JPH05260372A - Picture reader - Google Patents

Abstract

PURPOSE:To store much picture information by reading a picture on a silver salt photosensitive material under plural different read conditions, storing the picture so as to effectively utilize a wide dynamic range of a negative film. CONSTITUTION:A light radiates from a lighting device 2 to a negative film 1 being a silver salt photosensitive material and the transmitted light is made incident in an image pickup element 4 through an iris 3. The element 4 outputs a signal in response to a light receiving level to read the film. An output signal from the element 4 is stored in a storage section 7 through a process circuit 5 and a signal processing circuit 6. On the other hand, the output of the circuit 5 is inputted to an averaging circuit 8, the exposure condition is set variably by a setting section 9 based on a mean value of read picture signals and the device 2 or the iris 3 is adjusted according to the condition. An exposure level is changed based on the standard condition decided by the preliminary scanning device and the picture is read under plural different read conditions and the result is stored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, and more particularly to an apparatus for photoelectrically reading an image on a silver salt photosensitive material.

[0002]

2. Description of the Related Art Conventionally, image information from various video sources such as video cameras, still video cameras and VTRs is stored in a storage medium such as a magnetic disk or an optical disk, and the image information stored in this storage medium is displayed on a monitor television. There is an image system that can be displayed on or made a hard copy by a printer.

Further, in such an image system, an image of a silver salt photosensitive material such as a negative film or a print, or an image such as a print or an illustration is photoelectrically read by an image pickup device, and image information from the various image sources is read. In some cases, it is possible to input to the image system as described above.

[0004]

By the way, a negative film (or a reversal film) among silver salt light-sensitive materials is used.
In that case, the dynamic range of the image information is wide, but when photoelectrically reading the image of the negative film as described above by the image pickup device, only the level in a relatively narrow range corresponding to the reading condition is read. You will remember it. For this reason, in spite of having a wide dynamic range as a video source, in the image system, such a wide dynamic range cannot be effectively utilized, and the original white part or the blackout part of the read image is originally used. There is a problem in that the included image information cannot be obtained.

The present invention has been made in view of the above problems, and in an apparatus for photoelectrically reading an image of a silver salt photosensitive material such as a negative film and storing the image in a storage medium, a wide dynamic range of the negative film is provided. The purpose is to enable effective use and store a large amount of image information.

[0006]

Therefore, the image reading apparatus according to the present invention is constructed as shown in FIG. In FIG. 1, the image reading means photoelectrically reads the image of the silver salt photosensitive material and outputs an image signal, and the storage means:
The image signal is stored. On the other hand, the reading condition changing unit switches the reading condition of the image reading unit to a plurality of different conditions to read the same image a plurality of times.

Here, an average value detecting means for detecting the average value of the image signal output from the image reading means is provided, and the reading condition corresponding to the average value detected by this average value detecting means is used as the standard reading condition. On the other hand, while being set, the reading condition setting means based on the average value for setting the other reading conditions based on the standard reading condition can be provided.

In addition to the average value detecting means, a highlight portion detecting means for detecting the highlight portion of the image from the image signal output from the image reading means, and a shadow portion detecting means for detecting the shadow portion of the image. On the other hand, it is also possible to provide a reading condition setting means for each level for setting a plurality of different reading conditions based on the detection results of the average value detecting means, the highlight portion detecting means and the shadow portion detecting means. it can.

Further, a bracket photographing judging means for judging that the image of the silver halide photosensitive material read by the image reading means is a bracket photographing for photographing a plurality of the same subject under different exposure conditions, and the bracket photographing judging means. When it is determined by the shooting determination means that the image is taken by bracket shooting, switching of reading conditions is prohibited for each of a series of images in the bracket shooting,
It may be configured by providing condition switching prohibition means for performing only reading under a predetermined standard reading condition.

Further, instead of the condition switching prohibiting means,
There may be provided bracket condition setting means for setting a reading condition for each of a series of images in bracket shooting with reference to the exposure condition in the bracket shooting when the bracket shooting determination means determines that the image is a bracket shooting image. good. Further, the storage means stores a reference image signal of a plurality of image signals for the same image output from the image reading means in a predetermined standard format, and an image signal other than the reference image signal is a reference image signal. It is preferable to store only the whiteout or blackout portions in the above.

[0011]

According to the image reading apparatus having such a structure, when the image of the silver salt photosensitive material is photoelectrically read, the same image is not read under only one reading condition for one image but under a plurality of different reading conditions. By reading and storing image signals with different reading conditions for the same image, the wide dynamic range in the image of the silver salt photosensitive material can be retained and stored.

As the reading conditions, standard reading conditions may be set on the basis of the average value of the image signal, and different reading conditions may be set on the basis of the standard reading conditions. Alternatively, while the average value is detected, the highlight portion, It is preferable to detect the shadow portion and set the reading conditions corresponding to the highlight portion and the shadow portion so that the reading conditions are suitable for the characteristics of each image.

Further, when reading a plurality of images subjected to bracket photographing, switching of the reading condition is prohibited and only the standard reading condition is read, or the bracket photographing is performed based on the exposure condition in the bracket photographing. The reading conditions for the series of images are set to prevent unnecessary reading / memorizing of the bracket-captured image.

Further, in storing the image signal, the reference image signal among the image signals corresponding to the same image is stored in a predetermined standard format, and the image signals other than the reference image signal are overexposed in the reference image signal. Or, make sure to memorize only the blackened parts,
Aim to save storage capacity.

[0015]

EXAMPLES Examples of the present invention will be described below. FIG. 2 is a block diagram showing the hardware configuration of the first embodiment of the image reading apparatus according to the present invention. Here, the negative film 1 as the silver salt photosensitive material is irradiated with the illumination light from the lighting device 2, and the light passing through the negative film 1 passes through the iris 3 provided on the side opposite to the lighting device 2 and the image sensor. Four
The light is received by the (photometric element), and the image pickup element 4 outputs a signal according to the light receiving level, and the negative film 1 is photoelectrically read. The above lighting device 2,
A portion including the iris 3 and the image sensor 4 corresponds to the image reading unit in this embodiment.

Although the reading structure by the image pickup device 4 is simplified in FIG. 2, in reality, R, G, B
3 line sensors are provided, and R, G, B color image signals in the main scanning direction corresponding to the image on the negative film are obtained by scanning with these line sensors. Scanning in the sub-scanning direction is performed by moving the line sensor in a direction orthogonal to the main scanning direction.
There is a method of moving in the same direction. Also, instead of three line sensors, only one line sensor is provided, and R,
Scanning may be performed three times while switching the G and B color filters. Further, in an application field in which the number of pixels may be relatively small, an area sensor may be used to eliminate the mechanical movement of the sub-scan.

A signal from the image pickup device 4 is output to a storage section 7 (storage means) via a process circuit 5 and a signal processing circuit 6 for performing signal compression processing and the like, and is stored in a storage medium such as an optical disk or a magnetic disk. It is supposed to be remembered. Here, an average value detection circuit 8 (average value detection means) for inputting the output of the process circuit 5 is provided, and the exposure condition setting is performed based on the average value of the read image signal detected by the average value detection circuit 8. Part 9 (reading condition changing means)
Variably sets the exposure condition, and adjusts the illumination device 2 or the iris 3 according to the set exposure condition.

The operations of the signal processing circuit 6, the storage unit 7, the exposure condition setting unit 9 and the like are controlled by the CPU 10. The manner of reading control of the negative film 1 in such a configuration will be described with reference to the flowchart of FIG.
First, an image signal is obtained by prescanning under a preset reading condition (exposure condition), and the average value of this image signal is detected (S1).

The above pre-scan does not necessarily have to be performed by the actual reading device. For example, as shown in FIG. 2, another reading device (a portion surrounded by a dashed line in FIG. 2) may be provided in front of the film feeding path to perform prescan. Since high image quality is not required in the prescan, an area sensor is sufficient. With such a configuration, rapid processing can be expected. In addition, if there is an interval of one film or more between the actual reading portion and the actual reading portion, when the actual reading is performed, the actual reading is started based on the information of all frames of the film obtained by the prescan. You can In addition, although there is an image in which only one frame in the film is biased to a specific color, most of all frames contain three primary colors at a fixed ratio, so based on the data in the prescan of all frames. If you adjust the white balance, you can adjust the white balance with high accuracy.

Next, standard reading conditions corresponding to the read image of this time are set based on the detected average value (S2). Further, an overexposure reading condition (for example, + 2EV) and an underexposure reading condition (for example, -2EV) are set so that the exposure level is moved back and forth by a predetermined level around the standard condition (S).
3). The value for moving the exposure level forward or backward with respect to the standard condition may be a preset fixed value or may be arbitrarily variably set.

The above steps S1 to S3 correspond to the reading condition setting means based on the average value. As described above, when the standard condition and the two conditions in which the exposure level is shifted back and forth around the standard condition are set, the three reading conditions (for one frame of the negative film 1) Reading is performed based on the exposure conditions), and the respective reading results are stored (S4 to S6).

As described above, one image on the negative film 1 is read under the standard condition corresponding to the average value and under the two conditions in which the exposure level is moved forward and backward with respect to the standard. If the image signals with different reading conditions are stored, only a part of the density level of the wide dynamic range of the negative film 1 is not stored as read data, and as shown in FIG. It can be stored as read data over a wide range.

Therefore, for example, when the image data read under the standard condition is displayed and there is a whiteout portion or a blackout portion, the image data read is displayed with the exposure level reduced for the whiteout portion. By displaying the read image data by increasing the exposure level for the blackout portion, it is possible to obtain image information that cannot be confirmed under standard conditions. Further, it is possible to obtain an image signal having a large dynamic range by combining three image signals having different reading conditions.

In the above description, only the average value of the image signal is described, but various variations are possible. For example, the average value of the entire screen, the average value with a weighted central portion of the screen, the average value of a plurality of sample points, the average value excluding the extreme values of those sample points, each sample value and The backlight and over-forward light are discriminated from the sample position, only the sample points considered to be the main subject are selected, and the average value obtained from them is used. Since the point of the present embodiment is that the reading condition is changed around the standard reading condition and reading is performed a plurality of times, any of the above average values may be used in determining the standard reading condition.

In the above embodiment, the standard reading condition set based on the average value was used as a reference to set the three reading conditions by swinging the exposure condition forward and backward by a predetermined value. However, as shown in FIG. A highlight part detection circuit 11 (highlight part detection means) and a shadow part detection circuit 12 (shadow part detection means) are provided together with the circuit 8, and the average value detection circuit 8 is provided.
While the standard reading conditions are set based on the average value detected by, the reading conditions that match the highlight part are set based on the detection result of the highlight part, and the reading conditions that match the shadow part are set based on the detection result of the shadow part. It is advisable to set the reading conditions so that the reading conditions on the overexposure and underexposure sides as well as the standard conditions are set according to the actual image.

The setting of the reading conditions using the highlight detection circuit 11 and the shadow detection circuit 12 will be described with reference to the flowchart of FIG. First, the process of reading and storing the negative film 1 under the standard reading condition set based on the detection result of the average value is performed in the same manner as in the above-described embodiment (S11 to S13).

Next, from the reading result under the standard condition, the highlight portion and the shadow portion are detected by comparing the predetermined threshold level with the actual image signal in each circuit 11, 12 (S14). Then, when the highlight portion is larger than a predetermined value, the reading condition (in the case of a negative film, the light amount is increased,
In the case of a positive film, the amount of light is reduced) is set (S15, S16). Similarly, when the shadow portion is larger than a predetermined value, the reading condition (the light amount is reduced in the case of a negative film and the light amount is increased in the case of a positive film) is set according to the shadow portion (S17, S18). ).

The above steps S11 to S18 correspond to the reading condition setting means for each level. Here, reading is performed under the reading conditions corresponding to the highlight portion and the shadow portion set as described above, and the image signal thereof is stored (S19). In the case of the above-described embodiment, in addition to the standard condition based on the average value, the reading condition that matches the highlight part and the shadow part of the actual image is set and the reading is performed. It becomes possible to set more appropriate reading conditions as compared with the above-described embodiment in which the over reading conditions are determined.

As shown in FIG. 7, basically, one reading condition is set according to the detection of the highlight portion and the shadow portion, respectively, but from the detection results of the highlight portion and the shadow portion, respectively, Negative film 1 by setting two or more underexposed and overexposed scanning conditions.
One frame may be read four times or more under four or more types of reading conditions, and four or more image signals may be stored for the same frame.

As shown in FIG. 8, the negative film 1
When the dynamic range of the image density is wide over the highlight portion and the shadow portion, three or more reading conditions are set according to the flowchart of FIG. 6, but as shown in FIG. When the dynamic range of is narrow, most image information can be read by reading under standard conditions.

In the case of the negative film 1 as shown in FIG. 9, the reading condition other than the standard condition is not set by determining that the highlight portion or the shadow portion is small in the flowchart of FIG. Only the read result under the standard condition will be stored. Further, depending on the image on the negative film 1, the reading may be performed under two conditions, that is, a standard condition and a condition that matches either the highlight portion or the shadow portion.

Therefore, if the highlight portion and the shadow portion are detected as described above, it is possible to avoid unnecessary reading and storing. By the way, some silver halide photographic cameras have a function generally called auto bracket photographing for continuously and automatically photographing a plurality of photographs by changing the exposure condition for the same subject. The auto bracket shooting is a shooting mode in which a standard exposure amount obtained by automatic exposure adjustment is taken and also frames on the over-exposed side and the under-exposed side are automatically taken.

In the case of a series of images (usually three images) subjected to the bracket photographing as described above, it is similar to the case of changing the reading condition of one image (frame) of the negative film 1 and reading it a plurality of times. Since this is done in advance at the shooting stage, as shown in the flowchart in FIG. 10, even if each bracketed image is read under standard conditions (S21), one image is standardized. An image having a specific exposure level and image information on the overexposure side and the underexposure side can be obtained. Therefore, in this case, it is not necessary to switch the reading conditions for each image to perform the reading, and each bracketed image need only be read once under the standard conditions.

Further, with respect to the frame on which the underexposure side has been photographed by the bracket photographing, the frame is read under the standard condition and also under the reading condition so as to be further underside (S23). In addition to reading under the standard conditions for the frame in which the image was taken, the reading conditions are set so as to become the over side (S22), in addition to the three exposure levels at the time of shooting,
Furthermore, a wide range of image information can be read.

The above-mentioned step S21 corresponds to the condition switching prohibition means, and the portions S22 to S23 correspond to the bracket condition setting means. In order to set the scanning conditions for images taken with auto bracket as described above,
It is necessary to determine whether or not the image on the negative film 1 to be read is a bracketed image.

For example, when various photographing information including bracket photographing is magnetically recorded on the magnetic layer provided on the negative film 1 at the time of photographing, it is recorded on the magnetic layer as shown in FIG. A photographing information reading means 13 for reading information is provided, and as shown in the flowchart of FIG. 12, it is judged from the photographing information read by the photographing information reading means 13 (S31) whether or not it is a bracket photographing. Should be performed (S32).

Here, the photographing information reading means 13 and the drawing
The bracket photographing determination means is constituted by S31 and S32 shown in the flowchart of 12. If the image is taken by bracket shooting, either read all under standard conditions or read under (over) shot images under further (over) conditions, as shown in the flowchart of FIG. Then, a wider range of information can be obtained (S33). On the other hand, if the image is not a bracket image, the reading is performed under the standard conditions and the reading conditions are changed as necessary as in the above-described embodiment (S34).

If the means for recording the photographing information at the time of photographing is not provided as described above, the negative moving means for moving the negative film 1 for reading for discrimination of bracket photographing as shown in FIG. Negative film 1 provided with 14
It is possible to determine whether or not it is due to bracket photographing by reading the adjacent images above under standard conditions and comparing them.

Further, when the pre-scanning reading device shown in FIG. 2 is provided, the images before and after the image are read in advance. Processing can be performed quickly without the need to move the film. That is,
If the two images to be compared are included in a series of bracketed images, then the exposure level of the other image should be under or over for the other image, and none of these exposure levels The trend of difference should be constant over the entire image area. For example, in a case where a subject as shown in FIG. 14 is bracket-photographed and the image area is divided as shown in FIG. 14 and observed for each divided area, as shown in FIG. The areas of skip, normal, and underexposure should show a change corresponding to the increase in the exposure amount in the image with the increased exposure amount, and conversely, in the image with the reduced exposure amount, When the same areas are compared, they should show a change corresponding to the decrease of the exposure amount with respect to the image of the standard exposure amount.

Therefore, as shown in the flow chart of FIG. 16, adjacent images on the negative film 1 are read under standard conditions (S41), and the signal levels of both images in the same image area are compared to determine whether one image If the difference in the signal level of the other image with respect to the signal shows a constant magnitude relationship in the plurality of image regions, it can be determined that they are part of the bracket-captured image (S43), and both images are compared. If the differences in the signal level are different, it can be determined that the images are different images of different subjects (S44). The portions of S41 to S44 correspond to bracket photographing determination means.

Here, comparing the images by dividing them into very large areas, it is erroneously determined that the images in which the tendency of the exposure amount changes by chance in a constant direction even though they are not in bracket imaging are due to bracket imaging. I have a fear of doing
By appropriately setting the segmented regions, it is possible to discriminate bracket shooting with high accuracy. Note that the image processing device 15 shown in FIG. 13 compares the image signals by dividing the image regions. Specifically, the average value in each area is calculated according to a preset division, and the average value data detected in the same area is compared between the two images to determine the change direction of the exposure amount between the images. It is determined that bracket shooting is performed if the tendency is constant even in different areas.

Then, when the bracket photographing is performed three times including the standard, that is, the over side and the under side, the image next to the two images determined to be the bracket photographing is the image obtained by the bracket photographing. By comparing the two images that have already been determined to be
It is possible to determine whether it corresponds to standard, under, or over.

Further, it is not the average value of the signal level in the divided image area, but it is judged whether or not there is a blackout portion or an overexposed portion in that area, and such a tendency is determined on the negative film 1. It is also possible to determine whether or not it is due to bracket shooting by comparing adjacent images with. By the way, when a plurality of readings are performed by changing the reading condition for one image as described above, if all the images having different reading conditions are stored according to the standard format, a large amount of storage capacity is wasted. turn into.

Therefore, for example, an image signal read under standard conditions is stored as a reference image in a standard format, and for image signals read under other under or over conditions, difference data with respect to the reference image is stored as stored data. It is advisable to reduce the amount of data by transform coding. In addition, since the portion a in FIG. 17 or the portion c in FIG. 18 in which the signal varies in the image read by the above-mentioned under or overexposure corresponds to the blackout portion or the whiteout portion in the reference image, the signal variation portion ( Part a in FIG. 17 or c in FIG.
Part) image signal is stored, and which part of the image corresponds to this stored image signal is specified based on the information of the blackout or overexposure part of the reference image, and an under or over If the image read by exposure is reproduced, the storage capacity can be further saved.

In this embodiment, only the case of reading the negative film 1 as the silver salt photosensitive material has been described, but in addition to this, the technique can be applied to the reading of reversal film, color paper, instant print and the like. However, a particularly large effect can be obtained by applying it to a negative film or a reversal film having a wide dynamic range.

When a plurality of readings are performed on the same image under different reading conditions, it is preferable to store the information on the reading conditions together with the image signal.

[0047]

As described above, according to the image reading apparatus of the present invention, when an image of a silver salt photosensitive material such as a negative film is photoelectrically read and stored, a silver salt photosensitive material such as a negative film is stored. There is an effect that a large amount of image information can be read and stored by effectively utilizing the wide dynamic range. Further, by setting the reading condition based on the detection of the average value, the highlight portion, and the shadow portion, it is possible to perform the reading under the reading condition suitable for each image. Furthermore, by determining whether or not the image is taken by bracket shooting and setting the reading conditions based on this, useless reading and
You can avoid memory. Further, only the image signal read under the standard reading condition is normally stored, and for the image signal whose reading condition is under or over, only the signals of the blackout portion and the whiteout portion of the standard reading image are stored. Therefore, the storage capacity can be saved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of an image reading apparatus according to the present invention.

FIG. 2 is a block diagram showing a hardware configuration of the first embodiment.

FIG. 3 is a flowchart showing a plurality of condition settings based on an average value.

FIG. 4 is a diagram showing a reading range under a plurality of conditions based on an average value.

FIG. 5 is a block diagram showing a hardware configuration of a second embodiment.

FIG. 6 is a flowchart showing condition setting based on detection for each signal level.

FIG. 7 is a diagram showing a reading range under the condition for each signal level.

FIG. 8 is a diagram for explaining whether or not a plurality of negative images can be read.

FIG. 9 is a diagram for explaining the possibility of multiple reading with a negative image.

FIG. 10 is a flowchart showing condition setting in an image of bracket shooting.

FIG. 11 is a block diagram showing a hardware configuration of a third embodiment.

FIG. 12 is a flowchart showing the determination of bracket shooting.

FIG. 13 is a block diagram showing a hardware configuration of a fourth embodiment.

FIG. 14 is a diagram for explaining bracket shooting determination based on an image signal.

FIG. 15 is a diagram showing signal characteristics in the case of bracket shooting.

FIG. 16 is a flowchart showing bracket shooting determination based on an image signal.

FIG. 17 is a diagram showing an example of an overexposure image signal.

FIG. 18 is a diagram showing an example of an image signal of underexposure.

[Explanation of symbols]

 1 Negative Film 2 Illumination Device 3 Iris 4 Image Sensor 5 Process Circuit 6 Signal Processing Circuit 7 Storage Unit 8 Average Value Detection Circuit 9 Exposure Condition Setting Unit 10 CPU 11 Highlight Part Detection Circuit 12 Shadow Part Detection Circuit

Claims (6)

[Claims] 1. An image reading unit for photoelectrically reading an image on a silver salt photosensitive material to output an image signal, a storage unit for storing an image signal output from the image reading unit, and a reading by the image reading unit. An image reading apparatus comprising: a reading condition changing unit that switches a condition to a plurality of different conditions to read the same image a plurality of times. 2. The reading condition changing means detects an average value of an image signal output from the image reading means, and a reading condition corresponding to the average value detected by the average value detecting means. 2. The image according to claim 1, further comprising: a reading condition setting means based on an average value for setting other reading conditions with the standard reading condition as a reference. Reader. 3. A reading condition changing means, an average value detecting means for detecting an average value of an image signal output from the image reading means, and a highlight portion of an image from the image signal output from the image reading means. Highlight portion detecting means for detecting the shadow portion, shadow portion detecting means for detecting the shadow portion of the image from the image signal output from the image reading means, the average value detecting means, the highlight portion detecting means and the shadow portion detecting means The image reading apparatus according to claim 1, further comprising: level-dependent reading condition setting means for setting a plurality of different reading conditions based on respective detection results. 4. The read condition changing means determines that the image of the silver salt photosensitive material read by the image reading means is a bracket image of a plurality of images of the same subject under different exposure conditions. The bracket photographing determination means and, when the bracket photographing determination means determines that the image is the bracket photographing, prohibits switching of the reading condition for each of a series of images in the bracket photographing, and sets a predetermined standard reading condition. 2. The image reading apparatus according to claim 1, further comprising: a condition switching prohibition unit that allows only reading by the. 5. The reading condition changing means, the silver salt photosensitive material read by the image reading means,
Bracket shooting determination means for determining that the same subject is shot by bracket shooting in which a plurality of shots are taken with different exposure conditions, and when the bracket shooting determination means determines that the image is taken by bracket shooting, 2. The image reading apparatus according to claim 1, further comprising: bracket condition setting means for setting a reading condition for each of a series of images in bracket shooting with reference to an exposure condition in bracket shooting. 6. The storage means stores a reference image signal of a plurality of image signals for the same image output from the image reading means in a predetermined standard format, and stores image signals other than the reference image signal. 2. Only the portion of the reference image signal that is overexposed or underexposed is stored.
The image reading device according to any one of 3, 4, and 5.