JP2006279884A - Image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing method with which the sharp image of an object moving two-dimensionally can be obtained in a short period of time even when the image is picked up by an imaging apparatus comprising an interlaced scanning type imaging device. <P>SOLUTION: The present invention relates to an image processing method for processing an image picked up by an imaging apparatus 10 comprising an interlaced scanning type imaging device 13, wherein image signals of even-numbered fields outputted from the imaging apparatus 10 are generated from image signals of upper and lower horizontal lines (1, 3), (3, 5) of odd-numbered fields holding horizontal lines (2, 4) of each of the even-numbered field therebetween, and the generated respective image signals are set as image signals of the even-numbered field. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing method suitable for reducing image blur captured by an interlace scanning imaging device, particularly image blur of an object moving in the horizontal direction.

  2. Description of the Related Art In recent years, systems in which electrical characteristics of electronic components are inspected in the manufacturing process, inspection results are databased for each individual, and managed in the distribution process have become widespread. For example, in the pre-shipment inspection of manufactured semiconductors, the product identification number attached to the semiconductor surface is imaged with an electronic camera, the captured image signal is subjected to character recognition processing and converted to character data, and associated with the test result of the semiconductor Systems that store and manage server databases have been developed.

A product identification number assigned to a small device such as a semiconductor element is small and often unclear. Various techniques for recognizing characters from unclear image signals have been developed in order to increase the character recognition rate even in such a case (Patent Documents 1 and 2).
JP-A-8-212302 JP-A-9-269972

  When a subject moving in the vertical direction is picked up by an electronic camera using an interlaced scanning image sensor, if the image is blurred at a normal electronic shutter speed (1/60 seconds), 7 (A)), when imaging is performed at a high electronic shutter speed, blurring is reduced and a clear image can be obtained (FIG. 7B). However, since the interlace scanning type imaging device alternately outputs the image signals of the odd field and the even field every 1/60 seconds, a time shift of 1/60 seconds is generated between the odd field image and the even field image. Arise. Therefore, in the case of a subject moving in the horizontal direction with respect to the image sensor (FIG. 8B), image shift between odd and even fields can be prevented only by increasing the electronic shutter speed (shortening the exposure time). It was not possible to obtain a clear image (FIG. 8B).

  Further, the method of processing an image signal picked up by an interlace scanning type image pickup device by a conventional image processing method has a problem that the processing means is heavily loaded and takes a long processing time.

  The present invention has been made based on such a conventional technique, and even when an image is picked up by an image pickup apparatus having an interlace scanning type image pickup device, a clear image of an object moving two-dimensionally can be obtained in a short time. An object is to provide an image processing method.

  The present invention that solves the above-described conventional problems is an image processing method for processing an image captured by an imaging unit having an interlaced scanning type imaging device, and includes an odd-field image signal and an even number output from the imaging unit. The image signal of one field among the image signals of the field is generated from the image signals of the upper and lower horizontal lines of the other field sandwiching each horizontal line of the one field, and the generated image signals are It is characterized by a field image signal.

  More specifically, the average value of the pixel signals of the upper and lower horizontal lines of the other field across the horizontal lines is calculated, and the calculated image signals are replaced with the pixel signals of the one field, The pixel signal of one field is complemented.

  The electronic camera is preferably capable of a high-speed electronic shutter operation that is shorter than one field time, and the odd-field image signal and the even-field image signal output from the imaging means are imaged at the high-speed electronic shutter speed. Let it be an image signal.

  Actually, an image signal for one frame is generated from the image signal of one field output from the electronic camera and the image signal of the other field generated. In addition to the image signal for one frame, the image signal of the other field is generated from the image signals of the upper and lower horizontal lines of one field sandwiching each horizontal line of the other field, and the generated Each image signal may be used as the image signal of the other field, and an image signal for one frame may be generated from the image signal of the other field and the image signal of one field output from the imaging means.

  As described above, according to the present invention, the image signal of one field is complemented using the image signal of one field among the image signals of the odd field and the even field obtained from the image sensor of the interlace scanning method. Even if the image sensor moves in the horizontal direction, a clear frame image can be obtained with no image shift between odd and even fields.

  FIG. 1 shows an embodiment of an image input apparatus to which the image processing method of the present invention is applied. The image input apparatus used in this embodiment is an image pickup apparatus (electronic camera) 10 as an image pickup unit equipped with an interlace scanning type image pickup device 13. The light beam that has passed through the photographic lens 11 forms an optical image on the imaging surface of the image sensor 13, is photoelectrically converted by each pixel (photo diode) of the image sensor 13, accumulates charges, and then voltage is applied to each pixel. To be output as an electrical analog pixel signal. That is, the image sensor 13 outputs an odd-field image signal and an even-field image signal every 1/60 seconds while operating in the moving image mode. When operating in still image shooting, one odd field image signal and one even field image signal are output at 1/60 second intervals. Note that the image pickup device 13 performs an image pickup operation by a clock output from the image pickup device driving circuit 15 controlled by the camera control circuit 17.

  The odd-numbered field and even-numbered field image signals output from the image sensor 13 are subjected to processing such as predetermined analog signal correction in the camera signal processing circuit 19 and are output to the image processing circuit 21. In the image processing circuit 21, the input image signal is A / D converted pixel by pixel to form pixel data in the image memory. In this embodiment, the odd field pixel data is stored in the odd field memory 23 and the even field pixel data. Is stored in the even field memory 25. Here, each pixel data corresponds to luminance data of a subject received by each pixel.

  When the pixel data for one frame is stored in the odd and even field memories 23 and 25, the image processing circuit 21 sequentially reads the pixel data from one field memory 23 and 25 and calculates the pixel data of the other field. ,Complement. In other words, in this embodiment, the pixel data of the even field, the pixel data of the horizontal line of the odd field sandwiching each horizontal line of the even field are read from the odd field memory 23, and the pixel data of the two odd fields read out are read. The average value is calculated by addition, and the calculation result is set as pixel data of the pixels in the even field sandwiched between the pixels in the odd field. The set even-field pixel data may be overwritten on a corresponding address in the even-field memory 25, may be stored in a field memory (not shown), or may be stored together with the odd-field pixel data in a frame memory (not shown). Good.

  The basic configuration of the above image processing method in the imaging apparatus 10 will be described in more detail with reference to FIG. FIG. 2A shows an image of the subject 31 that vibrates in the horizontal direction and an enlarged view of the image. From this figure, it can be seen that the image in the odd field (1, 3, 5) and the image in the even field (2, 4) are shifted by about one pixel in the horizontal direction. As the moving speed of the subject 31 in the horizontal direction increases, the deviation further increases (FIG. 2B).

  Therefore, in the present embodiment, each pixel data of each horizontal line (2, 4) in the even field is converted into two horizontal lines (1, 3), (3, The corresponding pixel data of 4) are added to calculate an average value. Thus, the calculation pixel data is set as pixel data of each horizontal line (2, 4) in the even field (FIGS. 3A and 3B). As described above, the pixel data of the even field is calculated from the pixel data of the odd field and complemented to thereby reduce the image shift between the odd field and the even field, and a clear image can be obtained (FIG. 3B). .

A general formula of an image processing method in the imaging apparatus 10 will be described. The pixel data of the even field (2n) is Y (2n, i), the pixel data of the upper odd field (2n-1) sandwiching the even field (2n) is Y (2n-1, i), and the odd field of the lower field If the pixel data of (2n + 1) is Y (2n + 1, i),
Y (2n, i) = (Y (2n-1, i) + Y (2n + 1, i)) / 2
It becomes. However, n and i are integers of 1 or more, the maximum value of n is 1/2 of the number of effective pixels in the vertical direction, and the maximum value of i is the number of effective pixels in the horizontal direction (horizontal line).

  The above processing is repeated in order for pixel data for one horizontal line. When the pixel data of the even field is obtained by calculation for all the pixel data of one horizontal line, the pixel data of the one horizontal line of the next even field is obtained by calculation in the same manner. The above processing is repeated until the pixel data of all horizontal lines in the even field are obtained. Note that it is not necessary to perform the calculation for all the areas, and a configuration in which the calculation is performed for an area including a target subject or a preset area may be employed.

  Through the above processing, the pixel data in the even field is complemented by calculation. That is, the image data for one frame (screen) is obtained by synthesizing the actual image data of the odd field actually captured and the complemented image data of the complemented even field.

  The digital image signal for one frame obtained by the above processing is converted into an image signal of a predetermined format and output, input to another image processing apparatus, displayed on a display, or written in a memory. An example of the image displayed on the display is shown in FIG. In the figure, (A) is an image display when an electronic shutter is imaged at a normal speed (about 1/60 seconds), (B) is an image display when an image is captured with a high-speed electronic shutter, and (C) is It is an image display at the time of performing the image processing of this invention to the image data imaged with the high-speed electronic shutter. As described above, according to the imaging apparatus of this embodiment, the pixel data of each horizontal line in the even field is complemented by the average value of the pixel data of the upper and lower horizontal lines in the odd field sandwiching the horizontal line. There is no shift in the even field image, and an image with particularly clear left and right contours can be obtained.

  If the image data obtained by the image processing of the present embodiment is used for character recognition, it is possible to read the identification number assigned to the subject from a subject that moves and vibrates in the horizontal direction.

  Next, a usage example in which the imaging apparatus 10 is applied to an electrical characteristic test of a magnetic head will be described with reference to FIGS. In this use example, the unique manufacturing number assigned to the slider of the magnetic head is read when the electrical characteristics test of the magnetic head is performed by the electrical characteristics measuring device (FIG. 5), and the manufacturing number and the measurement result are associated with each other. The data is sent to a server (computer such as a personal computer or workstation), converted into a database in the server, and applied to a system used for inventory management, sales, etc. (FIG. 6).

  The electrical characteristic measuring device 50 includes an arm 53 to which the magnetic head 51 can be attached and detached, for example, a magnetic disk 55 that rotates at a constant speed of 7200 rpm, and a controller 57 that controls these to measure product characteristics. The arm 53 is driven to move the magnetic head 51 onto the magnetic disk 55, and a test signal can be written, erased, or read by the magnetic head 51 to measure the electrical characteristics of the magnetic head 51. (FIG. 5).

  The imaging apparatus 10 is fixed outside the magnetic disk 55 at a position and composition where the serial number attached to the tip surface of the magnetic head (slider) 51 can be imaged during the test. The composition is preferably adjustable. The magnetic head 51 under test vibrates in the vertical (vertical) direction following the minute unevenness of the magnetic disk 55, and vibrates in the radial (horizontal) direction in order to trace the slight fluctuation of the track of the magnetic disk 55. ing. When the magnetic head 51 (slider) vibrating in the vertical direction and the horizontal direction is imaged in this way, the captured image is blurred in the vertical direction (up and down direction) and the horizontal direction (radial direction). For this reason, conventionally, the magnetic head 51 is placed on a jig and is imaged by an electronic camera in a stationary state, and the test is performed after reading the product number, or the test is performed after reading.

  According to the imaging device 10 of the present invention, the image blur in the vertical direction can be reduced by increasing the speed of the electronic shutter, the image data in the even field can be complemented by image processing, and the image blur in the horizontal direction can be reduced. The product number can be read by imaging the magnetic head 51 during the test operation. An image obtained by imaging the number “2” attached to the magnetic head 51 that vibrates horizontally is as shown in FIG. 4A is an image obtained by normal imaging, FIG. 4B is an image obtained by imaging with a high-speed electronic shutter, and FIG. 4C is an image obtained by imaging with a high-speed electronic shutter. It is an image.

  In this way, pixel data for one frame, which is an image with a clear outline obtained by complementing the pixel data of one field, is output to the control device 57 or a personal computer. Then, a character identification process is performed by the control device 57, and the product number “xxxx” is read. Further, the measurement result “dd, pp, rr,...” Measured by the control device 57 and the product number “xxxx” are combined and transmitted to the server 60. The server 60 creates a database and uses it for inventory management, sales management, and the like. The characters and symbols used for product numbers are usually combinations of alphanumeric characters, but the number of digits differs depending on the product, and characters and symbols other than alphanumeric characters may be used. It can be applied to either case.

  If character recognition processing cannot be performed with one imaging data, the pixel data of the odd field may be obtained by the complementary calculation processing using the pixel data of the even field, and the imaging and complementary calculation processing is further performed multiple times. The character recognition processing may be executed by obtaining image data for a plurality of frames.

  As described above, according to the electrical characteristic measuring apparatus to which the present invention is applied, a clear image can be obtained by the imaging apparatus 10 even when the magnetic head 51 vibrates in the vertical direction and the horizontal direction. Since the product number of the magnetic head 51 can be imaged during the test and can be easily recognized and read in a short time, the product number can be imaged and read within the normal measurement time. In addition, a jig and process for mounting and stopping the magnetic head 51 for imaging are also unnecessary.

  Note that the digital image signal for one frame subjected to the complementing process can be converted into a video signal of a predetermined format and displayed on the display. Thus, when the switch SW is operated, pixel data for one frame is output to a personal computer or the like. Or, normally, a moving image is displayed in a moving image mode and a moving image is displayed on the display. When the switch SW is operated or an instruction is received from a personal computer, a still image is captured and the above-described field complementing process is executed. The digital image signal for one frame subjected to the complementary processing may be output to the personal computer (control device 57).

  In the embodiment, the pixel data of the even field is complemented and generated using the pixel data of the odd field. Conversely, the pixel data of the odd field may be generated by image complement processing using the pixel data of the even field, Both of these processes may be executed to generate image data for two frames. In the illustrated embodiment, the odd-numbered field memory and the even-numbered field memory are provided and the pixel data is stored in each. However, only the pixel data of one field may be stored.

  In the above embodiment, the image processing circuit 21 of the imaging device 10 is configured to complement the image data of one field by the image processing method. However, the image processing of the present invention is performed by a personal computer or the like separate from the imaging device 10. It may be configured to execute. As described above, according to the configuration in which image processing is performed by a separate device, the most common interlace scanning CCTV camera or the like can be used as it is as an imaging device.

It is the figure which showed the principal part of embodiment of the imaging device to which the image processing method of this invention was applied with the block. It is a figure explaining the relationship between an image and a pixel when a to-be-photographed object rolls, Comprising: (A) is a figure which showed the case where rolling is small, (B) is the figure which shows the case where rolling is large. FIG. 5 is a diagram for explaining the relationship between an image and a pixel when the image processing method of the present invention is applied, in which (A) shows an image of only an odd field, and (B) complements an image of an even field. It is the figure which showed the later relationship. 4A and 4B are diagrams illustrating an image captured by an imaging apparatus to which the present invention is applied, wherein FIG. 5A is a diagram illustrating an image when captured normally, and FIG. 5B is a diagram illustrating an image when captured with a high-speed electronic shutter; C) is a diagram showing an image obtained by imaging with a high-speed electronic shutter and applying the image processing method of the present invention. It is a figure which shows embodiment which applied the imaging device carrying the image processing method of this invention to the test apparatus of a magnetic head. It is a figure which shows the outline | summary of the product management system which manages the test result obtained by the testing apparatus of the magnetic head. It is a figure explaining the case where a subject is moving up and down, (A) shows a mode that a subject is moving up and down, and (B) shows an image which imaged the subject with a high-speed electronic shutter. FIG. It is a figure explaining the case where a subject is moving right and left, and (A) shows a mode that a subject is moving right and left, and (B) shows an image which imaged the subject with a high-speed electronic shutter. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image pick-up device 13 Image pick-up element 15 Image pick-up element drive circuit 17 Camera control circuit 19 Camera signal processing circuit 21 Image processing circuit 23 Odd field memory 25 Even field memory 50 Electrical characteristic measuring device 51 Magnetic head 55 Magnetic disk 57 Control device 60 Server

Claims (5)

An image processing method for processing an image picked up by an image pickup means having an image pickup element of an interlace scanning method,
Of the odd-field image signal and the even-field image signal output from the imaging means, the image signal of one field is converted into the image signal of the upper and lower horizontal lines of the other field sandwiching each horizontal line of the one field. And generating each of the generated image signals as the image signal of the one field. 2. The image processing method according to claim 1, wherein an average value of pixel signals of upper and lower horizontal lines of the other field sandwiching each horizontal line is calculated, and each of the calculated image signals is converted to each pixel signal of the one field. Image processing method to replace with. 3. The image processing method according to claim 1, wherein the imaging unit is capable of a high-speed electronic shutter operation shorter than one field time, and outputs an odd field image signal and an even field image output from the imaging unit. The image processing method, wherein the signal is an image signal captured at the high-speed electronic shutter speed. 4. The image processing method according to claim 1, wherein an image signal for one frame is obtained from the image signal of one field output from the imaging unit and the generated image signal of the other field. Image processing method to be generated. 4. The image processing method according to claim 1, further comprising: obtaining an image signal of the other field from image signals of upper and lower horizontal lines of one field sandwiching each horizontal line of the other field. Generate each image signal as the image signal of the other field, and generate an image signal for one frame from the image signal of the other field and the image signal of one field output from the imaging means. Image processing method.

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