JP7455589B2 - Imaging device and defective pixel detection method - Google Patents
Imaging device and defective pixel detection method Download PDFInfo
- Publication number
- JP7455589B2 JP7455589B2 JP2020006114A JP2020006114A JP7455589B2 JP 7455589 B2 JP7455589 B2 JP 7455589B2 JP 2020006114 A JP2020006114 A JP 2020006114A JP 2020006114 A JP2020006114 A JP 2020006114A JP 7455589 B2 JP7455589 B2 JP 7455589B2
- Authority
- JP
- Japan
- Prior art keywords
- defective pixel
- temperature
- image sensor
- defective
- pixel detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000002950 deficient Effects 0.000 title claims description 151
- 238000001514 detection method Methods 0.000 title claims description 93
- 238000003384 imaging method Methods 0.000 title claims description 30
- 238000000034 method Methods 0.000 claims description 17
- 230000007547 defect Effects 0.000 claims description 16
- 238000003860 storage Methods 0.000 claims description 11
- 239000011159 matrix material Substances 0.000 claims description 5
- 238000010586 diagram Methods 0.000 description 6
- 230000003287 optical effect Effects 0.000 description 5
- 238000004140 cleaning Methods 0.000 description 4
- 230000007704 transition Effects 0.000 description 4
- 230000006870 function Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Landscapes
- Transforming Light Signals Into Electric Signals (AREA)
Description
本発明は、撮像装置、および欠陥画素の検出方法に関する。 The present invention relates to an imaging device and a method for detecting defective pixels.
従来、撮像装置には複数の画素が行列状に配置された撮像素子が搭載されており、複数の画素には通常、正常に動作しない欠陥画素が含まれる。撮像装置の製造工程では、所定の条件下における出力値が所定値より大きい画素を欠陥画素として検出する。また、撮像装置の出荷後では、黒レベル調整やセンサークリーニング実施時に、出力値が所定値より大きい画素を欠陥画素として検出する。欠陥画素の出力値を欠陥画素の周辺の正常画素の出力値を用いた補間演算処理により補正することで、画質劣化を抑えることができる。特許文献１には、温度に応じて出力値が変化する欠陥画素を適切に検出するために、温度に応じて欠陥画素を検出する際の所定値を変化させる撮像装置が開示されている。 2. Description of the Related Art Conventionally, an imaging device is equipped with an imaging element in which a plurality of pixels are arranged in a matrix, and the plurality of pixels usually includes a defective pixel that does not operate normally. In the manufacturing process of an imaging device, a pixel whose output value is larger than a predetermined value under predetermined conditions is detected as a defective pixel. Further, after the imaging device is shipped, pixels whose output value is larger than a predetermined value are detected as defective pixels when adjusting the black level or performing sensor cleaning. Image quality deterioration can be suppressed by correcting the output value of a defective pixel through interpolation processing using the output values of normal pixels surrounding the defective pixel. Patent Document 1 discloses an imaging device that changes a predetermined value when detecting a defective pixel depending on the temperature in order to appropriately detect a defective pixel whose output value changes depending on the temperature.
監視カメラや車載カメラのように屋外で固定で使用するカメラは非常に高温となる可能性が高い。撮像素子には様々なノイズが発生するが、その中には撮像素子の温度に依存してノイズレベルが増大するものがある。特許文献１の撮像装置は、撮像素子の温度が高温である場合にノイズレベルが欠陥画素の出力値を上回るため、欠陥画素を適切に検出することができない。 Cameras that are used fixedly outdoors, such as surveillance cameras and vehicle-mounted cameras, are likely to become extremely hot. Various types of noise are generated in an image sensor, and some of them increase in noise level depending on the temperature of the image sensor. The imaging device of Patent Document 1 cannot appropriately detect defective pixels because the noise level exceeds the output value of the defective pixel when the temperature of the image sensor is high.
本発明は、撮像素子の温度が高温である場合に欠陥画素の誤検出を抑制可能な撮像装置、および欠陥画素の検出方法を提供することができる。 INDUSTRIAL APPLICATION This invention can provide the imaging device which can suppress false detection of a defective pixel when the temperature of an image sensor is high temperature, and the detection method of a defective pixel.
本発明の一側面としての撮像装置は、複数の画素が行列状に配置された撮像素子と、撮像素子の温度を検出する温度検出部と、記憶部と、出力値が所定値より大きい画素を欠陥画素として検出すると共に、検出した欠陥画素を記憶部に書き込む欠陥画素検出部とを有し、欠陥画素検出部は、撮像素子の温度が第１の温度より低い場合、所定値を欠陥画素が検出可能である範囲で撮像素子の温度に対応した値に変更し、撮像素子の温度が前記第１の温度より高い場合、所定値を欠陥画素が検出不可能となる値に設定することを特徴とする。 An imaging device according to one aspect of the present invention includes an imaging device in which a plurality of pixels are arranged in a matrix, a temperature detection section that detects the temperature of the imaging device, a storage section, and a pixel whose output value is larger than a predetermined value. The defective pixel detection unit detects the defective pixel as a defective pixel and writes the detected defective pixel into a storage unit, and the defective pixel detection unit sets a predetermined value to the defective pixel when the temperature of the image sensor is lower than the first temperature. The defective pixel is changed to a value corresponding to the temperature of the image sensor within a detectable range , and when the temperature of the image sensor is higher than the first temperature, the predetermined value is set to a value that makes it impossible to detect the defective pixel. shall be.
本発明によれば、撮像素子の温度が高温である場合に欠陥画素の誤検出を抑制可能な撮像装置、および欠陥画素の検出方法を提供することができる。 According to the present invention, it is possible to provide an imaging device and a method for detecting defective pixels that can suppress false detection of defective pixels when the temperature of the image sensor is high.
以下、本発明の実施例について、図面を参照しながら詳細に説明する。各図において、同一の部材については同一の参照番号を付し、重複する説明は省略する。
［第１の実施形態］
図１は、本実施形態の撮像装置のブロック図である。撮像装置は、光学系１０１、撮像素子１０２、駆動回路部１０３、信号処理部１０４、メモリ（記憶部）１０５、画像表示部１０６、画像記録部１０７、操作部１０８、およびシステム制御部１０９を有する。
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same reference numerals are given to the same members, and duplicate explanations will be omitted.
[First embodiment]
FIG. 1 is a block diagram of an imaging device according to this embodiment. The imaging device includes an optical system 101, an image sensor 102, a drive circuit section 103, a signal processing section 104, a memory (storage section) 105, an image display section 106, an image recording section 107, an operation section 108, and a system control section 109. .
光学系１０１は、被写体像を撮像素子１０２に結像させる合焦レンズ、光学ズームを行うズームレンズ、被写体像の明るさを調整する絞り、および露光を制御するシャッタを有する。 The optical system 101 includes a focusing lens that forms a subject image on the image sensor 102, a zoom lens that performs optical zoom, an aperture that adjusts the brightness of the subject image, and a shutter that controls exposure.
撮像素子１０２は、行列状に配置され、それぞれが光電変換素子を備える複数の画素、および複数の画素から読み出された信号を所定の順番で出力する回路を有する。温度検出部１１２は、撮像素子１０２内、又は撮像素子１０２が配置される基板上で撮像素子１０２の近傍に配置され、撮像素子１０２の温度（以下、撮像素子温度）を検出する。なお、撮像素子温度は、撮像素子１０２の温度に対応する温度であればよく、例えば撮像素子１０２の周辺温度であってもよい。 The image sensor 102 includes a plurality of pixels arranged in a matrix, each including a photoelectric conversion element, and a circuit that outputs signals read from the plurality of pixels in a predetermined order. The temperature detection unit 112 is disposed within the image sensor 102 or near the image sensor 102 on a substrate on which the image sensor 102 is arranged, and detects the temperature of the image sensor 102 (hereinafter referred to as image sensor temperature). Note that the image sensor temperature may be any temperature that corresponds to the temperature of the image sensor 102, and may be the ambient temperature of the image sensor 102, for example.
駆動回路部１０３は、システム制御部１０９からの制御信号により制御され、定電圧やドライブ能力を強化させたパルスを供給することで、光学系１０１および撮像素子１０２を動作させる。 The drive circuit section 103 is controlled by a control signal from the system control section 109, and operates the optical system 101 and the image sensor 102 by supplying a constant voltage or a pulse with enhanced drive capability.
信号処理部１０４は、システム制御部１０９からの制御信号により制御され、撮像素子１０２の出力信号に対して処理を行う。また、信号処理部１０４は、撮像素子１０２の出力信号から合焦状態や露光量等の測光データを検出すると共に、検出したデータをシステム制御部１０９に送信する。また、信号処理部１０４は、欠陥画素検出部１１１ａおよび補正部１１１ｂを備え、これらを用いて欠陥画素の補正処理を行う。また、信号処理部１０４は、メモリ１０５や画像記録部１０７に対してデジタル信号に変換された撮像素子１０２の出力信号や画像データを出力する。また、信号処理部１０４は、メモリ１０５や画像記録部１０７から取得した画像データに対して処理を行う。 The signal processing unit 104 is controlled by a control signal from the system control unit 109 and processes the output signal of the image sensor 102. Further, the signal processing unit 104 detects photometric data such as a focus state and exposure amount from the output signal of the image sensor 102, and transmits the detected data to the system control unit 109. Further, the signal processing unit 104 includes a defective pixel detection unit 111a and a correction unit 111b, and uses these to perform correction processing for defective pixels. Further, the signal processing unit 104 outputs the output signal and image data of the image sensor 102 that have been converted into digital signals to the memory 105 and the image recording unit 107. Further, the signal processing unit 104 processes image data acquired from the memory 105 and the image recording unit 107.
メモリ１０５は、システム制御部１０９からの制御信号により制御され、デジタル信号に変換された撮像素子１０２の出力信号や画像データを記憶する。また、メモリ１０５は、表示用の画像データを画像表示部１０６に出力する。また、メモリ１０５は、後述する欠陥画素が検出不可能となる欠陥画素検出限界温度を記憶する。 The memory 105 is controlled by a control signal from the system control unit 109 and stores the output signal of the image sensor 102 and image data that have been converted into digital signals. The memory 105 also outputs image data for display to the image display unit 106. The memory 105 also stores a defective pixel detection limit temperature at which a defective pixel cannot be detected, which will be described later.
画像表示部１０６は、システム制御部１０９からの制御信号により制御され、メモリ１０５が記憶している表示用の画像データを、撮影前の構図決めや撮影後の画像の確認を行うために表示する。画像表示部１０６は例えば、電子ビューファインダー（ＥＶＦ）や液晶ディスプレイ（ＬＣＤ）で構成される。 The image display unit 106 is controlled by a control signal from the system control unit 109, and displays image data for display stored in the memory 105 for determining the composition before shooting and checking the image after shooting. . The image display unit 106 includes, for example, an electronic viewfinder (EVF) or a liquid crystal display (LCD).
画像記録部１０７は、着脱可能なメモリ等を備え、システム制御部１０９からの制御信号により制御される。画像記録部１０７は、デジタル信号に変換された撮像素子１０２の出力信号や画像データの記録、および着脱可能なメモリからの読み出しを行う。 The image recording unit 107 includes a removable memory and the like, and is controlled by control signals from the system control unit 109. The image recording unit 107 records output signals and image data of the image sensor 102 that have been converted into digital signals, and reads them from a removable memory.
操作部１０８は、スイッチや押しボタン等の操作部材を備え、操作部材の操作による指示、例えば、電源のＯＮ／ＯＦＦの指示、撮影前の画像表示の指示、撮影の各種指示をシステム制御部１０９に伝達する。また、操作部１０８は、ＬＣＤやフォトダイオード等の表示部材を備え、操作部１０８の表示部材又は画像表示部１０６を用いて、システム制御部１０９からの制御信号により撮像装置の状態を表示することができる。なお、操作部１０８を用いることなく、画像表示部１０６に装着したタッチパネルを用いて、オンスクリーンでの操作を行ってもよい。 The operation unit 108 includes operation members such as switches and push buttons, and transmits instructions by operating the operation members, such as instructions to turn the power on/off, instructions to display an image before shooting, and various shooting instructions, to the system control unit 109. The operation unit 108 also includes a display member such as an LCD or a photodiode, and can display the state of the imaging device using a control signal from the system control unit 109, using the display member of the operation unit 108 or the image display unit 106. Note that on-screen operations may be performed using a touch panel attached to the image display unit 106, without using the operation unit 108.
システム制御部１０９は、操作部１０８から伝達された指示により、撮像装置全体を制御する。また、システム制御部１０９は、信号処理部１０４から送られてくる合焦状態や露光量等の測光データに応じて光学系１０１を制御して、最適な被写体像を撮像素子１０２に結像させる。また、システム制御部１０９は、メモリ１０５や画像記録部１０７の着脱可能なメモリの使用状況を検出することができる。 The system control unit 109 controls the entire imaging apparatus based on instructions transmitted from the operation unit 108. Furthermore, the system control unit 109 controls the optical system 101 according to photometric data such as the focus state and exposure amount sent from the signal processing unit 104 to form an optimal subject image on the image sensor 102. . Furthermore, the system control unit 109 can detect the usage status of the memory 105 and the removable memory of the image recording unit 107.
以下、本実施形態の静止画撮影を行う際の欠陥画素の補正処理について説明する。欠陥原因が例えば白キズである場合、出力値が異常に高い欠陥画素が現れる。この場合、欠陥画素検出部１１１ａは、例えば工場出荷前に異常な出力値であるかどうか（出力値が欠陥画素検出閾値（所定値）より大きいかどうか）を判断することで欠陥画素を検出する。また、欠陥画素検出部１１１ａは、遮光時（暗時）に顕著に表れる欠陥画素、例えば暗時白キズや暗時黒キズ等の欠陥原因により現れる欠陥画素を、出荷後のブラックバランス調整時やセンサークリーニング実行時に合わせて検出する。また、欠陥画素検出部１１１ａは、遮光時以外（明時）では、撮影中に欠陥画素を検出する場合もある。検出された欠陥画素は、メモリ１０５に保存される。補正部１１１ｂは、欠陥画素の出力値を欠陥画素の周辺の正常画素の出力値を用いた補間演算処理により補正する。 Hereinafter, a process for correcting defective pixels when photographing a still image according to the present embodiment will be described. If the cause of the defect is, for example, a white scratch, a defective pixel with an abnormally high output value will appear. In this case, the defective pixel detection unit 111a detects the defective pixel by determining, for example, whether the output value is abnormal (whether the output value is greater than the defective pixel detection threshold (predetermined value)) before shipment from the factory. . In addition, the defective pixel detection unit 111a detects defective pixels that appear conspicuously when light is blocked (dark), for example, defective pixels that appear due to defective causes such as white scratches in the dark and black scratches in the dark, during black balance adjustment after shipment. Detected when sensor cleaning is performed. Furthermore, the defective pixel detection unit 111a may detect defective pixels during photographing, except when light is blocked (during bright conditions). The detected defective pixels are stored in the memory 105. The correction unit 111b corrects the output value of the defective pixel through interpolation calculation processing using the output values of normal pixels surrounding the defective pixel.
欠陥原因の種類によっては撮像素子温度に依存して欠陥画素の出力値が変化するため、欠陥画素検出部１１１ａは欠陥画素検出閾値を撮像素子温度に対応する値に設定して欠陥画素の検出を行う。しかしながら、撮像素子の温度が高温となり、ノイズレベルが欠陥画素の出力値を上回ると、欠陥画素でない画素が欠陥画素として検出されてしまう。ユーザー使用時に行われる欠陥画素の検出は、どのような環境で行われるかの予測は難しい。例えば、撮像素子温度が想定以上の高温となる環境で欠陥画素の検出が行われる可能性がある。 Since the output value of a defective pixel changes depending on the type of defect cause depending on the image sensor temperature, the defective pixel detection unit 111a sets the defective pixel detection threshold to a value corresponding to the image sensor temperature to detect the defective pixel. conduct. However, if the temperature of the image sensor becomes high and the noise level exceeds the output value of the defective pixel, a pixel that is not a defective pixel will be detected as a defective pixel. It is difficult to predict in what environment defective pixels will be detected during use by a user. For example, a defective pixel may be detected in an environment where the temperature of the image sensor is higher than expected.
そこで、本発明は、撮像素子温度が、ノイズレベルが欠陥画素の出力値より大きくなり、欠陥画素が検出不可能となる欠陥画素検出限界温度より高い場合に、メモリ１０５が欠陥画素を取得しないように構成される。本発明の一例として、本実施形態では、欠陥画素検出部１１１ａは、撮像素子温度が欠陥画素検出限界温度より高い場合に欠陥画素の検出を実行しない。 Therefore, the present invention prevents the memory 105 from acquiring a defective pixel when the image sensor temperature is higher than the defective pixel detection limit temperature at which the noise level becomes larger than the output value of the defective pixel and the defective pixel becomes undetectable. It is composed of As an example of the present invention, in this embodiment, the defective pixel detection unit 111a does not detect a defective pixel when the image sensor temperature is higher than the defective pixel detection limit temperature.
図２は、本実施形態の欠陥画素の検出方法を示すフローチャートである。欠陥画素検出限界温度Ｔｔｈはあらかじめ測定され、メモリ１０５に保存されている。 FIG. 2 is a flowchart showing the defective pixel detection method of this embodiment. The defective pixel detection limit temperature T th is measured in advance and stored in the memory 105 .
ステップＳ２０１では、欠陥画素検出部１１１ａは、温度検出部１１２から撮像素子温度を取得する。 In step S201, the defective pixel detection unit 111a acquires the image sensor temperature from the temperature detection unit 112.
ステップＳ２０２では、欠陥画素検出部１１１ａは、撮像素子温度が欠陥画素検出限界温度Ｔｔｈより低いかどうかを判断する。撮像素子温度が欠陥画素検出限界温度Ｔｔｈより低い場合、ステップＳ２０３に進み、高い場合、本フローを終了する。なお、撮像素子温度が欠陥画素検出限界温度Ｔｔｈに等しい場合、どちらに進むかは任意に設定可能である。 In step S202, the defective pixel detection unit 111a determines whether the image sensor temperature is lower than the defective pixel detection limit temperature Tth . If the image sensor temperature is lower than the defective pixel detection limit temperature T th , the process advances to step S203, and if it is higher, the flow ends. Note that when the image sensor temperature is equal to the defective pixel detection limit temperature Tth , it is possible to arbitrarily set which direction to proceed to.
ステップＳ２０３では、欠陥画素検出部１１１ａは、欠陥画素を検出する。 In step S203, the defective pixel detection unit 111a detects a defective pixel.
ステップＳ２０４では、欠陥画素検出部１１１ａは、検出結果をメモリ１０５に書き込む。 In step S204, the defective pixel detection unit 111a writes the detection result into the memory 105.
本実施形態では、撮像素子温度を欠陥画素検出限界温度Ｔｔｈと比較し、欠陥画素検出を行うかどうかを判断することで、撮像素子の温度が高温である場合に欠陥画素の検出が行われ、欠陥画素が誤検出されることを抑制可能である。
［第２の実施形態］
本実施形態の撮像装置は、第１の実施形態の撮像装置と同様の構成を有する。図３は、本実施形態の欠陥画素の検出方法を示すフローチャートである。欠陥画素検出限界温度Ｔｔｈはあらかじめ測定され、メモリ１０５に保存されている。
In this embodiment, a defective pixel is detected when the temperature of the image sensor is high by comparing the image sensor temperature with the defective pixel detection limit temperature T th and determining whether to perform defective pixel detection. , it is possible to suppress erroneous detection of defective pixels.
[Second embodiment]
The imaging device of this embodiment has the same configuration as the imaging device of the first embodiment. FIG. 3 is a flowchart showing the defective pixel detection method of this embodiment. The defective pixel detection limit temperature T th is measured in advance and stored in the memory 105 .
ステップＳ３０１では、欠陥画素検出部１１１ａは、温度検出部１１２から撮像素子温度を取得する。 In step S301, the defective pixel detection unit 111a acquires the image sensor temperature from the temperature detection unit 112.
ステップＳ３０２では、欠陥画素検出部１１１ａは、撮像素子温度が欠陥画素検出限界温度Ｔｔｈより低いかどうかを判断する。撮像素子温度が欠陥画素検出限界温度Ｔｔｈより低い場合、ステップＳ３０４に進み、高い場合、ステップＳ３０３に進む。なお、撮像素子温度が欠陥画素検出限界温度Ｔｔｈに等しい場合、どちらに進むかは任意に設定可能である。 In step S302, the defective pixel detection unit 111a determines whether the image sensor temperature is lower than the defective pixel detection limit temperature Tth . If the image sensor temperature is lower than the defective pixel detection limit temperature T th , the process proceeds to step S304, and if it is higher, the process proceeds to step S303. Note that when the image sensor temperature is equal to the defective pixel detection limit temperature Tth , it is possible to arbitrarily set which direction to proceed to.
ステップＳ３０３では、欠陥画素検出部１１１ａは、欠陥画素検出閾値を欠陥画素が検出不可能となる任意の値に設定する。図４を参照して、本ステップの詳細について説明する。図４は、欠陥画素検出閾値の撮像素子温度に対する遷移を示す図である。横軸は撮像素子温度、縦軸は欠陥画素検出閾値を表している。撮像素子温度が上昇すると出力値も上昇する種類の欠陥では、撮像素子温度が欠陥画素検出限界温度Ｔｔｈに到達するまで欠陥画素検出閾値を撮像素子温度の上昇に応じて上昇させる。撮像素子温度が欠陥画素検出限界温度Ｔｔｈを越えると、欠陥画素検出閾値は欠陥画素が検出不可能となる任意の値に設定される。ここで、任意の値は、欠陥画素検出閾値として設定可能な範囲の最大値であることが望ましい。 In step S303, the defective pixel detection unit 111a sets the defective pixel detection threshold to an arbitrary value that makes it impossible to detect defective pixels. Details of this step will be explained with reference to FIG. 4. FIG. 4 is a diagram showing the transition of the defective pixel detection threshold value with respect to the image sensor temperature. The horizontal axis represents the image sensor temperature, and the vertical axis represents the defective pixel detection threshold. For a type of defect in which the output value also increases as the image sensor temperature rises, the defective pixel detection threshold is increased in accordance with the rise in the image sensor temperature until the image sensor temperature reaches the defective pixel detection limit temperature T th . When the image sensor temperature exceeds the defective pixel detection limit temperature T th , the defective pixel detection threshold is set to an arbitrary value that makes it impossible to detect the defective pixel. Here, it is desirable that the arbitrary value be the maximum value in a range that can be set as the defective pixel detection threshold.
ステップＳ３０４では、欠陥画素検出部１１１ａは、欠陥画素を検出する。ステップＳ３０５では、欠陥画素検出部１１１ａは、検出結果をメモリ１０５に書き込む。 In step S304, the defective pixel detection unit 111a detects a defective pixel. In step S305, the defective pixel detection unit 111a writes the detection result into the memory 105.
本実施形態では、撮像素子温度が欠陥画素検出限界温度Ｔｔｈより高い場合でも欠陥画素の検出は実行されるが、欠陥画素検出閾値が変更され、欠陥画素は検出されない。そのため、撮像素子の温度が高温である場合に欠陥画素の誤検出を抑制可能である。また、欠陥画素の検出が行われるブラックバランス調整やセンサークリーニングにかかる時間が撮像素子温度が通常温度である場合とほぼ変わらない。
［第３の実施形態］
本実施形態の撮像装置は、第１の実施形態の撮像装置と同様の構成を有する。図５は、本実施形態の欠陥画素の検出方法を示すフローチャートである。欠陥画素検出限界温度Ｔｔｈはあらかじめ測定され、メモリ１０５に保存されている。
In this embodiment, defective pixels are detected even when the image sensor temperature is higher than the defective pixel detection limit temperature T th , but the defective pixel detection threshold is changed and the defective pixels are not detected. Therefore, it is possible to suppress erroneous detection of defective pixels when the temperature of the image sensor is high. Furthermore, the time required for black balance adjustment and sensor cleaning to detect defective pixels is almost the same as when the image sensor temperature is normal.
[Third embodiment]
The imaging device of this embodiment has the same configuration as the imaging device of the first embodiment. FIG. 5 is a flowchart showing the defective pixel detection method of this embodiment. The defective pixel detection limit temperature T th is measured in advance and stored in the memory 105 .
ステップＳ５０１では、欠陥画素検出部１１１ａは、温度検出部１１２から撮像素子温度を取得する。 In step S501, the defective pixel detection unit 111a acquires the image sensor temperature from the temperature detection unit 112.
ステップＳ５０２では、欠陥画素検出部１１１ａは、欠陥画素を検出する。 In step S502, the defective pixel detection unit 111a detects a defective pixel.
ステップＳ５０３では、欠陥画素検出部１１１ａは、撮像素子温度が欠陥画素検出限界温度Ｔｔｈより低いかどうかを判断する。撮像素子温度が欠陥画素検出限界温度Ｔｔｈより低い場合、ステップＳ５０４に進み、高い場合、本フローを終了する。なお、撮像素子温度が欠陥画素検出限界温度Ｔｔｈに等しい場合、どちらに進むかは任意に設定可能である。 In step S503, the defective pixel detection unit 111a determines whether the image sensor temperature is lower than the defective pixel detection limit temperature Tth . If the image sensor temperature is lower than the defective pixel detection limit temperature T th , the process advances to step S504, and if it is higher, the flow ends. Note that when the image sensor temperature is equal to the defective pixel detection limit temperature Tth , it is possible to arbitrarily set which direction to proceed to.
ステップＳ５０４では、欠陥画素検出部１１１ａは、検出結果をメモリ１０５に書き込む。 In step S504, the defective pixel detection unit 111a writes the detection result into the memory 105.
本実施形態では、撮像素子温度が欠陥画素検出限界温度Ｔｔｈより高い場合でも欠陥画素の検出は実行されるが、検出結果はメモリ１０５に書き込まれない。そのため、撮像素子温度が高温である場合の欠陥画素の誤検出を抑制することができる。また、欠陥画素の検出が行われるブラックバランス調整やセンサークリーニングにかかる時間が撮像素子温度が通常温度である場合とほぼ変わらない。
［第４の実施形態］
本実施形態の撮像装置は、第１の実施形態の撮像装置と同様の構成を有する。本実施形態では、欠陥原因が異なる複数の欠陥画素を検出する方法の一例について説明する。欠陥原因には白キズや黒キズ等の複数の種類があり、欠陥原因の種類によって欠陥画素の出力値は異なる。したがって、欠陥原因の種類によって欠陥画素検出限界温度も異なる。本実施形態では、メモリ１０５は、欠陥原因の種類ごとの複数の欠陥画素検出限界温度を記憶する。
In this embodiment, even when the image sensor temperature is higher than the defective pixel detection limit temperature T th , defective pixel detection is performed, but the detection result is not written to the memory 105 . Therefore, erroneous detection of defective pixels when the image sensor temperature is high can be suppressed. Furthermore, the time required for black balance adjustment and sensor cleaning to detect defective pixels is almost the same as when the image sensor temperature is normal.
[Fourth embodiment]
The imaging device of this embodiment has the same configuration as the imaging device of the first embodiment. In this embodiment, an example of a method for detecting a plurality of defective pixels having different defect causes will be described. There are multiple types of defect causes, such as white scratches and black scratches, and the output value of a defective pixel differs depending on the type of defect cause. Therefore, the defective pixel detection limit temperature also differs depending on the type of defect cause. In this embodiment, the memory 105 stores a plurality of defective pixel detection limit temperatures for each type of defect cause.
図６は、欠陥原因の種類ごとの欠陥画素検出閾値の撮像素子温度に対する遷移を示す図である。横軸は撮像素子温度、縦軸は欠陥画素検出閾値を表している。図６には、欠陥原因の種類Ａ～Ｃの例を示している。種類Ａ～Ｃの順で、欠陥画素検出閾値は高くなっている。欠陥画素検出閾値が低い方が欠陥画素検出限界温度が低くなる。そのため、種類Ａ～Ｃの順で、対応する欠陥画素検出限界温度Ｔｔｈ１，Ｔｔｈ２，Ｔｔｈ３は低くなる。 FIG. 6 is a diagram showing the transition of the defective pixel detection threshold for each type of defect cause with respect to the image sensor temperature. The horizontal axis represents the image sensor temperature, and the vertical axis represents the defective pixel detection threshold. FIG. 6 shows examples of types A to C of defect causes. The defective pixel detection threshold value increases in the order of types A to C. The lower the defective pixel detection threshold, the lower the defective pixel detection limit temperature. Therefore, in the order of types A to C, the corresponding defective pixel detection limit temperatures T th1 , T th2 , and T th3 become lower.
以上説明したように、欠陥原因の種類に対応する欠陥画素検出限界温度を使用することで撮像素子温度が高温である場合に欠陥画素の誤検出をより高い精度で抑制することができる。 As described above, by using the defective pixel detection limit temperature that corresponds to the type of defect cause, it is possible to suppress erroneous detection of defective pixels with higher accuracy when the image sensor temperature is high.
なお、本実施形態では、撮像素子温度が欠陥画素検出限界温度より高い場合に第２の実施形態と同様に欠陥画素が検出できないように欠陥画素検出閾値を設定しているが、本発明はこれに限定されない。第１の実施形態や第３の実施形態の方法を用いてもよい。また、撮像素子温度の影響を受けにくい（撮像素子温度に依存しない）欠陥原因により現れた欠陥画素を撮像素子温度に関係なく検出するようにしてもよい。
［その他の実施形態］
本発明は、上述の実施形態の１以上の機能を実現するプログラムを、ネットワーク又は記憶媒体を介してシステム又は装置に供給し、そのシステム又は装置のコンピュータにおける１つ以上のプロセッサがプログラムを読出し実行する処理でも実現可能である。また、１以上の機能を実現する回路（例えば、ＡＳＩＣ）によっても実現可能である。
Note that in this embodiment, the defective pixel detection threshold is set so that a defective pixel cannot be detected when the image sensor temperature is higher than the defective pixel detection limit temperature, as in the second embodiment. but not limited to. The method of the first embodiment or the third embodiment may also be used. Furthermore, a defective pixel that appears due to a defect cause that is not easily affected by the image sensor temperature (independent of the image sensor temperature) may be detected regardless of the image sensor temperature.
[Other embodiments]
The present invention provides a system or device with a program that implements one or more functions of the embodiments described above via a network or a storage medium, and one or more processors in a computer of the system or device reads and executes the program. This can also be achieved by processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.
以上、本発明の好ましい実施形態について説明したが、本発明はこれらの実施形態に限定されず、その要旨の範囲内で種々の変形及び変更が可能である。 Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.
１０２ 撮像素子
１０５ メモリ（記憶部）
１１１ａ 欠陥画素検出部
１１２ 温度検出部
102 Image sensor 105 Memory (storage unit)
111a Defective pixel detection unit 112 Temperature detection unit
Claims (4)
前記撮像素子の温度を検出する温度検出部と、
記憶部と、
出力値が所定値より大きい画素を欠陥画素として検出すると共に、検出した前記欠陥画素を前記記憶部に書き込む欠陥画素検出部とを有し、
前記欠陥画素検出部は、前記撮像素子の温度が第１の温度より低い場合、前記所定値を前記欠陥画素が検出可能である範囲で前記撮像素子の温度に対応した値に変更し、前記撮像素子の温度が前記第１の温度より高い場合、前記所定値を前記欠陥画素が検出不可能となる値に設定することを特徴とする撮像装置。 an image sensor in which a plurality of pixels are arranged in a matrix;
a temperature detection unit that detects the temperature of the image sensor;
storage section and
a defective pixel detection unit that detects a pixel whose output value is larger than a predetermined value as a defective pixel and writes the detected defective pixel into the storage unit,
When the temperature of the image sensor is lower than a first temperature, the defective pixel detection unit changes the predetermined value to a value corresponding to the temperature of the image sensor within a range in which the defective pixel can be detected , and An imaging apparatus characterized in that when the temperature of the element is higher than the first temperature, the predetermined value is set to a value that makes it impossible to detect the defective pixel .
前記複数の限界温度のそれぞれは前記欠陥画素が検出不可能となる温度であって、
前記欠陥画素検出部は、前記欠陥原因の種類ごとに前記限界温度を前記第１の温度に設定することを特徴とする請求項１に記載の撮像装置。 The storage unit stores a plurality of limit temperatures for each type of defect cause,
Each of the plurality of limit temperatures is a temperature at which the defective pixel becomes undetectable,
The imaging device according to claim 1, wherein the defective pixel detection unit sets the limit temperature to the first temperature for each type of defect cause .
出力値が所定値より大きい画素を欠陥画素として検出するステップと、
検出された前記欠陥画素を前記記憶部に書き込むステップとを有し、
前記検出するステップは、前記撮像素子の温度が第１の温度より低い場合、前記所定値を前記欠陥画素が検出可能である範囲で前記撮像素子の温度に対応し値に変更し、前記撮像素子の温度が前記第１の温度より高い場合、前記所定値を前記欠陥画素が検出不可能となる値に設定することを特徴とする欠陥画素の検出方法。 A method for detecting a defective pixel in an imaging device including an imaging device in which a plurality of pixels are arranged in a matrix, a temperature detection unit that detects the temperature of the imaging device, and a storage unit, the method comprising:
detecting a pixel whose output value is larger than a predetermined value as a defective pixel;
writing the detected defective pixel into the storage unit,
In the step of detecting , when the temperature of the image sensor is lower than a first temperature, the predetermined value is changed to a value corresponding to the temperature of the image sensor within a range in which the defective pixel can be detected , and the temperature of the image sensor is A method for detecting a defective pixel, characterized in that when the temperature of the defective pixel is higher than the first temperature, the predetermined value is set to a value that makes it impossible to detect the defective pixel .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020006114A JP7455589B2 (en) | 2020-01-17 | 2020-01-17 | Imaging device and defective pixel detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020006114A JP7455589B2 (en) | 2020-01-17 | 2020-01-17 | Imaging device and defective pixel detection method |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| JP2021114686A JP2021114686A (en) | 2021-08-05 |
| JP2021114686A5 JP2021114686A5 (en) | 2023-01-20 |
| JP7455589B2 true JP7455589B2 (en) | 2024-03-26 |
Family
ID=77077678
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2020006114A Active JP7455589B2 (en) | 2020-01-17 | 2020-01-17 | Imaging device and defective pixel detection method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP7455589B2 (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004120621A (en) | 2002-09-27 | 2004-04-15 | Olympus Corp | Pixel defect detecting apparatus of imaging element, its detecting method, and imaging apparatus for microscope |
| JP2007006024A (en) | 2005-06-22 | 2007-01-11 | Fujifilm Holdings Corp | Imaging apparatus |
| JP2010118780A (en) | 2008-11-11 | 2010-05-27 | Olympus Imaging Corp | System and method for detecting pixel defect of imaging device |
| JP2011040893A (en) | 2009-08-07 | 2011-02-24 | Canon Inc | Device for correcting defective pixel data, imaging device, and method of correcting defective pixel data |
| JP2012134684A (en) | 2010-12-21 | 2012-07-12 | Hitachi Ltd | Image signal processing device and image signal processing method |
-
2020
- 2020-01-17 JP JP2020006114A patent/JP7455589B2/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004120621A (en) | 2002-09-27 | 2004-04-15 | Olympus Corp | Pixel defect detecting apparatus of imaging element, its detecting method, and imaging apparatus for microscope |
| JP2007006024A (en) | 2005-06-22 | 2007-01-11 | Fujifilm Holdings Corp | Imaging apparatus |
| JP2010118780A (en) | 2008-11-11 | 2010-05-27 | Olympus Imaging Corp | System and method for detecting pixel defect of imaging device |
| JP2011040893A (en) | 2009-08-07 | 2011-02-24 | Canon Inc | Device for correcting defective pixel data, imaging device, and method of correcting defective pixel data |
| JP2012134684A (en) | 2010-12-21 | 2012-07-12 | Hitachi Ltd | Image signal processing device and image signal processing method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2021114686A (en) | 2021-08-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100335529B1 (en) | Pixel defect detector for solid-state imaging device | |
| JPH10322603A (en) | Electronic camera | |
| JP5656561B2 (en) | Image processing apparatus, control method thereof, and control program | |
| US8922681B2 (en) | Image processing device that performs image processing to correct target pixels in a region surrounding a defective pixel | |
| JP5615155B2 (en) | Image processing apparatus and method | |
| US20150195462A1 (en) | Image capturing apparatus, control method thereof, and storage medium | |
| US9900533B2 (en) | Image processing apparatus and method, and image capturing apparatus | |
| JP7455589B2 (en) | Imaging device and defective pixel detection method | |
| JP5978636B2 (en) | Imaging apparatus and program | |
| US8218040B2 (en) | Image processing apparatus, image processing method and computer-readable storage medium | |
| JP2007006024A (en) | Imaging apparatus | |
| JP2020022135A (en) | Defective pixel correction device, imaging device, and defective pixel correction method | |
| US8259197B2 (en) | Imaging device | |
| JP2006166194A (en) | Pixel defect detection circuit and pixel defect detection method | |
| JP2011166422A (en) | Imaging apparatus | |
| KR20070098263A (en) | Compensation apparatus of defected pixel and compensation method of defected pixel | |
| US20210243395A1 (en) | Image pickup apparatus for inferring noise and learning device | |
| JP6118133B2 (en) | Signal processing apparatus and imaging apparatus | |
| JP2007028338A (en) | Imaging apparatus and control method thereof, program, and storage medium | |
| JPWO2011141972A1 (en) | Luminance correction apparatus, luminance correction system, and luminance correction method | |
| JP4585021B2 (en) | Image pickup apparatus for microscope and pixel defect detection method of image pickup element | |
| JP2006217113A (en) | Electronic camera and method of inspecting electronic camera | |
| JP4587717B2 (en) | Digital camera | |
| JP4546664B2 (en) | Imaging apparatus and pixel defect correction method | |
| JP2002152601A (en) | Solid-state imaging unit and method for correcting defective pixel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20230110 |
|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20230110 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20230929 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20231010 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20231204 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20240213 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20240313 |
|
| R151 | Written notification of patent or utility model registration |
Ref document number: 7455589 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R151 |