JP2022072293A - Driver monitoring device - Google Patents

Driver monitoring device Download PDF

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JP2022072293A
JP2022072293A JP2020181655A JP2020181655A JP2022072293A JP 2022072293 A JP2022072293 A JP 2022072293A JP 2020181655 A JP2020181655 A JP 2020181655A JP 2020181655 A JP2020181655 A JP 2020181655A JP 2022072293 A JP2022072293 A JP 2022072293A
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light
driver
infrared
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temperature
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雄治 猪坂
Yuji Inosaka
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Nippon Seiki Co Ltd
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Nippon Seiki Co Ltd
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Abstract

To provide a driver monitoring device capable of reducing effects of sunlight on imaging.SOLUTION: A driver monitoring device includes: an infrared light irradiation unit 12 which irradiates a driver of a vehicle with infrared light according to lighting of an infrared LED; a camera 13 which periodically images a driver using infrared light reflected on the driver; a control unit 16 which periodically turns on the light of the infrared LED in synchronization with imaging of the camera 13; a filter which makes infrared light of a prescribed wavelength range incident on the camera 13; and a thermistor which detects ambient temperature of the infrared LED. If the temperature detected by the thermistor is lower than a reference temperature, the control unit 16 changes lighting time per one cycle of the infrared LED so that it is longer compared to when a detected temperature is equal to or higher than the reference temperature.SELECTED DRAWING: Figure 3

Description

本発明は、車両の運転者を撮像してその状態を監視する運転者監視装置に関する。 The present invention relates to a driver monitoring device that captures an image of the driver of a vehicle and monitors the state thereof.

車両のフロントウインドシールドやコンバイナ等の反射透光部材を透過する実景(車両前方の風景)に重ねて、その反射透光部材に反射された表示光により虚像を生成して表示するヘッドアップディスプレイ装置には、運転者に赤外光を照射して運転者を撮像し、運転者の状態を監視する運転者監視装置(ドライバーモニタリングシステム)の機能を有するものがある。 A head-up display device that creates and displays a virtual image by the display light reflected by the reflected light-transmitting member, which is superimposed on the actual scene (scenery in front of the vehicle) that passes through the reflected light-transmitting member such as the front windshield or combiner of the vehicle. Some have the function of a driver monitoring device (driver monitoring system) that irradiates the driver with infrared light to image the driver and monitors the driver's condition.

例えば特許文献1に記載のヘッドアップディスプレイ装置は、表示手段から発せられる可視光をコンバイナ部材にて運転者に向けて反射して表示像を結像するもので、運転者に向けて赤外線を照射する赤外線照射手段と、表示手段から発せられる可視光をコンバイナ部材に向けて反射し、運転者及びコンバイナ部材にて反射される赤外線を透過するミラー部材と、ミラー部材を透過する赤外線を感受して運転者をそれぞれ異なる方向から撮像する複数の撮像手段と、撮像手段によって撮像された画像に基づいて運転者の目の位置を算出する画像処理手段とを備え、運転者の目の位置の算出結果は、脇見、居眠り等の運転者の状態判定に利用可能である。 For example, the head-up display device described in Patent Document 1 reflects visible light emitted from a display means toward a driver by a combiner member to form a display image, and irradiates the driver with infrared rays. The infrared irradiation means and the mirror member that reflects the visible light emitted from the display means toward the combiner member and transmits the infrared rays reflected by the driver and the combiner member, and the infrared rays transmitted through the mirror member are sensed. A plurality of imaging means for imaging the driver from different directions and an image processing means for calculating the position of the driver's eyes based on the images captured by the imaging means are provided, and the calculation result of the position of the driver's eyes is provided. Can be used to determine the driver's condition such as looking aside or taking a nap.

特開2008-126984号公報Japanese Unexamined Patent Publication No. 2008-126984

ところで、特許文献1に記載のヘッドアップディスプレイ装置では、赤外線照射手段の赤外線LEDから赤外線が発せられ、これが運転者の顔等で反射されてコールドミラーを透過して撮像手段に入射するが、赤外線LEDの発光波長は周囲の温度によって変化する(温度が低いと短くなり、温度が高いと長くなる)ので、撮像手段への太陽光の入射を抑制するためにフィルタ(コールドミラー)の透過波長域を狭めると、撮像に必要な赤外線の波長もフィルタでカットされるおそれが生じ、撮像に対する太陽光の影響を十分に小さくすることができないという問題があった。 By the way, in the head-up display device described in Patent Document 1, infrared rays are emitted from the infrared LED of the infrared irradiation means, which are reflected by the driver's face or the like, pass through a cold mirror, and are incident on the image pickup means. Since the emission wavelength of the LED changes depending on the ambient temperature (it becomes shorter when the temperature is low and becomes longer when the temperature is high), the transmission wavelength range of the filter (cold mirror) is used to suppress the incident of sunlight on the imaging means. If it is narrowed, the infrared wavelength required for imaging may be cut by the filter, and there is a problem that the influence of sunlight on imaging cannot be sufficiently reduced.

本発明は、上記の事情に鑑みてなされたもので、撮像に対する太陽光の影響を低減させることができる運転者監視装置を提供することを課題としている。 The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a driver monitoring device capable of reducing the influence of sunlight on imaging.

上記課題を解決するために、本発明に係る運転者監視装置は、赤外LEDの点灯により車両の運転者に赤外光を照射する照明手段と、前記運転者で反射された赤外光により前記運転者を周期的に撮像する撮像手段と、前記撮像手段の撮像に同期させて前記赤外LEDを周期的に点灯させる制御手段と、前記撮像手段に所定の波長帯の赤外光を入射させるフィルタ手段と、前記赤外LEDの周囲温度を検出する温度検出手段とを備え、前記制御手段は、前記温度検出手段の検出温度が基準温度よりも低い場合、前記赤外LEDの1周期あたりの点灯時間を前記検出温度が前記基準温度以上の場合より長くなるように変化させることを特徴とする。 In order to solve the above problems, the driver monitoring device according to the present invention uses lighting means for irradiating the driver of a vehicle with infrared light by lighting an infrared LED and infrared light reflected by the driver. An image pickup means that periodically images the driver, a control means that periodically turns on the infrared LED in synchronization with the image pickup of the image pickup means, and an infrared light of a predetermined wavelength band incident on the image pickup means. The control means includes a filter means for detecting the ambient temperature of the infrared LED, and the control means per cycle of the infrared LED when the detection temperature of the temperature detection means is lower than the reference temperature. The lighting time of the light is changed so as to be longer than when the detected temperature is equal to or higher than the reference temperature.

前記制御手段は、前記検出温度が前記基準温度よりも低い場合、前記点灯時間を前記検出温度に応じて変化させてもよい。 When the detection temperature is lower than the reference temperature, the control means may change the lighting time according to the detection temperature.

また、本発明に係る運転者監視装置は、前記運転者で反射された赤外光が前記フィルタ手段に入射するまでに通る撮像光路上に、可視光の波長帯の光を透過させて赤外光の波長帯の光を反射させる波長選択光学手段を備えてもよい。 Further, the driver monitoring device according to the present invention transmits light in the wavelength band of visible light on the imaging optical path through which the infrared light reflected by the driver passes by the time it is incident on the filter means, and is infrared. A wavelength selection optical means for reflecting light in the wavelength band of light may be provided.

このとき、前記フィルタ手段は、前記赤外光の波長帯の光のうち第一の閾値よりも低波長の光を透過させず、前記第一の閾値よりも高波長の光を透過させるロングパスフィルタであっても、あるいは、前記赤外光の波長帯の光のうち第二の閾値よりも低波長の光を透過させず、前記第二の閾値よりも高波長で第三の閾値よりも低波長の光を透過させ、前記第三の閾値よりも高波長の光を透過させないバンドパスフィルタであってもよい。 At this time, the filter means is a long-pass filter that does not transmit light having a wavelength lower than the first threshold value among the light in the wavelength band of the infrared light, but transmits light having a wavelength higher than the first threshold value. Even if, or, light having a wavelength lower than the second threshold of the light in the wavelength band of the infrared light is not transmitted, and the wavelength is higher than the second threshold and lower than the third threshold. A bandpass filter that transmits light having a wavelength and does not transmit light having a wavelength higher than the third threshold value may be used.

さらに、前記制御手段は、前記撮像手段が撮像を行っていない期間で前記点灯時間を変化させてもよい。 Further, the control means may change the lighting time during a period during which the image pickup means is not performing an image pickup.

本発明によれば、撮像に対する太陽光の影響を低減させることができるという効果を奏する。 According to the present invention, there is an effect that the influence of sunlight on imaging can be reduced.

発明を実施するための形態に係る運転者監視装置を内蔵するヘッドアップディスプレイ装置が設けられた車両を示す説明図である。It is explanatory drawing which shows the vehicle provided with the head-up display device which built in the driver monitoring device which concerns on embodiment for carrying out the invention. 図1のフロントウインドシールドの透過特性を示す説明図である。It is explanatory drawing which shows the transmission characteristic of the front windshield of FIG. 図1の運転者監視装置の主要構成を示すブロック図である。It is a block diagram which shows the main composition of the driver monitoring apparatus of FIG. 図1の赤外線照射ユニット及びカメラの詳細構成を示す説明図である。It is explanatory drawing which shows the detailed structure of the infrared irradiation unit and a camera of FIG. 図1のフィルタの透過特性を示す説明図である。It is explanatory drawing which shows the transmission characteristic of the filter of FIG. 図1の運転者監視装置の撮像同期信号とカメラ及び赤外LEDの動作タイミングを示す説明図である。It is explanatory drawing which shows the image pickup synchronization signal of the driver monitoring apparatus of FIG. 1, and the operation timing of a camera and an infrared LED. 図1の制御部による処理を示す流れ図である。It is a flow chart which shows the process by the control part of FIG. フィルタの透過特性の他の例を示す説明図である。It is explanatory drawing which shows the other example of the transmission characteristic of a filter. 運転者監視装置の他の例を示す説明図である。It is explanatory drawing which shows the other example of the driver monitoring apparatus. 検出温度に応じた点灯時間の制御例を示す説明図である。It is explanatory drawing which shows the control example of the lighting time according to the detection temperature. 検出温度に応じた点灯時間の他の制御例を示す説明図である。It is explanatory drawing which shows the other control example of the lighting time according to the detection temperature.

本発明を実施するための形態について、図面に基づいて説明する。 A mode for carrying out the present invention will be described with reference to the drawings.

図1に示すように、本実施の形態に係る運転者監視装置を内蔵するヘッドアップディスプレイ装置(HUD)1は、車両2のフロントウインドシールド3の下方にあるインストルメントパネル4の内部に設けられ、フロントウインドシールド3に可視光である表示光Lを投影する。表示光Lは、フロントウインドシールド3に反射されて虚像Vを生成し、ステアリングホイール5の後方の図示を略す運転席に座る運転者Dにフロントウインドシールド3を透過する実景に重ねて虚像Vを視認させる。 As shown in FIG. 1, the head-up display device (HUD) 1 incorporating the driver monitoring device according to the present embodiment is provided inside the instrument panel 4 below the front windshield 3 of the vehicle 2. , The display light L1 which is visible light is projected on the front windshield 3. The display light L 1 is reflected by the front windshield 3 to generate a virtual image V, and the virtual image V is superimposed on the actual view transmitted through the front windshield 3 to the driver D sitting in the driver's seat, which is not shown behind the steering wheel 5. To be visually recognized.

また、HUD1は、運転者Dの状態を監視(モニター)するために、赤外光Lを照射してフロントウインドシールド3に反射させ、運転者Dを照明し、運転者Dで反射された赤外光Lにより運転者Dを撮像する。 Further, in order to monitor the state of the driver D, the HUD 1 irradiates the infrared light L 2 and reflects it on the front windshield 3, illuminates the driver D, and is reflected by the driver D. The driver D is imaged by the infrared light L 2 .

詳細には、フロントウインドシールド3は、図2に示すように、可視光の波長帯の光(例えば波長が800nm(800ナノメートル)未満の光)を透過させて赤外光の波長帯の光(例えば、波長が800nm以上の光)を透過させずに反射する特性を有し、フロントウインドシールド3の表示光Lが投影される部位には、図示を略すハーフミラーフィルムが設けられている。 Specifically, as shown in FIG. 2, the front windshield 3 transmits light in the wavelength band of visible light (for example, light having a wavelength of less than 800 nm (800 nanometers)) to transmit light in the wavelength band of infrared light. A half mirror film (not shown) is provided at a portion of the front windshield 3 where the display light L1 is projected, which has a characteristic of reflecting light without transmitting (for example, light having a wavelength of 800 nm or more). ..

HUD1は、黒色のABS樹脂等により成形されて外光の侵入が防止されたハウジング6に覆われて外部と区画され、ハウジング6にはポリカーボネート等からなる透明なカバーガラス7が取り付けられた開口部8が形成されている。ハウジング6の内部には、表示器ユニット9と、平面鏡10と、凹面鏡11と、赤外光照射ユニット12と、カメラ13と、フィルタ14と、遮蔽片15と、制御部16とが保持・収容され、制御部16は、図3に示すように、表示器ユニット9、赤外光照射ユニット12及びカメラ13に接続されている。 The HUD 1 is separated from the outside by being covered with a housing 6 molded from black ABS resin or the like to prevent the intrusion of outside light, and the housing 6 has an opening to which a transparent cover glass 7 made of polycarbonate or the like is attached. 8 is formed. Inside the housing 6, a display unit 9, a plane mirror 10, a concave mirror 11, an infrared light irradiation unit 12, a camera 13, a filter 14, a shielding piece 15, and a control unit 16 are held and housed. The control unit 16 is connected to the display unit 9, the infrared light irradiation unit 12, and the camera 13 as shown in FIG.

表示器ユニット9は、光源及び液晶パネル等からなる表示器17を備え、制御部16に制御されて表示器17から可視光である映像光(表示光L)を投影表示する。平面鏡10は、平面部分を有するように成形されたガラスにアルミニウム等の金属もしくは誘電体多層膜を蒸着してなり、可視光を単純に反射する。凹面鏡11は、凹面部分を有するように成形されたポリカーボネート等の樹脂にアルミニウム等の金属を蒸着してなり、可視光を拡大して反射する。 The display unit 9 includes a display 17 including a light source and a liquid crystal panel, and is controlled by the control unit 16 to project and display visible light (display light L1) from the display unit 17. The plane mirror 10 is formed by depositing a metal such as aluminum or a dielectric multilayer film on glass formed so as to have a flat portion, and simply reflects visible light. The concave mirror 11 is formed by depositing a metal such as aluminum on a resin such as polycarbonate molded so as to have a concave portion, and magnifies and reflects visible light.

赤外光照射ユニット12は、図4に示すように、赤外光源としての赤外LED18と、サーミスタ19と、赤外LED18及びサーミスタ19が設けられた基板20とを備え、ハウジング6においてカバーガラス7の下方に設けられている。赤外LED18は、制御部16に点灯制御されて近赤外線(赤外光L)を発し、サーミスタ19は、赤外LED18の周囲の温度を検出し、その検出温度は基板20を介して制御部16に出力される。赤外光照射ユニット12は、赤外光Lを遮蔽片15及びカバーガラス7を通してフロントウインドシールド3に向けて照射する。 As shown in FIG. 4, the infrared light irradiation unit 12 includes an infrared LED 18 as an infrared light source, a thermistor 19, and a substrate 20 provided with the infrared LED 18 and the thermistor 19, and a cover glass in the housing 6. It is provided below 7. The infrared LED 18 is controlled to be lit by the control unit 16 to emit near infrared rays (infrared light L 2 ), the thermistor 19 detects the temperature around the infrared LED 18, and the detected temperature is controlled via the substrate 20. It is output to the unit 16. The infrared light irradiation unit 12 irradiates the infrared light L 2 toward the front window shield 3 through the shield piece 15 and the cover glass 7.

カメラ13は、ハウジング6においてカバーガラス7の下方で赤外光照射ユニット12と前後に並んで設けられ、特に950nm前後の波長帯の光に感度を有する撮像素子21と、赤外光L(又は、赤外光Lのうちフィルタ14を透過する波長帯の光)を透過して撮像素子21に結像させるレンズ22とを備える。赤外光照射ユニット12から照射された赤外光Lがフロントウインドシールド3で反射され、運転者D、フロントウインドシールド3で反射されてカメラ13に入射すると、カメラ13は運転者Dの近赤外線画像を所定のフレームレートで周期的に撮像する。 The camera 13 is provided in the housing 6 under the cover glass 7 side by side with the infrared light irradiation unit 12, and particularly has an image pickup element 21 having sensitivity to light in a wavelength band of about 950 nm, and an infrared light L 2 ( Alternatively, it includes a lens 22 that transmits light in the wavelength band that passes through the filter 14 of the infrared light L 2 and forms an image on the image pickup element 21. When the infrared light L 2 emitted from the infrared light irradiation unit 12 is reflected by the front windshield 3 and reflected by the driver D and the front windshield 3 and is incident on the camera 13, the camera 13 is close to the driver D. Infrared images are periodically imaged at a predetermined frame rate.

フィルタ14は、カメラ13の撮像素子21に所定の波長帯の赤外光を入射させるもので、ここでは、図5に示すように、赤外光の波長帯の光のうち閾値λ=900nmよりも低波長の光を透過させず、閾値λよりも高波長の光を透過させるロングパスフィルタが用いられる。このフィルタ14との関係で、フロントウインドシールド3は、運転者Dで反射された赤外光Lがフィルタ14に入射するまでに通る撮像光路上にあるといえる。 The filter 14 incidents infrared light in a predetermined wavelength band on the image pickup element 21 of the camera 13. Here, as shown in FIG. 5, the threshold value λ 1 = 900 nm of the light in the wavelength band of infrared light. A long-pass filter that does not transmit light with a lower wavelength than that and transmits light with a wavelength higher than the threshold value λ 1 is used. In relation to the filter 14, it can be said that the front windshield 3 is on the imaging light path through which the infrared light L2 reflected by the driver D passes by the time it is incident on the filter 14.

遮蔽片15は、可視光を遮光して赤外光を透過させるもので、ハウジング5において、赤外光照射ユニット12及びカメラ13の上方に設けられている。 The shielding piece 15 shields visible light and transmits infrared light, and is provided above the infrared light irradiation unit 12 and the camera 13 in the housing 5.

制御部16は、カメラ13から撮像同期信号を取得し、図6に示すように、カメラ13の撮像(カメラ13のシャッターのON)に同期させて赤外LED18を周期的に点灯させる。このとき、制御部16は、サーミスタ19の検出温度Tを取得し、検出温度Tが所定の基準温度Tよりも低い場合、赤外LED18の1周期あたりの点灯時間を検出温度Tが基準温度T以上T未満の場合のtよりも長いtとなるように変化させ、検出温度Tが基準温度T以上の場合、赤外LED18の1周期あたりの点灯時間をtよりも短いtとなるように変化させる。換言すれば、本例の場合、赤外LED18の温度調節を赤外LED18の点灯時間(の大小)で行っている構成であるとも言える。なお、この点灯時間の変化(長期化、短期化)は、カメラ13が撮像を行っていない期間(カメラ13のシャッターがOFFの期間)で行われる。 The control unit 16 acquires an image pickup synchronization signal from the camera 13, and as shown in FIG. 6, periodically turns on the infrared LED 18 in synchronization with the image pickup of the camera 13 (ON of the shutter of the camera 13). At this time, the control unit 16 acquires the detection temperature T of the thermistor 19, and when the detection temperature T is lower than the predetermined reference temperature T1, the detection temperature T determines the lighting time per cycle of the infrared LED 18. Change so that t 1 is longer than t when T 1 or more and less than T 2 , and when the detection temperature T is the reference temperature T 2 or more, the lighting time per cycle of the infrared LED 18 is shorter than t t. Change to 2 . In other words, in the case of this example, it can be said that the temperature of the infrared LED 18 is controlled by the lighting time (large or small) of the infrared LED 18. It should be noted that this change in lighting time (prolonged or shortened) is performed during a period during which the camera 13 is not performing imaging (a period during which the shutter of the camera 13 is OFF).

HUD1において、表示器ユニット9からの表示光Lは、平面鏡10で反射され、次いで、凹面鏡11で拡大して反射され、カバーガラス7を通過してフロントウインドシールド3に投影される。フロントウインドシールド3に投影された表示光Lは、ハーフミラーフィルムにより運転者Dの側に拡大して反射され、虚像Vを生成してフロントウインドシールド3を透過する実景に重ねて運転者Dに表示する。 In the HUD 1, the display light L 1 from the display unit 9 is reflected by the plane mirror 10, then enlarged and reflected by the concave mirror 11, passes through the cover glass 7, and is projected onto the front windshield 3. The display light L1 projected on the front windshield 3 is magnified and reflected toward the driver D by the half mirror film, and a virtual image V is generated and superimposed on the actual scene transmitted through the front windshield 3 by the driver D. Display on.

一方、赤外光照射ユニット12から照射された赤外光Lは、遮蔽片15及びカバーガラス7を通過してフロントウインドシールド3に投影され、フロントウインドシールド3で運転者Dの側に反射されて運転者Dを照明する。そして、運転者Dで反射された赤外光Lの一部は逆の経路を辿り、カバーガラス7、遮蔽片15及びフィルタ14を通過してカメラ13に入射し、運転者Dが撮像される。 On the other hand, the infrared light L 2 emitted from the infrared light irradiation unit 12 passes through the shield piece 15 and the cover glass 7 and is projected onto the front windshield 3, and is reflected by the front windshield 3 toward the driver D. And illuminate driver D. Then, a part of the infrared light L 2 reflected by the driver D follows the reverse path, passes through the cover glass 7, the shielding piece 15, and the filter 14 and is incident on the camera 13, and the driver D is imaged. To.

その際、制御部16は、図7に示すように、カメラ13から撮像同期信号が入力されると(ステップ1(図7において「S.1」と記載。以下同様。))、サーミスタ19の検出温度Tを取得して赤外LED18の1周期あたりの点灯時間を決定し(ステップ2,3)、赤外LED18を点灯させる(ステップ4)。そして、決定した点灯時間が経過すると、赤外LED18を消灯させる(ステップ5,6)。この赤外LED18の点灯から消灯までの間にカメラ13のシャッターのON/OFFが行われることは、上記のとおりである。 At that time, as shown in FIG. 7, when the image pickup synchronization signal is input from the camera 13 (step 1 (described as “S.1” in FIG. 7; the same applies hereinafter)), the control unit 16 of the thermistor 19 The detection temperature T is acquired to determine the lighting time per cycle of the infrared LED 18 (steps 2 and 3), and the infrared LED 18 is turned on (step 4). Then, when the determined lighting time elapses, the infrared LED 18 is turned off (steps 5 and 6). As described above, the shutter of the camera 13 is turned on / off between the time when the infrared LED 18 is turned on and the time when the infrared LED 18 is turned off.

本実施の形態に係る運転者監視装置は、赤外LED18の点灯により車両2の運転者Dに赤外光Lを照射して照明する赤外光照射ユニット12と、運転者Dで反射された赤外光Lにより運転者Dを周期的に撮像するカメラ13と、カメラ13の撮像に同期させて赤外LED18を周期的に点灯させる制御部16と、カメラ13に所定の波長帯の赤外光を入射させるフィルタ14と、赤外LED18の周囲温度を検出するサーミスタ19とを備え、制御部16は、サーミスタ19の検出温度Tが基準温度Tよりも低い場合、赤外LED18の1周期あたりの点灯時間を検出温度が基準温度T以上の場合より長くなるように変化させるので、一般に赤外LEDの発光波長は温度が低いと短くなる(波長ずれが生じる)が、赤外LED18の点灯時間を長くすることにより(いわば赤外LED18の自己発熱により)温度を高くして、そのような波長ずれを抑制することができる。これにより、フィルタ14の透過波長域を狭めて撮像に対する太陽光の影響を低減させることができる。 The driver monitoring device according to the present embodiment is reflected by the infrared light irradiation unit 12 that illuminates the driver D of the vehicle 2 by illuminating the driver D of the vehicle 2 by lighting the infrared LED 18, and the driver D. A camera 13 that periodically takes an image of the driver D by the infrared light L 2 , a control unit 16 that periodically turns on the infrared LED 18 in synchronization with the image taken by the camera 13, and the camera 13 having a predetermined wavelength band. A filter 14 for incident infrared light and a thermista 19 for detecting the ambient temperature of the infrared LED 18 are provided, and the control unit 16 of the infrared LED 18 has a detection temperature T lower than the reference temperature T 1 when the detection temperature T of the thermista 19 is lower than the reference temperature T 1. Since the lighting time per cycle is changed so that the detection temperature is longer than when the detection temperature is T 1 or higher, the emission wavelength of the infrared LED is generally shorter when the temperature is low (wavelength shift occurs), but the infrared By lengthening the lighting time of the LED 18, the temperature can be raised (so to speak, by the self-heating of the infrared LED 18), and such wavelength deviation can be suppressed. As a result, the transmission wavelength range of the filter 14 can be narrowed to reduce the influence of sunlight on the image pickup.

ここでは、制御部16は、サーミスタ19の検出温度Tが基準温度T以上の場合、赤外LED18の1周期あたりの点灯時間を検出温度が基準温度T未満の場合より短くなるように変化させるので、赤外LED18の周囲温度が高い場合の赤外LED18の点灯時間を短くして周囲温度を下げることにより波長ずれを抑制し、フィルタ14の透過波長域を長波長側も狭めて撮像に対する太陽光の影響をさらに低減させることができる。 Here, the control unit 16 changes the lighting time per cycle of the infrared LED 18 to be shorter when the detection temperature T of the thermista 19 is equal to or higher than the reference temperature T 2 than when the detection temperature is less than the reference temperature T 2 . Therefore, when the ambient temperature of the infrared LED 18 is high, the lighting time of the infrared LED 18 is shortened to lower the ambient temperature to suppress the wavelength shift, and the transmission wavelength range of the filter 14 is narrowed to the long wavelength side for imaging. The influence of sunlight can be further reduced.

また、フィルタ14には、フロントウインドシールド3で反射された赤外光Lのうち閾値λよりも低波長の光を透過させず、閾値λよりも高波長の光を透過させるロングパスフィルタが用いられているので、撮像に必要な950nm前後の波長の赤外光よりも低波長な太陽光の成分をカットすることができ、撮像に対する太陽光の影響が一層低減する。 Further, the filter 14 is a long-pass filter that does not transmit light having a wavelength lower than the threshold value λ 1 of the infrared light L 2 reflected by the front windshield 3 and transmits light having a wavelength higher than the threshold value λ 1 . Is used, so that it is possible to cut the component of sunlight having a wavelength lower than that of infrared light having a wavelength of about 950 nm, which is necessary for imaging, and the influence of sunlight on imaging is further reduced.

さらに、制御部16は、カメラ13が撮像を行っていない期間で赤外LED18の点灯時間を変化させるので、波長ずれの抑制と撮像中の照明輝度を一定に保つこととを両立させることができる。 Further, since the control unit 16 changes the lighting time of the infrared LED 18 during the period when the camera 13 is not performing imaging, it is possible to suppress the wavelength shift and keep the illumination brightness constant during imaging at the same time. ..

図8は、赤外光の波長帯の光のうち閾値λ=900nmよりも低波長の光を透過させず、閾値λよりも高波長で閾値λ=1000nmよりも低波長の光を透過させ、λ=1000nmよりも高波長の光を透過させないバンドパスフィルタがフィルタ14に用いられる場合の、そのフィルタ14の透過特性を示す。このフィルタ14によると、撮像に必要な950nm前後の波長の赤外光よりも低波長な太陽光の成分と高波長な太陽光の成分をカットすることができ、撮像に対する太陽光の影響が一層低減する。 FIG. 8 shows light in the wavelength band of infrared light that does not transmit light having a wavelength lower than the threshold λ 2 = 900 nm, and emits light having a wavelength higher than the threshold λ 2 and a wavelength lower than the threshold λ 3 = 1000 nm. The transmission characteristics of the filter 14 are shown when a bandpass filter that transmits light and does not transmit light having a wavelength higher than λ 3 = 1000 nm is used for the filter 14. According to this filter 14, it is possible to cut the components of sunlight having a lower wavelength and the components of sunlight having a higher wavelength than the infrared light having a wavelength of about 950 nm required for imaging, and the influence of sunlight on imaging is further increased. Reduce.

以上、本発明を実施するための形態について例示したが、本発明の実施形態は上述したものに限られず、発明の趣旨を逸脱しない範囲で適宜変更等してもよい。 Although the embodiments for carrying out the present invention have been illustrated above, the embodiments of the present invention are not limited to those described above, and may be appropriately modified without departing from the spirit of the invention.

例えば、図9に示すように、表示器ユニット9と平面鏡10との間の表示光Lの光路上に可視光の波長帯の光を透過させて赤外光の波長帯の光を反射させるホットミラー23が設けられ、赤外線照射ユニット12、カメラ13及びフィルタ14は、ホットミラー23を挟んで凹面鏡11の反対側に設けられ、赤外光照射ユニット12から照射された赤外光Lが、ホットミラー23、平面鏡10、凹面鏡11及び遮蔽片15を通過してカバーガラス7から出射し、カバーガラス7から入射した赤外光Lが、遮蔽片15、凹面鏡11、平面鏡10、ホットミラー23及びフィルタ14を通過してカメラ13に入射するように構成してもよい。 For example, as shown in FIG. 9, light in the visible light wavelength band is transmitted on the optical path of the display light L1 between the display unit 9 and the plane mirror 10 to reflect light in the infrared light wavelength band. The hot mirror 23 is provided, and the infrared irradiation unit 12, the camera 13, and the filter 14 are provided on the opposite side of the concave mirror 11 with the hot mirror 23 interposed therebetween, and the infrared light L2 emitted from the infrared light irradiation unit 12 is provided. , The infrared light L2 emitted from the cover glass 7 after passing through the hot mirror 23, the plane mirror 10, the concave mirror 11 and the shield piece 15, and incident from the cover glass 7, is the shield piece 15, the concave mirror 11, the plane mirror 10, and the hot mirror. It may be configured to pass through the 23 and the filter 14 and enter the camera 13.

また、制御部16は、検出温度Tが基準温度Tよりも低い場合、点灯時間を一律にtに変化させるのではなく、検出温度Tに応じて変化させてもよい。図10は、検出温度TがT≦T<T及びT≦T<Tの場合には点灯時間が連続的に変化し、検出温度TがT≦T<Tの場合には点灯時間が不変となっている例を示し、図11は、検出温度TがT≦T<T、T≦T<T、T≦T<Tの各範囲で点灯時間が段階的に変化する例を示す。このような点灯時間の変化方法は、検出温度Tが基準温度T以上の場合にも採用してかまわない。 Further, when the detection temperature T is lower than the reference temperature T 1 , the control unit 16 may change the lighting time according to the detection temperature T instead of uniformly changing the lighting time to t 1 . In FIG. 10, when the detection temperature T is T 5 ≤ T <T 4 and T 3 ≤ T <T 1 , the lighting time changes continuously, and when the detection temperature T is T 4 ≤ T <T 3 , the lighting time changes continuously. Shows an example in which the lighting time does not change, and FIG. 11 shows a lighting time in each range where the detected temperature T is T 5 ≤ T <T 4 , T 4 ≤ T <T 3 , and T 3 ≤ T <T 1 . Is shown as an example in which is changed step by step. Such a method of changing the lighting time may be adopted even when the detected temperature T is equal to or higher than the reference temperature T 2 .

さらに、フィルタ14はカメラ13の外部ではなく内部に設けられてもよく、サーミスタ19は赤外光照射ユニット12の内部ではなく外部に設けられ、赤外LED18の周囲温度として赤外光照射ユニット12の周囲温度を検出してもよい。 Further, the filter 14 may be provided inside the camera 13 instead of outside, and the thermistor 19 is provided outside the infrared light irradiation unit 12 instead of inside the infrared light irradiation unit 12 as the ambient temperature of the infrared LED 18. The ambient temperature of the may be detected.

1 ヘッドアップディスプレイ装置(運転者監視装置)
2 車両
3 フロントウインドシールド(波長選択光学手段)
12 赤外光照射ユニット(照明手段)
13 カメラ(撮像手段)
14 フィルタ(フィルタ手段)
16 制御部(制御手段)
18 赤外LED
19 サーミスタ(温度検出手段)
D 運転者
赤外光
T 検出温度
基準温度
λ 閾値(第一の閾値)
λ 閾値(第二の閾値)
λ 閾値(第三の閾値)
1 Head-up display device (driver monitoring device)
2 Vehicle 3 Front windshield (wavelength selection optical means)
12 Infrared light irradiation unit (illumination means)
13 Camera (imaging means)
14 Filter (filter means)
16 Control unit (control means)
18 infrared LED
19 Thermistor (Temperature detection means)
D Driver L 2 Infrared light T Detection temperature T 1 Reference temperature λ 1 Threshold (first threshold)
λ 2 threshold (second threshold)
λ 3 threshold (third threshold)

Claims (6)

赤外LEDの点灯により車両の運転者に赤外光を照射する照明手段と、
前記運転者で反射された赤外光により前記運転者を周期的に撮像する撮像手段と、
前記撮像手段の撮像に同期させて前記赤外LEDを周期的に点灯させる制御手段と、
前記撮像手段に所定の波長帯の赤外光を入射させるフィルタ手段と、
前記赤外LEDの周囲温度を検出する温度検出手段とを備え、
前記制御手段は、前記温度検出手段の検出温度が基準温度よりも低い場合、前記赤外LEDの1周期あたりの点灯時間を前記検出温度が前記基準温度以上の場合より長くなるように変化させることを特徴とする運転者監視装置。
Lighting means that irradiates the driver of the vehicle with infrared light by lighting the infrared LED,
An imaging means that periodically images the driver with infrared light reflected by the driver, and
A control means for periodically turning on the infrared LED in synchronization with the image pickup of the image pickup means,
A filter means for incident infrared light in a predetermined wavelength band on the image pickup means, and a filter means.
A temperature detecting means for detecting the ambient temperature of the infrared LED is provided.
When the detection temperature of the temperature detecting means is lower than the reference temperature, the control means changes the lighting time per cycle of the infrared LED so as to be longer than when the detection temperature is equal to or higher than the reference temperature. A driver monitoring device characterized by.
前記制御手段は、前記検出温度が前記基準温度よりも低い場合、前記点灯時間を前記検出温度に応じて変化させることを特徴とする請求項1に記載の運転者監視装置。 The driver monitoring device according to claim 1, wherein the control means changes the lighting time according to the detection temperature when the detection temperature is lower than the reference temperature. 前記運転者で反射された赤外光が前記フィルタ手段に入射するまでに通る撮像光路上に、可視光の波長帯の光を透過させて赤外光の波長帯の光を反射させる波長選択光学手段を備えることを特徴とする請求項1又は請求項2に記載の運転者監視装置。 Frequency selection optics that transmits light in the visible light wavelength band and reflects light in the infrared light wavelength band on the imaging light path through which the infrared light reflected by the driver enters the filter means. The driver monitoring device according to claim 1 or 2, wherein the driver monitoring device comprises means. 前記フィルタ手段は、前記赤外光の波長帯の光のうち第一の閾値よりも低波長の光を透過させず、前記第一の閾値よりも高波長の光を透過させるロングパスフィルタであることを特徴とする請求項3に記載の運転者監視装置。 The filter means is a long-pass filter that does not transmit light having a wavelength lower than the first threshold value among the light in the wavelength band of the infrared light and transmits light having a wavelength higher than the first threshold value. 3. The driver monitoring device according to claim 3. 前記フィルタ手段は、前記赤外光の波長帯の光のうち第二の閾値よりも低波長の光を透過させず、前記第二の閾値よりも高波長で第三の閾値よりも低波長の光を透過させ、前記第三の閾値よりも高波長の光を透過させないバンドパスフィルタであることを特徴とする請求項3に記載の運転者監視装置。 The filter means does not transmit light having a wavelength lower than the second threshold of the light in the wavelength band of the infrared light, and has a wavelength higher than the second threshold and a wavelength lower than the third threshold. The driver monitoring device according to claim 3, further comprising a bandpass filter that transmits light and does not transmit light having a wavelength higher than the third threshold. 前記制御手段は、前記撮像手段が撮像を行っていない期間で前記点灯時間を変化させることを特徴とする請求項1乃至請求項5のいずれか1項に記載の運転者監視装置。 The driver monitoring device according to any one of claims 1 to 5, wherein the control means changes the lighting time during a period during which the image pickup means is not performing an image pickup.
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