KR20180036609A - Imaging apparatuses, systems, and moving imaging objects - Google Patents

Abstract

An imaging arrangement comprises a plurality of pixels arranged in a matrix and a signal processing arrangement. Each of a first line and a second line of the matrix includes a light receiving pixel and a reference pixel. The light receiving pixel individually receives incident light and outputs an optical signal based on the incident light. Each reference pixel outputs a pixel signal for forming an address signal. The processing arrangement provides a first address signal and a second address signal. The first address signal indicates a position of the first line and includes a signal value based on the pixel signal from the first line. The second address signal indicates a position of the second line and includes a signal value based on the pixel signal from the second line. The signal value of the first address signal is different from the signal value of the second address signal.

Description

[0001] IMAGING APPARATUS, SYSTEMS, AND MOVING IMAGING OBJECTS [0002]

The present invention relates to an imaging apparatus, an imaging system, a moving body, and a method of operating such a system.

The image pickup apparatus described in Japanese Patent Application Laid-Open No. 2009-118427 includes an effective pixel region and a non-effective pixel region. The effective pixel region is arranged to receive external light and is used for capturing an image. The pixels arranged in the effective pixel region each include a photodiode for generating an electric signal by photoelectric conversion. On the other hand, the entire surface of the non-effective pixel region is covered with a light-shielding film. The non-effective pixel region includes a reference region and a failure-detection pattern region. The pixels arranged in the reference region generate a signal used as a reference of the image signal level. In the failure-detection pattern area, pixels (pixels provided with a photodiode (PD)) each having the photodiodes and pixels (non-PD pixels without pixels) each having no photodiode are arranged. A signal corresponding to a pattern in which these PD pixels and non-PD pixels are arranged is obtained from the failure-detection pattern region. Based on these signals, a fault is judged.

In an exemplary embodiment according to an aspect of the present invention, an imaging device comprises a plurality of pixels arranged in a matrix comprising at least a first row and a second row, wherein each of the first row and the second row Receiving pixel and a reference pixel, wherein the light-receiving pixel receives the incident light and outputs a pixel signal based on the incident light, and the reference pixel outputs a pixel signal for forming an address signal indicating the position of the row to which the reference pixel belongs And the signal value of the address signal output from the first row and the signal value of the address signal output from the second row are different from each other.

In an exemplary embodiment according to another aspect of the present invention, an imaging device includes a plurality of pixels arranged in a matrix comprising at least a first column and a second column, And the light receiving pixel is configured to receive the incident light and output the pixel signal based on the incident light, and the reference pixel is configured to output the pixel signal for forming the address signal indicating the position of the column to which the reference pixel belongs And the signal value of the address signal outputted from the first column and the signal value of the address signal outputted from the second column are different from each other.

In an exemplary embodiment according to another aspect of the present invention, an imaging apparatus includes a plurality of pixels, wherein the plurality of pixels are at least a first light receiving pixel and a second light receiving pixel, and each of the light receiving pixels receives incident light, A first reference pixel arranged to provide a pixel signal in parallel with the pixel signal from the first light receiving pixel, and a second reference pixel arranged to output a pixel signal from the second light receiving pixel, A second reference pixel arranged to provide a pixel signal in parallel with the first reference pixel, and an output control circuit, wherein the pixel signal provided by the first reference pixel and the pixel signal provided by the second reference pixel And control the levels of the pixel signals from the first reference pixel and the second reference pixel, respectively, so as to have different levels.

In an exemplary embodiment according to another aspect of the present invention, an imaging system includes a signal processing unit configured to process a pixel signal output from a light-receiving pixel of an imaging device to provide an image signal based on the pixel signal, The plurality of address signals have different signal values, and the signal processing unit determines whether or not the pixel signals of the light-receiving pixels are normally outputted from the image pickup apparatus based on the plurality of address signals .

Additional features of the present invention will become apparent from the following detailed description of illustrative embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view schematically showing an overall configuration of an image pickup apparatus. Fig.
2A and 2B are diagrams showing equivalent circuits of pixels of an image pickup device, respectively.
3 is a timing chart schematically showing the operation of a pixel of an image pickup apparatus.
4 is a view schematically showing an address signal outputted from an image pickup apparatus;
5 is a flow chart showing a method for judging the operation of the image pickup apparatus;
6A, 6B and 6C schematically show address signals output from the image pickup apparatus;
7 is a view schematically showing an address signal outputted from an image pickup apparatus;
8 is a flow chart showing a method for judging the operation of the image pickup apparatus;
9 is a view for schematically explaining an address signal outputted from an image pickup apparatus;
10 is a view schematically showing an address signal outputted from an image pickup apparatus;
11 is a block diagram showing an exemplary embodiment of an imaging system;
12A and 12B are block diagrams showing an exemplary embodiment of a moving body, respectively.
13 is a view schematically showing a planar configuration of a pixel of an image pickup apparatus;
14 is a view schematically showing a planar configuration of a pixel of an image pickup apparatus;
15A and 15B are diagrams schematically showing a sectional configuration of a pixel of an image pickup apparatus.

According to various exemplary embodiments, the failure can be accurately detected.

According to the technique described in Japanese Patent Application Publication No. 2009-118427, it is determined whether the signal obtained from the failure-detection pattern region matches a predetermined pattern. However, this method has a problem that the failure and malfunction of the imaging apparatus can not be accurately detected. For example, due to a failure of the driving circuit of the imaging device, the pixel signal may not be normally read from the designated pixel in the effective pixel region. On the other hand, when the pixels in the failure-detection pattern region are normal, the signal obtained from the failure-detection pattern region indicates that the imaging apparatus is normally operating. That is, this failure can not be detected despite the failure of the imaging device.

One exemplary embodiment according to the present invention is an imaging device. The imaging device includes a plurality of pixels arranged to form a matrix. The plurality of pixels include a light receiving pixel and a reference pixel. External light is incident on the light receiving pixel from the outside. The light receiving pixel outputs a pixel signal corresponding to the incident light - that is, the light receiving pixel is arranged to provide an optical signal corresponding to the receiving light. The reference pixel outputs a pixel signal for forming an address signal.

The address signal includes information about the position of the row or column. Address signals having different signal values are assigned to at least two rows or two columns. One address signal is formed by a pixel signal from one reference pixel or a pixel signal from a plurality of reference pixels. Thus, for example, at least a first address signal is generated based on a pixel signal from a first row / column of the matrix, and a second address signal is generated based on a pixel signal from a second row / column of the matrix . In this manner, the first address signal is associated with the first row and the second address signal is associated with the second row.

In an exemplary embodiment in which an address signal is formed by a pixel signal from a reference pixel, at least one reference pixel is arranged for each row. And the reference pixels of the other rows output a plurality of pixel signals of different levels. Level means a current value or a voltage value of the pixel signal. The level of the pixel signal of the reference pixel indicates the signal value of the address signal. That is, the signal value of the address signal may be based on the pixel signal - for example, the signal value of the address signal may correspond to the level (s) of one or more pixel signals. In one example, one reference pixel is arranged in each row, a reference pixel in an odd row outputs a high-level pixel signal, and a reference pixel in an even row outputs a low-level pixel signal. With this configuration, it is possible to judge, for example, whether or not the image pickup apparatus reads the signals of the even-numbered rows or the signals of the odd-numbered rows. Alternatively, the reference pixel for each row outputs a pixel signal at a level unique to the row to which the reference pixel belongs. When the image pickup apparatus includes 4000 rows of pixels, the reference pixels output 4000 level pixel signals. With this configuration, it is possible to determine which row of signals the imaging device reads.

In another exemplary embodiment, a plurality of reference pixels are arranged for each row. In this exemplary embodiment, one address signal is formed by pixel signals from a plurality of reference pixels. For example, each of the reference pixels outputs a high-level pixel signal or a low-level pixel signal. When N reference pixels are arranged, the address signal is formed as an N-bit digital signal based on a combination of a high-level pixel signal and a low-level pixel signal. The high-level pixel signal corresponds to "1" in each bit, and the low-level pixel signal corresponds to "0" in each bit. In this case, the arrangement pattern of the digital signal in which 0 and 1 are arranged represents the signal value of the address signal. By arranging the 12 reference pixels, an address signal having a signal value unique to each of 4096 rows can be generated. It is not necessary to generate a unique address signal for each row. The number of reference pixels included in each row for 4096 rows of pixels may be less than 12 reference pixels. In this case, address signals having the same signal value are assigned to a plurality of rows.

In each of the above-described exemplary embodiments, each reference pixel can output at least two pixel signals of different levels. Alternatively, each of the above-described exemplary embodiments may be configured in such a manner that each reference pixel outputs only one level of pixel signals. Also, while an imaging device in which each row includes a reference pixel is cited as an example in the above description, the exemplary embodiment may also be referred to in the present disclosure by replacing the term "row" And the like.

One exemplary embodiment according to the present invention is an imaging system. The imaging system includes a signal processing unit for processing the pixel signals output from the imaging device to acquire an image signal. The signal processing unit further receives an address signal output from the image sensing apparatus, and determines whether or not the pixel signal is normally output from the image sensing apparatus. The address signal may be any address signal described herein-for example, the same as the address signal described in the above-described exemplary embodiment for an imaging device. The method described herein may be used to detect the coupling of the read circuit (s), for example, which provides a control signal to read the pixel signal (s). This makes it possible to more accurately determine whether the pixel signal is normally output from the light-receiving pixel.

In one exemplary embodiment, the signal processing unit determines whether pixel signals of a plurality of rows are output in a predetermined order. The signal processing unit determines whether or not a plurality of address signals sequentially output with the reading of the pixel signals of the plurality of rows are predicted. For example, when address signals having different signal values are assigned to odd-numbered rows and even-numbered rows, the signal processing unit determines whether these address signals having different signal values are alternately output. With this configuration, it is possible to determine whether or not the pixel signals of a plurality of rows are output in a predetermined order.

Alternatively, the signal processing unit judges whether or not the pixel signal of the designated row is appropriately outputted. The signal processing unit determines whether or not the signal value of the address signal output with the pixel signal matches the signal value assigned to the designated row, that is, coincides with the signal value (s) set to be provided by the reference pixel Or not. With this configuration, it is possible to judge whether or not the pixel signal of the predetermined row is output normally.

In this exemplary embodiment, it is determined that while the address signal outputs the predicted signal value, the imaging apparatus operates normally and normally outputs a signal. When the signal value of the address signal differs from the predicted signal value, the signal processing unit judges that the image pickup apparatus does not operate normally or that the image pickup apparatus has failed. Thus, for example, the determination as to whether the light-signal is normally output is based on whether the signal value of the address signal matches the predicted signal value (i.e., the signal value corresponding to the pixel signal that the reference pixel has been set to provide) .

In the present exemplary embodiment, the signal processing unit provided outside the image pickup apparatus determines whether or not the image pickup apparatus normally outputs the pixel signal. On the other hand, in an exemplary embodiment of the image pickup apparatus, a circuit provided inside the image pickup apparatus can judge whether or not the signal is outputted normally. Thus, the determination can be made by the processing arrangement located within or outside the imaging apparatus.

The imaging apparatus and the imaging system described above are used for a camera, a monitoring apparatus, a robot, and the like. Alternatively, the imaging apparatus and the imaging system described above are used in a moving body. Particularly, in a moving body for transporting a person such as a car, an airplane, or a ship, it is desirable that the equipments equipped have high reliability. Thus, the term moving body is a movable object such as a car, boat, airplane, bicycle, or other type of car or robot. Preferably, the moving body may be an autonomous vehicle. More generally, the mobile may also be a vehicle that carries for example goods or people. According to the imaging device and the imaging system of the above-described exemplary embodiments, it is possible to determine whether or not the pixel signals are output normally from the imaging device. Therefore, when a failure occurs in the imaging apparatus, the imaging operation can be stopped and / or a warning indicating occurrence of a failure can be issued.

In various exemplary embodiments, the imaging device or imaging system includes a unit configured to detect an anomaly in a reference pixel. More specifically, when the signal value of the address signal outputted from the reference pixel does not coincide with the predicted signal value, it is judged whether this inconsistency is due to an abnormality or failure of the reference pixel, Is read or not. Such a means can further improve the reliability of the imaging device, the imaging system, or the moving body using them.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the exemplary embodiments described below. The exemplary embodiment of the present invention also includes a modification in which a part of the configuration of the exemplary embodiment described below is changed without departing from the technical spirit of the present invention. Further, exemplary embodiments of the present invention include examples in which some of the constituent elements of the following exemplary embodiments are added to other exemplary embodiments or substituted for some of the constituent elements of other exemplary embodiments.

The first exemplary embodiment will be described. Fig. 1 schematically shows the configuration of an image pickup apparatus according to the first exemplary embodiment. The imaging device has a plurality of pixels (305, 306, 307) arranged to form a matrix. The plurality of pixels includes a light receiving pixel as a pixel 305, an optical black pixel (hereinafter referred to as OB pixel) as a pixel 306, and a reference pixel as a pixel 307. The image pickup device also includes a vertical scanning circuit 301, a column circuit 302, a horizontal scanning circuit 303, an output control circuit 304, an output line 308, a drive control line 309, and an output control line 310 ).

A plurality of pixels 305, 306, and 307 included in one row are connected to a common drive control line 309. The vertical scanning circuit 301 supplies driving signals to the plurality of pixels 305, 306, and 307 through the driving control line 309, respectively. Based on the driving signal, the pixel signals are output from the plurality of pixels 305, 306, and 307 included in one row to the output line 308 in parallel. A plurality of pixels 305, 306, and 307 included in one column are connected to a common output line 308. The pixel signal output to the output line 308 is input to the column circuit 302. One column circuit 302 is disposed for the discrete output line 308. [ The column circuit 302 performs operations such as amplification of a pixel signal, conversion of an analog signal to a digital signal into a pixel signal, maintenance of a pixel signal, noise removal of a pixel signal, and the like. The pixel signals are sequentially read out from the column circuit 302 by the horizontal scanning circuit 303. [

The light-receiving pixel 305 is configured to receive light from the outside. The light-receiving pixel 305 outputs a pixel signal corresponding to the incident light. The OB pixel 306 is covered with a light-shielding film (not shown). The light-shielding film is arranged to expose the light-receiving pixels 305. The OB pixel 306 outputs a pixel signal corresponding to a state in which there is no incident light, that is, a dark level pixel signal. The pixel signal output from the OB pixel 306 may include a different noise component for each pixel. Therefore, the pixel signal output from the OB pixel 306 may be different depending on the position. However, the amount of noise component depends, for example, on manufacturing variations and thermal noise, and is therefore random. Therefore, the pixel signal from the OB pixel 306 is not information for specifying the position of a row or a column.

The reference pixel 307 outputs a pixel signal for forming an address signal. Any of the address signals described above are used in the present exemplary embodiment. In this exemplary embodiment, the output control circuit 304 controls the level of the output signal output from the reference pixel 307. [ More specifically, the output control circuit 304 supplies a predetermined voltage to the output control line 310. The reference pixel 307 outputs a pixel signal having a level corresponding to the voltage of the output control line 310. The reference pixel 307 can be covered with a light-shielding film (not shown). Alternatively, the reference pixel 307 may be exposed because the reference pixel 307 does not have a photodiode.

Next, the configurations of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 will be described. 2A shows equivalent circuits of the light-receiving pixel 305 and the OB pixel 306, respectively. Fig. 2B shows an equivalent circuit of the reference pixel 307. Fig.

2A, each of the light-receiving pixel 305 and the OB pixel 306 includes a photodiode (hereinafter, referred to as PD) 401. The PD 401 converts incident light into electric charge by photoelectric conversion. That is, the PD 401 is an example of the photoelectric conversion unit. Since external light is incident on the PD 401 of the light-receiving pixel 305, the charges generated from the photoelectric conversion are accumulated in the PD 401 of the light-receiving pixel 305. On the other hand, the PD 401 of the OB pixel 306 is cut off from the light. Therefore, charge that can be a noise such as a dark current is accumulated in the PD 401 of the OB pixel 306. The PD 401 of the OB pixel 306 may be omitted.

As shown in FIG. 2B, the reference pixel 307 does not include the PD 401. Instead, reference pixel 307 is connected to output control line 310. In this exemplary embodiment, an output control line 310 for supplying a voltage Va and an output control line 310 for supplying a voltage Vb different from the voltage Va are connected to the reference pixel 307 . The output control circuit 304 selects one of the two output control lines 310 to supply the voltage. With this configuration, the reference pixel 307 can selectively output the pixel signal of the level corresponding to the voltage Va and the pixel signal of the level corresponding to the voltage Vb. When the reference pixel 307 does not output a plurality of pixel signals of different levels, the reference pixel 307 includes an output control line 310 for supplying a voltage Va and an output control line 310 for supplying a voltage Vb 310). ≪ / RTI >

Each of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 includes a transfer transistor 402. The transfer transistor 402 of each of the light-receiving pixel 305 and the OB pixel 306 transfers the charge of the PD 401 to the floating diffusion (FD) node. On the other hand, the transfer transistor 402 of the reference pixel 307 transfers the voltage Va or the voltage Vb to the FD node. The gate of the transfer transistor 402 is connected to a drive control line 309 which supplies a drive signal TX. The transfer transistor 402 is controlled by a drive signal TX.

Each of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 includes an amplifying transistor 404. The FD node is connected to the gate of the amplifying transistor 404. The amplifying transistor 404 outputs a pixel signal based on the voltage of the FD node to the output line 308. [ For example, a current source, not shown, connected to the amplifying transistor 404 and the output line 308 forms a source follower circuit.

Each of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 includes a reset transistor 403. The reset transistor 403 resets the voltage of the FD node. The drain of the reset transistor 403 is connected to the node that supplies the reset voltage Vres. In the present exemplary embodiment, the power source voltage VDD is used as the reset voltage Vres. The gate of the reset transistor 403 is connected to a drive control line 309 for supplying a drive signal RES. The reset transistor 403 is controlled to be turned on and off by the driving signal RES.

Each of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 includes a selection transistor 405. The selection transistor 405 is placed in the electrical path between the amplification transistor 404 and the output line 308. The gate of the selection transistor 405 is electrically connected to the drive control line 309 which supplies the drive signal SEL. The selection transistor 405 is controlled to be switched on and off in accordance with the driving signal SEL. When the selection transistor 405 is turned on, the pixel signal is output from the corresponding amplifying transistor 404 to the output line 308. [ The selection transistor 405 of a part of the pixels among the plurality of pixels connected to one output line 308 is turned on and the remaining selection transistors 405 of the pixels among them are turned off, Is selected. Two or more pixels connected to one output line 308 may be selected at the same time.

With this configuration, the light-receiving pixel 305 can output the pixel signal corresponding to the incident light. The OB pixel 306 can output a pixel signal of a dark level. The reference pixel 307 selectively outputs the pixel signal of the level corresponding to the voltage Va and the pixel signal of the level corresponding to the voltage Vb.

The configuration of each of the light-receiving pixel 305 and the reference pixel 307 will be described in detail. 13 schematically shows the planar configuration of each of the light-receiving pixel 305 and the reference pixel 307 of the image pickup apparatus. In Fig. 13, the same reference numerals as those used in Figs. 2A and 2B are also used to indicate members having the same functions as the members shown in Figs. 2A and 2B.

The power supply wiring 201 is a wiring for transmitting the power supply voltage VDD to the pixels for image capturing. The light-receiving pixel 305 has a semiconductor region 203 which is a part of the PD 401. [ The semiconductor region 203 is a charge accumulation portion in which charges generated from the photoelectric conversion are accumulated. In this example, it is assumed that the conductivity type of the semiconductor region 203 is n-type. It is assumed that electrons accumulated in the semiconductor region 203 are electrons.

The light receiving pixel 305 has a transfer gate 204 of the transfer transistor 402 and a floating diffusion region 205 which is a part of the FD node. 13 shows a configuration in which two light-receiving pixels 305 share one amplifying transistor 404 therebetween. 13 shows a state in which the semiconductor region 203 and the floating diffusion region 205 included in the first light receiving pixel 305A and the pair of the semiconductor region 203 and the floating diffusion region 205 included in the second light receiving pixel 305B, Lt; RTI ID = 0.0 > 205 < / RTI >

The light receiving pixel 305 is connected to the gate 206 (selection gate) of the selection transistor 405, the gate 207 (amplification gate) of the amplification transistor 404 and the gate 208 . Further, the light-receiving pixel 305 includes the FD connection contact 209, the first FD connection wiring 210, and the second FD connection wiring 211. Hereinafter, the contact is referred to as CNT.

The semiconductor region 203 is connected to the floating diffusion region 205 via the transfer gate 204. Charges accumulated in the semiconductor region 203 are transferred to the floating diffusion region 205 via the transfer gate 204. [ The floating diffusion region 205 is connected to the amplification gate 207 via the FD connection CNT 209 and FD connection wirings 210 and 211.

The floating diffusion region 205 is connected to the reset transistor 403 via the FD connecting CNT 209 and the FD connecting wirings 210 and 211.

A part of the configuration of the reference pixel 307 is similar to the light-receiving pixel 305. [ A portion having a configuration similar to the light-receiving pixel 305 is denoted by the same reference numeral as the light-receiving pixel 305. [ The redundant description is omitted here. 13 shows a configuration in which two reference pixels 307 share one amplifying transistor 404 therebetween. 13 shows a state in which the semiconductor region 203 and the floating diffusion region 205 included in the first reference pixel 307A and the semiconductor region 203 and the floating diffusion region 205 included in the second reference pixel 307B, Lt; RTI ID = 0.0 > 205 < / RTI >

The semiconductor region 203 constituting the PD 401 of the reference pixel 307 is connected to the first voltage supply line 212 or the second voltage supply line 213. [ The first voltage supply line 212 or the second voltage supply line 213 is a wiring forming the output control line 310. The connection between the semiconductor region 203 and the first voltage supply line 212 or the second voltage supply line 213 is established via the CNT 215, the wiring 214, and the via 216. The via 216 connects the voltage supply line 212 or 213 and the wiring 214 to each other.

The first voltage supply line 212 and the voltage supply line 213 are disposed on the upper portion of the PD 401 of the reference pixel 307. That is, the first voltage supply line 212 and the PD 401 overlap each other in a plan view relative to the light receiving surface, and the second voltage supply line 213 and the PD 401 overlap with each other.

The potential applied to the semiconductor region 203 via the first voltage supply line 212 or the second voltage supply line 213 in the reference pixel 307 is supplied to the floating diffusion region 205 .

The configuration of each of the light-receiving pixel 305 and the reference pixel 307 described with reference to Fig. 13 will be further described with reference to Fig. 14, with the PD 401 as the center. Fig. 14 shows the light receiving pixel 305, the PD 401 of the reference pixel 307, and the transfer transistor 402. Fig. In Fig. 14, the same reference numerals as those used in Fig. 13 are also used to denote the same members as those shown in Fig.

First, the light-receiving pixel 305 will be described. In the plan view, the semiconductor region 203 in which the charge is accumulated overlaps the p-type semiconductor region 220. As described below with reference to FIGS. 15A and 15B, the p-type semiconductor region 220 functions as a surface protection layer for protecting the surface of the semiconductor region 203. Thereafter, the semiconductor region 220 may be referred to as a surface protection layer.

Next, the reference pixel 307 will be described. In the plan view, the p-type semiconductor region 221 is provided between the portion of the semiconductor region 203 to which the CNT 215 is connected and the transfer gate 204.

Fig. 15A schematically shows a sectional configuration of a pixel taken along the line C-D in Fig. Fig. 15B schematically shows a cross-sectional configuration of a pixel taken along the line A-B in Fig.

First, the light-receiving pixel 305 (cross section corresponding to line C-D) shown in Fig. 15A will be described. A semiconductor region 203 in which charges are accumulated is formed in a lower portion of the p-type semiconductor region 220. With this structure, the p-type semiconductor region 220 functions as a surface protection layer for protecting the surface of the semiconductor region 203. The p-type semiconductor region 220 is formed between the main surface 250 of the semiconductor substrate and the semiconductor region 203.

Next, the reference pixel 307 (cross section corresponding to line A-B) shown in Fig. 15B will be described. The CNT 215 is connected to a part of the semiconductor region 203 in which electric charges are accumulated. The p-type semiconductor region 221 is not formed under the CNTs 215. A p-type semiconductor region 221 is provided between the portion of the semiconductor region 203 to which the CNT 215 is connected and the transfer gate 204. The semiconductor region 203 is provided below the p-type semiconductor region 221 with respect to a portion where the p-type semiconductor region 221 and the semiconductor region 203 overlap with each other in a plan view. The p-type semiconductor region 221 is formed between the main surface 250 of the semiconductor substrate and the semiconductor region 203.

When the conductivity type of the semiconductor region 203 is n-type, the conductivity type of the semiconductor region 221 is p-type. Therefore, the p-type semiconductor region 221 has a lower potential than the semiconductor region 203A. That is, the potential of the p-type semiconductor region 221 is set to the potential between the potential of the transfer gate 204 and the potential of the semiconductor region 203 when the transfer gate 204 is turned off. When the p-type semiconductor region 221 is not formed, an electric field corresponding to the potential difference between the transfer gate 204 and the semiconductor region 203 is applied to the transfer gate 204. On the other hand, in this exemplary embodiment, the provision of the p-type semiconductor region 221 is such that the electric field applied to the transfer gate 204 corresponds to the potential difference between the transfer gate 204 and the p-type semiconductor region 221 To an electric field of the This reduction can make it difficult for the transfer transistor 402 of the reference pixel 307 to fail. That is, according to the pixel configuration of the present exemplary embodiment, the failure of the reference pixel 307 can be caused less.

A semiconductor region having the same conductivity type as that of the semiconductor region 203 and having a higher impurity concentration than the semiconductor region 203 may be provided between the semiconductor region 203 and the CNTs 215. [ According to this configuration, the connection resistance can be reduced.

Next, the operation of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 will be described. 3 is a timing chart of the drive signal SEL, the drive signal RES, and the drive signal TX. When the drive signal is at the high level, the corresponding transistor is turned on. When the driving signal is at the low level, the corresponding transistor is turned off. Figure 3 also shows the voltage at the FD node.

At time T1, the selection transistor 405 is turned on. At this time, the reset transistor 403 is turned on. Therefore, the voltage of the FD node is the reset voltage Vres. After the selection transistor 405 is turned on, the reset transistor 403 is turned off. The amplifying transistor 404 outputs a pixel signal (noise signal) at a level corresponding to the reset voltage Vres to the output line 308.

At time T2, the transfer transistor 402 is turned on. The charge of the PD 401 is transferred to the FD node in each of the light-receiving pixel 305 and the OB pixel 306. [ The voltage of the FD node changes from the reset voltage Vres to the signal voltage Vsig. The amplifying transistor 404 outputs the pixel signal of the level corresponding to the voltage Vsig to the output line 308. [

In the reference pixel 307, when the transfer transistor 402 is turned on, the voltage Va or the voltage Vb output from the output control circuit 304 is supplied to the FD node. When the voltage Va is supplied, the voltage of the FD node changes from the reset voltage Vres to the voltage Va. When the voltage Vb is supplied, the voltage of the FD node changes from the reset voltage Vres to the voltage Vb. The amplifying transistor 404 outputs the pixel signal of the level corresponding to the voltage Va or the voltage Vb to the output line 308. [ The pixel signal output from the reference pixel 307 forms an address signal.

At time T3, the reset transistor 403 is turned on, and subsequently, the selection transistor 405 is turned off. As a result, the reading operation of the pixel signal from each of the plurality of pixels 305, 306, and 307 included in one row is terminated.

The column circuit 302 performs the differential processing of the pixel signal using the noise signal output at the reset time. With this processing, a pixel signal with reduced noise can be obtained. The column circuit 302 further performs processing such as the maintenance of the pixel signal, the conversion from the analog signal to the digital signal, and the like as necessary.

In this exemplary embodiment, the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 included in the same row are connected to a common drive control line 309. [ Therefore, the pixel signals are read out from the reference pixels 307 in parallel with the pixel signals read from the light-receiving pixel 305 and the OB pixels 306, respectively. As described above, the pixel signal from the reference pixel 307 forms an address signal indicating a row to which the reference pixel 307 belongs. Therefore, with this configuration, it is possible to judge whether or not the pixel signal is outputted normally from the designated line. The light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 included in the same row can be connected to the respective separate drive control lines, which are electrically separated from each other. The connection of the light receiving pixel 305, the OB pixel 306, and the reference pixel 307 in the same row to the common drive control line 309 is an example of a configuration in which these pixel signals are read in parallel.

An address signal formed by the pixel signal output from the reference pixel 307 will be described in detail. As an address signal according to the present exemplary embodiment, a digital signal is used. That is, the pixel signal of the reference pixel 307 corresponds to the signal value of each bit of the digital signal. As shown in Fig. 3, the pixel signal of the level corresponding to the voltage Va indicates "0 ", and the pixel signal of the level corresponding to the voltage Vb indicates" 1 ". In order to distinguish the pixel signals from each other, a code D (m, n) is given to the pixel signal. In the code, m represents a row number, and n represents a column number.

4 schematically shows the signal value of the address signal according to the present exemplary embodiment. 4 shows a pixel signal of a reference pixel 307 having 16 rows x 12 columns as an example. However, the number of reference pixels 307 is not limited thereto.

12 reference pixels 307 are included in one row. That is, in the present exemplary embodiment, the address signal is expressed as a 12-bit digital signal. The address signal formed by the pixel signal from the reference pixel 307 of one row includes three sets of sub-signals having the same signal value. For example, in one row, the reference pixels 307 of column numbers 0 to 3 output sub-signals having the signal value "0001 ". Reference pixels 307 in column numbers 4 to 7 in one row output sub signals having the same signal value "0001 ". Then, the reference pixels 307 of column numbers 8 to 11 in one row output sub signals having the same signal value "0001 ".

Further, the address signal has a different signal value for each row. For example, the sub signal of the address signal for the first row has the signal value "0001 ". The sub signal of the address signal for the second row has the signal value "0010 ". "0001" and "0010" are different signal values.

Next, a method for determining whether or not the image pickup apparatus normally outputs the pixel signal based on the address signal will be described. 5 is a flowchart for judging the operation of the image pickup apparatus. This determination processing is performed by, for example, a signal processing unit provided outside the imaging device. Alternatively, this determination processing is performed by the signal processing circuit provided inside the image pickup apparatus.

In step S200, the signal processing unit or circuit acquires the address signal for the Nth row. As described above, the address signal includes three sets of sub-signals.

In step S201, the signal processing unit or circuit determines whether or not the signal values of the three sets of sub signals match each other. When the signal values of the three sets of sub signals match each other, the signal processing unit or circuit judges that there is no abnormality in the reference pixel 307 (NO in step S201). In this case, the process proceeds to the next step (S203). If any one of the three sets of sub-signals has a signal value different from the other signal values, the signal processing unit or circuit determines that there is an abnormality in a part of the reference pixels 307 (YES in step S201). In this case, the process proceeds to step S202.

In step S202, the signal processing unit or circuit adopts the signal value of a plurality of sub signals as an address signal representing this row. That is, in step S202, the signal processing unit or circuit makes judgment by majority decision using three sub-signals. For example, when the signal values of the three sub signals are "0001", "0001", and "0101", the signal processing unit or circuit adopts "0001" as the signal value of the address signal representing the Nth row do.

In step S203, the signal processing unit or circuit generates an address signal having the signal value obtained in the previous step as an address signal representing the Nth row. If the signal values of the three sets of sub signals match each other (NO in step S201), an address signal having such a matching signal value is generated. If any one of the sub signals has a signal value different from the other signal values (YES in step S201), an address signal having a signal value selected by a majority vote is generated in step S202.

In step S204, the signal processing unit or circuit compares the generated address signal with the predicted value of the address signal of the Nth row. If the signal value of the address signal coincides with the predicted value (YES in step S204), the process proceeds to step S205. In step S205, the signal processing unit or circuit judges that the image pickup apparatus operates normally. Then, the process proceeds to the (N + 1) -th read operation.

If the signal value of the address signal does not match the predicted value in step S204 (NO in step S204), the process proceeds to step S207. In step S207, the signal processing unit or circuit judges that the operation of the image pickup apparatus is abnormal. That is, the signal processing unit or circuit judges that a failure has occurred in the image pickup apparatus. In this case, in step S208, the signal processing unit or circuit stops the operation of the image pickup apparatus or issues a warning indicating that a failure has occurred in the image pickup apparatus.

In the above-described manner, in this exemplary embodiment, the pixel signal output from the reference pixel 307 forms an address signal indicating the position of the row to which the reference pixel 307 belongs. With this configuration, it is possible to judge whether or not a pixel signal is output normally from a designated line. As a result, the failure of the imaging device can be accurately detected.

Further, in the present exemplary embodiment, one address signal includes three sets of sub-signals having the same signal value with each other. With such a configuration, even if an error occurs in a part of the reference pixels 307, it is possible to accurately determine whether or not the imaging apparatus is malfunctioning. That is, a plurality of reference pixels 307 included in one row function as a detection unit configured to detect an abnormality of a reference pixel as a whole.

In the above description, the address signal for each row is cited as an example, but the operation of the image pickup apparatus can be determined using the address signal for each column. In this case, the present exemplary embodiment can be realized by replacing the term "row" with the term "column" in the present disclosure.

A second exemplary embodiment will be described. The structure of the address signal is different from that of the image pickup apparatus of the first exemplary embodiment. Therefore, in the following description, the second exemplary embodiment will mainly be described mainly on the differences from the first exemplary embodiment, and description of features similar to those of the first exemplary embodiment will be omitted.

6A, 6B and 6C each schematically show the signal value of the address signal according to the present exemplary embodiment. In the image pickup apparatus shown in Fig. 6A, each row includes one reference pixel 307. In Fig. The reference pixel 307 outputs a pixel signal indicating whether the row to which the reference pixel 307 belongs is an even row or an odd row. For example, the reference pixel 307 of the even-numbered row outputs a pixel signal of a level indicating "0 ". And the odd-numbered reference pixels 307 output a pixel signal having a level indicating "1 ". Other configurations are similar to the first exemplary embodiment, and the description thereof is omitted here.

With this configuration, it is possible to judge whether or not the signals are output from the image pickup apparatus in the correct order. For example, when the operation of outputting the pixel signals in order from all the rows is performed, the signal value of the output address signal alternates between "0" and "1 ". By detecting the change of the address signal, it can be determined that the image pickup apparatus outputs the pixel signal correctly.

Figure 6B illustrates another exemplary embodiment. In the image pickup apparatus shown in Fig. 6B, the reference pixel 307 outputs a pixel signal at a level unique to the row to which the reference pixel 307 belongs. The level of the pixel signal output from the reference pixel 307 represents the signal value of the address signal. That is, the address signal according to the present exemplary embodiment is an analog signal. More specifically, the reference pixel 307 of the 0th row outputs the pixel signal of the level corresponding to the voltage V0. Similarly, the reference pixel 307 of the n-th row outputs a pixel signal of a level corresponding to the voltage Vn. Each of the voltages from the voltage V0 to the voltage Vn has a value different from the other voltage.

With this configuration, it is possible to judge whether or not the pixel signal of the designated row is appropriately outputted. For example, when a pixel signal is read from each of the light-receiving pixel 305 and the OB pixel 306 in the second row, the signal value of the address signal (based on the signal value output from the reference pixel 307) In particular, in this example, the signal V2 (e.g., the signal value predicted to be generated based on the pixel value setting (s) applied to the reference pixel (s) in the second row) ). ≪ / RTI > If they do not coincide with each other, the pixel signal may fail to be read out from each of the light-receiving pixel 305 and the OB pixel 306 in the second row, thereby making it possible to determine that a failure has occurred in the imaging device.

Figure 6C illustrates another exemplary embodiment. In the image pickup apparatus shown in Fig. 6C, one reference pixel 307 is arranged in one column. The reference pixel 307 outputs a pixel signal indicating whether the column to which the reference pixel 307 belongs is an even-numbered column or an odd-numbered column. Other configurations are similar to those described with reference to Fig. 6A. Further, the image pickup device can be configured in such a manner that the reference pixels 307 in the respective columns output pixel signals at different levels as shown in Fig. 6B.

In the above-described manner, according to the present exemplary embodiment, the pixel signal output from the reference pixel 307 forms an address signal indicating the position of the row or column to which the reference pixel 307 belongs. With this configuration, it is possible to determine whether or not the pixel signal is output normally from the designated row or column. As a result, it is possible to accurately detect the failure of the imaging apparatus.

Further, in the present exemplary embodiment, one row includes only one reference pixel 307, or one column includes only one reference pixel 307. [ Therefore, the number of reference pixels 307 can be reduced, which can downsize the size of the imaging device.

This exemplary embodiment does not include a detection unit configured to detect an abnormality of the reference pixel 307. [ Therefore, in the flowchart shown in Fig. 5, steps S201 and S202 are not performed. The pixel signal output from the reference pixel 307 is directly used as an address signal. As a modification of the present exemplary embodiment, a detection unit configured to detect an abnormality of the reference pixel 307 may be added, as in the first exemplary embodiment.

A third exemplary embodiment will be described. The structure of the address signal is different from the first exemplary embodiment. Therefore, in the following description, the third exemplary embodiment mainly focuses on differences from the first exemplary embodiment, and description of features similar to those of the first exemplary embodiment is omitted.

The configuration of the image pickup apparatus according to the present exemplary embodiment is similar to the first exemplary embodiment. That is, Fig. 1 schematically shows the configuration of an image pickup apparatus according to the third exemplary embodiment. A detailed description thereof is omitted here.

The configuration and operation of each of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 according to the present exemplary embodiment are similar to those of the first exemplary embodiment. 2A and 2B respectively show equivalent circuits of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 according to the present exemplary embodiment, respectively. The configurations of the light-receiving pixel 305 and the reference pixel 307 are shown in Figs. 13 to 15A and 15B, respectively. 3 is a timing chart of a drive signal used in the image pickup apparatus according to the present exemplary embodiment. The detailed description is omitted here.

In this exemplary embodiment, the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 included in the same row are connected to a common drive control line 309. [ Therefore, the pixel signals are read out from the reference pixels 307 in parallel with the pixel signals read from the light-receiving pixel 305 and the OB pixels 306, respectively. The pixel signal from the reference pixel 307 forms an address signal indicating a row to which the reference pixel 307 belongs. Therefore, with this configuration, it is possible to determine whether or not the pixel signal is output normally from the designated row. The light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 included in the same row may be connected to the respective electrically-separated drive control lines, respectively. The connection of the light receiving pixel 305, the OB pixel 306, and the reference pixel 307 in the same row to the common drive control line 309 is an example of a configuration in which these pixel signals are read in parallel.

The address signal formed by the pixel signal output from the reference pixel 307 will be described in detail. A digital signal is used as an address signal in accordance with the present exemplary embodiment. That is, the pixel signal of the reference pixel 307 corresponds to the signal value of each bit of the digital signal. As shown in Fig. 3, the pixel signal of the level corresponding to the voltage Va indicates "0 ", and the pixel signal of the level corresponding to the voltage Vb indicates" 1 ". In order to distinguish the pixel signals from each other, a code D (m, n) is given to the pixel signal. In this code, m represents a row number, and n represents a column number.

7 schematically shows the signal value of the address signal according to the present exemplary embodiment. 7 shows a pixel signal of a reference pixel 307 having 16 rows x 7 columns as an example. However, the number of reference pixels 307 is not limited thereto.

Seven reference pixels 307 are included in one row. That is, in the present exemplary embodiment, the address signal is expressed as a 7-bit digital signal. The address signal formed by the pixel signal from the reference pixel 307 of one row includes a sub address signal indicating the position of the row to which the reference pixel 307 belongs and a check signal. The pixel signals output from the reference pixels 307 at column numbers 0 to 3 in each row form a sub-address signal. The pixel signals output from the reference pixels 307 of column numbers 4 to 6 of each row form check signals. The check signal includes information for correcting the error of the address signal. The check signal according to the present exemplary embodiment is set by performing a Hamming encoding operation on the sub address signal. That is, a Hamming code is used as an address signal according to the present exemplary embodiment. As an example other than this example, a check signal can be generated as a parity bit.

The Hamming encoding operation will be described. In the present exemplary embodiment, the sub-address signal is a 4-bit digital signal. D0 to D3 can be used to represent four bits constituting the sub address signal, respectively. The check signal is a 3-bit digital signal. P0 to P2 can be used to represent the three bits constituting the check signal, respectively. The signal value of each bit of the check signal can be obtained by calculating an operation represented by the following equations (1) to (3).

P2 = D3 + D2 + D1 (1)

P1 = D3 + D1 + D0 (2)

P0 = D2 + D1 + D0 (3)

In each of the expressions (1) to (3), "+" means that the logical operation of the exclusive-OR (EXOR) is performed. If the two logical values are different from each other, the operation result is "1 ". When the two logical values are equal to each other, the operation result is "0 ".

The sub address signal of the 0 < th > row has the signal value "0000 ". Therefore, the check signal of the 0 < th > row has the signal value "000 ". The sub-address signal of the first row has the signal value "0001 ". Therefore, the check signal of the first row has the signal value "011 ". The sub-address signal of the second row has the signal value "0010 ". Therefore, the check signal of the second row has the signal value "111 ". For other rows, the signal value of the check signal is also set in a similar manner. In the present exemplary embodiment, the address signal has a signal value for each row.

Next, a method for determining whether or not the image pickup apparatus normally outputs the pixel signal based on the address signal will be described. 8 is a flowchart for judging the operation of the image pickup apparatus. The step in which an operation similar to that of FIG. 5 is performed is indicated by the same step number as in FIG. This determination processing is performed, for example, by a signal processing unit provided outside the imaging apparatus. Alternatively, this determination processing is performed by the signal processing circuit provided inside the image pickup apparatus.

In step S200, the signal processing unit or circuit acquires the address signal for the Nth row. As described above, the address signal includes a sub-address signal and a check signal.

In step S801, the signal processing unit or circuit judges whether an error has occurred in the reference pixel 307 using the address signal encoded according to the Hamming encoding operation. More specifically, the signal processing unit or circuit performs a decoding process on the address signal. With this processing, it is possible to judge which bit among the bits of the address signal has occurred. For the decoding process, a known decoding technique of the Hamming code is used.

If the abnormality of the reference pixel 307 is detected (YES in step S801) in step S801, the signal processing unit or circuit corrects the signal value of the address signal in step S802. More specifically, the signal processing unit or circuit inverts the signal value of the bit corresponding to the reference pixel 307 determined to have an error. Thereafter, the process proceeds to step S803. In the step S801, if the abnormality of the reference pixel 307 is not detected (NO in the step S801), the process directly proceeds to the step S803.

In step S803, the signal processing unit or circuit generates an address signal having the signal value acquired in the previous step as an address signal representing the Nth row. If there is no abnormality in the reference pixel 307 (NO in step S801), an address signal having the signal value of the sub address signal is generated. If there is an error in the reference pixel 307 (YES in step S801), an address signal having a signal value of the sub-address signal corrected in step S802 is generated.

The subsequent operation is similar to the first exemplary embodiment. In step S204, the signal processing unit or circuit compares the generated address signal with the predicted value of the address signal of the Nth row. When the signal value of the address signal coincides with the predicted value (YES in step S204), the process proceeds to step S205. In step S205, the signal processing unit or circuit judges that the image pickup apparatus operates normally. Then, the process shifts to the (N + 1) th row read operation.

If the signal value of the address signal does not match the predicted value in step S204 (NO in step S204), the process proceeds to step S207. In step S207, the signal processing unit or circuit judges that the operation of the image pickup apparatus is abnormal. That is, the signal processing unit or circuit judges that a failure has occurred in the image pickup apparatus. In this case, in step S208, the signal processing unit or circuit stops the operation of the image pickup apparatus or issues a warning indicating that the image pickup apparatus has failed.

In the above-described manner, in the present exemplary embodiment, the pixel signal output from the reference pixel 307 forms an address signal indicating the position of the row to which the reference pixel 307 belongs. With this configuration, it is possible to judge whether or not a pixel signal is output normally from a designated line. As a result, it is possible to accurately detect the failure of the imaging apparatus.

Further, in the present exemplary embodiment, the address signal includes a check signal calculated based on a Hamming encoding operation. With such a configuration, even if an error occurs in a part of the reference pixels 307, it is possible to accurately determine whether or not the imaging apparatus is faulty. That is, the reference pixel 307 for outputting the pixel signal constituting the check signal functions as a detection unit configured to detect an error in the reference pixel.

In the above description, although the address signal for each row is cited as an example, the operation of the imaging device can be determined using the address signal for each column. In this case, the present exemplary embodiment can be realized by replacing the term "row" with the term "column" in the present disclosure.

A fourth exemplary embodiment will be described. The image pickup apparatus according to the present exemplary embodiment is different from the first exemplary embodiment in terms of a configuration in which one reference pixel outputs a plurality of pixel signals at different levels. In addition, the fourth exemplary embodiment is also different from the first exemplary embodiment in terms of a method of detecting anomaly in the reference pixel 307. [ Therefore, in the following description, the fourth exemplary embodiment will be mainly described by focusing on differences from the first exemplary embodiment, and description similar to the first exemplary embodiment will be appropriately omitted.

The configuration of the image pickup apparatus according to the present exemplary embodiment is similar to the first exemplary embodiment. That is, Fig. 1 schematically shows the configuration of an image pickup apparatus according to the fourth exemplary embodiment. A detailed description thereof is omitted here.

The configuration and operation of each of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 according to the present exemplary embodiment are similar to those of the first exemplary embodiment. 2A and 2B each show an equivalent circuit of each of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 according to the present exemplary embodiment. The configuration of each of the light-receiving pixel 305 and the reference pixel 307 is shown in Figs. 13 to 15A and 15B. 3 is a timing chart of the drive signal used in the image pickup apparatus according to the present exemplary embodiment. A detailed description thereof is omitted here.

The reference pixel 307 according to the first exemplary embodiment generates the pixel signal of the level corresponding to the voltage Va and the pixel signal of the level corresponding to the voltage Vb based on the control of the output control circuit 304. [ As shown in FIG. However, in the first exemplary embodiment, one reference pixel 307 does not necessarily output two pixel signals at different levels. On the other hand, the reference pixel 307 according to the present exemplary embodiment is configured to output the pixel signal of the level corresponding to the voltage Va and the pixel of the level corresponding to the voltage (Vb), based on the control of the output control circuit 304 And outputs both signals. The abnormality of the reference pixel 307 can be judged by judging whether the level of the pixel signal outputted from the reference pixel 307 changes as predicted.

In this exemplary embodiment, the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 included in the same row are connected to a common drive control line 309. [ Therefore, the pixels are read out from the reference pixels 307 in parallel with the pixel signals output from the light-receiving pixels 305 and the OB pixels 306, respectively. As described above, the pixel signal from the reference pixel 307 forms an address signal indicating the row to which the reference pixel 307 belongs. Therefore, with this configuration, it is possible to judge whether or not the pixel signal is outputted normally from the designated line. The light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 included in the same row may be connected to the respective electrically-separated drive control lines, respectively. The connection to the common drive control line 309 of the light-receiving pixel 305, the OB pixel 306, and the reference pixel 307 in the same row is an example of a configuration for reading these pixel signals in parallel.

The address signal formed by the pixel signal output from the reference pixel 307 will be described in detail. As an address signal according to the present exemplary embodiment, a digital signal is used. That is, the pixel signal of the reference pixel 307 corresponds to the signal value of each bit of the digital signal. As shown in Fig. 3, the pixel signal of the level corresponding to the voltage Va indicates "0 ", and the pixel signal of the level corresponding to the voltage Vb indicates" 1 ". In order to distinguish the pixel signals from each other, a code D (m, n) is given to the pixel signal. In the code, m represents a row number, and n represents a column number.

9 schematically shows the signal value of the address signal according to the present exemplary embodiment. 9 shows a pixel signal of a reference pixel 307 having 16 rows x 4 columns as an example. However, the number of reference pixels 307 is not limited thereto. Four reference pixels 307 are included in one row. That is, in this exemplary embodiment, the address signal is represented as a 4-bit digital signal.

9 shows an example in which the address signals for the respective rows have different signal values depending on the operation state of the image pickup apparatus. More specifically, the address signal in the odd-numbered frame and the address signal in the even-numbered frame have mutually inverted signal values. For example, the address signal for the second row has the signal value "0010" in the odd frame. On the other hand, the address signal for the second row has the signal value "1101" in the even-numbered frames. Similarly, as shown in Fig. 9, the signal value of each bit of the address signal is inverted between the odd frame and the even frame. The output control circuit 304 switches the voltage supplied to the reference pixel 307 between the voltage Va and the voltage Vb for each frame so that the signal value of each bit of the address signal is inverted .

Now, when there is an error in the reference pixel 307, the level of the pixel signal output from this reference pixel 307 does not change. FIG. 9 shows an example in which the reference pixel 307 is abnormal in column number (2) of the second row. The address signal for the second row has the signal value "0000" in the odd frame. On the other hand, the address signal for the second row has the signal value "1101" in the even-numbered frame. In this way, it can be detected that the signal value D (2, 2) is not inverted and accordingly, the reference pixel 307 is abnormal in the column number 2 of the second row.

Another example of how the signal value of the address signal is changed will be described. 10 schematically shows the signal value of the address signal according to the present exemplary embodiment. 10 shows a pixel signal of a reference pixel 307 having 16 rows x 4 columns as an example. However, the number of reference pixels 307 is not limited thereto. Four reference pixels 307 are included in one row. That is, in this exemplary embodiment, the address signal is represented as a 4-bit digital signal.

In the example shown in Fig. 10, the signal value of the address signal formed by the pixel signal output from the same reference pixel 307 differs between the period during which imaging is performed and the other period. An operation of reading the pixel signal of the reference pixel 307 is performed before outputting the pixel signal from each of the light-receiving pixel 305 and the OB pixel 306 or before imaging corresponding to one frame do. First, the output control circuit 304 supplies a voltage Va corresponding to the signal value "0 " to all the reference pixels 307. [ In this state, the pixel signal of the reference pixel 307 is read. This read operation can be referred to as a read operation of the frame 1 before being picked up. Subsequently, the output control circuit 304 supplies the voltage Vb corresponding to the signal value "1 " to all the reference pixels 307. [ In this state, the pixel signal of the reference pixel 307 is read. This read operation can be referred to as a read operation of the pre-pickup frame 2. When there is no abnormality in the reference pixel 307, all the pixel signals output from the respective reference pixels 307 alternately indicate "0" and "1".

If there is an error in the reference pixel 307, the level of the pixel signal output from the reference pixel 307 does not change. 10 shows an example in which the reference pixel 307 is abnormal in column number (2) of the second row. When the read operation of the pre-image pickup frame 1 and the readout operation of the pre-image pickup frame 2 described above are performed, it is understood that the signal value D (2, 2) is not inverted as shown in Fig. 10 . That is, it is possible to detect that there is an error in the reference pixel 307 in the column number (2) of the second row.

Then, in the case of imaging, the output control circuit 304 selects any one of the voltage Va and the voltage Vb so that the address signal for each row has a signal value unique to the row to which the address signal belongs And supplies it to the reference pixel 307.

In this way, according to the image pickup apparatus of the present exemplary embodiment, the abnormality of the reference pixel 307 can be detected by the method shown in Fig. 9 or Fig. When the address signal including the pixel signal of the abnormal reference pixel 307 is received, for example, it is possible to restrict (i.e., not compare) the comparison between the address signal and the predicted value (As opposed to step S204 shown in FIG. 8). This process can reduce the possibility of erroneously determining that a failure has occurred in the imaging apparatus. In other words, in the present exemplary embodiment, the output control circuit 304 functions as a detection unit configured to detect an abnormality of the reference pixel.

In a fifth exemplary embodiment, an imaging system is described. Examples of imaging systems include digital still cameras, digital camcorders, camera heads, copiers, fax machines, cell phones, in-vehicle cameras, and observation satellites. Fig. 11 shows a block diagram of a digital still camera as an example of an image pickup system.

In Fig. 11, the barrier 1001 serves to protect the lens. The lens 1002 allows an optical image of an object to be formed in the image pickup apparatus 1004. The diaphragm 1003 functions to change the amount of light transmitted through the lens 1002. The imaging apparatuses described in any of the above-described individual exemplary embodiments are used as the imaging apparatus 1004. [

The signal processing unit 1007 performs processing such as correction and data compression on the pixel signals output from the image capturing apparatus 1004 and acquires image signals. 11, the timing generating unit 1008 outputs various timing signals to the image capturing apparatus 1004 and the signal processing unit 1007, and the overall control unit 1009 controls the entire digital still camera as a whole. The frame memory unit 1010 has a function of temporarily storing image data. The recording medium control interface unit 1011 has a function of recording on the recording medium or reading the recording medium. A removable recording medium 1012 such as a semiconductor memory has a function of reading or writing image pickup data. The interface unit 1013 functions to communicate with an external computer or the like.

The imaging system must include at least the imaging device 1004 and the signal processing unit 1007 that processes the pixel signals output from the imaging device 1004. [ In that case, another configuration is arranged outside the imaging system.

In the present exemplary embodiment, the signal processing unit 1007 judges whether or not a pixel signal is normally output from the image pickup apparatus 1004. Therefore, the signal processing unit 1007 receives a plurality of address signals output from the image pickup apparatus 1004. The address signal output from the image pickup apparatus 1004 is similar to the address signal described in any of the above-described individual exemplary embodiments. The method by which the signal processing unit 1007 judges the operation of the image capturing apparatus 1004 is similar to the method described in the description of the flowchart and described in Fig. 5 or Fig. That is, the description of the first to fourth exemplary embodiments is incorporated in its entirety by this exemplary embodiment.

The signal processing unit 1007 can also judge whether there is an abnormality in the reference pixel 307 included in the image pickup apparatus 1004 based on the address signal. More specifically, as shown in Fig. 5, the signal processing unit 1007 compares the signal values of the three sub-signals included in each address signal, and compares the signal values of the two or more sub- The operation of the image sensing apparatus 1004 is determined.

Alternatively, as shown in Fig. 8, the signal processing unit 1007 corrects the address signal using the check signal included in each address signal. Then, the signal processing unit 1007 judges the operation of the image pickup apparatus 1004 based on the sub address signal included in the address signal after correction. The sub signal and the check signal are similar to those described in the third exemplary embodiment.

The signal processing unit 1007 does not necessarily detect whether there is an abnormality in the pixel. For example, when the imaging apparatus according to the second exemplary embodiment is used, the signal processing unit 1007 does not detect whether there is an abnormality in the pixel.

In the above-described manner, in an exemplary embodiment of the image pickup system, an image pickup apparatus according to any one of the first to fourth exemplary embodiments is used as the image pickup apparatus 1004. According to this configuration, it is possible to accurately detect the failure of the image sensing apparatus 1004.

In a sixth exemplary embodiment, a moving body is described. The moving body according to the present exemplary embodiment is an automobile having an in-vehicle camera. 12A schematically shows an appearance and a main internal configuration of the automobile 100. Fig. The vehicle 100 includes an imaging device 102, an imaging system integrated circuit, in particular an application specific integrated circuit (ASIC) 103, a warning device 112, and a main control unit 113.

Any one of the imaging apparatuses described in the first to fourth exemplary embodiments described above is used as each of the imaging apparatuses 102. [ The alarm device 112 issues a warning to the driver when receiving a signal indicating an abnormality from the image pickup system, the vehicle sensor, the control unit or the like. The main control unit 113 comprehensively controls the operations of the imaging system, the vehicle sensor, the control unit, and the like. The automobile 100 does not need to have the main control unit 113. [ In this case, the imaging system, the vehicle sensor, and the control unit each have separate communication interfaces, each of which transmits and receives control signals through a communication network (e.g., the Measurement Controller Network (CAN) standard).

12B is a block diagram showing a system configuration of the automobile 100. As shown in Fig. The automobile (100) includes a first imaging device (102) and a second imaging device (102). That is, the in-vehicle camera according to the present exemplary embodiment is a stereo camera. An image of the subject is formed in each of the imaging apparatuses 102 by the optical unit 114. The pixel signals output from each of the imaging devices 102 are processed by the image preprocessing unit 115 and transferred to the imaging system integrated circuit 103. The image preprocessing unit 115 performs processing such as signal-noise (S-N) operation and addition of a synchronization signal.

The imaging system integrated circuit 103 includes an image processing unit 104, a memory 105, an optical frame unit 106, a parallax calculation unit 107, an object recognition unit 108, an anomaly detection unit 109, And an interface (I / F) unit 116. The image processing unit 104 processes the pixel signal to generate an image signal. Further, the image processing unit 104 corrects the image signal and compensates for the abnormal pixel. The memory 105 temporarily stores the image signal therein. Further, the memory 105 can internally store the position of the abnormal pixel in the known image pickup device 102. [ The optical focal plane unit 106 measures the distance to the subject using the image signal or focuses the image capture device 102 on the subject. The time difference arithmetic unit 107 performs object matching (stereo matching) between parallax images. The object recognition unit 108 analyzes the image signal and recognizes a subject such as a car, a person, a sign, and a road. The anomaly detection unit 109 detects a failure or a malfunction of each of the imaging apparatuses 102. When the malfunction detection unit 109 detects a malfunction or malfunction, the malfunction detection unit 109 transmits a signal indicating that the malfunction has been detected to the main control unit 113. [ The external I / F unit 116 mediates supply and reception of information between each unit of the imaging system integrated circuit 103 and, for example, the main control unit 113 or various control units.

The vehicle 100 includes a vehicle information obtaining unit 110 and a driving support unit 111. [ The vehicle information obtaining unit 110 includes a vehicle sensor such as a speed / acceleration sensor, an angular velocity sensor, a steering angle sensor, a sidelight radar, and a pressure sensor.

The driving support unit 111 includes a collision determination unit. The collision judging unit judges whether or not the automobile 100 can collide with an object based on the information from the optical ground unit 106, the parallax arithmetic unit 107, and / or the object recognition unit 108. [ The optical side unit 106 and the parallax calculating unit 107 are examples of the distance information obtaining unit for obtaining the distance information to the object. That is, the distance information refers to information about parallax, defocus amount, distance to the object, and / or the like. The collision judging unit can judge the possibility of collision using any of these distance information. The distance information obtaining unit can be realized by dedicated designed hardware or can be realized by a software module.

Although the present exemplary embodiment has been described on the basis of an example in which the driving support unit 111 controls the automobile 100 so as to prevent the automobile 100 from colliding with another object, A control for automatically operating the automobile 100 so as to prevent the automobile 100 from deviating from the lane, and the like.

The automobile 100 further includes a drive unit used when the automobile 100 travels, such as an airbag, an accelerator, a brake, a steering, and a transmission. In addition, the automobile 100 includes a control unit for these. The control units control the corresponding drive units based on the control signals from the main control unit 113, respectively.

In the present exemplary embodiment, the anomaly detection unit 109 of the imaging system integrated circuit 103 determines whether or not the pixel signals are normally output from each of the imaging devices 102. Accordingly, the anomaly detection unit 109 receives a plurality of address signals output from each of the image pickup devices 102. [ The address signals output from each of the image pickup devices 102 are similar to the address signals described in any of the above-described individual exemplary embodiments. The manner in which the anomaly detection unit 109 determines the operation of each of the imaging apparatuses 102 is similar to the method described in Fig. 5 or 8 and the method described in the description of this flowchart. That is, the description of the first to fourth exemplary embodiments is entirely integrated in this exemplary embodiment.

Further, the anomaly detection unit 109 can determine whether there is an abnormality in the reference pixels 307 included in each of the image pickup apparatuses 102 based on the address signals. More specifically, as shown in Fig. 5, the anomaly detection unit 109 compares the signal values of the three sub signals included in each address signal, and compares the signal values of two or more sub signals The operation of each of the imaging apparatuses 102 is determined.

Alternatively, as shown in Fig. 8, the abnormality detection unit 109 corrects the address signal using the check signal included in each address signal. Then, the abnormality detection unit 109 judges the operation of each of the image pickup apparatuses 102 based on the sub address signals contained in the address signals after the correction. The subsignals and check signals are similar to those described in the third exemplary embodiment.

The anomaly detection unit 109 does not necessarily detect whether there is an abnormality in the pixel. For example, when the image pickup apparatus according to the second exemplary embodiment is used, the anomaly detection unit 109 does not detect whether there is an abnormality in the pixel. In addition, the detection of the failure and the detection of the reference pixel 307 having an error can be performed by the image preprocessing unit 115 and / or the image processing unit 104. [

The imaging system used in the present exemplary embodiment is not applied to an automobile only, and can be applied to a moving object (mobile device) such as a ship, an aircraft, or an industrial robot, for example. Further, the imaging system used in the present exemplary embodiment can be applied to an apparatus widely used for object recognition, such as a highway traffic system (ITS), without being acted on only a moving object.

In the above-described manner, in the exemplary embodiment of the automobile, any one of the image pickup apparatuses according to the first to fourth exemplary embodiments is used as each of the image pickup apparatuses 102. [ According to this configuration, it is possible to accurately detect the failure of the imaging device.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims (39)

An imaging device comprising:
A plurality of pixels arranged in a matrix including at least a first row and a second row,
Wherein each of the first row and the second row includes a light receiving pixel and a reference pixel, the light receiving pixel receives the incident light and outputs a pixel signal based on the incident light, And to output a pixel signal for forming an address signal indicating a position of a row,
Wherein a signal value of the address signal outputted from the first row and a signal value of the address signal outputted from the second row are different from each other. The method according to claim 1,
And a detection unit configured to detect an abnormality in the reference pixel. 3. The method according to claim 1 or 2,
Wherein each of the first row and the second row includes a plurality of the reference pixels,
Wherein the address signal comprises three or more sub-signals having the same signal value. 3. The method according to claim 1 or 2,
Wherein each of the first row and the second row includes a plurality of the reference pixels,
Wherein the address signal includes a check signal based on a Hamming encoding operation. 3. The method according to claim 1 or 2,
Wherein each of the first row and the second row outputs a plurality of the address signals having different signal values from each other. 6. The method of claim 5,
Wherein the reference pixel is arranged to change a pixel signal output according to each frame of the imaging operation so that the signal value of the address signal changes according to each frame of the imaging operation. 6. The method of claim 5,
The signal value of the address signal in the first period in which the pixel signal of the light-receiving pixel is read out is different from the signal value of the address signal in the second period different from the first period. 3. The method according to claim 1 or 2,
Wherein the reference pixels are configured to output a plurality of pixel signals having different voltages. 3. The method according to claim 1 or 2,
And a control line connected to both the light-receiving pixel and the reference pixel located in the first row. 3. The method according to claim 1 or 2,
And a light shielding film which is arranged to cover the reference pixel and expose the light receiving pixel with respect to incident light. 3. The method according to claim 1 or 2,
Wherein the reference pixels in the first row are arranged to provide the pixel signals in parallel with the pixel signals from the light-receiving pixels in the first row, and the reference pixels in the second row are arranged to receive the light- And is arranged to provide the pixel signal in parallel with the pixel signal from the pixel. 3. The method according to claim 1 or 2,
Wherein the reference pixel is arranged to provide a plurality of different pixel signals at different levels and the imaging device comprises control circuitry arranged to provide a control signal to the reference pixel to control the level of the pixel signal, . The method of claim 3,
Wherein the detection unit of the image pickup apparatus comprises:
And compare the signal values in the at least three sub-signals of the address signal and to determine whether there is an abnormal reference pixel based on one sub-signal different from the other sub- Device. 5. The method of claim 4,
Wherein the detection unit of the image pickup apparatus is arranged to judge whether or not there is an abnormal reference pixel based on the check signal. 15. The method of claim 14,
Wherein the detection unit of the imaging device is arranged to correct the signal value of the first address signal based on the check signal. An imaging device comprising:
A plurality of pixels arranged in a matrix including at least a first column and a second column,
Wherein each of the first column and the second column includes a light receiving pixel and a reference pixel, the light receiving pixel is configured to receive incident light and output a pixel signal based on the incident light, And to output a pixel signal for forming an address signal indicating a position of a column,
Wherein a signal value of the address signal outputted from the first column and a signal value of the address signal outputted from the second column are different from each other. 17. The method of claim 16,
And a detection unit configured to detect an abnormality in the reference pixel based on the address signal. 18. The method according to claim 16 or 17,
Wherein each of the first column and the second column outputs a plurality of the address signals having different signal values from each other. 18. The method according to claim 16 or 17,
Wherein the reference pixels are configured to output a plurality of pixel signals having different voltages. An imaging device comprising:
As a plurality of pixels,
A first light-receiving pixel and a second light-receiving pixel configured as a first light-receiving pixel and a second light-receiving pixel, each of the light-receiving pixels receiving incident light and outputting a pixel signal based on the incident light;
A first reference pixel arranged to provide a pixel signal in parallel with the pixel signal from the first light-receiving pixel; And
And a second reference pixel arranged to provide a pixel signal in parallel with the pixel signal from the second light-receiving pixel,
A plurality of pixels,
And an output control circuit for outputting the pixel signal from the first reference pixel and the second reference pixel so that the pixel signal provided by the first reference pixel and the pixel signal provided by the second reference pixel have different levels, And an output control circuit configured to control a level of the pixel signal. 21. The method of claim 20,
Wherein the plurality of pixels include:
Wherein each of the first reference pixels is arranged to provide respective pixel signals in parallel with the pixel signals from the first light receiving pixels,
Each of the second reference pixels being arranged to provide respective pixel signals in parallel with the pixel signals from the second light-receiving pixels, as a plurality of second reference pixels, . 22. The method of claim 21,
The first reference pixel is arranged to provide a high-level pixel signal or a low-level pixel signal, respectively,
Wherein the plurality of pixel signals provided from the plurality of first reference pixels form a plurality of signals having the same value represented by the same combination of the high-level pixel signal and the low-level pixel signal. 23. The method according to any one of claims 20 to 22,
The first light receiving pixel and the first reference pixel are connected to a first drive control line,
And the second light receiving pixel and the second reference pixel are connected to a second drive control line electrically disconnected from the first drive control line. 23. The method according to any one of claims 20 to 22,
Wherein each of the first reference pixel and the second reference pixel is configured to provide a plurality of pixel signals at different levels from each other. 23. The method according to any one of claims 20 to 22,
And a detection unit configured to detect an abnormality in the first reference pixel and the second reference pixel. 23. The method according to any one of claims 20 to 22,
And a light shielding film arranged to cover the first reference pixel and the second reference pixel and to expose the first light receiving pixel and the second light receiving pixel with respect to the incident light. An imaging system comprising:
An image pickup apparatus according to any one of claims 1, 16 and 20,
And a processing device configured to process the pixel signal output from the light-receiving pixel of the imaging device and to provide an image signal based on the pixel signal. Mobile,
An image pickup apparatus according to any one of claims 1, 16 and 20,
A processing device configured to perform processing on the pixel signal output from the light-receiving pixel of the imaging device;
And a control unit configured to control the moving body based on a result of the processing. An imaging system comprising:
And a signal processing unit configured to process a pixel signal output from the light-receiving pixel of the imaging device and to provide an image signal based on the pixel signal,
Wherein the signal processing unit receives a plurality of address signals outputted from the image pickup device, the plurality of address signals having different signal values,
Wherein the signal processing unit determines whether or not a pixel signal of the light-receiving pixel is normally outputted from the image pickup apparatus, based on the plurality of address signals. 30. The method of claim 29,
Each of the address signals comprising three or more sub-signals having the same signal value,
For one or more address signals, the signal processing unit compares the signal values in the three or more sub signals and, based on two or more sub signals having the same signal value, To be output normally. 30. The method of claim 29,
Each of the address signals including a check signal based on a Hamming encoding operation,
Wherein the signal processing unit is arranged to correct at least one of the address signals based on the check signal. 32. The method according to any one of claims 29 to 31,
Further comprising a control unit configured to stop the operation of the imaging device when the signal processing unit determines that the pixel signal from the light-receiving pixel is not normally output from the imaging device. Mobile,
32. An imaging system, comprising: an imaging system according to any one of claims 29 to 31;
And a control unit configured to control the moving object based on the image signal. 34. The method of claim 33,
Further comprising a warning device configured to issue a warning indicating that there is an error in the operation of the imaging device when the signal processing unit determines that the pixel signal from the light receiving pixel is not output normally from the imaging device, . A method for determining an abnormality in an imaging arrangement,
The imaging arrangement comprising a matrix of pixels, the lines of the matrix comprising a plurality of reference pixels each arranged to provide different levels of pixel signals,
A method for determining an abnormality in the imaging arrangement,
Setting a different set of reference pixels to provide the same set of pixel signals,
Generating an address signal that includes three or more sub-signals, each sub-signal having a signal value based on a set of pixel signals from a different set of the reference pixels;
Comparing signal values in the at least three sub-signals,
Determining whether there is an anomalous reference pixel in a line of the matrix based on one sub-signal different from other sub-signals of the sub-signal. 36. The method of claim 35,
Determining a most common signal value within the address signal;
Generating a new address signal having the most common signal value;
Comparing the predicted value of the address signal with the new address signal;
And determining that the imaging device operates abnormally when the new address signal is different from the predicted value of the address signal. A method for determining an abnormality in an imaging arrangement,
Wherein the imaging array comprises a matrix of pixels and the lines of the matrix each comprise a plurality of reference pixels arranged to provide different levels of pixel signals,
A method for determining an abnormality in the imaging arrangement,
Generating an address signal including a check signal based on a signal value of the set of reference pixels;
And determining whether an abnormal reference pixel is present in the set of reference pixels based on the check signal. An imaging system comprising:
An image pickup apparatus according to claim 15,
And a processing device configured to process the pixel signal output from the light-receiving pixel of the imaging device to acquire an image signal. Mobile,
An image pickup apparatus according to claim 15,
A processing device configured to perform processing on the pixel signal output from the light-receiving pixel of the imaging device;
And a control unit configured to control the moving body based on a result of the processing.

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