JPH073558B2 - Image information detection processing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image information detection processing method in which image information of an original image film such as a negative film is detected by a two-dimensional image sensor having a relatively coarse pixel density. Regarding

(Technical background of the invention and its problems) In a photographic printing apparatus, the density of an original image film (for example, a negative film) must be measured in order to determine the exposure amount or correction amount of the printing, but conventionally, the optical path of the printing optical system is used. The average density of the negative film is measured by a photo sensor such as a photodiode arranged in the vicinity of the LATD (Large Area Transmi
(ttance Density) I am trying to measure light. The image detection by this LATD is to measure the average of the negative film and not to measure the image density of the negative film accurately and over the entire screen.Therefore, printing exposure or correction is not reliable. . As a device that solves this problem, the present applicant has proposed Japanese Patent Application No. 60-154244,
No. 60-151631, Japanese Patent Laid-Open No. 60-220325, etc. are proposed. However, if the pixel density of the image sensor used for this is high, the cost of the image sensor and its peripheral circuits is very high, and further exposure is required. There is a problem that the calculation processing time for the amount and the like becomes long. Therefore, it is desirable that the pixel density of the image sensor is relatively coarse in order to calculate the exposure amount and the like.

Further, in the photo printing apparatus, it is necessary to accurately position the frame of the original film on the optical frame in order to properly print the frame image of the original film on the printing paper. For this reason, conventionally, a notch is provided at the side end portion of the original image film, and this is detected by an optical sensor or the like for positioning, but it is necessary to accurately correspond to the frame when the notch is provided. There is a drawback that it requires a lot of labor. Further, there is also a method of positioning the original image film by constantly feeding a fixed distance to the original image film, but there is a drawback that the positional deviation is accumulated and the accuracy is poor. Furthermore, a method has also been proposed in which an optical sensor such as a photodiode is arranged according to the shape of the frame of the original film and the positioning is performed according to the detection state or order of each optical sensor, but the structure and control algorithm are complicated. There is a drawback that becomes. Furthermore, although a slit mask is attached to increase the resolution, there is a drawback that the sensitivity is lowered.

As a device that solves this problem, the applicant of the present invention has disclosed in Japanese Patent Laid-Open No.
No. 40 and Japanese Patent Application No. 60-185793 have been proposed, but the pixel density of the image sensor normally used for this requires high resolution. This is because the conveyance control cannot be accurately performed unless the edge of the image frame is accurately detected. Here, although the resolution can be increased by interpolating the pixel pitch of the image sensor, it is necessary to capture the data each time the fine pitch is fed and detect the data over a plurality of predetermined pixels. Takes
There is a problem in high-speed data processing, and particularly when using the edge detection information during negative feed, the total negative feed time is extremely long, and there is a problem in work.

(Object of the Invention) The present invention has been made under the circumstances described above.
An object of the present invention is to detect image information by pixel pitch interpolation for finely feeding an original image film such as a negative film with a two-dimensional image sensor having a relatively low resolution, improve resolution, and detect high-speed and accurate image information. It is to provide a method of performing processing.

(Summary of the Invention) The present invention relates to a method in which an original image film and a two-dimensional sensor move relative to each other, and an image of the original image film is measured by the two-dimensional sensor. By interpolating the pixel pitch by processing the output of the pixel row detected at a pitch relatively smaller than the pixel pitch in the moving direction, and by synthesizing the data of the plurality of pixel rows corresponding to a predetermined detection range The high resolution image information can be detected at high speed.

(Embodiment of the Invention) First, a photometry method of a negative film as an original image film, which is a premise of the present invention, will be described. The detection of the negative film by the two-dimensional image sensor is carried out by a method as disclosed in, for example, JP-A-60-196740.

According to the present invention, as shown in FIG. 1, an image information detecting device 10 having a surface scanning type two-dimensional image sensor 11 made of, for example, a CCD, is arranged in the vicinity of the negative film 2 of the printing part. The image information of the entire screen is divided into a large number of aligned pixels and detected. That is, by giving a predetermined drive signal to the image sensor 11 from a drive circuit (not shown), the two-dimensional image sensor 11 receives the transmitted light of the negative film 2 placed on the printing portion through the lens system 12. Therefore, the two-dimensional image sensor 11 divides the entire negative film 2 into a large number of aligned small pixels 21 as shown in FIG. 2A, and the screen of the negative film 2 is sequentially arranged according to the scanning line SL. The whole can be scanned.
Then, the image signals are sequentially output from the output register section of the image sensor 11 according to the scanning of the entire screen, the sample and hold circuits sample and hold the image signals, and the hold values are converted into digital signals by the AD converter. AD
The digital signal from the converter has an array corresponding to the pixel 21 as shown in FIG. 2 (B) in the memory under the control of the write control circuit, and the true digital value of the negative film 2 (or table conversion or the like). The density value will be stored.

Then, when the negative film 2 is conveyed to the printing unit and printing is performed, it is necessary to accurately position the image frames 2A, 2B, 2C, ... Taken as shown in FIG. 3 (A) on the negative carrier. Yes, after printing the frame of the image, negative film 2
Is conveyed to position the next image frame and stop. In order to stop the detection of such an image frame, conventionally, a notcher is used to previously make a notch in the negative film to automatically stop the image frame at a predetermined position. On the other hand, regarding the negative film 2 as shown in FIG. 3A, if image information for each pixel of the image sensor 11 as shown in FIG. From this, it is possible to detect the image frames 2A, 2B, 2C, ... And also the unphotographed regions (snake part) RA, RB, RC, ... Between the adjacent image frames can be detected from their exact numerical value data. This makes it possible to stop the detection of the image frame together with the size information. Here, a resolution of several mm unit on the negative film is sufficient for the exposure correction calculation, and the low resolution image sensor is cheaper and easier to handle. On the other hand, edge detection requires a resolution of several tenths of a mm unit on a negative film. Therefore, as shown in FIG. 2 (A), a pixel row 40 that is at the central portion (or peripheral portion) of the two-dimensional image sensor 11 and is orthogonal to the transport direction of the negative film 2 is electrically extracted, This pixel row
At 40, the edge of the image frame of the negative film 2 is detected.

By the way, in the detection of the image sensor 11 described above, the ability of edge detection becomes high in the case of a sensor having a high resolution, but since the number of pixels is large, the calculation processing of the exposure amount and the like becomes complicated, and FIG. In the case of detecting by the pixel row 40 as shown in (), a negative conveyance time corresponding to the number of pixels of the detection target range is required. For this reason, in the present invention, in order to increase the resolution of the image sensor, a minute pitch feed of an integer of one pixel of the memory is carried out, during which a plurality of pixel column outputs in the detection target range are fetched as data in the memory at every minute feed pitch. At the time when the transportation of one pixel (a plurality of stored pixel data) is completed, the plurality of pixel column data on the memory are combined (combined) and the edge identification of the image frame is calculated. Even if the detection target range is 5 to 10 pixel rows, this method can capture data in a detection time of 1 pixel row, so the detection time of 1 pixel row by fine pitch feed is 20 mm. Seconds (1 pitch is 2 milliseconds and 10 pitches
20 milliseconds), it is usually 5 to 10 times 10
Since it takes 0 to 200 milliseconds, according to the present invention, the detection time can be greatly shortened and the capability of the photographic printing system can be further improved.

By the way, the basis of dimension measurement by an image sensor, for example, a line sensor, is that the object to be measured (diameter D) 22 imaged on the line sensor 20 through a lens 21 as shown in FIG.
Image of the slice level SL of FIG.
By binarizing, a photoelectric element of light or dark, that is, the number N of pixels (for example, 1024 to 2048) is obtained, N × Pi is obtained with the pixel pitch Pi (for example, 14 to 28 μ) being a constant value, and the lens 21 Dimension D of DUT 22
Depends on what is required. Therefore, this measuring method has the following features.

(1) The measurement time is short (0.5 to 100 milliseconds).

(2) It has semi-permanent durability because it has no moving parts.

(3) Wide application range as non-contact measurement.

(4) There is no limitation on the illumination light as long as it is within the sensitivity wavelength range of the image sensor.

(5) The position tolerance of the object to be measured is wide.

From these points, it is considered that this method can meet the on-line measurement required by modern industry, but since there are processes of imaging and photoelectric conversion, there are causes of various measurement errors. Further, as a fundamental problem, there is a drawback that the measurement accuracy and the measurement range are limited by the number of pixels N and the pixel pitch Pi. Pixels have been miniaturized due to technological advances in LSI manufacturing, and several μ-pitch ones have been developed.However, when performing arithmetic processing such as exposure correction, the resolution of several mm units is used on a negative film image frame. It is generally desirable to divide the pixel into units of several hundreds in terms of characteristics for extracting the features of the picture, it is advantageous in terms of cost, and it is convenient in performing image processing at high speed.

In the present invention, the pixel pitch of the two-dimensional image sensor is interpolated to be read, and the dimension measurement resolution (tenths of a millimeter) about 10 times the pixel pitch Pi is achieved, and the negative film can be put to practical use. Has completed the edge detection method for image frames. That is, when measuring the size of the image by using the two-dimensional image sensor, it is common sense that it is impossible to improve the measurement accuracy more than the pixel pitch. this is,
It is a result of the notion that image reading is digital. Pixel output pitch interpolation in this invention is a method of treating a pixel output as a continuous analog signal and detecting a minute change in the output, and has the same meaning as a combination of digital and analog, that is, a vernier caliper scale. There is. This principle is that when the output waveform of the image sensor that is sampled and held in a staircase shape shown by the solid line RL in FIG. 5 is obtained, the slice level SL normally causes N ₁ and N ₃ bright pixel numbers, N ₂ By creating a waveform such as a broken line BL for the number of dark pixels and the area to be read, it is possible to detect ΔN subdivided from the pixels. ΔN is the _first pixel output N, (N _{1 + 1)} -th to detect pixel output converted A / D, it is also possible to determine the intersection of the slice level SL by proportional calculation. However, this has the drawback that the circuit becomes complicated, the calculation requires time, and it is difficult to accurately detect minute changes. On the other hand, in the method of the present invention, ΔN is detected in real time with a simple configuration, that is, the pixel output is detected at a minute pitch as shown by the broken line BL in FIG. 5, and the image is statistically analyzed by the interpolated variable distribution. The edge of the frame is detected. Processing the output of the pixel array that detects the negative film at a pitch relatively smaller than the pitch in the moving direction of the two-dimensional sensor,
This is achieved by detecting the length of the binarized signal based on the interpolated signal indicated by W ₁ , W _2, etc. In FIG. 5, the signal length W ₁ is obtained by the following equation.

W ₁ = N ₁ · T + ΔN · T = T (N ₁ + ΔN) ……… (1) This is measured at clock t, and T = kt ……… (2) From equation (1), W ₁ = kt (N ₁ + ΔN) (3) Here, if k is 10, ΔN is counted up to a length of 0.1 pixel, and an interpolated measurement value is obtained.

Next, the method will be described in detail.

In the present invention, as shown in FIG. 6, with respect to the pixel column P of the two-dimensional image sensor 11, a plurality of memory pixel column data areas M (for example, 10 pixels corresponding to # 1 to # 10) are provided on the memory. To form one pixel data. For example,
The pixel data M ₁ stored in the memory corresponding to the light receiving pixel P ₁ is the 7th pixel.
A M ₁₁ ~M ₁₁₀ as shown in FIG, the storage pixel data M ₂ in the memory corresponding to the light receiving pixel P ₂ is the M ₂₁ ~M _210. Similarly, the other light receiving pixels Sij are also formed by the storage pixel data of # 1 to # 10. According to the present invention, as shown in FIG. 8, when the amount of negative film conveyance required to fill each memory pixel column data area of the memory with data is, for example, 2.0 mm, one minute conveyance of the negative film is performed. Repeat 10 times with the amount being 0.2 mm, and stop period P between them
The negative film is measured on each of 1 to P10 with a two-dimensional image sensor. The data of the divided pixels as shown in FIG. 2 (B) can be obtained by the detection by the image sensor once.
In the present invention, as shown in FIG. 8, the data obtained by the photometry of P1 is M ₁₁₁ , M ₁₂₁ , M ₁₃₁ , ..., M ₂₁₁ , M ₂₂₁ ,
The data stored in the area of M ₂₃₁ , ... and obtained by the photometry of P2 is the data of M ₁₁₂ , M ₁₂₂ , M ₁₃₂ , ..., M ₂₁₂ , M ₂₂₂ , M ₂₃₂ , ...
Area, and the corresponding storage pixel column data area is sequentially stored. Therefore, the negative film is 2.0m
When the data obtained by P10 photometry during m transport is stored in the memory M ₁₁₁₀ , M ₁₂₁₀ , ..., M ₂₁₁₀ , M ₂₂₁₀ , ..., the data is stored in all areas of the memory corresponding to the predetermined detection range. Is remembered.

Thereafter, as shown in FIG. 9, by processing the pixel row data stored in the memory, that is, the image information detected by interpolating the pixel pitch of the negative film 2, the non-photographing between the frames of the negative film 2 is performed. The area R and the edge of the image frame are detected. In this example, the exact value of light intensity is 8 bits (0 to 255)
I am getting at. Further, in this case, since the frame size of the negative film 2 is known by measurement or input, the detection area of the image information and the pixel row 40 are switched and used according to the frame size as shown in FIG. When all the pixels of the image sensor 11 are composed of j columns (1 to 40) and i rows (1 to 30), the area F2 is used for the 135F size and the area F1 is used for the 110 size, for example. And the image sensor 11
Let TSij be the measured value of the pixel Sij of No. 1 and the true value of the jn-th sampling point in the j-th column. In the case of 135F size, the average number of pixels is 23-7 = 16, Becomes When detecting the negative film 2 with a fine pitch,
135F size exact THS of each adjacent sampling point
_135F is Similarly, in the case of 110 size, the average value T is 19-11 = 8 because the number of pixels is 19-11 = 8. Becomes When detecting the negative film 2 with a fine pitch,
The exact _110- size THS _{110 of} each adjacent sampling point
Is Required by. When the measured values thus obtained are sampled to obtain the frequency distribution, an exact numerical value curve as shown in FIG. 9 is obtained.

In this way, when the negative film 2 is conveyed by one pixel, as shown in FIG. 9, the vicinity of the unphotographed area between each frame within the predetermined detection range is relatively enlarged from the entire image data. Since it is possible to obtain with high resolution, and the position of the uncaptured area between frames can be known and the edge of the image frame can be detected, the negative film can be controlled to accurately position the image frame as described above. can do.

FIG. 11 is a flowchart showing an example of a method for stopping the detection of image frames. First, a negative carrier having a size corresponding to the size of the negative film 2 to be printed is loaded at a predetermined position of the printing section (step S1), and the negative film is printed. The size of the opening of the carrier is measured by the image sensor 11 as in JP-A-60-151626 (step S2). The size measurement may be visually input. According to this size measurement, the conveyance amount of the negative film 2 is set, the above-mentioned pixel row 40 (P) is automatically selected and extracted, and the printing exposure amount and its correction amount are controlled.

Next, the negative film 2 to be printed is loaded at a position where the idle shooting frame at the tip of the negative film substantially corresponds to the opening of the negative carrier (step S3), and the tip of the negative film 2 is loaded on the negative drive roller. Then, the pulse motor is driven to convey the negative film 2 at a high speed quantitatively by a little less than half of the frame interval D S ₁ (step S4), and then a low-speed minute pitch feed is performed (step S5), during which the image sensor 11 is operated. The image information is detected by the method, and the data for each pixel is obtained as shown in FIG. As is apparent from the correspondence between FIGS. 3 (A) and 3 (B), the negative film 2
Since there is a significant difference in the true value between the image frames 2A, 2B, 2C, ... and the unphotographed area RA (RB, RC, ...) between the frames, By searching the pixel row 40 of the image sensor 11 for an area within a certain change range in the vertical direction (the direction perpendicular to the transport direction of the negative film 2) which is a certain value or more and is a sharp change in the horizontal direction of the true value. ,
It is possible to detect the unphotographed areas RA, RB, RC, ... Of the image frames 2A, 2B, 2C, ... And the edges of the image frames and the unphotographed areas.
FIG. 12 shows this state. The negative film 2 is conveyed to the printing portion of the negative carrier 32 in the N direction, and the pixel row 40 of the image information detecting device 10 detects the vicinity of the unphotographed region RB between frames. ing. The pixel column 40 of the image sensor 11 is arranged to come to the center of the opening of the negative carrier 32.

The negative film 2 is continuously conveyed at a fine pitch until the edge of the image frame is detected (step S5). When the edges of the image frame 2A and the unphotographed region RB are detected, the size measurement is performed (step S5). Distance S ₂ from the size information obtained in S2) until the frame is positioned on the printing part
Only the high-speed fixed amount conveyance is performed (steps S6, S7, S8), and then stopped (step S9). In this case, the distance E until the edge of the image frame 2A and the non-photographed region RB of the image frames 2A and 2B located at the substantially central portion of the negative carrier 32 after the high-speed fixed amount transport S ₁ is the above This is a parameter (variable) for correcting the variation in the distance of the unphotographed region RB, and if the feed amount D = S ₁ + E + S ₂ of the image frame 2A is conveyed in the state of FIG. 12,
Eventually, the image frame of the negative film 2 is stopped while being accurately positioned on the printing portion.

After the negative film 2 is conveyed and stopped, it is judged whether or not the stopped frame is suitable for printing (step S10). If it is not suitable for printing, skip to step S12, and if it is suitable for printing, Whether or not the negative film 2 is still present, because the printing of the stopped frame is performed with the determined exposure amount and correction amount (step S11), and the next image frame is conveyed to the printing unit and printed after the printing of the frame is finished. And the negative film 2 is conveyed at a high speed by a little less than 1/2 of the frame interval according to the size information obtained in step S2 (step S2).
12, S4). Hereinafter, by repeating the above-described conveyance and stop, it is possible to automatically print each image frame in sequence. Then, when the negative film 2 is used up in step S12, the negative drive roller is automatically stopped from idling, and the process ends. Here, the image information is detected in the central portion of the negative film located in the central portion of the negative carrier, but it may be near the central portion or in the peripheral portion.

Although the pixel column data area stored in the memory is “10 columns” for each light receiving pixel column in the above description, it may be arbitrary as long as it corresponds to the minute feed detection pitch of the negative film.
Also, the ij column of the detection area in FIG. 10 can be arbitrarily changed. Although the detection is performed by the two-dimensional image sensor in the above description, the present invention is not limited to the CCD or MOS type two-dimensional image sensor, and photodiodes and line sensors are arranged adjacent to each other by a predetermined detection range. But good.

(Effects of the Invention) As described above, according to the method of the present invention, a high resolution can be achieved even when an image sensor having a relatively low resolution is used, and the film can be conveyed by a distance corresponding to one pixel. Since it is the same as when all the detection range is detected, even if an image information detection device with a relatively low resolution for exposure correction calculation is used, image frame detection and positioning at a predetermined position can be performed automatically and at high speed. It can be performed, and efficient and reliable photo processing can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example in which the present invention is applied to a photographic printing apparatus, and FIGS. 2A and 2B are views for explaining an example of a correspondence relationship between pixel division of an original image film and stored data. 3 (A) and 3 (B) are diagrams showing the relationship between the negative film and image information, FIGS. 4 and 5 are diagrams for explaining the principle of the present invention, and FIGS. 6-8. FIG. 9 is a diagram for explaining the relationship between the detection data of a pixel array and storage in a memory according to the present invention, FIG. 9 is a diagram for explaining the synthesis of detection data, and FIG. 10 is a range of use of pixel examples. Figure for the
FIG. 11 is a flowchart showing an example of the operation of stopping the detection of image frames, and FIG. 12 is a diagram showing the state of the negative carrier section. 2 ... Negative film, 3 ... Filter, 4 ... Light source, 5,
12 ... Lens system, 6 ... Black shutter, 7 ... Photographic paper, 8 ... Optical sensor, 10 ... Image information detection device, 30
...... Film transport device.

Claims (3)

[Claims] 1. A method in which an original image film and a two-dimensional sensor move relative to each other, and an image of the original image film is measured by the two-dimensional sensor, wherein the original image film has a pixel pitch in the moving direction of the two-dimensional sensor. High resolution image information by interpolating the pixel pitch by processing the output of the pixel row detected at a pitch relatively smaller than the above, and further synthesizing the data of the plurality of pixel rows corresponding to a predetermined detection range. A method for detecting and processing image information, which is capable of detecting at high speed. 2. The image information detection processing method according to claim 1, wherein the relatively small pitch is an integral fraction of the pixel pitch. 3. The image information detection processing method according to claim 1, wherein the two-dimensional sensor is an image sensor.