JP2006313965A - Photographic apparatus, and photographed image processing method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a photographed image, the luminance of the bright part and the dark part of which has been adjusted. <P>SOLUTION: A digital camera 1 sets an exposure amount for optimizing the luminance of the bright region of a white board 2 for photographing the white board 2, and sets the exposure amount for optimizing the luminance of the dark region of the white board 2 to photograph the white board 2. The digital camera 1 carries out luminance correction of the two images to produce luminance distributions of the respective corrected images. The digital camera 1 composites the two regional images so that two peaks, appearing in the luminance distributions, lie within a preset luminance range. Thus, the digital camera 1 can adjust the luminance of the white board 2, even if there are bright regions and the dark regions on the white board 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a photographing apparatus, a photographed image processing method, and a program.

As a photographing apparatus, there is one in which a projector photographs a whiteboard (for example, see Patent Document 1). Such a photographing apparatus is used for meetings and presentations because it can store handwritten characters and figures written on a whiteboard.
JP 2004-239967 A (4th and 5th pages, FIGS. 1 and 2)

  However, in such a photographing apparatus, as shown in FIG. 11, if there is a large luminance difference between the area where the image is projected by the projector and the peripheral area where the image is not projected on the whiteboard, the image is projected brightly. It is difficult to adjust the luminance values of the area and the surrounding dark area.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a photographing apparatus, a photographed image processing method, and a program capable of acquiring a photographed image with an adjusted luminance value. To do.

In order to achieve this object, an imaging device according to the first aspect of the present invention provides:
In an imaging device for imaging an imaging target having a plurality of areas with different brightness,
The exposure value is set so that the brightness value corresponding to each area of the captured image obtained by capturing the capturing target is within a preset brightness range, and the capturing target is captured a plurality of times. A shooting unit to
From a plurality of photographed images obtained by photographing of the photographing unit, using a luminance distribution indicating a relationship between the luminance value of each photographed image and the number of pixels having the luminance value, respectively, And an image processing unit that cuts out a region image corresponding to the region and having a luminance value within the luminance range, and synthesizes the plurality of cut out region images.

  The image processing unit may compare the brightness of each area to be imaged using the luminance distribution and whiten the background of the area image corresponding to the dark area.

  The image processing unit generates the luminance distribution for each photographed image obtained by the photographing of the photographing unit a plurality of times, and displays an image in which the maximum value appearing in each of the generated luminance distributions is within the luminance range. A region image having a luminance value within the range may be cut out and a plurality of cut out region images may be combined.

The captured image processing method according to the second aspect of the present invention includes:
A photographed image processing method for photographing a subject having a plurality of areas with different brightness and performing image processing on the obtained photographed image,
The exposure value is set so that the brightness value corresponding to each area of the captured image obtained by capturing the capturing target is within a preset brightness range, and the capturing target is captured a plurality of times. And steps to
Corresponding to the area to be imaged using a luminance distribution indicating the relationship between the luminance value of each captured image and the number of pixels having the luminance value, from a plurality of captured images obtained by the imaging. Cutting out a region image having a luminance value within the luminance range, and synthesizing the plurality of cut out region images.

The program according to the third aspect of the present invention is:
The exposure amount is set so that the luminance value corresponding to each of the areas of the captured image obtained by imaging the imaging target having a plurality of areas with different brightness falls within a preset luminance range, and the imaging Procedures for shooting the subject multiple times,
Corresponding to the area to be imaged, using a luminance distribution indicating the relationship between the luminance value of each captured image and the number of pixels having the luminance value from a plurality of captured images obtained by the imaging Cutting out a region image having a luminance value within the luminance range, and synthesizing a plurality of cut out region images;
Is to execute.

  According to the present invention, it is possible to acquire a photographed image whose luminance value has been adjusted.

  Hereinafter, an imaging device according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the photographing apparatus is described as a digital camera.

An appearance of the digital camera 1 according to this embodiment is shown in FIG.
The digital camera 1 according to the present embodiment performs shooting twice so that the brightness of the bright area and the dark area of the whiteboard 2 is optimized, and performs brightness correction on the two obtained images. Both corrected images are synthesized. The digital camera 1 includes a photographic lens unit 11, a liquid crystal monitor 12, and a shutter button 13.

  The photographing lens unit 11 includes a lens that collects light and the like, and collects light from characters, drawings, photographs, and the like of the whiteboard 2 and the like.

The liquid crystal monitor 12 is for projecting an image taken in through the photographing lens unit 11.
The shutter button 13 is pressed when shooting a shooting target.

  As shown in FIG. 2, the digital camera 1 includes an optical lens device 21, an image sensor 22, a memory 23, a display device 24, an image processing device 25, an operation unit 26, a computer interface unit 27, An external storage IO device 28 and a program code storage device 29 are provided.

  The optical lens device 21 includes a photographic lens unit 11, a driving unit thereof, and an exposure adjustment unit (not shown). On the image sensor 22, characters, drawings, photographs, and the like of the whiteboard 2. The light from is condensed to form an image. For example, the exposure adjustment unit adjusts the exposure amount by setting an exposure time.

  It is assumed that the whiteboard 2 includes a bright region Sp1 and a dark region Sp2, as shown in FIG. 3, as a plurality of regions having different brightness. For example, the bright region Sp1 is a region where an image is projected by a projector or the like, and the dark region Sp2 is a region where light is not projected.

  When such a whiteboard 2 is photographed, a photographed image having a luminance distribution as shown in FIG. In FIG. 4A, L_bright indicates the luminance value having the largest number of pixels (maximum) as the luminance value of the captured image corresponding to the bright region Sp1. L_dark indicates the luminance value having the largest number of pixels (maximum) as the luminance value of the captured image corresponding to the dark region Sp2. The range Range indicates the optimum luminance range, and the corrected luminance peaks 1 and 2 indicate the upper limit value and the lower limit value of the luminance range Range, respectively. As shown in FIG. 4A, when one or both of the luminance values L_bright and L_dark are out of the luminance range Range, an optimum captured image is not obtained.

  For this reason, the exposure adjustment unit first sets the exposure amount so that the luminance value L_bright is within the luminance range Range, and the optical lens device 21 captures an image of the photographing target with the exposure amount set by the exposure adjustment unit. Thereby, the digital camera 1 acquires a captured image having a luminance distribution as shown in FIG. The luminance value corresponding to the bright area Sp1 of the photographed image is optimum.

  Next, the exposure adjustment unit sets the exposure amount so that the luminance value L_dark falls within the luminance range Range, and the optical lens device 21 captures an image of the photographing target with the exposure amount set by the exposure adjustment unit. Thereby, the digital camera 1 acquires a captured image having a luminance distribution as shown in FIG. The luminance value corresponding to the dark area Sp2 of the captured image is optimum.

  The image sensor 22 is for capturing a formed image as digitized image data, and is configured by a CCD (Charge Coupled Device) or the like.

  The image sensor 22 is controlled by the CPU 30 to generate data of a low resolution image and a high resolution image. When the shooting mode is set to the low resolution shooting mode by the CPU 30, the image sensor 22 generates image data with a low resolution for preview, and periodically sends this image data to the memory 23 at intervals of about 30 sheets per second. To do.

  When the shooting mode is set to the high resolution shooting mode by the CPU 30, the image sensor 22 generates high resolution image data.

  The memory 23 stores image data and the like. As shown in FIG. 5, the memory 23 includes a sensor image storage area 23a, a processed image storage area 23b, a display image storage area 23c, and a work data storage area 23d.

  The sensor image storage area 23a is an area for temporarily storing the image data sent from the image sensor 22 every time it is photographed. The processed image storage area 23b is an area for the image processing apparatus 25 to store image data necessary for processing. The display image storage area 23c is an area for storing image data for display subjected to image processing. The work data storage area 23d is an area for storing data necessary for work such as coordinate data.

  The display device 24 includes the liquid crystal monitor 12 and displays the image on the liquid crystal monitor 12. The display device 24 displays a low resolution preview image or a high resolution image temporarily stored in the display image storage area 23 c of the memory 23 on the liquid crystal monitor 12.

  The image processing device 25 is for performing image processing such as image distortion correction, compression, and image composition on the image data temporarily stored in the processed image storage area 23 b of the memory 23.

  In the image distortion correction processing, as shown in FIG. 6A, the digital camera 1 captures the character w or the like from the left direction or the right direction as shown in FIG. 6B or 6C. This is a process of generating an image W ′ as if it was taken from the front as shown in FIG.

  The image processing device 25 generates an image W ′ as shown in FIG. 6D by cutting out an image of the original from the image shown in FIG. 6B or 6C and performing processing such as affine transformation. To do.

  The image composition process is a process for compositing two images obtained by photographing with the photographing lens unit 11, and the image processing device 25 generates a brightness distribution for each photographed image, and based on each brightness distribution. Synthesize a plurality of captured images.

  That is, the image processing device 25 generates a luminance distribution as shown in FIGS. 4B and 4C from a captured image obtained by capturing with the optical lens device 21.

  Next, the image processing device 25 compares the brightness of each area to be imaged using the luminance distribution, and takes an image so that the luminance value of the area image corresponding to the dark area Sp2 of the whiteboard 2 is optimal. The background of the image obtained by performing the above is whitened. The image processing device 25 also whitens the background of the image obtained by shooting so that the brightness value of the area image corresponding to the bright area Sp1 of the whiteboard 2 becomes the optimum brightness value.

  Background whitening processing is processing in which the color of a portion considered to be the background in an image is set to white (Y: 255, U: 0, V: 0) or a color close thereto when the background is not sufficiently whitened. It is.

  FIG. 7A is a diagram showing the rate of increase of the luminance value with respect to the luminance value of this pixel with the luminance value of a certain pixel as the reference (0). The horizontal axis represents the luminance value, and the vertical axis represents the luminance value raising rate. FIG. 7B is a diagram showing the color difference and the change rate of the color difference. The horizontal axis indicates the color difference, and the vertical axis indicates the change rate of the color difference.

  In the figure, C0 indicates a range from 0 in which the luminance and the color difference are increased by 100%, and C1 indicates a range in which the increase rate is varied according to the luminance value. As shown in FIGS. 7A and 7B, the color of a pixel whose luminance (Y) value is equal to or greater than a certain value (Yw) and whose color difference (U, V) is within a certain range (C0) is defined as a whitening range. The brightness value is raised and the color difference is set to zero.

  Then, the image processing device 25, as shown in FIG. 4A, has a region image having a luminance value equal to or lower than the corrected luminance peak 1 and a luminance value equal to or higher than the corrected luminance peak 2 as shown in FIG. And a region image having.

  The image processing apparatus 25 generates a composite image having a luminance distribution as shown in FIG. 8 by performing such a composite process. In this synthesized image, the two luminance values L_bright and L_dark are close to each other and become a uniform image as a whole. The image processing device 25 stores the generated composite image in the processed image storage area 23 b of the memory 23.

  The image data compression process is a process of, for example, JPEG compressing the image data when storing the image data in the memory card 31.

  The operation unit 26 is a switch group including switches and keys for controlling the functions of the digital camera 1. The operation unit 26 includes a shutter button 13, a power key, a save key, and the like as these switches and keys.

  The power key is a key that is pressed when the digital camera 1 is powered on. The save key is a key that is pressed when storing image data obtained by shooting. When the user presses these keys and switches, the operation unit 26 responds and transmits the operation information at this time to the CPU 30.

  The computer interface unit 27 operates as a USB store registration class driver when the digital camera 1 is connected to a computer (not shown). Thus, when a computer (not shown) is connected to the digital camera 1, the memory card 31 is handled as an external storage device of the computer.

  The external storage IO device 28 inputs and outputs image data and the like with the memory card 31. The memory card 31 stores image data and the like supplied from the external storage IO device 28.

  The program code storage device 29 is for storing a program executed by the CPU 30, and is configured by a ROM or the like.

  The CPU 30 controls the entire system according to a program stored in the program code storage device 29.

  When operation information is transmitted from the operation unit 26 by pressing a switch or key of the operation unit 26, the CPU 30 performs image sensor 22, memory 23, display device 24, image processing device based on the operation information. 25 etc. are controlled.

  Specifically, when the operation information indicating that the power key is pressed is transmitted from the operation unit 26, the CPU 30 initializes the digital camera 1, initializes the memory 23, initializes the synthesis process, and the like. .

  As initialization of the digital camera 1, the CPU 30 initializes conditions for performing camera shooting and a shooting mode. The shooting conditions include the focus of the digital camera 1, the shutter speed (exposure time), the exposure of the aperture, white balance, sensitivity, and the like.

  Further, the CPU 30 determines whether or not the shutter button 13 has been pressed based on the operation information from the operation unit 26. When the shutter button 13 is not pressed, the CPU 30 sets the shooting mode to the low resolution shooting mode, and when the shutter button 13 is pressed, the CPU 30 sets the shooting mode to the high resolution shooting mode.

  When the shooting mode is set to the high-resolution shooting mode, the CPU 30 sets the optical lens device 21 so that the brightness of each of the bright area Sp1 and the dark area Sp2 of the whiteboard 2 shown in FIG. Control multiple shots.

  When the image processing device 25 generates a composite image and stores it in the processed image storage area 23b of the memory 23, the CPU 30 reads the composite image from the processed image storage area 23b of the memory 23. Then, the CPU 30 stores the read composite image in the memory card 31 via the external storage IO device 28.

Next, the operation of the digital camera 1 according to this embodiment will be described.
When the user presses the power key of the digital camera 1, the CPU 30 is activated and acquires program data stored in the program code storage device 29.

  When the user presses the shooting button, the operation unit 26 transmits this operation information to the CPU 30. The CPU 30 receives this operation information, and the CPU 30, the image processing device 25, etc. execute camera control processing according to the flowchart shown in FIG.

  The CPU 30 initializes the digital camera 1 and the memory 23 (step S11).

  The CPU 30 determines whether the shutter button 13 has been pressed based on the operation information from the operation unit 26 (step S12).

  If it is determined that the shutter button 13 has not been pressed (No in step S12), the CPU 30 sets the shooting mode to the low resolution shooting mode (step S13).

  When the photographing mode is set to the low resolution photographing mode, the CPU 30 controls the photographing lens unit 11 and the optical lens device 21 to perform low resolution photographing (step S14). The image sensor 22 generates low-resolution image data and sends the generated low-resolution image data to the memory 23. The memory 23 stores the low-resolution image data in the sensor image storage area 23a.

  The CPU 30 reads out the low resolution image data from the sensor image storage area 23a of the memory 23 and writes it in the display image storage area 23c. The display device 24 reads out the low-resolution image data written in the display image storage area 23c and displays it on the liquid crystal monitor 12 (step S15).

  The CPU 30 determines whether the power key is pressed based on the operation information from the operation unit 26 (step S16).

  When it is determined that the power key is not pressed (No in step S16), the CPU 30 determines again whether or not the shutter button 13 is pressed (step S12).

  If it is determined that the shutter button 13 has been pressed (Yes in step S12), the CPU 30 sets the shooting mode to the high resolution shooting mode (step S17).

  The CPU 30 executes image composition processing on the read high-resolution image data according to the flowchart shown in FIG. 10 (step S20).

  That is, the exposure adjusting unit of the optical lens device 21 adjusts the brightness so that the brightness value L_bright of the corresponding area image is within the brightness range Range by adjusting the brightness to the bright area Sp1 of the whiteboard 2, and the optical lens. The device 21 performs photographing with the exposure amount set by the exposure adjustment unit (step S31). The image sensor 22 stores the obtained image data in the sensor image storage area 23 a of the memory 23.

  The image processing device 25 reads the image data from the sensor image storage area 23a of the memory 23, cuts out the projected image on the whiteboard 2, performs keystone correction, and corrects the front image (step S32). The image processing device 25 stores the corrected image data in the processed image storage area 23 b of the memory 23.

  The exposure adjusting unit of the optical lens device 21 adjusts the luminance to the dark region Sp2 of the whiteboard 2 and sets the exposure amount so that the luminance value L_dark of the corresponding region image is within the luminance range Range. Takes a picture with the exposure amount set by the exposure adjustment unit (step S33). The image sensor 22 stores the obtained image data in the sensor image storage area 23 a of the memory 23.

  The image processing device 25 reads the image data of the two photographed images from the sensor image storage area 23a of the memory 23, cuts out the portion of the whiteboard 2, performs keystone correction, and corrects it to the front image (step S34). . The image processing device 25 stores the corrected image data in the processed image storage area 23 b of the memory 23.

  The image processing device 25 acquires the corrected luminance peak 1 (step S35). The image processing device 25 stores the acquired corrected luminance peak 1 in the work data storage area 23 d of the memory 23.

  The image processing device 25 acquires the corrected luminance peak 2 (step S36). The image processing device 25 stores the acquired corrected luminance peak 2 in the work data storage area 23 d of the memory 23.

  The image processing device 25 whitens the background of the photographed image obtained by photographing corresponding to the dark part of the whiteboard 2 (step S37).

  The image processing apparatus 25 determines whether there is a bright rectangular area in the whiteboard 2 (step S38).

  When it is determined that there is a bright rectangular area in the whiteboard 2 (Yes in step S38), the image processing device 25 whites the background of the photographed image obtained by photographing corresponding to the bright rectangular area of the whiteboard 2. (Step S39).

  If it is determined that there is no bright rectangular area in the whiteboard 2 (No in step S38), the image processing device 25 proceeds to the next step 40 without whitening the background.

  The image processing device 25 includes a region image having a luminance value equal to or lower than the corrected luminance peak 1 of a captured image obtained by photographing so that the luminance value of the region image corresponding to the dark region Sp2 is optimal, and a bright region Sp1. A synthesized image is generated by synthesizing a region image having a luminance value equal to or higher than the corrected luminance peak 2 of the photographed image obtained by photographing so that the luminance value is optimal (step S40). The image processing device 25 stores the generated composite image in the processed image storage area 23 b of the memory 23.

  When the CPU 30 and the image processing device 25 execute such an image composition process, the CPU 30 reads the composite image from the processed image storage area 23b of the memory 23 and stores it in the memory card 31 (step S19 in FIG. 9).

  If it is determined that the power key is pressed (Yes in step S16), the CPU 30 ends the camera control process.

  As described above, according to the present embodiment, the digital camera 1 performs shooting so that the brightness of the bright area Sp1 of the whiteboard 2 is optimal, and performs shooting so that the brightness of the dark area Sp2 is optimal. Do. The digital camera 1 synthesizes a region image having a luminance value not higher than the corrected luminance peak 1 and a region image having a luminance value not smaller than the corrected luminance peak 2 with respect to the luminance distribution as a reference for the captured images obtained by both shootings. I did it.

  Therefore, even when the whiteboard 2 has a bright area Sp1 and a dark area Sp2, a captured image can be acquired so that the entire whiteboard 2 has an optimum luminance value by simple calculation.

  In addition, the digital camera 1 performs whitening of the background on a captured image obtained by performing imaging so that the luminance value of the dark area Sp2 of the whiteboard 2 is optimized. For this reason, even when the projector projects an image on the whiteboard 2, the background of the projected image can be whitened, and correction can be made so that the surface of the whiteboard 2 becomes whiter.

  In addition, a region image with a corrected luminance peak of 1 or less is obtained from a photographed image obtained by photographing so that the luminance value of the dark region Sp2 of the whiteboard 2 is optimized, and the background is whitened from the data. Since this is done, the surface of the whiteboard 2 can be made whiter.

In carrying out the present invention, various forms are conceivable and the present invention is not limited to the above embodiment.
For example, if there is an intermediate brightness area other than the bright area Sp1 and the dark area Sp2, the digital camera 1 is 3 so that the brightness of the bright area Sp1, the dark area Sp2, and the intermediate brightness area is optimal. You can also synthesize images by taking multiple shots. Further, the number of shootings may be more than that.

  The subject to be photographed is not limited to the whiteboard 2, and this embodiment can be applied even to a glossy photograph (paper) or the like.

  Further, in the above embodiment, the digital camera 1 has been described as executing the image composition process. However, a configuration in which a computer is connected to the digital camera 1 and image composition processing is executed on the computer may be employed.

  In the above embodiment, the program is described as being stored in advance in a memory or the like. However, a program for causing a computer to operate as the whole or a part of the apparatus or to execute the above-described processing is a flexible disk, a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disk), The information may be stored in a computer-readable recording medium such as an MO (Magneto Optical disk) and distributed, installed in another computer, operated as the above-described means, or the above-described steps may be executed.

  Furthermore, the program may be stored in a disk device or the like of a server device on the Internet, and may be downloaded onto a computer by being superimposed on a carrier wave, for example.

It is a figure which shows the external appearance of the digital camera which concerns on embodiment of this invention. It is a block diagram which shows the structure of the digital camera shown in FIG. It is a figure which shows the bright area and dark area on a white board. It is a figure which shows the luminance distribution at the time of imaging | photography with the exposure amount which the exposure adjustment part of the optical lens apparatus shown in FIG. 2 set. FIG. 3 is a block diagram showing each storage area of the memory shown in FIG. 2. It is a figure which shows an image distortion correction process. It is a figure which shows whitening of a background. It is a figure which shows the luminance distribution of a synthesized image. It is a flowchart which shows the camera control process which a digital camera performs. It is a flowchart which shows the image composition process which a digital camera performs. It is a figure which shows the conventional subject.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Digital camera, 2 ... White board, 11 ... Shooting lens part, 12 ... Liquid crystal monitor, 13 ... Shutter button, 21 ... Optical lens apparatus, 22 ... Image sensor , 23 ... Memory, 24 ... Display device, 25 ... Image processing device, 30 ... CPU, 31 ... Memory card

Claims (5)

In an imaging device for imaging an imaging target having a plurality of areas with different brightness,
The exposure value is set so that the brightness value corresponding to each area of the captured image obtained by capturing the capturing target is within a preset brightness range, and the capturing target is captured a plurality of times. A shooting unit to
From a plurality of photographed images obtained by photographing of the photographing unit, using a luminance distribution indicating a relationship between the luminance value of each photographed image and the number of pixels having the luminance value, respectively, An image processing unit that cuts out a region image corresponding to a region and having a luminance value within the luminance range, and combines the plurality of cut out region images;
An imaging apparatus characterized by that. The image processing unit compares the brightness of each area to be imaged using the luminance distribution, and whitens the background of the area image corresponding to the dark area.
The imaging apparatus according to claim 1, wherein: The image processing unit generates the luminance distribution for each photographed image obtained by the photographing of the photographing unit a plurality of times, and displays an image in which the maximum value appearing in each of the generated luminance distributions is within the luminance range. Cut out as a region image having a luminance value within the range, and combine the cut out region images,
The photographing apparatus according to claim 1 or 2, characterized in that A photographed image processing method for photographing a subject having a plurality of areas with different brightness and performing image processing on the obtained photographed image,
The exposure value is set so that the brightness value corresponding to each area of the captured image obtained by capturing the capturing target is within a preset brightness range, and the capturing target is captured a plurality of times. And steps to
Using a luminance distribution indicating a relationship between the luminance value of each captured image and the number of pixels having the luminance value from a plurality of captured images obtained by the imaging, each corresponds to the region to be captured. Cutting out a region image having a luminance value within the luminance range, and synthesizing a plurality of cut out region images,
A captured image processing method. On the computer,
The exposure amount is set so that the luminance value corresponding to each of the areas of the captured image obtained by imaging the imaging target having a plurality of areas with different brightness falls within a preset luminance range, and the imaging Procedures for shooting the subject multiple times,
Corresponding to the area to be imaged, using a luminance distribution indicating the relationship between the luminance value of each captured image and the number of pixels having the luminance value from a plurality of captured images obtained by the imaging Cutting out a region image having a luminance value within the luminance range, and synthesizing a plurality of cut out region images;
A program for running