JP2019125987A - Camera evaluation system - Google Patents

Abstract

To provide a camera evaluation system capable of evaluating a camera with high reproducibility.SOLUTION: A camera evaluation system 1 includes an image display device 3 and a data analysis device 2. The image display device 3 is asynchronous with a camera 4 to be evaluated, and displays a display image PV having a predetermined frame rate PF on the basis of input video data VD. A data analysis device 2 analyzes the detection result data PD generated on the basis of a captured image CV obtained by imaging the display image PV by the camera 4. The image display device 3 has a liquid crystal display device 20 which displays the display image PV in a frame-sequential manner by switching it for each frame.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a camera evaluation system.

  In the case of newly developing a camera as described in Patent Document 1, evaluation of the camera is performed by photographing a different place with the camera under development.

Unexamined-Japanese-Patent No. 2004-247979

  Therefore, it takes time for evaluation, and the photographing conditions differ depending on the weather or the photographing time even in the same place, so it is difficult to evaluate the camera with good reproducibility.

  An object of the present invention is to provide a camera evaluation system capable of evaluating a camera with good reproducibility.

  The present invention is an image display device that is asynchronous to a camera to be evaluated and displays a display image having a predetermined frame rate based on input video data, and based on a captured image obtained by capturing the display image by the camera Camera evaluation system characterized by comprising a data analysis device for analyzing detection result data generated by the image display device, and the image display device including a liquid crystal display device for switching the display image for each frame and displaying the I will provide a.

  According to the camera evaluation system of the present invention, the camera can be evaluated with good reproducibility.

It is a block diagram which shows the camera evaluation system of one Embodiment. It is a block diagram which shows the projector in the camera evaluation system of one Embodiment. It is a figure which shows the timing of the frame rate of a display image, the frame rate of a camera, and the exposure time of a camera. It is a figure which shows the timing of the frame rate of a display image, the frame rate of a camera, and the exposure time of a camera. It is a figure which shows the timing of the frame rate of a display image, the frame rate of a camera, and the exposure time of a camera. It is a figure which shows the timing of the frame rate of a display image, the frame rate of a camera, and the exposure time of a camera. It is a figure which shows the timing of the frame rate of a display image, the frame rate of a camera, and the exposure time of a camera.

  A camera evaluation system according to an embodiment will be described with reference to FIG. A camera evaluation system 1 for evaluating a camera 4 to be evaluated includes a data analysis device 2 and an image display device 3. A moving image captured under a variety of conditions according to different places, different times, different weather, or different seasons is input to the image display device 3 as video data VD.

  The case where a projector is used as the image display device 3 will be described. The image display device 3 is configured of a projector 10 and a screen 6. Video data VD is input to the projector 10. The projector 10 generates a moving image based on the video data VD and projects it on the screen 6. The moving image is projected on the screen 6 as a display image PV. That is, the projector 10 displays the display image PV having a predetermined frame rate on the screen 6.

  The camera 4 to be evaluated captures the display image PV projected on the screen 6 as a captured image CV. When the camera 4 is an on-vehicle camera, the camera 4 detects, for example, a center line on the road based on the captured image CV, generates detection result data PD, and outputs the detection result data PD to the data analysis device 2. The data analysis device 2 analyzes the detection result data PD. The camera 4 is evaluated based on the analysis result.

  The projector 10 will be described with reference to FIG. The projector 10 includes an image data processing unit 11 and a liquid crystal display device 20. The video data processing unit 11 may be configured by software executed by a CPU (Central Processing Unit), or may be configured by hardware such as a circuit.

  Video data VD is input to the video data processing unit 11 as a digital signal. The video data processing unit 11 converts the video data VD into a video signal VS which is an analog signal, and sequentially outputs the video data VD to the liquid crystal display device 20 in pixel units.

  The liquid crystal display device 20 is a field sequential active matrix type liquid crystal display device that switches and displays a moving image (display image PV) for each frame. The liquid crystal display device 20 includes a horizontal scanning circuit 21, a vertical scanning circuit 22, and a display pixel unit 23. The horizontal scanning circuit 21 receives the video signal VS from the video data processing unit 11 sequentially in pixel units.

  The horizontal scanning circuit 21 is connected to a plurality of (x) column data lines D (D1 to Dx) arranged in the horizontal direction. The vertical scanning circuit 22 is connected to a plurality (y) of row scanning lines G (G1 to Gy) arranged in the vertical direction. FIG. 2 shows only two column data lines D1 and Dx and two row scanning lines G1 and Gy.

  The display pixel unit 23 has a plurality of (x × y) pixels 30 arranged in a matrix at each intersection of the column data lines D and the row scanning lines G. Note that FIG. 2 shows only four pixels 30 corresponding to the column data lines D1 and Dx and the two row scanning lines G1 and Gy.

  The pixel 30 includes a switching transistor TR1, a switching transistor TR2, a capacitor C1 (second storage unit), a capacitor C2 (first storage unit), and a liquid crystal display element 40.

  The liquid crystal display element 40 has a reflective electrode 41, a common electrode 42, and a liquid crystal 43. The reflective electrode 41 is formed for each pixel 30. The common electrode 42 is formed in common to all the pixels 30. The liquid crystal 43 is filled in the gap (cell gap) between the reflective electrode 41 and the common electrode 42.

  The switching transistor TR1 has a gate connected to the row scanning line G, a drain connected to the column data line D, and a source connected to the drain of the switching transistor TR2 and one terminal of the capacitor C1. The switching transistor TR2 has a gate connected to the control signal line CL, a drain connected to the source of the switching transistor TR1 and one terminal of the capacitor C1, and a source connected to the reflective electrode 41 and one terminal of the capacitor C2. ing.

  One terminal of the capacitor C1 is connected to the source of the switching transistor TR1 and the drain of the switching transistor TR2. One terminal of the capacitor C2 is connected to the source of the switching transistor TR2 and the reflective electrode 41. The other terminal of the capacitor C1 and the other terminal of the capacitor C2 are connected to the common terminal CT1. The common electrode 42 is connected to the common terminal CT2.

  The operation of the liquid crystal display device 20 will be described. The vertical synchronization signal VST and the vertical shift clock signal VCK are input to the vertical scanning circuit 22 from the video data processing unit 11. The vertical scanning circuit 22 generates a row selection signal SS based on the vertical synchronization signal VST and the vertical shift clock signal VCK, and selects the row scanning line G every one horizontal period. The switching transistors TR1 for one pixel row connected to the selected row scanning line G are simultaneously turned on by the row selection signal SS.

  The horizontal scanning circuit 21 receives the video signal VS from the video data processing unit 11 sequentially in pixel units. Further, the horizontal synchronization signal HST and the horizontal shift clock signal HCK are input to the horizontal scanning circuit 21 from the video data processing unit 11.

  The horizontal scanning circuit 21 outputs the video signal VS to the column data lines D1 to Dx based on the horizontal synchronization signal HST and the horizontal shift clock signal HCK. Thus, the video signal VS corresponding to each pixel 30 is written to the capacitor C1 of each pixel 30 of the pixel row selected by the vertical scanning circuit 22 via the switching transistor TR1.

  The capacitor C1 holds the video signal VS. When all the pixel rows are selected by the vertical scanning circuit 22, video data for one frame is written to the capacitors C1 of all the pixels 30. The switching transistor TR1 and the capacitor C1 constitute a first holding means.

  When the video signal VS is written to the capacitors C1 of all the pixels 30, the control signal CS is input to the switching transistors TR2 of all the pixels 30 from the control signal line CL. As a result, the switching transistors TR2 of all the pixels 30 are turned on, and the video signal VS written to the capacitor C1 is simultaneously transferred to all the pixels 30 to the corresponding capacitor C2. The switching transistor TR2 constitutes a transfer means.

  The capacitor C2 holds the video signal VS. Therefore, video data of one frame is written in the capacitors C2 of all the pixels 30. Video data for one frame is held in each capacitor C2 for one frame period. The capacitor C2 constitutes a second holding means.

  A driving voltage corresponding to the video signal VS held by the corresponding capacitor C2 is applied to the reflective electrode 41 of the liquid crystal display element 40. A common voltage is applied to the common electrode 42 of the liquid crystal display element 40 to all the pixels 30 from the common terminal CT2. The liquid crystal 43 is driven according to the potential difference between the reflective electrode 41 and the common electrode 42. When illumination light is irradiated to the display pixel unit 23 from the outside, the illumination light is modulated for each pixel 30 and displayed as an image of one frame.

  The liquid crystal display device 20 holds the video data of one frame in the capacitors C2 of all the pixels 30 as the video signal VS for only one frame period, and the video data of the next one frame is stored in the capacitors C1 of all the pixels 30 for one frame The next video signal VS is sequentially written to the inside. As a result, the liquid crystal display device 20 can switch moving images frame by frame and display them frame-sequentially.

  It is assumed that only the evaluation result data PD is output from the camera 4 to be evaluated, and a signal necessary for synchronizing external devices such as a video signal and a synchronization signal is not output. In addition, it is assumed that the camera 4 does not have a function of inputting a synchronization signal from an external device to synchronize the camera 4 with the external device. Therefore, it is not easy to synchronize the projector 10 and the camera 4.

  Therefore, on the premise that the camera 4 and the projector 10 are asynchronous, the display image PV captured by the camera 4 will be described. 3A to 3E show timings of the frame rate of the display image PV, the frame rate of the camera 4 (captured image CV), and the exposure time of the camera 4 in a state where the camera 4 and the projector 10 are asynchronous. SP shown in FIGS. 3A to 3E indicates the exposure time of the camera 4. It is assumed that the frame rate (frame period) of the camera 4 can be confirmed in advance. Also, the exposure time SP of the camera is described as being about half of one frame period of the camera.

  FIG. 3A shows the case where the frame rate of the display image PV is lower than the frame rate of the camera 4. FIG. 3A shows, for example, a case where one frame period PF of the display image PV is 1/25 second and one frame period CF of the camera 4 is 1/40 second (PF> CF). That is, FIG. 3A shows a case where the frame rate of the display image PV is 25 fps and the frame rate of the camera 4 is 40 fps.

  As shown in FIG. 3A, when the frame rate of the display image PV is lower than the frame rate of the camera 4, the camera 4 may capture an image corresponding to one frame of the projector 10 over two frame periods, An image slower than the frame rate of the camera 4 is taken. Taking an image slower than the frame rate of the camera 4 with the on-vehicle camera is not suitable for lane control and a driving support system for improving safety such as collision avoidance.

  FIGS. 3B and 3C show the case where the frame rate of the display image PV is the same as the frame rate of the camera 4. FIGS. 3B and 3C show, for example, the case where one frame period PF of the display image PV and one frame period CF of the camera 4 are 1/40 seconds (PF = CF). That is, FIG. 3B and FIG. 3C show the case where the frame rate of the display image PV and the frame rate of the camera 4 are 40 fps.

  Although the camera 4 and the projector 10 are asynchronous, when the frame rate of the display image PV is the same as the frame rate of the camera 4, the phase relationship between the exposure time SP of the camera 4 and one frame period of the display image PV changes. There is no continuous state. The phase relationship between the exposure time SP of the camera 4 and one frame period of the display image PV is determined by the timing of the projection start of the display image PV and the photographing start of the camera 4.

  FIG. 3B shows a case where the exposure time SP of the camera 4 falls within one frame period PF of the display image PV. In this case, the camera 4 continues to capture the display image PV in the frame period PF. FIG. 3C shows a case where the exposure time SP of the camera 4 is switched to one frame period PF of the display image PV. In this case, the camera 4 continues to capture the display image PV at the switching of the frame period PF.

  Therefore, when the one frame period PF of the display image PV and the one frame period CF of the camera 4 are the same, the camera 4 continues to capture the display image PV within the one frame period PF of the display image PV, and the display At the timing when the frame period PF of the image PV changes, the case where the display image PV is continuously taken occurs.

  The photographed image CV is largely different between the case where the exposure time SP of the camera 4 falls within one frame period PF of the display image PV and the case where the exposure time SP of the camera 4 switches one frame period PF of the display image PV. Therefore, when the frame rate of the display image PV is the same as the frame rate of the camera 4, it is difficult to evaluate the camera 4 with good reproducibility.

  FIG. 3D shows the case where the frame rate of the display image PV is higher than the frame rate of the camera 4. FIG. 3D shows, for example, a case where one frame period PF of the display image PV is 1/60 seconds and one frame period CF of the camera 4 is 1/40 seconds (PF <CF). That is, FIG. 3D shows a case where the frame rate of the display image PV is 60 fps and the frame rate of the camera 4 is 40 fps.

  As shown in FIG. 3D, the camera 4 captures the display image PV in a state where the timing at which the frame period PF of the display image PV switches and the timing at which the frame period PF does not switch coexist. Therefore, the display image PV can be captured with good reproducibility as compared with the case where one frame period PF of the display image PV and one frame period CF of the camera 4 are the same. Therefore, the camera 4 can be evaluated with good reproducibility.

  FIG. 3E shows the case where the frame rate of the display image PV is the same as the frame rate twice the frame rate of the camera 4. FIG. 3E shows a case where one frame period PF of the display image PV is, for example, 1/80 seconds, and one frame period CF of the camera 4 is, for example, 1/40 seconds (1/2 × CF = PF). That is, FIG. 3E shows a case where the frame rate of the display image PV is 80 fps and the frame rate of the camera 4 is 40 fps.

  As shown in FIG. 3E, since the camera 4 always keeps shooting an image including switching of the display image PV, the camera 4 can be evaluated with higher reproducibility compared to the case described in FIG. 3D.

  Therefore, it is desirable that the frame rate of the display image PV is higher than the frame rate of the camera 4 (PF <CF), and the frame rate is twice or more the frame rate of the camera 4 (2 × PF ≦ CF) Is even more desirable.

  Therefore, the projector 10 displays the display image PV at a predetermined frame rate higher than the frame rate of the camera 4. Further, it is more preferable that the projector 10 display the display image PV at a predetermined frame rate equal to or higher than a frame rate twice the frame rate of the camera 4.

  The frame rate of the display image PV is set based on the video data VD input to the projector 10 (image display device 3). Alternatively, the video data processing unit 11 may adjust the frame rate of the video data VD and convert it into the video signal VS so that the display image PV has a predetermined frame rate. For example, the video data processing unit 11 can change the video data VD to a frame rate of double speed by generating interpolation frame data from frame data before and after.

  The camera evaluation system 1 of the present embodiment includes the image display device 3 that is asynchronous with the camera 4 and causes the display image PV to be displayed at a predetermined frame rate. The image display device 3 has an active matrix type liquid crystal display device that switches the display image PV frame by frame and displays the image in a frame sequential manner.

  According to the camera evaluation system 1 of the present embodiment, the image display device 3 displays the display image PV at a predetermined frame rate while the camera 4 and the image display device 3 (projector 10) are asynchronous. More preferably, the frame rate of the display image PV is higher than the frame rate of the camera 4 and is equal to or higher than twice the frame rate of the camera 4. Thereby, the camera 4 can capture the display image PV with high reproducibility. Therefore, according to the camera evaluation system 1 of the present embodiment, the camera 4 can be evaluated with good reproducibility.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  In the embodiment described above, the projector 10 is used as the image display device 3. However, the present invention is also applicable to image display devices other than the projector as long as the image display device can switch and display the display image PV frame by frame. Applicable

  When the camera evaluation system 1 evaluates many types of cameras 4, the frame rate may be different for each camera 4. When the frame rate is different for each camera 4, the image display device 3 may automatically change the frame rate of the display image PV according to the input video data VD. Alternatively, the image display device 3 may change the video data VD to a target frame rate according to the number of interpolation frames by generating interpolation frame data from a plurality of frame data constituting the video data VD. .

  The camera evaluation system 1 may be configured to include a plurality of image display devices 3 corresponding to the frame rate of the camera 4. By displaying the display image PV by the image display device 3 corresponding to the frame rate of the camera 4, the camera 4 can be evaluated with good reproducibility.

1 camera evaluation system 2 data analysis device 3 image display device 4 camera 10 projector 11 image data processing unit 20 liquid crystal display device VD image data PV display image CV photographed image PD detection result data

Claims (6)

An image display device that displays a display image having a predetermined frame rate based on input video data, which is asynchronous with a camera to be evaluated;
A data analysis device that analyzes detection result data generated based on a captured image captured by the camera, the display image;
Equipped with
A camera evaluation system characterized in that the image display device includes a liquid crystal display device that switches the display image frame by frame and displays the image in a frame sequential manner. The camera evaluation system according to claim 1, wherein the image display device displays a display image having a frame rate higher than a frame rate of the camera. The camera evaluation system according to claim 1, wherein the image display device displays a display image having a frame rate equal to or higher than twice the frame rate of the camera. The liquid crystal display device has a display pixel unit in which a plurality of pixels are arranged,
The plurality of pixels are
A first storage unit that holds video data of one frame;
A second storage unit that holds video data of the next one frame;
The camera evaluation system according to any one of claims 1 to 3, comprising: The camera evaluation system according to any one of claims 1 to 4, wherein a frame rate of the display image is set based on the video data. The image display apparatus includes a video data processing unit that adjusts a frame rate of the video data so that the display image has a predetermined frame rate. Camera evaluation system according to the item.

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