCD 201.
[0003]
FIG. 6 is a diagram showing a configuration example of a CCD linear image sensor 201 used in a conventional color image reading device.
In FIG. 6, reference numerals 301, 302, and 303 denote light receiving units having R, G, and B color filters, respectively. In this light receiving section, a diode for converting photons into electric charges (electrons) is arranged for each pixel. The light reception for a predetermined time and the charges generated thereby are transferred to CCD transfer units (charge transfer units) 304, 306, 308 for ODD pixels and CCD transfer units (charge transfer units) 305, 307, 309 for EVEN pixels, respectively. Shift). The charges transferred (shifted) to the CCD transfer unit are sequentially transferred in a constant direction in the CCD transfer unit while the light receiving unit is receiving and storing the next line, and sequentially transferred by the amplifiers 310 to 316. It is converted into a voltage signal and output.
[0004]
[Problems to be solved by the invention]
However, as shown in FIG. 6, the conventionally used color linear image sensor has a CCD transfer unit for charge transfer between the R, G, and B light receiving units. As shown, the distance between the R and G light receiving sections and the distance between the G and B light receiving sections need to be set large.
[0005]
When the distance between the light receiving units is widened, when signal processing such as masking operation is performed on the read R, G, and B signals, a memory for correcting the reading positions of R, G, and B is required. , G and B, the larger the interval, the larger the required memory capacity.
However, recently, a structure has been proposed in which a CCD transfer unit is not adjacent to a light receiving unit, but is arranged with light receiving units of different colors interposed therebetween.
[0006]
In this case, since there is no need to arrange a CCD transfer unit between the light receiving units of each color, it is possible to greatly reduce the distance between the R, G, and B light receiving units as compared with the conventional sensor.
However, on the other hand, in order to transfer (shift) the received and accumulated charge to the CCD transfer unit, it is necessary to pass through a light receiving unit (pixel) of a different color. In the case of performing the so-called intra-pixel transfer, light is irradiated even when the light passes through a light-receiving portion of a different color, so that there is a problem that a slight color mixture is caused at the time of transfer (shift).
[0007]
Therefore, the present invention has been made in view of the above-described problem, and an object of the present invention is to achieve color mixing even when using a linear image sensor in which a charge transfer unit is interposed between light receiving units of different colors. An object of the present invention is to provide an image reading device and an image reading method that are unlikely to occur.
[0008]
[Means for Solving the Problems]
To solve the above problems and achieve the object, an image reading apparatus according to the present invention, red for generating a received light charge signals reflected light from the object, green, corresponding to different colors of blue Imaging means having first, second, and third light receiving sections arranged in order and a signal transfer section for transferring and outputting the charge signal, wherein the imaging means and the subject are relatively moved. As a result , the reflected light from the subject is imaged in the order of the first, second, and third light receiving sections, and the charge signal accumulated in the first light receiving section is the second, third light receiving section. The charge signal stored in the second light receiving unit is shifted to the signal transfer unit via the third light receiving unit via the third light receiving unit. The charge signal accumulated in the section passes through the first and second light receiving sections. It is characterized by being shifted to the signal transfer unit on.
[0009]
Further, the image reading method according to the present invention includes a first, a second, and a second array arranged in order corresponding to different colors among red, green, and blue, which receive reflected light from a subject and generate a charge signal. In an image reading method for reading the subject image by an imaging unit having a third light receiving unit and a signal transfer unit that transfers and outputs the charge signal, the image reading method includes moving the imaging unit and the subject relatively to each other . The reflected light from the subject is imaged in the order of the first, second, and third light receiving sections, and the charge signal accumulated in the first light receiving section is passed through the second and third light receiving sections. The charge signal stored in the third light receiving unit is shifted to the signal transfer unit, and the charge signal stored in the second light receiving unit is shifted to the signal transfer unit via the third light receiving unit. The first and second light receiving sections It is characterized by shifting to the signal transfer unit without passing through.
[0010]
Further, the imaging apparatus according to the present invention includes first, second, and second light-receiving elements arranged in order corresponding to different colors among red, green, and blue, which receive reflected light from a subject and generate a charge signal. 3. An image pickup apparatus comprising: a light receiving unit of No. 3; and a signal transfer unit for transferring and outputting the charge signal, wherein the first, second, and third objects are moved by relatively moving the image pickup unit and the subject . The reflected light from the subject is imaged in the order of the light receiving sections, and the charge signal accumulated in the first light receiving section is shifted to the signal transfer section via the second and third light receiving sections, The charge signal accumulated in the second light receiving section is shifted to the signal transfer section via the third light receiving section, and the charge signal accumulated in the third light receiving section is shifted to the first and second light receiving sections. characterized in that it is shifted to the signal transfer unit without passing through the second light receiving portion There.
[0012]
[Action]
As described above, since the image reading device, the image reading method, and the imaging device according to the present invention are configured, when transferring the charge signals received and accumulated by the light receiving unit via the light receiving units of different colors, By making the transfer direction of the electric charges coincide with the sub-scanning direction in which the image information is scanned on the linear image sensor, the position of the image information to be mixed is compared with the case where the electric charges are transferred in the opposite direction to the sub-scanning direction. Since the colors approach each other, the influence of the color mixture on the deterioration of the image quality can be reduced.
[0013]
【Example】
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of a CCD linear image sensor 201 used in a color image reading device according to a first embodiment of the present invention. In FIG. 1, reference numerals 101, 102, and 103 denote light receiving units having R (red), G (green), and B (blue) color filters, respectively. In this light receiving section, a diode for converting photons into electric charges (electrons) is arranged for each pixel. Unlike the conventional linear image sensor, the linear image sensor does not include a CCD transfer unit between the light receiving units, so that the interval between the light receiving units can be reduced. In the figure, the distance between the light receiving portions of G and R, and the distance between the light receiving portions of R and B can be reduced to about 2 times the distance of 2 A, where A is the size of one side of the pixel of the light receiving system. It is fully feasible. Therefore, it is possible to set the interval between the light receiving sections to be narrower than when a linear image sensor is configured by arranging a CCD transfer section between the respective light receiving sections as in the related art. The required read position correction memory capacity can be reduced.
[0014]
Further, in the configuration of the first embodiment, when the electric charge received and accumulated by the light receiving unit is transferred through the light receiving unit of a different color, the direction in which the electric charge is transferred in the sub-scanning direction is determined by a linear image sensor. The upper part is set to match the direction in which the image information is scanned. In FIG. 1, the charges received and accumulated by the R light receiving unit 102 are transferred to the CCD transfer units 106 and 107 via the B light receiving unit 103. Further, the transferred charges are output as R-ODD output and R-EVEN output via the amplifiers 112 and 113. As described above, in this embodiment, the transfer direction of the charges in the sub-scanning direction is set from the upper side to the lower side in the drawing, that is, the direction of the image information is scanned on the linear image sensor. I have.
[0015]
Next, in the case where charges are transferred via light receiving units of different colors, how the effect of color mixing caused by light irradiation during transfer also appears depending on the image scanning direction and the charge transfer direction. This will be described below.
In FIG. 2, a case is considered where the image information shown in (a) temporally moves in the sub-scanning direction 401. The image information is scanned in the sub-scanning direction 401 while being combined with the light receiving surfaces of the light receiving units 403, 404, and 405 shown in FIG. Here, the direction perpendicular to the paper surface is the main scanning direction, which is the direction in which the light receiving units (pixels) are arranged. (C), (d), and (e) show changes in the amount of charge generated in each of the light receiving units 403, 404, and 405 when the leading end 409 of the image information temporally moves along the sub-scanning direction 401. . It is assumed that, when the image information scans the light receiving section 404 of R, the electric charge of the portion indicated by the hatched portion 407 is integrated and accumulated. At this time, it is assumed that the direction in which the charges are transferred via the light receiving units of different colors is transferred in a direction indicated by an arrow 402 which is opposite to the sub-scanning direction 401. The charges accumulated in the R light receiving unit 404 are transferred via the G light receiving unit 403. At this time, since the transfer is performed immediately after the accumulation for a certain period in the R light receiving unit 404 is completed, when the charge accumulated in the R light receiving unit 404 is transferred via the G light receiving unit 403, the color mixing is performed. It is considered that the generated charge is a part of the charge amount indicated by the shaded portion 406. The information of the hatched portion 406 corresponds to the hatched portion 408 in consideration of the charge generated temporally in the light receiving portion 404 of R. Therefore, when the sub-scanning direction 401 and the transfer direction 402 are opposite, the information of the hatched portion 404 It can be seen that the information to be mixed is a part of the charge amount of the G light receiving unit 402 corresponding to the shaded portion 408 which is the image information of the position delayed by L1 in time.
[0016]
Further, as shown in FIG. 3, the case where the sub-scanning direction 501 and the transfer direction 502 in the present embodiment are the same is considered in the same manner. Assuming that the charges generated in the light receiving portion 507 of R are accumulated and transferred during the period of the shaded portion 507, the charges to be mixed are the charges of the shaded portion 506 generated in the light receiving portion 505 of B. The information in the shaded area 506 corresponds to the shaded area 508 when considering the charges generated in the R light receiving section 504 with time, so the information mixed in the light receiving section R 504 is the image at the position advanced by L2 in time. It turns out to be information. What is important here is how far the image information affected by the color mixture is from the image information read by its own light receiving unit. In the case where the amount of change in the contrast of the image information is large and the cycle is short like a thin line pattern, the more the image information affected by the color mixture is the information closer to the image information read by its own light receiving unit, the more the charge It is clear that the effect of color mixing is small. Now, assuming that the size of one side of the light receiving unit is A and the pitch of the light receiving unit in the sub-scanning direction is 2A, the position of the image information to be mixed due to the difference between the transfer direction and the sub-scanning direction is as follows.
L1 = 2.5A
L2 = 1.5A
It becomes.
[0017]
As is clear from the above values, it is very effective that the direction in which the image information is sub-scanned on the image sensor coincides with the direction in which charges are transferred via different colors. (Example 2)
As shown in FIG. 4, when the CCD transfer unit is not arranged between the light-receiving units of the respective colors, and the electric charges accumulated and received through the light-receiving units (pixels) of different colors to transfer (shift) to the CCD transfer unit. Even in the case where the position of the CCD transfer unit is arranged in one direction in the sub-scanning direction with respect to the light receiving unit, the direction in which the charge is transferred should match the direction in which image information is scanned on the linear image sensor. The effect of color mixing of charges can be reduced as in the first embodiment.
[0018]
As described above, according to the above-described embodiment, when the charges received and accumulated by the light receiving unit are transferred via the light receiving units of different colors, the direction in which the charges are transferred in the sub-scanning direction is a linear image. By configuring the sensor to match the direction in which the image information is scanned, the image information affected by the color mixture becomes information that is close in position to the image information read by its own light receiving unit, and the effect of the color mixture is reduced. It is possible to reduce it.
[0019]
Note that the present invention can be applied to a modification or modification of the above embodiment without departing from the spirit thereof.
[0020]
【The invention's effect】
As described above, according to the image reading device, the image reading method, and the imaging device of the present invention, when transferring the charge signal received and accumulated by the light receiving unit via the light receiving unit of a different color, the charge is transferred. By making the transfer direction coincide with the sub-scanning direction in which the image information is scanned on the linear image sensor, the position of the image information to be mixed is different for each color as compared with the case where charges are transferred in the reverse direction to the sub-scanning direction. As a result, the influence of the color mixture on the deterioration of the image quality can be reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a linear image sensor according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating charge accumulation and color mixing when the scanning direction and the transfer direction are opposite.
FIG. 3 is a diagram illustrating charge accumulation and color mixing when the scanning direction and the transfer direction are the same.
FIG. 4 is a configuration diagram of an image sensor in which a CCD transfer unit is arranged on one side in a sub-scanning direction with respect to a light receiving unit.
FIG. 5 is a diagram illustrating a color image reading device using a linear image sensor.
FIG. 6 is a configuration diagram of a conventional linear image sensor.
[Explanation of symbols]
101G light receiving section 102R light receiving section 103B light receiving section 104, 105, 106, 107, 108, 109 CCD transfer section 110, 111, 112, 113, 114, 115 Amplifier A One side 201 CCD of pixel
202 Lens 203 Broken line portion 205 Second mirror 206 Third mirror 207 Broken line portion 208 First mirror 209 Reflecting shade 210 Light source 211 Platen glass 212 Document 301 R Light receiving portion 302 G Light receiving portion 303 B Light receiving portions 304 and 305, 306, 307, 308, 309 CCD transfer units 310, 312, 313, 314, 315, 316 Amplifiers 401, 501 Sub-scanning directions 402, 502 Transfer directions 403, 503 Light receiving units 404, 504 G Light receiving units 405, 505 R B light receiving portion 406, 506 Mixed charge 407, 507 Accumulated charge 408, 508 Position of mixed charge 409, 509 Top of image information

Claims

Transfer red to generate a received light charge signals reflected light from the object, green, first arranged in the order corresponding to the different colors of blue, the second, the charge signal and the third light receiving portion Imaging means having a signal transfer unit for performing and outputting
When the imaging unit and the subject are relatively moved, reflected light from the subject is imaged in the order of the first, second, and third light receiving units ,
The charge signal stored in the first light receiving portion is shifted to the signal transfer portion via the second and third light receiving portions, and the charge signal stored in the second light receiving portion is shifted to the third light receiving portion. And the charge signal accumulated in the third light receiving unit is shifted to the signal transfer unit without passing through the first and second light receiving units. An image reading device characterized by being performed .

The image reading device according to claim 1, wherein the first, second, and third light receiving units include color filters corresponding to different colors.

The first, second, and third light receiving portions are formed in a line in the main scanning direction in which the charge signal is transferred by the signal transfer portion, and the subject image is formed by the first, second, and third light receiving portions. The image reading apparatus according to claim 1, wherein the imaging unit and the subject are relatively moved in a sub-scanning direction in which the image is scanned.

Transfer red to generate a received light charge signals reflected light from the object, green, first arranged in the order corresponding to the different colors of blue, the second, the charge signal and the third light receiving portion An image reading method for reading the subject image by an imaging unit having a signal transfer unit for performing and outputting
By relatively moving the imaging means and the subject, the reflected light from the subject is imaged in the order of the first, second, and third light receiving sections, and the reflected light is accumulated in the first light receiving section. The charge signal is shifted to the signal transfer section via the second and third light receiving sections, and the charge signal accumulated in the second light receiving section is transferred to the signal transfer section via the third light receiving section. An image reading method wherein the charge signal stored in the third light receiving unit is shifted to the signal transfer unit without passing through the first and second light receiving units .

The image reading method according to claim 4 , wherein the first, second, and third light receiving units include color filters corresponding to different colors.

The first, second, and third light receiving portions are formed in a line in the main scanning direction in which the charge signal is transferred by the signal transfer portion, and the subject image is formed by the first, second, and third light receiving portions. The image reading method according to claim 4 , wherein the imaging unit and the subject are relatively moved in a sub-scanning direction in which a light receiving unit is scanned.

Transfer red to generate a received light charge signals reflected light from the object, green, first arranged in the order corresponding to the different colors of blue, the second, the charge signal and the third light receiving portion An image pickup apparatus having a signal transfer unit for outputting and outputting
The relative movement between the imaging means and the subject forms reflected light from the subject in the order of the first, second, and third light receiving units, and the reflected light from the subject is accumulated in the first light receiving unit. The transferred charge signal is shifted to the signal transfer section via the second and third light receiving sections, and the charge signal stored in the second light receiving section is shifted to the signal via the third light receiving section. An image pickup apparatus , wherein a charge signal shifted to a transfer unit and stored in the third light receiving unit is shifted to the signal transfer unit without passing through the first and second light receiving units.

The imaging apparatus according to claim 7 , wherein the first, second, and third light receiving units include color filters corresponding to different colors.

The first, second, and third light receiving portions are formed in a line in the main scanning direction in which the charge signal is transferred by the signal transfer portion, and the subject image is formed by the first, second, and third light receiving portions. The imaging apparatus according to claim 7 , wherein the imaging unit and the subject are relatively moved in a sub-scanning direction for scanning a light receiving unit.