Background technology
High-speed camera is in Industry Control, and many fields such as aircraft control, traffic monitoring all are widely used.But much higher times of the cost ratio common camera of high-speed camera.And the enterprise that can produce high-speed camera is also worldwide very few.
High-speed camera is divided into two types of Linear Array Realtime and planar array types, Linear Array Realtime is generally used for takes straight-line object, planar array type relatively is suitable for taking the object of random motion, area array camera also can be realized the function of high speed linear array video camera from the principle, is reduced into the effect of face battle array shooting under the control of software algorithm.
If we can enough common camera realize the shooting effect of high speed linear array video camera, that has just broken the Yi Tiaoxin road for a large amount of video camera producer.
State Intellectual Property Office of the People's Republic of China discloses the patent documentation that publication No. is CN10280075A on November 28th, 2012, title is based on image split-joint method and the device that line-scan digital camera is taken, concrete grammar is: comprising: image to be spliced is divided into to a plurality of rectangular area XiYj according to width directions X and length Y-direction, wherein, directions X is stitching direction, i=1 ~ m, j=1 ~ n; I is set, the j initial value is 1; The side-play amount of the lap of zoning XiYj and regional Xi+1Yj; The side-play amount that gained is calculated in judgement whether in the preset value scope, if set the side-play amount that the side-play amount of calculating gained is corresponding Xi, arranges i=i+1 and j=1 afterwards; J=j+1 is set if not; Repeat described calculating and determining step, until i=m or j=n; Complete splicing according to the side-play amount of described corresponding Xi.This scheme is calculated side-play amount by cutting apart intersection, has reduced the area that needs calculating section, thereby has improved splicing speed, but still be only applicable to line-scan digital camera, and can't obtain by common area array cameras the shooting effect of high speed linear array video camera.
Summary of the invention
The present invention solves that prior art is existing can't obtain the technical problem of the shooting effect of high speed linear array video camera by common area array cameras, the implementation method of the high-speed camera that provide a kind of shooting effect by common area array cameras acquisition high speed linear array video camera, effectively reduces costs.
The present invention is directed to above-mentioned technical problem is mainly solved by following technical proposals: a kind of implementation method of high-speed camera, realize high speed linear array video camera shooting effect by common area array camera, and step is as follows:
One, make subject opposite face array camera rectilinear motion on camera plane, the direction of motion is vertical and parallel with the column direction of pel array with the line direction of the pel array of area array camera;
Two, read successively the capable image that every a line pixel obtains;
Three, will go image recovers to obtain image with line array video camera Recovery image algorithm, line frequency during recovery is P, the time interval of remembering the picture element scan that two row are adjacent is F, distance between the adjacent pixel of two row is m, operating distance during shooting is H, and focal length is h, and in time F, the relative motion of area array camera and object distance is L, m be mapped on object apart from M=H * m/h, P=L/ (F * L-F * M).
As preferably, in described step 3, the algorithm adopted during Recovery image is liftering algorithm or Wiener filtering algorithm.
As preferably, this programme also comprises the image rectification flow process, is specially: (1) is set and is demarcated thing in pending subject image; (2) detect the boundary point of demarcating in thing; (3) solve the kinematic parameter of demarcating thing; (4) according to the result of calculation of step (3), the corresponding points in pending subject image are carried out to affine transformation, the image obtained after conversion is correcting image.By proofreading and correct the reduction degree that can make to improve final image.
Figure 1 shows that the work schematic diagram of line array video camera, the light-sensitive image vegetarian refreshments is " exposure " one by one, and the photosensitive pixel on line forms a frame, and the pixel line number of per second exposure is frame frequency.General high speed linear array video camera frame frequency does not wait to frames up to ten thousand at several thousand frames.
Figure 2 shows that the work schematic diagram of area array camera, photosensitive pixel is pointwise " exposure " line by line.First first element of " exposure " the first row, second pixel then, by that analogy, until that the first row pixel is all exposed is complete.Next second row that exposes again, the third line, to the last a line.Next again from first element of the first row.From first element of the first row, to last element of last column, end up being a frame.The number of times of whole pixels of having exposed each second is frame frequency.The frame frequency of typical case's high-speed area array camera is the hundreds of frame.
As shown in Figure 3, this programme is considered as a line array video camera by every a line pixel in Fig. 3 to the schematic diagram of common area array camera, a total n line array video camera (line number that n is common area array camera).The parameter of the common area array camera of current typical case of take is example:
Sensitive chip size: 5mm*5mm
Pixel scale: 640*480
Frame frequency: 30fps
Line frequency: 30*480=14400lps
Line space is from 5mm/480=10.4um
Pixel clock: 640*480*30=9.2MHz
As can be seen from the above data, line frequency reaches 1.4 ten thousand row/second, and this is the basis of realizing high-speed camera.The image that we obtain by every row pixel is spliced into new images again, just as obtain image with the ordinary lines array camera.
The triangle thing transverse movement to the right shown in Fig. 4 of take is example.For the ordinary lines array camera, because object of which movement, the image that the first row and the second line scanning obtain just as shown in Figure 4.But, because we use area array camera, between the first row and the second row pixel, a distance is arranged on sensitive chip, as shown in Figure 5.
The frame frequency that this result is equivalent to line array video camera has improved, if obtain the object image according to the algorithm of line array video camera Recovery image again, and will distortion.The method that solves distortion is exactly to adjust the frame frequency of the position ordinary lines array camera of the second row pixel when Recovery image.The principle of concrete method of adjustment is as follows:
Because common line frequency is known, so the time interval between scan line A and scan line B is known, be designated as F.
The movement velocity of subject is known, and in time F, the distance of its motion is designated as L.
As shown in Figure 6, operating distance and focal length are the basic parameters of video camera to the image-forming principle of video camera, are also known.
Distance on common area array camera sensitive chip between two row pixels is known, is designated as m.If the typical data provided with us, m=10.4um.
The distance that m is mapped on object is: M=operating distance * m/ focal length
The object L that moved in the time interval F of the video camera twice sweep of standard line frequency.That object moved line frequency interval time of L-M distance should be F-f, and the pass between them is:
(L-M)/L=(F-f)/F
Arrange above formula, the solution formula that obtains f is as follows:
f=M*F/L
Line frequency originally is 1/F, and the line frequency after adjustment is 1/ (F-f), is designated as P.Making the line frequency parameter with P when " lines " image restoration obtained with line scanning becomes normal picture gets final product.
The substantial effect that the present invention brings is, obtains the shooting effect of high speed linear array video camera by common area array cameras, effectively reduces costs, and has higher recovery degree, and algorithm simply is easy to realize.
Embodiment
Below by embodiment, and by reference to the accompanying drawings, technical scheme of the present invention is described in further detail.
Embodiment: the implementation method of a kind of high-speed camera of the present embodiment, realize high speed linear array video camera shooting effect by common area array camera, step is as follows:
One, make subject opposite face array camera rectilinear motion on camera plane, the direction of motion is vertical and parallel with the column direction of pel array with the line direction of the pel array of area array camera;
Two, read successively the capable image that every a line pixel obtains;
Three, will go image recovers to obtain image with line array video camera Recovery image algorithm, line frequency during recovery is P, the time interval of remembering the picture element scan that two row are adjacent is F, distance between the adjacent pixel of two row is m, and as shown in Figure 6, operating distance during shooting is H, focal length is h, in time F, the relative motion of area array camera and object distance is L, m be mapped on object apart from M=H * m/h, P=L/ (F * L-F * M).
The parameter of common area array camera is:
Sensitive chip size: 5mm*5mm
Pixel scale: 640*480
Frame frequency: 30fps
Line frequency 1/F:30*480=14400lps
Line space is from m:5mm/480=10.4um
Pixel clock: 640*480*30=9.2MHz
In step 3, the algorithm adopted during Recovery image is liftering algorithm or Wiener filtering algorithm.
This programme also comprises the image rectification flow process, is specially: (1) is set and is demarcated thing in pending subject image; (2) detect the boundary point of demarcating in thing; (3) solve the kinematic parameter of demarcating thing; (4) according to the result of calculation of step (3), the corresponding points in pending subject image are carried out to affine transformation, the image obtained after conversion is correcting image.By proofreading and correct the reduction degree that can make to improve final image.
Specific embodiment described herein is only to the explanation for example of the present invention's spirit.Those skilled in the art can make various modifications or supplement or adopt similar mode to substitute described specific embodiment, but can't depart from spirit of the present invention or surmount the defined scope of appended claims.
Although this paper has more been used the terms such as area array camera, line frequency, do not get rid of the possibility of using other term.Using these terms is only in order to describe more easily and explain essence of the present invention; They are construed to any additional restriction is all contrary with spirit of the present invention.