JP4369573B2 - 3D image detection device - Google Patents

Description

となる。なお、パルス幅Ｔ_D は

と表せる。このとき被写体までの距離ｒは
ｒ＝Ｃ・ＳＭ₁₀／（２・ｋ・Ｎ・Ｒ・Ｉ） ・・・（５）
で表せる。したがって比例定数ｋ、反射率Ｒ、輝度Ｉを予め求めておけば距離ｒが求められる。
【００４３】
図１０は、発光装置１４Ｒ、１４Ｇ、１４Ｂからそれぞれ出力されるレーザ光の出力特性と、ＣＣＤ２８の各フォトダイオードに設けられた色フィルタの透過率特性を表したものである。
【００４４】
曲線Ｔｒ、Ｔｇ、Ｔｂは、ＣＣＤ２８の各フォトダイオード５１にそれぞれ設けられた赤（Ｒ）、緑（Ｇ）、青（Ｂ）の色フィルタが光の波長に対して示す透過率特性を表している。各色フィルタはそれぞれ波長λｒ、λｇ、λｂにおいて透過率が最大であり、波長λｒ、λｇ、λｂから離れるにしたがい各々透過率が減少する。また、曲線Ｐｒ、Ｐｇ、Ｐｂは、発光装置１４Ｒ、１４Ｇ、１４Ｂから出力されるレーザ光の出力特性を表しており、各レーザ光の波長はＲＧＢの色フィルタの透過率特性に合致するように設定されている。すなわち発光装置１４Ｒ、１４Ｇ、１４Ｂはそれぞれ波長λｒ、λｇ、λｂのレーザ光を照射する。波長λｒ、λｇ、λｂのレーザ光は、それぞれ波長領域が極めて狭いので、発光装置１４Ｒ、１４Ｇ、１４Ｂから出力されるレーザ光は、被写体表面で反射され、それぞれの波長に対応するＲＧＢの色フィルタが設けられたフォトダイオード５１においてのみ検出される。これにより被写体のカラー画像が得られる。
【００４５】
波長λｒ、λｇ、λｂのレーザ光は、被写体が配置された距離では略同一の領域に照射され、各光源から照射されるレーザ光の出力もそれぞれ等しい。したがって、２次元画像を検出する際に３つの発光装置を同時に照射すると、ＲＧＢの各色フィルタが配されたフォトダイオード５１では、白色のフラッシュを照射して撮影したときと同様のＲＧＢに関する信号出力が得られる。このことから波長λｒ、λｇ、λｂのレーザ光を発光装置１４Ｒ、１４Ｇ、１４Ｂから同時に照射することにより、フラッシュ照明用の光源として利用することができる。
【００４６】
一方、３次元画像を検出する距離情報検出動作では、被写体の視覚情報である２次元画像の検出とは異なり、発光装置１４Ｒ、１４Ｇ、１４Ｂのうちの何れか１つの光源を測距光として照射すれば、原理的には被写体までの距離情報を検出することができる。図１１（ａ）、図１１（ｂ）、図１１（ｃ）は、ＲＧＢの各色に対応するレーザ光が単独で照射されたときにＲＧＢの各色フィルタが設けられたフォトダイオード５１（図５参照）からの信号電荷の出力を表したものである。すなわち、図１１（ａ）は、発光装置１４Ｒから測距光が単独で照射されたときに、ＲＧＢそれぞれに対応するフォトダイオード５１からの出力を表しており、図１１（ｂ）、図１１（ｃ）は、発光装置１４Ｇ、１４Ｂからそれぞれ測距光が単独で照射されたときのものである。なお、図１１の最上段に示された３つの検出領域Ｒ、Ｇ、Ｂは、それぞれＲＧＢの色フィルタが設けられたフォトダイオード５１とその垂直転送部５２に対応しており（図５参照）、各フォトダイオードの空間的な配置を表している。すなわち、検出領域Ｒには、Ｒの色フィルタが設けられたフォトダイオード５１とそれに隣接する垂直転送部５２が配置されており、検出領域Ｇ、Ｂには、それぞれＧ、Ｂの色フィルタが設けられたフォトダイオード５１とそれに隣接する垂直転送部５２が配置されている。また、破線で仕切られた各区間は、検出領域Ｒ、Ｇ、Ｂにそれぞれ対応を表している。
【００４７】
しかし、単色のレーザ光を被写体に照射した場合、光の反射率は表面の色によって異なるため、ＣＣＤ２８における反射光の受光量は、被写体までの距離だけではなく被写体の色にも影響される。例えば、λｒの波長の光を赤色の被写体に照射するときと、同一距離にある緑色の被写体に照射するときでは、前者の方が後者に比べその受光量が大きくなる。したがって、緑色の場合には信号出力が小さいためＳ／Ｎ比が悪化する。また、被写体が多数の色で構成される場合には、各部分の色の違いによって光の反射率が異なるため、距離情報に被写体各部の色の違いによる誤差が含まれることとなる。
【００４８】
これらのことから本実施形態では、３つの発光装置１４Ｒ、１４Ｇ、１４Ｂを全て照射して被写体までの距離情報の検出を行なっている。発光装置１４Ｒ、１４Ｇ、１４Ｂから照射されるレーザ光は、それぞれ対応する色フィルタを備えたフォトダイオード５１において検出される。図１２は、このときに各色フィルタを備えたフォトダイオード５１から出力される信号電荷を表したものであり、被写体までの距離情報は、これら３つのフォトダイオード５１から出力される信号電荷の和として求められる。１つのフォトダイオード５１において検出される距離情報には、上述のように被写体の色による誤差が含まれる。しかし、３つのフォトダイオードの出力が加算され、Ｒ色光、Ｇ色光、Ｂ色光の距離情報が合成されると、それぞれの距離情報に含まれる誤差が相殺されるため、１つの測距光を用いて測距を行なった場合に比べその誤差を減ずることができる。
【００４９】
以上のように、本実施形態によればＣＣＤの色フィルタ（ＲＧＢの色フィルタ）の透過率特性に合わせた３つのレーザ光源（ＲＧＢの光源）を備えることにより、測距及びフラッシュ照明を行なう際に光源を兼用させることができる。また、ＲＧＢのレーザ光源を全て測距に用いるとともにＲＧＢの各々に対応した信号出力を合成することにより、距離情報に含まれる被写体の色の違いによる誤差を減ずることができる。
【００５０】
なお、本実施形態では、ＣＣＤはＲＧＢの色フィルタを用いていたが他の表色系であってもよいし、色分解プリズムなどを用いたものであってもよい。
【００５１】
本実施形態の距離情報検出動作では、３つの発光装置１４Ｒ、１４Ｇ、１４Ｂ全てを用いて被写体の距離情報の検出を行なったが、被写体の色の違いによって生じる検出距離の誤差が小さいときには、３つの発光装置のうちの何れか１つを単独で用いて測距を行なってもよい。
【００５２】
【発明の効果】
以上のように本発明によれば、３次元画像を検出する際に用いられる測距用光源を、２次元画像を検出する際に照明用の光源として利用できる３次元画像検出装置を得ることができる。
【図面の簡単な説明】
【図１】本発明の実施形態であるカメラ型の３次元画像検出装置の斜視図である。
【図２】図１に示すカメラの回路構成を示すブロック図である。
【図３】測距光による距離測定の原理を説明するための図である。
【図４】測距光、反射光、ゲートパルス、およびＣＣＤが受光する光量分布を示す図である。
【図５】ＣＣＤに設けられるフォトダイオードと垂直転送部の配置を示す図である。
【図６】ＣＣＤを基板に垂直な平面で切断して示す断面図である。
【図７】被写体までの距離に関するデータを検出する距離情報検出動作のタイミングチャートである。
【図８】撮影処理動作のプログラムにおいて距離情報検出動作に関わる部分のフローチャートである。
【図９】撮影処理動作のプログラムにおいて２次元画像検出動作に関わる部分のフローチャートである。
【図１０】ＣＣＤに設けられた色フィルタの透過率特性と、発光装置から照射されるレーザ光の出力特性を表す図である。
【図１１】ＲＧＢに対応したレーザ光のうちの１つを単独で測距光として用いたときに、各色フィルタを備えたフォトダイオードから出力される信号を表したものである。
【図１２】ＲＧＢに対応したレーザ光の全てを測距光として用いたときに、各色フィルタを備えたフォトダイオードから出力される信号を表したものである。
【符号の説明】
１４Ｂ 発光装置（光源）
１４Ｇ 発光装置（光源）
１４Ｒ 発光装置（光源）
２２ 色フィルタ
２８ ＣＣＤ（撮像部）
Ｐｂ 発光装置１４Ｂの出力特性
Ｐｇ 発光装置１４Ｇの出力特性
Ｐｒ 発光装置１４Ｒの出力特性
Ｔｂ 色フィルタ透過率特性
Ｔｇ 色フィルタ透過率特性
Ｔｒ 色フィルタ透過率特性[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional image detection apparatus that detects a three-dimensional shape or the like of a subject using a light propagation time measurement method.
[0002]
[Prior art]
Conventionally, as a three-dimensional image detection device for detecting the distance to a subject for each pixel, those described in “Measurement Science and Technology” (S. Christie et al., Vol. 6, p1301-1308, 1995) Those disclosed in International Publication No. 97/01111 are known. In these three-dimensional image detection apparatuses, pulse-modulated laser light is irradiated onto a subject, and the reflected light is received by a two-dimensional CCD sensor and converted into an electrical signal. At this time, an electrical signal correlated with the distance to the subject can be detected for each pixel of the CCD by one-time shutter operation of an electrical engineering shutter composed of a mechanical or liquid crystal element combined with a two-dimensional CCD. Information on the distance from the electrical signal to the subject is detected for each pixel of the CCD and obtained as a three-dimensional image.
[0003]
[Problems to be solved by the invention]
In these three-dimensional image detection devices, when taking a normal two-dimensional image by CCD video control, it is necessary to provide flash lighting such as a strobe to enable photographing in an environment where illumination light is insufficient. There is.
[0004]
It is an object of the present invention to obtain a three-dimensional image detection apparatus that can use a distance measuring light source used when detecting a three-dimensional image as a light source for illumination when detecting a two-dimensional image.
[0005]
[Means for Solving the Problems]
The three-dimensional image detection apparatus of the present invention irradiates a subject with distance measuring light from a plurality of light sources each irradiating light having different wavelengths, and one or more light sources, and receives the reflected light to obtain a distance to the subject. A distance information detecting means for detecting information; and an image detecting means for detecting a color image of a subject by color-separating incident light, wherein the wavelength of light emitted from each light source is a color separation characteristic in the image detecting means. It is characterized by meeting.
[0006]
Preferably, in color separation, incident light is separated into three primary colors. At this time, the three primary colors are, for example, red, green, and blue.
[0007]
Preferably, the color separation is performed by a plurality of color filters provided in the imaging unit. In this case, preferably, the wavelength of light emitted from each light source is set to a wavelength that maximizes the transmittance of light transmitted through each color filter.
[0008]
Preferably, in driving the image detecting means, each light source emits light at the same time and can be used as a light source for illumination.
[0009]
Preferably, ranging light is emitted from each light source corresponding to each color component separated by color separation, distance information is detected for each color component, and distance information to the subject is detected by combining them.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a camera-type three-dimensional image detection apparatus according to an embodiment of the present invention.
[0011]
A finder window 12 is provided at the upper left of the photographing lens 11 on the front surface of the camera body 10. Three light emitting devices (light sources) 14R, 14G, and 14B are disposed on the upper surface of the camera body 10 and directly above the photographing lens 11. The light emitting devices 14R, 14G, and 14B are light sources for irradiating distance measuring light and are also used as light sources for flash illumination. A release switch 15 and a liquid crystal display panel 16 are provided on the left side of the light emitting devices 14R, 14G, and 14B, and a mode change dial 17 and a V / D mode change switch 18 are provided on the right side. A card insertion slot 19 for inserting a recording medium such as an IC memory card is formed on the side surface of the camera body 10, and a video output terminal 20 and an interface connector 21 are provided.
[0012]
FIG. 2 is a block diagram showing a circuit configuration of the camera shown in FIG.
A diaphragm 25 is provided in the photographic lens 11. The opening degree of the diaphragm 25 is adjusted by the iris drive circuit 26. The focus adjustment operation and zooming operation of the photographic lens 11 are controlled by the lens driving circuit 27.
[0013]
On the optical axis of the photographic lens 11, an RGB color filter 22 and a CCD (imaging unit) 28 are disposed. A subject image is formed on the CCD 28 by the photographing lens 11 and a charge corresponding to the subject image is generated. Operations such as charge accumulation operation and charge read operation in the CCD 28 are controlled by the CCD drive circuit 30. The charge signal read from the CCD 28, that is, the image signal is amplified by the amplifier 31 and converted from an analog signal to a digital signal by the A / D converter 32. The digital image signal is subjected to processing such as gamma correction in the imaging signal processing circuit 33 and temporarily stored in the image memory 34. The iris drive circuit 26, lens drive circuit 27, CCD drive circuit 30, and imaging signal processing circuit 33 are controlled by a system control circuit 35.
[0014]
The image signal is read from the image memory 34 and supplied to the LCD drive circuit 36. The LCD drive circuit 36 operates in accordance with the image signal, whereby an image corresponding to the image signal is displayed on the image display LCD panel 37.
[0015]
If the camera is connected to a monitor TV provided outside the camera body 10 with a cable, the image signal read from the image memory 34 can be transmitted to the monitor TV via the TV signal encoder 38 and the video output terminal 20. . The system control circuit 35 is connected to the interface circuit 40, and the interface circuit 40 is connected to the interface connector 21. Therefore, if the camera is connected to a computer provided outside the camera body 10 via an interface cable, the image signal read from the image memory 34 can be transmitted to the computer. Further, the system control circuit 35 is connected to the image recording device 43 via the recording medium control circuit 42. Therefore, the image signal read from the image memory 34 can be recorded on a recording medium M such as an IC memory card attached to the image recording device 43.
[0016]
The light emitting devices 14R, 14G, and 14B are respectively composed of light emitting elements 13R, 13G, and 13B and illumination lenses 13r, 13g, and 13b, and the light emitting operations of the light emitting elements 13R, 13G, and 13B are controlled by the light emitting element control circuit 44. The light emitting elements 13R, 13G, and 13B are laser diodes (LD), and the laser light emitted from each light emitting element is irradiated to the entire subject via the illumination lenses 13r, 13g, and 13b, respectively. These laser beams are used as ranging light when performing ranging, and are used as illumination light when capturing a normal two-dimensional image. The wavelengths of the laser beams emitted from the light emitting elements 13R, 13G, and 13B correspond to the wavelengths of red (R), green (G), and blue (B), respectively, and the irradiation areas of the respective laser beams are subjects. Is adjusted to be substantially the same at the distance where the
[0017]
The system control circuit 35 includes photometry means 46, a release switch 15, a mode switch dial 17, and a V / D mode switch 18 for determining whether or not illumination is necessary when taking a normal two-dimensional image. A switch group 45 and a liquid crystal display panel (display element) 16 are connected.
[0018]
Next, the principle of distance measurement in this embodiment will be described with reference to FIGS. In FIG. 4, the horizontal axis represents time t.
[0019]
The distance measuring light output from the distance measuring device B is reflected by the subject S and received by a CCD (not shown). The distance measuring light is pulsed light having a predetermined pulse width H. Therefore, the reflected light from the subject S is also pulsed light having the same pulse width H. The rising edge of the reflected light pulse is delayed by a time δ · t (where δ is a delay coefficient) from the rising edge of the ranging light pulse. The distance measuring light and the reflected light have traveled twice as much distance r between the distance measuring device B and the subject S, so that the distance r is r = δ · t · C / 2 (1)
Is obtained. However, C is the speed of light.
[0020]
For example, when the reflected light is detected from the rising edge of the ranging light pulse and switched to the undetectable state before the reflected light pulse falls, that is, when the reflected light detection period T is provided, The received light amount A in the reflected light detection period T is a function of the distance r. That is, the received light amount A decreases as the distance r increases (the time δ · t increases).
[0021]
In the present embodiment, by utilizing the above-described principle, each point on the surface of the subject S is detected from the camera body 10 by detecting the received light amount A in each of a plurality of photodiodes provided in the CCD 28 and two-dimensionally arranged. 3D image data relating to the surface shape of the subject S are input in a lump.
[0022]
FIG. 5 is a diagram showing an arrangement of the photodiode 51 and the vertical transfer unit 52 provided in the CCD 28. FIG. 6 is a cross-sectional view showing the CCD 28 cut along a plane perpendicular to the substrate 53. The CCD 28 is a conventionally known interline CCD, and uses a VOD (vertical overflow drain) system for sweeping out unnecessary charges.
[0023]
The photodiode 51 and the vertical transfer portion 52 are formed along the surface of the n-type substrate 53. The photodiodes 51 are two-dimensionally arranged in a lattice pattern, and the vertical transfer units 52 are provided adjacent to the photodiodes 51 arranged in a line in a predetermined direction (vertical direction in FIG. 5). The vertical transfer unit 52 has four vertical transfer electrodes 52 a, 52 b, 52 c, 52 d for one photodiode 51. Therefore, in the vertical transfer section 52, wells with four potentials can be formed, and signal charges can be output from the CCD 28 by controlling the depths of these wells as is conventionally known. The number of vertical transfer electrodes can be freely changed according to the purpose.
[0024]
A photodiode 51 is formed in a p-type well formed on the surface of the substrate 53, and the p-type well is completely depleted by a reverse bias voltage applied between the p-type well and the n-type substrate 53. In this state, charges corresponding to the amount of incident light (reflected light from the subject) are accumulated in the photodiode 51. When the substrate voltage Vsub is increased to a predetermined value or more, the charge accumulated in the photodiode 51 is swept out to the substrate 53 side. On the other hand, when a charge transfer signal (voltage signal) is applied to the transfer gate portion 54, the charge accumulated in the photodiode 51 is transferred to the vertical transfer portion 52. That is, after the charge is swept to the substrate 53 side by the charge sweep signal, the signal charge accumulated in the photodiode 51 is transferred to the vertical transfer unit 52 side by the charge transfer signal. By repeating such an operation, the signal charges are integrated in the vertical transfer unit 52, and a so-called electronic shutter operation is realized.
[0025]
FIG. 7 is a timing chart in the distance information detection operation, and the distance information detection operation in this embodiment will be described with reference to FIGS. 1, 2, and 5 to 7. In the distance information detection operation of this embodiment, unlike the description of the principle of distance measurement performed with reference to FIG. 4, the distance information is reflected from the falling edge of the distance measuring light pulse in order to reduce noise due to the influence of external light. Although the timing chart is configured so that the light can be detected and switched to an undetectable state after the reflected light pulse falls, there is no difference in principle.
[0026]
A charge sweep signal (pulse signal) S1 is output in synchronization with the output of a vertical synchronization signal (not shown), whereby unnecessary charges stored in the photodiode 51 are swept in the direction of the substrate 53, and the photodiode The accumulated charge amount at 51 becomes zero (reference S2). After the start of the output of the charge sweep signal S1, pulsed ranging light S3 having a constant pulse width is output. The period (pulse width) during which the ranging light S3 is output can be adjusted, and in the illustrated example, the ranging light S3 is adjusted to be turned off simultaneously with the output of the charge sweep signal S1.
[0027]
The distance measuring light S <b> 3 is reflected by the subject and enters the CCD 28. That is, the reflected light S4 from the subject is received by the CCD 28, but no charge is accumulated in the photodiode 51 while the charge sweep signal S1 is being output (reference S2). When the output of the charge sweep signal S1 is stopped, the photodiode 51 starts to accumulate charges by receiving the reflected light S4, and a signal charge S5 caused by the reflected light S4 and external light is generated. When the reflected light S4 is extinguished (reference S6), in the photodiode 51, the charge accumulation based on the reflected light ends (reference S7), but the charge accumulation caused only by the external light continues (reference S8).
[0028]
Thereafter, when the charge transfer signal S9 is output, the charges accumulated in the photodiode 51 are transferred to the vertical transfer unit 52. This charge transfer is completed when the output of the charge transfer signal ends (reference S10). That is, the charge accumulation is continued in the photodiode 51 due to the presence of external light, but the signal charge S11 accumulated in the photodiode 51 is transferred to the vertical transfer unit 52 until the output of the charge transfer signal is completed. The charge S14 accumulated after the completion of the output of the charge transfer signal remains in the photodiode 51 as it is.
[0029]
In this way, during the period T _U1 from the end of the output of the charge sweep signal S1 to the end of the output of the charge transfer signal S9, the signal charge corresponding to the distance to the subject is accumulated in the photodiode 51. Then, the charges accumulated in the photodiode 51 until the reception of the reflected light S4 (symbol S6) is transferred to the vertical transfer unit 52 as a signal charge S12 (shaded portion) corresponding to the distance information of the subject, and other signals. The charge S13 is caused only by outside light.
[0030]
After a predetermined time has elapsed from the output of the charge transfer signal S9, the charge sweep signal S1 is output again, and unnecessary charges accumulated in the photodiode 51 after the transfer of the signal charge to the vertical transfer unit 52 are swept in the direction of the substrate 53. Is issued. That is, signal charge accumulation is newly started in the photodiode 51. As described above, when the charge accumulation period T _U1 has elapsed, the signal charge is transferred to the vertical transfer unit 52.
[0031]
The transfer operation of the signal charge S11 to the vertical transfer unit 52 is repeatedly executed until the next vertical synchronization signal is output. As a result, in the vertical transfer unit 52, the signal charge S11 is integrated, and the signal charge S11 integrated in a period of one field (a period sandwiched between two vertical synchronization signals) is considered that the subject is stationary during that period. If possible, it corresponds to distance information to the subject. Since the signal charge S13 is minute compared to the signal charge S12, the signal charge S11 can be regarded as being equal to the signal charge S12.
[0032]
The detection operation of the signal charge S11 described above relates to one photodiode 51, and such a detection operation is performed in all the photodiodes 51. As a result of the detection operation in the period of one field, distance information detected by the photodiode 51 is held in each part of the vertical transfer unit 52 adjacent to each photodiode 51. This distance information is output from the CCD 28 by the vertical transfer operation in the vertical transfer unit 52 and the horizontal transfer operation in the horizontal transfer unit (not shown), and is taken out of the CCD 28.
[0033]
Next, the distance information detection operation and the two-dimensional image detection operation will be described with reference to FIGS. 8 and 9 which are flowcharts of the shooting processing operation program executed in the present embodiment.
[0034]
If it is confirmed in step 101 that the release switch 15 is fully pressed, step 102 is executed to determine whether the video (V) mode or the distance measurement (D) mode is selected. Switching between these modes is performed by operating the V / D mode switch 18.
[0035]
When the D mode is selected, the variable n is set to 1 in step 102. The variable n is a variable corresponding to each of the light emitting devices 14R, 14G, and 14B, n = 1 corresponds to the light emitting device 14R, n = 2 corresponds to the light emitting device 14G, and n = 3 corresponds to the light emitting device 14B. In step 104, a vertical synchronizing signal is output and ranging light control is started using a light emitting device corresponding to the variable n. That is, the light emitting device 14R is driven, and the pulsed ranging light S3 is intermittently output. Next, step 105 is executed, and detection control by the CCD 28 is started. That is, the distance information detection operation described with reference to FIG. 7 is started, the charge sweep signal S1 and the charge transfer signal S9 are alternately output, and the distance measuring light (R color light) emitted from the light emitting device 14R The signal charge S11 of distance information is integrated in each vertical transfer unit 52.
[0036]
In step 106, it is determined whether one field period has ended since the start of the distance information detection operation, that is, whether a new vertical synchronization signal has been output. When one field period ends, the routine proceeds to step 107, where the signal charge S11 of distance information by R color light is output from the CCD. This signal charge S11 is temporarily stored in the image memory 34 in step 108.
[0037]
In step 109, 1 is added to the variable n, and in step 110, it is determined whether or not n = 4. If it is determined in step 110 that n ≠ 4, the process returns to step 104, and the ranging operation from step 104 to step 108 is performed again. That is, if n = 2, the light emitting device 14G is driven to perform distance measurement, and if n = 3, the light emitting device 14B is driven to perform distance measurement. The distance measuring operation using these light emitting devices 14G and 14B is the same as the distance measuring operation performed by driving the light emitting device 14R. The signal charge S11 of the distance information detected for each distance measuring operation is step 108. Are temporarily stored in the image memory 34. That is, the image memory 34 stores distance information by R color light, G color light, and B color light independently.
[0038]
If it is determined in step 110 that n = 4, the process proceeds to step 111. In step 111, the distance measuring light control is switched to the off state, and all the light emitting operations of the light emitting devices 14R, 14G, and 14B are stopped. In step 112, distance data calculation processing is performed based on distance information detected for each of R color light, G color light, and B color light. The distance data is calculated independently for each distance information of R color light, G color light, and B color light, and is also calculated based on the synthesized distance information by combining the distance information of each color component. That is, in step 112, distance data based on distance information of R color light, distance data based on distance information of G color light, distance data based on distance information of B color light, and distance information of R color light, G color light, and B color light. Distance data based on the distance information obtained by synthesizing is calculated. These distance data are stored in the recording medium M or the like in step 110, and this photographing processing operation ends.
[0039]
On the other hand, when it is determined in step 102 that the V mode is selected, a normal photographing operation (CCD video control) by the CCD 28 is set to the on state in step 114. In step 115, it is determined whether or not the flash is emitted. This is performed based on the photometric result obtained by driving the photometric means 46 (see FIG. 2). If it is determined from the photometric result that flash is necessary, in step 116, flash control of the light emitting devices 14R, 14G, and 14B is started. In step 117, the light emitting devices 14R, 14G, and 14B emit light at the same time and irradiate the subject as flash illumination. At this time, a two-dimensional image is detected, and the data is stored in the recording medium M. As a result, the photographing processing operation ends.
[0040]
If it is determined in step 115 that the flash is not necessary, the flash control of the light emitting devices 14R, 14G, and 14B is started, and the process proceeds to step 117, where a two-dimensional image is detected without emitting the flash. Data is stored in the recording medium M. This completes the photographing processing operation.
[0041]
Next, the contents of the arithmetic processing executed in step 112 will be described with reference to FIG.
Assume that a subject having a reflectance R is illuminated and this subject is regarded as a secondary light source having luminance I and is imaged on a CCD. At this time, the output Sn obtained by integrating the charge generated in the photodiode during the charge accumulation time t is:
Sn = k · R · I · t (2)
It is represented by Here, k is a proportional constant, which varies depending on the F number of the photographing lens, the magnification, and the like.
[0042]
As shown in FIG. 7, the charge accumulation time is T _U1 , the pulse width of the distance measuring light S3 is T _S , the pulse width of the distance information signal charge S12 is T _D, and the charge accumulation time in one field period is N If it is repeated once, the resulting output SM ₁₀ is

It becomes. The pulse width T _D is

It can be expressed. At this time, the distance r to the subject is r = C · SM ₁₀ / (2 · k · N · R · I) (5)
It can be expressed as Therefore, if the proportionality constant k, the reflectance R, and the luminance I are obtained in advance, the distance r can be obtained.
[0043]
FIG. 10 shows the output characteristics of the laser beams output from the light emitting devices 14R, 14G, and 14B, and the transmittance characteristics of the color filters provided in the photodiodes of the CCD 28, respectively.
[0044]
Curves Tr, Tg, and Tb represent transmittance characteristics that the red (R), green (G), and blue (B) color filters provided in the respective photodiodes 51 of the CCD 28 exhibit with respect to the wavelength of light. Yes. Each color filter has the maximum transmittance at wavelengths λr, λg, and λb, and the transmittance decreases as the distance from the wavelengths λr, λg, and λb increases. Curves Pr, Pg, and Pb represent the output characteristics of the laser light output from the light emitting devices 14R, 14G, and 14B, and the wavelength of each laser light matches the transmittance characteristics of the RGB color filters. Is set. That is, the light emitting devices 14R, 14G, and 14B irradiate laser beams having wavelengths λr, λg, and λb, respectively. Since the laser light having the wavelengths λr, λg, and λb has a very narrow wavelength region, the laser light output from the light emitting devices 14R, 14G, and 14B is reflected on the surface of the subject, and RGB color filters corresponding to the respective wavelengths. It is detected only in the photodiode 51 provided with. Thereby, a color image of the subject is obtained.
[0045]
The laser beams having wavelengths λr, λg, and λb are applied to substantially the same region at the distance where the subject is disposed, and the outputs of the laser beams emitted from the respective light sources are also equal. Therefore, when three light emitting devices are simultaneously irradiated when detecting a two-dimensional image, the photodiode 51 provided with the RGB color filters outputs the same RGB signal output as when photographing with a white flash. can get. Therefore, by simultaneously irradiating laser beams of wavelengths λr, λg, and λb from the light emitting devices 14R, 14G, and 14B, it can be used as a light source for flash illumination.
[0046]
On the other hand, in the distance information detection operation for detecting the three-dimensional image, unlike the detection of the two-dimensional image that is the visual information of the subject, any one light source of the light emitting devices 14R, 14G, and 14B is irradiated as the distance measuring light. In principle, distance information to the subject can be detected. 11 (a), 11 (b), and 11 (c) show a photodiode 51 (see FIG. 5) in which RGB color filters are provided when laser beams corresponding to RGB colors are individually irradiated. ) Represents the output of the signal charge from. That is, FIG. 11A shows the output from the photodiode 51 corresponding to each of RGB when the distance measuring light is irradiated from the light emitting device 14R alone, and FIG. 11B and FIG. c) is a case where distance measuring light is individually irradiated from the light emitting devices 14G and 14B. The three detection regions R, G, and B shown at the top of FIG. 11 correspond to the photodiode 51 provided with RGB color filters and its vertical transfer unit 52 (see FIG. 5). , Represents the spatial arrangement of each photodiode. That is, a photodiode 51 provided with an R color filter and a vertical transfer unit 52 adjacent thereto are arranged in the detection region R, and G and B color filters are provided in the detection regions G and B, respectively. A photodiode 51 and a vertical transfer unit 52 adjacent to the photodiode 51 are arranged. In addition, each section partitioned by a broken line represents a correspondence with each of the detection regions R, G, and B.
[0047]
However, when the subject is irradiated with monochromatic laser light, the reflectance of the light varies depending on the color of the surface, and therefore the amount of reflected light received by the CCD 28 is influenced not only by the distance to the subject but also by the subject color. For example, when irradiating a red subject with light having a wavelength of λr and when irradiating a green subject at the same distance, the former receives a larger amount of light than the latter. Therefore, in the case of green, the signal output is small and the S / N ratio is deteriorated. In addition, when the subject is composed of a large number of colors, the reflectance of light varies depending on the color of each part, and thus the distance information includes an error due to the color difference of each part of the subject.
[0048]
Therefore, in the present embodiment, the distance information to the subject is detected by irradiating all the three light emitting devices 14R, 14G, and 14B. Laser light emitted from the light emitting devices 14R, 14G, and 14B is detected by a photodiode 51 having a corresponding color filter. FIG. 12 shows the signal charges output from the photodiodes 51 provided with the respective color filters at this time, and the distance information to the subject is the sum of the signal charges output from these three photodiodes 51. Desired. The distance information detected by one photodiode 51 includes an error due to the color of the subject as described above. However, when the outputs of the three photodiodes are added and the distance information of the R color light, the G color light, and the B color light is combined, an error included in each distance information is canceled out, so one distance measurement light is used. The error can be reduced compared with the case where the distance measurement is performed.
[0049]
As described above, according to the present embodiment, by providing three laser light sources (RGB light sources) that match the transmittance characteristics of the CCD color filter (RGB color filter), distance measurement and flash illumination are performed. Can also be used as a light source. Further, by using all the RGB laser light sources for distance measurement and synthesizing the signal outputs corresponding to each of RGB, it is possible to reduce an error due to the difference in the color of the subject included in the distance information.
[0050]
In this embodiment, the CCD uses RGB color filters. However, other color systems may be used, or a color separation prism or the like may be used.
[0051]
In the distance information detection operation of the present embodiment, the distance information of the subject is detected using all three light emitting devices 14R, 14G, and 14B, but when the detection distance error caused by the color difference of the subject is small, 3 Ranging may be performed using any one of the two light emitting devices alone.
[0052]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a three-dimensional image detection apparatus that can be used as a light source for distance measurement used when detecting a three-dimensional image as a light source for illumination when detecting a two-dimensional image. it can.
[Brief description of the drawings]
FIG. 1 is a perspective view of a camera-type three-dimensional image detection apparatus according to an embodiment of the present invention.
2 is a block diagram showing a circuit configuration of the camera shown in FIG. 1. FIG.
FIG. 3 is a diagram for explaining the principle of distance measurement using distance measuring light;
FIG. 4 is a diagram illustrating distance distribution light, reflected light, gate pulse, and light quantity distribution received by a CCD.
FIG. 5 is a diagram illustrating an arrangement of photodiodes and vertical transfer units provided in a CCD.
FIG. 6 is a cross-sectional view showing a CCD cut along a plane perpendicular to the substrate.
FIG. 7 is a timing chart of a distance information detection operation for detecting data related to a distance to a subject.
FIG. 8 is a flowchart of a portion related to a distance information detection operation in a program for an imaging processing operation.
FIG. 9 is a flowchart of a portion related to a two-dimensional image detection operation in a program for an imaging processing operation.
FIG. 10 is a diagram illustrating transmittance characteristics of a color filter provided in a CCD and output characteristics of laser light emitted from a light emitting device.
FIG. 11 shows a signal output from a photodiode having each color filter when one of laser beams corresponding to RGB is used alone as a distance measuring light.
FIG. 12 shows a signal output from a photodiode provided with each color filter when all laser beams corresponding to RGB are used as distance measuring light.
[Explanation of symbols]
14B Light emitting device (light source)
14G light emitting device (light source)
14R light emitting device (light source)
22 color filter 28 CCD (imaging part)
Pb Output characteristics Pg of the light emitting device 14B Output characteristics Pr of the light emitting device 14G Pr Output characteristics of the light emitting device 14R Tb Color filter transmittance characteristics Tg Color filter transmittance characteristics Tr Color filter transmittance characteristics

Claims (7)

A plurality of light sources each irradiating light of different wavelengths;
Distance information detection means for detecting distance information to the subject by irradiating the subject with ranging light from one or more light sources and receiving the reflected light;
Image detection means for detecting a color image of a subject by color-separating incident light,
3. A three-dimensional image detection apparatus, wherein a wavelength of light emitted from each light source matches a color separation characteristic in the image detection means. The three-dimensional image detection apparatus according to claim 1, wherein in the color separation, the incident light is separated into three primary colors. The three-dimensional image detection apparatus according to claim 2, wherein the three primary colors are red, green, and blue. The three-dimensional image detection apparatus according to claim 1, wherein the color separation is performed by a plurality of color filters provided in an imaging unit. 5. The three-dimensional image detection apparatus according to claim 4, wherein the wavelength of the light emitted from each of the light sources is adjusted to a wavelength that maximizes the transmittance of the light transmitted through each of the color filters. 2. The three-dimensional image detection apparatus according to claim 1, wherein in the driving of the image detection unit, each of the light sources emits light at the same time and can be used as a light source for illumination. Ranging light is emitted from each light source corresponding to each color component separated by the color separation, distance information is detected for each color component, and distance information to the subject is detected by combining them. The three-dimensional image detection apparatus according to claim 1, wherein

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