JP3373319B2 - Video scanner device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video scanner for obtaining image data by scanning a line sensor having a predetermined number of photoelectric conversion elements arranged on a line, and more particularly to a unit. The present invention relates to a video scanner device which captures image data with a focus state being an optimum state for each line. 2. Description of the Related Art In recent years, image data read by scanning a line sensor having a predetermined number of photoelectric conversion elements arranged on a line is directly converted into an electronic image, and from a flat material to a three-dimensional object, it is faithful as it is. Video scanner devices that can be converted into electronic files have been developed. The resolution of image data obtained by such a line sensor is, for example, 1
Since it can capture an area as wide as 0 times, it is expected to be used in various fields. As one of the uses, for example, in the case of performing a geological survey, in order to analyze the surface of a cylindrical three-dimensional sample bored by a boring machine, the three-dimensional sample is incorporated by a camera-type scanner incorporating the above-described line sensor. It is possible to take in the peripheral surface in a divided manner and develop the plane. That is, as shown in FIG. 6, the camera-type scanner 1 captures an image of the peripheral surface of a three-dimensional sample 2 which is a subject bored by a boring machine.
While rotating the three-dimensional sample 2 around the rotation axis 3 one time, photographing is performed every time a predetermined angle (for example, 90 degrees) is rotated, and the captured images are successively connected, so that the surface of the three-dimensional sample 2 is highly defined. Can be developed on a plane. In this case, a three-dimensional sample 2 to be developed in a plane
In order to focus on the entire surface at a predetermined angle, it is necessary to arrange the three-dimensional sample 2 on the focal plane of the camera-type scanner 1. Therefore, in this case, the three-dimensional sample 2 must be arranged at a position where the central axis 3 of the three-dimensional sample 2 is orthogonal to the lens optical axis 4 of the camera-type scanner 1. With such an arrangement maintained, the focus of the lens is adjusted so as to focus on a specific position (for example, the point (a)) of the three-dimensional sample 2, so that the other on the same focal plane can be obtained. Focusing can be obtained in the same manner also for the portion. [0006] As described above, a position including a position at which a focus is adjusted by a camera-type scanner 1 incorporating a line sensor with respect to a specific portion of a peripheral surface of a three-dimensional sample 2 as a subject is included. It is necessary to arrange the three-dimensional sample 2 in a positional relationship where the central axis 3 of the three-dimensional sample 2 is orthogonal to the lens optical axis 4 of the camera-type scanner 1. Therefore, for example, as shown in FIG.
When the photographing of the three-dimensional sample 2 is performed in a state in which the position of the center axis 3 of the three-dimensional sample 2 orthogonal to the lens optical axis 4 is broken, the position at which the focus adjustment is performed (shaded area A)
Otherwise, the focus will be out of focus. Also, the three-dimensional sample 2 obtained by, for example, boring for geological survey is not always an accurate columnar body. Each time the stereoscopic sample 2 is rotated, the distance between the lens optical axis 4 of the camera-type scanner 1 and the peripheral surface of the stereoscopic sample 2 changes during one rotation. If this is not possible, out-of-focus spots will be formed in the planar developed image of the surface of the three-dimensional sample 2. Furthermore, if the surface of the three-dimensional sample 2 has irregularities, the out-of-focus state will occur even for a camera lens beyond the range of the depth of field. The present invention has been made in view of such circumstances, and provides a video scanner device which can always obtain an in-focus image regardless of the positional relationship between the lens optical axis and a subject. The purpose is to: In order to achieve the above object, a video scanner according to the present invention receives a lens, reflected light from a subject input through the lens, and receives the received light. A photoelectric conversion element that generates an electric signal according to the following, a line sensor in which a predetermined number of the photoelectric conversion elements are arranged on a line, a memory unit that stores an output of the line sensor in accordance with a first control signal, Transfer means for transferring the line sensor by unit lines in accordance with a second control signal, focus adjustment means for adjusting the focus of the lens in accordance with the output of the line sensor, and the focus state of the lens from the output of the line sensor When the optimal state is detected by the focus state detecting means for detecting that , And control signal generating means for outputting the first control signal and the second control signal. In the video scanner device of the present invention, when image data is taken in each unit line by a line sensor having a predetermined number of photoelectric conversion elements arranged on a line, the output of the line sensor is taken for each line. The focus of the lens is adjusted accordingly, and when it is detected that the focus state of the lens is in the optimum state, the image data of the line sensor output is stored and the line sensor is moved to the next line. Therefore, an in-focus image is always obtained regardless of the positional relationship between the lens optical axis and the subject. Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, portions common to FIGS. 6 and 7 are denoted by the same reference numerals, and redundant description will be omitted. FIG. 1 shows a camera-type scanner according to an embodiment of the video scanner device of the present invention. As shown in the figure, image data is obtained by capturing reflected light from a subject captured by a lens 10 incorporated in a camera-type scanner by a line sensor 11. In the line sensor 11, a predetermined number of photoelectric conversion elements for generating an electric signal corresponding to the received light amount are arranged on a line. (A so-called exposure amount). The image output from the line sensor 11 is A /
The image data is converted into digital image data by the D converter 12 and stored line by line in a memory 13 controlled by the system controller 15 according to a predetermined address. The focus control device 14 moves the lens 10 in the focus direction in accordance with a known technique called a hill-climbing method, based on image data captured by the line sensor 11 as an output of the A / D converter 12. Focusing control is performed by controlling the driving of the motor 17. The system controller 15 is a controller for controlling the overall control of the present system.
A / D conversion control in the D converter 12, control of writing / reading of image data in the memory 13, and driving of the line transfer motor 16 for moving (scanning) the line sensor 11 in a predetermined direction are performed. Control. Here, the line transfer motor 16 is a pulse motor, and the rotation angle of the rotor from the reference position is proportional to the number of input pulse signals from the system controller 15. The sensor 11 is driven so that the distance of one line is 14 μm depending on the size of the photoelectric conversion element (pixel) of the sensor 11. FIG. 2 shows the details of the focus control device 14. As shown in FIG.
It selectively captures image data captured by the line sensor 11, which is the output of the / D converter 12, and determines the gate period according to a control signal from the system controller 15. The high-pass filter 21 is a filter for a spatial frequency. For example, by adding peripheral data weighted by a 5 × 5 matrix calculating means, a portion having a high spatial frequency (in other words, the degree of focus) is obtained. Can be recognized. Here, the focus evaluation value indicating the degree of focusing in a known method called a hill-climbing method generally has a mountain shape as shown in FIG. 3, but by changing the above-mentioned weighting amount, the focus evaluation value shown in FIG. a) or a steep one as shown in FIG. That is, the output of the high-pass filter 21 utilizes the fact that the output level increases as the focus is increased, and is used to determine the focus direction of the lens 10. By the way, in the case of a gentle mountain shape as shown in FIG. 3A, a certain focus evaluation value can be obtained even when the focus is considerably out of focus.
It is possible to move 0 in the focus direction,
It is not suitable for performing fine focus servo. In the case of a sharp streak as shown in FIG. 3B, fine focus servo can be performed. However, since the slope is very small at the foot of the mountain, the focus servo can be performed in the out-of-focus state. It is difficult to determine the focus direction of the lens 10. Therefore, the focus servo can be adjusted by taking an intermediate shape between FIGS. 1A and 1B or using one of FIGS. 1A and 1B depending on the state. Can be performed accurately. The peak hold circuit 22 stores the current peak value of the output of the high-pass filter 21 into the line sensor 11.
Is held until the next peak value from the peak hold circuit 22 obtained by the next line scan is obtained. The peak value of the peak hold circuit 22 is output to the first memory 23 and the system controller 15. The first memory 23 stores only the latest peak value. When the peak value of the next scan is output from the peak hold circuit 22, the first memory 23 stores the currently held one line period. After sending the previous peak value to the second memory 24, it is updated to the peak value of the new line period. The output of the first memory 23 and the output of the second memory 24 are compared by a comparator 25, and the focus motor 17 is driven according to the difference. That is, the direction in which the output level of the high-pass filter 21 becomes maximum is determined by the hill-climbing method shown in FIG. 3, and the lens 10 is moved in the in-focus direction. On the other hand, the system controller 15 compares the output signal of the peak hold circuit 22 with a predetermined reference level, recognizes that the focus has been obtained when the output signal exceeds the reference level, and moves the line sensor 11 to the next line. Next, the operation of the video scanner device having such a configuration will be described with reference to FIGS. First,
As shown in FIG. 5, it is assumed that the imaging of the three-dimensional sample 2 is performed in a state where the positional relationship of the center axis 3 of the three-dimensional sample 2 orthogonal to the lens optical axis 4 is broken. Then, first, image data from the upper end to the lower end of the three-dimensional sample 2 is obtained by the scanning of the line sensor 11, but a difference occurs in the distance of the lens optical axis 4 from the upper end to the lower end. If the focus is uniquely adjusted at the position of the hatched portion (a), the focus will be blurred otherwise. Therefore, first, the line sensor 11
The image output of the three-dimensional sample 2 at the line is taken in, and A /
When the image data output from the D converter 12 is taken into the high-pass filter 21 via the gate 20 of the focus control device 14, the peak value of the output of the high-pass filter 21 is held by the peak hold circuit 22, and the peak hold circuit 22 Is stored in the first memory 23 and output to the system controller 15. Here, when the first image is taken in the first line by the line sensor 11, the peak hold circuit 22 holds the peak value of the output of the high-pass filter 21 for the first time. Since the peak value is stored and the peak value is not sent to the second memory 24, the output of the first memory 23 and the output of the second memory 24 are compared by the comparator 25. I can't. Therefore, the focus control device 14 drives the focus motor 17 so as to move the lens 10 in a predetermined direction by a predetermined amount. In this state, when the image of the first line similar to the above is captured again by the line sensor 11, the image data output from the A / D converter 12 is captured by the high-pass filter 21 via the gate 20, and the high-pass filter 21 outputs the image data. The new peak value, which is the output of 21, is held by the peak hold circuit 22. When the new peak value held by the peak hold circuit 22 is output, the first memory 2
3 transmits the currently held peak value to the second memory 24 and is updated to a new peak value. In this state, the comparator 2
5, the comparator 25 compares the output of the first memory 23 with the output of the second memory 24, and the direction in which the output level of the high-pass filter 21 is maximized by the hill-climbing method described with reference to FIG. Is determined, and the lens 10 is moved in the focus direction. With several movements of the lens 10 in the focusing direction, the image data of the first line is repeatedly fetched until the output level of the high-pass filter 21 becomes maximum, and the output level of the high-pass filter 21 becomes maximum. Then, the system controller 15 compares the output signal of the peak hold circuit 22 with a predetermined reference level, recognizes that the focus has been obtained when the output signal is equal to or higher than the reference level, drives the line transfer motor 16, and causes the line sensor 11 to operate next. (The second line) by 14 μm. Next, when the image output of the three-dimensional sample 2 on the second line is captured by the line sensor 11, A /
The image data output from the D converter 12 is taken into the high-pass filter 21 via the gate 20, and a new peak value output from the high-pass filter 21 is held by the peak hold circuit 22. At this time, the peak hold circuit 22 holds the peak value of the output of the high-pass filter 21 of the first line scanned last time, and outputs the new peak value which is the output of the high-pass filter 21 of the second line. Then, the peak value is held. When the new peak value held by the peak hold circuit 22 is output, the first memory 23 sends the currently held peak value to the second memory 24 and then updates the new peak value. When the first memory 23 stores the new peak value, the comparator 25 compares the output of the first memory 23 with the output of the second memory 24, and outputs the output level of the high-pass filter 21 by the above-mentioned hill-climbing method. Is determined, and the lens 10 is moved in the focus direction. At this time, as described above, the capture of the image data of the first line is repeatedly performed along with the movement of the lens 10 in the focus direction until the output level of the high-pass filter 21 reaches the maximum. When a certain difference becomes 0, the system controller 15 compares the output signal of the peak hold circuit 22 with a predetermined reference level, recognizes that the focus has been obtained when the signal is equal to or higher than the reference level, and drives the line transfer motor 16, The line sensor 11 is transferred to the next line (third line) by 14 μm. In this way, the image data from the upper end to the lower end of the three-dimensional sample 2 is taken in a state where the focus is taken for each scanning line of the line sensor 11. Thereafter, every time the three-dimensional sample 2 is rotated, for example, 90 degrees about the rotation axis 3, the image data from the upper end to the lower end of the three-dimensional sample 2 is captured. By performing the measurement in the taken state, a planar developed image of the surface of the three-dimensional sample 2 can be obtained without any out-of-focus spots. As described above, in this embodiment, when image data is taken in unit lines by the line sensor 11 in which a predetermined number of photoelectric conversion elements are arranged on a line, the output of the line sensor 11 is taken for each line. Lens 1 according to
The focus adjustment of 0 is performed, and when it is detected that the focus state of the lens 10 is in the optimum state, the image data of the output of the line sensor 11 is stored, and the line sensor 11 is moved to the next line. Therefore, an in-focus image is always obtained regardless of the positional relationship between the lens optical axis and the three-dimensional sample 2 as the subject. When the surface of the three-dimensional sample 2 has irregularities, even if the surface of the three-dimensional sample 2 is beyond the range of the depth of field of the camera lens, the focus adjustment for each unit line of the line sensor 11 causes out-of-focus. No more. As described above, according to the video scanner of the present invention, when the image data is taken in each unit line by the line sensor having a predetermined number of photoelectric conversion elements arranged on the line, For each line, the focus of the lens is adjusted in accordance with the output of the line sensor, and when it is detected that the focus state of the lens is in the optimum state, the image data of the line sensor output is stored and the line sensor is Since the image is transferred to the next line, an in-focus image can always be obtained regardless of the positional relationship between the lens optical axis and the subject.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a camera-type scanner according to an embodiment of the video scanner device of the present invention. FIG. 2 is a diagram illustrating details of a focus control device in FIG. 1; FIG. 3 is a diagram for explaining a hill-climbing method in focus control of the focus control device of FIG. 1; FIG. 4 is a flowchart for explaining the operation of the camera-type scanner shown in FIG. 1; FIG. 5 is a diagram for explaining the operation of the camera-type scanner shown in FIG. 1; FIG. 6 is a diagram showing a conventional camera-type scanner. FIG. 7 is a diagram showing a conventional camera-type scanner. DESCRIPTION OF SYMBOLS 10 Lens 11 Line sensor 12 A / D converter 13 Memory 14 Focus controller 15 System controller 16 Line transfer motor 17 Focus motor 20 Gate 21 High pass filter 23 First memory 24 Second memory 25 Comparator

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/222-5/257 H04N 1/19

Claims (1)

(57) A lens, a lens, a photoelectric conversion element that receives reflected light from a subject input through the lens, and generates an electric signal according to the received light amount; A line sensor in which a predetermined number of photoelectric conversion elements are arranged on a line; memory means for storing an output of the line sensor in accordance with a first control signal; and transfer of the line sensor in unit lines in accordance with a second control signal A transfer unit that performs focus adjustment of the lens in accordance with an output of the line sensor; and a focus state detection unit that detects that the focus state of the lens is in an optimal state from the output of the line sensor. A control signal generator that outputs the first control signal and the second control signal when the optimum state is detected by the focus state detection unit; And a video scanner device.