JP2004320281A - Circuit for detecting motion of object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly detect the standstill / moving state of an object imaged by a camera for printing and calligraphy. <P>SOLUTION: One image imaged by a camera for printing and calligraphy is divided into M blocks, N blocks among the M blocks are selected for a detection object, divided into three images at prescribed time intervals, averages of each of R,G and B components of each of the N blocks are calculated and variances are calculated on the basis of the averages. It is determined that the object comes to a standstill in the case that a consecutive state by the number of standstill detection times or over is consecutive for a standstill detection time or over for all of the N blocks, the consecutive state indicating that the variances are a predetermined standstill discrimination value or below. Even when one of the variances is the standstill discrimination value or over or all the variances are the standstill discrimination value or below, it is determined that the object is moving when the consecutive state by the number of standstill detection times or below is consecutive for a motion detection time or over. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image captured by a two-dimensional CCD (Charge Coupled Device) sensor constituting a document camera and an image control technique for controlling a resolution and a frame rate in a liquid crystal panel for drawing the image in accordance with stillness / movement of the image. Things.
[0002]
[Prior art]
Conventionally, a projector with a document camera is known.
In this document camera, a subject placed on a subject table is imaged by the document camera and projected in an enlarged manner. If this enlarged projection image is to be displayed at the resolution of the projector, it will be displayed at a low frame rate. Therefore, when enlarging and projecting a subject using this projector with a document camera, the subject is moved on a subject mounting table in order to place the subject in an optimal position. At this time, the enlarged projected image is smoothed in accordance with the movement of the subject. There was a problem that does not work.
[0003]
Conventionally, the following means have been adopted to solve this drawback.
This conventional technique will be described with reference to FIG.
FIG. 5 shows a structure in which a document camera portion of an optical system such as a CCD camera or a lens for imaging is housed in a housing of the projector, and a projection method is illustrated as front projection. In addition, only the basic optical path is shown for the optical system belonging to the known technology.
[0004]
As shown in FIG. 5, the conventional projector with a document camera includes a CCD imaging unit 1, a CCD signal processing unit 2, a liquid crystal projection unit 3, and a motion detection image control unit 4.
[0005]
The CCD imaging unit 1 includes 11 two-dimensional CCD sensors, 12 imaging lenses, 14 glass plates on which subjects are mounted, 15 white illumination lamps for illuminating the imaging surface of 15 subjects through the glass plates, and 16 light from the subjects. Is reflected over the entire visible light range and is incident on the imaging lens 12, a buffer amplifier for sending the output of the two-dimensional CCD sensor 11 to the CCD signal processing unit 2, and a CCD for driving the two-dimensional CCD sensor 11. It is composed of a drive circuit. Reference numeral 13 denotes a planar subject.
[0006]
The subject 13 placed in contact with the glass plate 14 forms an image on the light receiving surface of the two-dimensional CCD sensor 11 through the total reflection mirror 16 and the imaging lens 12 and is photoelectrically converted.
The output of the two-dimensional CCD sensor 11 is sequentially read out by the timing signal of the CCD drive circuit 18, and is guided to the CCD signal processing unit 2 as an analog image signal by the buffer amplifier 17.
[0007]
The CCD signal processing unit 2 includes 21 image signal switching circuits, 22 A / D conversion circuits, 23 image processing circuits, and 24 external image signal input connectors.
The image signal switching circuit 21 selects either the internal image signal from the CCD image pickup unit 1 or the external image signal from the external image signal input connector 24. The A / D conversion circuit 22 converts an analog image signal output from the image signal switching circuit 21 into a digital signal and inputs the digital signal to the image processing circuit 23.
The image processing circuit 23 digitally processes the setting of the reference black level, the γ correction, the shading correction, and the enhancement of the image quality such as contour enhancement and the like, and transfers them to the liquid crystal projection unit 3.
[0008]
The liquid crystal projection unit 3 includes 31 frame memories, 32 image calculation circuits, 33 video output circuits, 34 liquid crystal panels, 35 light source lamps, 36 cold mirrors, 37 total reflection mirrors, and 38 projection lenses. Become.
[0009]
The frame memory 31 stores a digital image signal output from the image processing circuit 23.
The image calculation circuit 32 converts the resolution of the image signal stored in the frame memory 31 into a resolution in consideration of the resolution of the liquid crystal panel 34. For example, resolution conversion for compressing image data for converting 1280 × 1024 pixels on an SXGA (Super Extended Graphics Array) screen to 1024 × 768 pixels on an XGA (extended Graphics Array) screen is performed.
[0010]
The image signal having undergone the resolution conversion is sent to the video output circuit 33 at a predetermined frame rate.
The video output circuit 33 D / A converts the output of the image operation circuit 32 and generates a video signal required for drawing on the liquid crystal panel 34.
The white light of the light source lamp 35 passes through a liquid crystal panel 34 on which a subject is drawn after removing unnecessary infrared light by a cold mirror 36, is refracted in an optical path by a total reflection mirror 37, and is guided to a projection lens 38.
The subject captured by the two-dimensional CCD sensor 11 is stored in the frame memory 31 as an image signal, drawn on the liquid crystal panel 34, and projected on a screen (not shown).
[0011]
The motion detection image control function, which is a feature of the related art, is achieved by adding the motion detection image control unit 4 to the above-described configuration.
The movement of the image can be electrically recognized by monitoring the contents of the frame memory 31 and detecting a change. The motion detection control circuit 41 incorporated in the motion detection image control unit 4 reads the image stored in the frame memory 31 every time a frame is updated, and detects a change in pixel data for the previous and next frames.
[0012]
When there is no change in the pixel data, the motion detection control circuit 41 determines that the image is a still image with no motion, obtains the resolution information of the projected image from the image calculation circuit 32, and reads out the entire pixels from the CCD drive circuit. Instruct 18.
The CCD drive circuit 18 generates a timing pulse for reading out all pixels and sends it to the two-dimensional CCD sensor 11.
Upon receiving this, the two-dimensional CCD sensor 11 sends out sensor output signals of all pixels to the CCD signal processing unit 2.
[0013]
The CCD signal processor 2 A / D converts the sensor output signal in the same manner as described above. Thereafter, the image is corrected and stored in the frame memory 31 of the liquid crystal projection unit 3.
The liquid crystal projection unit 3 reads image data from the frame memory 31, generates a video signal, draws the video signal on the liquid crystal panel 34, and projects the image on a screen (not shown) by an optical path.
When the motion detection control circuit 41 detects a change in pixel data, it determines that the image is a moving image, and instructs the CCD driving circuit 18 to thin out and read pixels by referring to the resolution information from the image calculation circuit 32. The CCD drive circuit 18 receives this and generates a timing pulse and sends it to the two-dimensional CCD sensor 11.
By performing the pixel thinning-out reading in this manner, the image quality becomes coarse, but the drawing of the screen becomes faster, and the projection that follows the moving subject can be performed.
[0014]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-109422
[Problems to be solved by the invention]
As described above, the conventional projector with a document camera adds a motion detection image detection unit, monitors the change of pixel data on a frame-by-frame basis, determines that there is a moving image if there is a change, and The thinning-out reading is performed. In this way, a moving image is read out by thinning out the pixels to follow the movement of the subject, and an image without movement is read out without thinning out the pixels so that a fine image is obtained without following the movement of the subject. .
[0016]
However, since this conventional method monitors a change in pixel data on a frame-by-frame basis, even if there is a change in even one pixel, it is determined that the subject is moving and pixel thinning-out reading is performed. However, there is a problem that a coarse image is displayed even though the camera is actually still.
SUMMARY An advantage of some aspects of the invention is to provide a subject motion detection circuit capable of accurately capturing the actual movement of a subject and detecting the stillness / movement of the subject. I do.
[0017]
[Means for Solving the Problems]
The subject motion detection circuit according to the present invention includes:
In detecting the stillness / movement of the subject when capturing the subject with the document camera,
A time interval for capturing an image from the document camera, a stillness determination value and the number of times of stillness detection, which are parameters for detecting that the subject is in a partial still state, and a parameter for detecting that the subject is in a completely still state. An operation unit for setting each parameter consisting of a stillness detection time, a motion detection time that is a parameter for detecting a state in which the subject is moving,
The image captured by the document camera is divided into predetermined M (M is an integer equal to or greater than 2) blocks, and R is set for each block in units of image capture time intervals from the document camera set by the operation unit. , An image processing unit that calculates and stores an average value of each component of G, B,
The average value of the R, G, and B components of each of N (N <M, where N is an integer) blocks at a predetermined position among the M blocks and a stationary determination value set by the operation unit A control unit for detecting the stillness / movement of the subject by the following procedure based on the number of stillness detections, the stillness detection time, and the motion detection time;
Which is characterized by having
1) Calculate the total value of the R, G, and B components for each of the N blocks of the i-th image.
2) To calculate the total value of each of the R, G, and B components for each of the N blocks of the (i-1) th image.
3) Calculate the total value of the R, G, and B components for each of the N blocks of the (i-2) th image.
4) An average value is calculated for each corresponding block from the total value calculated in 1) to 3).
5) A variance value is calculated for each block from the total value and the average value obtained in 1) to 4).
6) Comparing the variance value with the stillness determination value for each block, determining that the variance value is smaller than the stillness determination value for more than the stillness detection time is determined to be partial stillness, otherwise determining partial motion. .
7) When all of the N blocks are determined to be partially stationary, a stationary state is determined. When this state continues for the stationary detection time or longer, the subject is determined to be stationary, and otherwise, it is determined to be a partial motion.
8) To determine that the subject is moving when the state determined to be the partial motion continues for the motion detection time or longer.
[0018]
In the motion detection circuit for the subject, M is 64 and N is 4.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. Here, a document will be described as an example of a subject.
FIG. 1 is a block diagram of a subject motion detection circuit according to an embodiment of the present invention.
Reference numeral 1 denotes a time interval for capturing an image from the document camera 2, a stillness determination value and the number of times of stillness detection, which are parameters for detecting that the document is in a partially stationary state, and parameters for detecting that the document is in a completely stationary state. An operation unit for setting each parameter including a stationary detection time and a motion detection time which is a parameter for detecting a state in which the document is moving, 2 is a document camera for capturing the document, and 3 is an A / D image from the document camera 2. An A / D converter for conversion.
[0020]
4 divides the image from the A / D conversion unit 3 into 64 (= 8 × 8) blocks, and sets R, G for each block in units of image capture time intervals from the document camera 2 set by the operation unit 1. , B calculating and storing an average value of each component of each of the four blocks at predetermined positions from the average values of the R, G, and B components of each of the 64 blocks. Based on the average value of each of the R, G, and B components and the stillness determination value, the number of times of stillness detection, the stillness detection time, and the motion detection time set by the operation unit 1 to detect the stillness / movement of the document according to a procedure described later. Department.
[0021]
The flow of image data captured by the document camera 2 is as follows.
A document is imaged by the document camera 2, converted into a digital image by the A / D converter 3, and input to the image processor 4.
The image processing unit 4 divides an input image into 8 × 8 (= 64) blocks for each frame, calculates an average value of R, G, and B components for each block and stores the average value. At the same time, under the control of the control unit 5, the average values of the R, G, and B components of the four blocks at the predetermined positions are sent to the control unit 5.
[0022]
Next, the operation and operation of this circuit will be described.
In this embodiment, as shown in FIG. 4, a screen of one frame is divided into 8 × 8 (= 64) blocks, of which (3, 3), (3, 6), (6, 3) For the four blocks corresponding to (6) and (6), it is determined from the image data whether the document is moving or stationary.
[0023]
First, a stillness determination value STOP_LEVEL, the number of times of stillness detection STOP_COUNT, a stillness detection time, and a motion detection time are set as parameters from the operation unit 1 in the control unit 5. These parameters are used as follows.
When the state in which the variance value calculated for each of the four blocks is less than the stillness determination value STOP_LEVEL continues for the number of times of stillness detection STOP_COUNT, the block is determined to be partially still. Otherwise, it is determined to be a partial motion. When all four blocks are partially stationary, it is determined to be stationary. When the stillness determination is continued for more than the stillness detection time, it is determined that the document is stationary. Conversely, when the determination of the partial motion continues for the motion detection time or longer, it is determined that the document is moving.
[0024]
FIGS. 2 and 3 show flowcharts of document still / movement detection according to the present invention.
Hereinafter, a procedure for detecting the stationary / moving state of the document will be described with reference to FIGS.
FIG. 2 is a flowchart corresponding to a stage before detecting whether or not the document is stationary in the flowchart of the document stillness / movement detection of the present invention, and is a portion for detecting whether or not each block is partially stationary. FIG. 3 shows a portion for finally detecting the stillness / movement of the document for all four blocks.
[0025]
The control unit 5 outputs R, of four blocks corresponding to (3, 3), (3, 6), (6, 3), and (6, 6) among the 8 × 8 (= 64) blocks from the image processing unit 4, The average value of each of the G and B components is continuously obtained in units of image capture time intervals.
The four blocks described above from the i-th, (i-1) -th, and (i-2) -th images based on the average values of the R, G, and B components periodically acquired in this manner. Based on the flowcharts shown in FIGS. 2 and 3, it is detected whether or not the document is stationary.
[0026]
Here, whether or not each block is stationary will be described by taking as an example a block (3, 3) which is one of the four blocks.
First, the total value SUM (0) of each of the R, G, and B components is calculated from the i-th image by the following formula (S101).
SUM (0) = R (0) (3,3) + G (0) (3,3) + B (0) (3,3) where R (0) (3,3) is the i-th image The average value of the R component of the (3,3) block, G (0) (3,3) is the average value of the G component of the (3,3) block of the ith image, B (0) (3,3) Is the average value of the B component of the (3, 3) block of the i-th image.
[0027]
Next, the total value SUM (-1) of each of the R, G, and B components is calculated from the (i-1) th image using the same calculation formula as described above (S102).
SUM (-1) = R (-1) (3,3) + G (-1) (3,3) + B (-1) (3,3)
Here, R (−1) (3,3) is the average value of the R component of the (3,3) block of the (i−1) th image, and G (−1) (3,3) is (i−3). The average value of the G component of the (3,3) block of the 1) th image, and B (−1) (3,3) is the average of the B component of the (3,3) block of the (i−1) th image. Value.
[0028]
Subsequently, the total value SUM (−2) of each of the R, G, and B components is calculated from the matrix two times before using the same calculation formula as described above (S103).
SUM (-2) = R (-2) (3,3) + G (-2) (3,3) + B (-2) (3,3)
Here, R (−2) (3,3) is the average value of the R component of the (3,3) block of the last two-time matrix, and G (−2) (3,3) is (3,3) of the second-last matrix. ) The average value of the G component of the block, B (−2) (3,3) is the average value of the B component of the (3,3) block of the previous matrix.
[0029]
Next, an average value AVE is calculated from the sum of these three values SUM (0), SUM (-1) and SUM (-2) by the following equation (S104).
AVE = (SUM (0) + SUM (-1) + SUM (-2)) / 3
[0030]
Next, the variance value VAR (3, 3) is calculated for the three images by the following equation (S105).
VAR (3,3) = (A ² + B ² + C ² ) / 3
Here, A, B, and C are as follows.
A = AVE-SUM (0)
B = AVE-SUM (-1)
C = AVE-SUM (-2)
[0031]
It is determined from the variance value VAR (3, 3) obtained in this way, the set stationary determination value STOP_LEVEL, and the number of times of stationary detection STOP_COUNT whether or not the vehicle is partially stationary (S106). The determination is performed as follows.
When the state in which the variance value VAR (3, 3) is equal to or less than the stillness determination value STOP_LEVEL continues for more than the number of times of stillness detection STOP_COUNT, it is determined to be partial stillness. If it is not determined that the document is still, it is determined that the document is partially moving.
[0032]
In the above description, one of the four blocks for detecting stillness has been described. The explanation of the selected one block is completed, and the determination state proceeds to the detection of the partial stillness of four blocks. In this determination, detection of partial stillness as described above is executed for all four blocks.
[0033]
First, it is determined whether or not it is in the stationary state (S107). The determination as to whether or not the block is in the stationary state is made by determining whether or not all four blocks to be subjected to the stationary state are partially stationary. When all four blocks are partially stationary, it is determined that the block is in the stationary state. Otherwise, it is determined that the original is a partial movement.
[0034]
Next, it is determined whether or not the stationary state has continued for a certain period of time (S108). This determination is made based on whether or not the stationary state continues for the stationary detection time or longer. Here, if the stationary state has continued for a predetermined time or more, it is determined that the document is stationary (S110), and otherwise, it is determined that the document is partially moving.
[0035]
When it is determined that the original is a partial movement, it is determined whether or not the moving state has continued for a predetermined time or more (S109). This determination is made based on whether or not the motion state continues for a motion detection time or longer. If the moving state has continued for a certain period of time, it is determined that the document is moving (S111).
[0036]
Based on this determination, a high-resolution image at a low frame rate is determined when the original is determined to be stationary, and a low-resolution image is determined at a high frame rate when the original is determined to be moving. An image having a resolution is output from the document camera 2.
[0037]
【The invention's effect】
According to the present invention, as described above, one screen imaged by the document camera is divided into M blocks, and N blocks among them are detected, and each of the N blocks is divided into three screens at predetermined time intervals. The average value of each component of R, G, and B is calculated for each block, and the variance value is calculated based on the average value. When the state in which the variance value is equal to or less than the predetermined stillness determination value continues for the number of times of stillness detection continues for all N blocks for the stillness detection time or longer, it is determined that the subject is stationary, It is determined that the subject is moving when one of the variance values is equal to or greater than the stillness determination value, or when all of the variance values are equal to or less than the stillness determination value and the state is equal to or less than the number of times of stillness detection and continues for more than the motion detection time. As a result, the stillness / movement of the subject can be reliably detected. In addition, using the detection results, the document camera outputs a high-resolution image at a low frame rate when the camera is stationary, and outputs a low-resolution image at a high frame rate when the camera is moving. Therefore, when the subject is aligned, an image following the movement of the subject can be obtained, so that the alignment can be easily performed, and a document camera capable of obtaining a fine image after the completion of the alignment can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram of a subject motion detection circuit according to an embodiment of the present invention.
FIG. 2 is a first half of a flowchart of motion detection of a subject.
FIG. 3 is a second half of a flowchart for detecting a motion of a subject.
FIG. 4 is a diagram showing a state in which one screen imaged by a document camera is divided into 64 parts.
FIG. 5 is a diagram illustrating a conventional motion detection technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Operation part 2 Document camera 3 A / D conversion part 4 Image processing part 5 Control part

Claims (2)

In detecting the stillness / movement of the subject when capturing the subject with the document camera,
A time interval for capturing an image from the document camera, a stillness determination value and the number of times of stillness detection, which are parameters for detecting that the subject is in a partial still state, and a parameter for detecting that the subject is in a completely still state. An operation unit configured to set each parameter including a motion detection time, which is a parameter for detecting a still state, a state in which the subject is moving,
The image captured by the document camera is divided into predetermined M (M is an integer equal to or greater than 2) blocks, and R is set for each block in units of image capture time intervals from the document camera set by the operation unit. , An image processing unit that calculates and stores an average value of each component of G, B,
The average value of the R, G, and B components of each of N (N <M, where N is an integer) blocks at a predetermined position among the M blocks and a stationary determination value set by the operation unit A control unit for detecting the stillness / movement of the subject based on the number of stillness detections, the stillness detection time, and the motion detection time according to the following procedure:
A motion detection circuit for a subject.
1) Calculate the total value of the R, G, and B components for each of the N blocks of the i-th image.
2) To calculate the total value of each of the R, G, and B components for each of the N blocks of the (i-1) th image.
3) calculating the total value of the R, G, and B components for each of the N blocks of the (i-2) th image.
4) An average value is calculated for each corresponding block from the total value calculated in 1) to 3).
5) A variance value is calculated for each block from the total value and the average value obtained in 1) to 4).
6) Comparing the variance value with the stillness determination value for each block, determining that the variance value is smaller than the stillness determination value for more than the stillness detection time is determined to be partial stillness, otherwise determining partial motion. .
7) When all of the N blocks are determined to be partially stationary, a stationary state is determined. When this state continues for the stationary detection time or longer, the subject is determined to be stationary, and otherwise, it is determined to be a partial motion.
8) To determine that the subject is moving when the state determined to be the partial motion continues for the motion detection time or longer. 2. The circuit according to claim 1, wherein M is 64 and N is 4.

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