JP7608809B2 - Image capture device and method for controlling image capture device - Google Patents

Description

The present invention relates to an imaging device and a method for controlling the imaging device.

The imaging device may superimpose a watermark image onto video data captured by the imaging unit, and record the data on a recording medium or distribute it over a network (see Patent Document 1).

JP 2004-328747 A

With the recent spread of smartphones and high-speed, large-capacity communication lines, video data with a watermark image superimposed thereon may be received and displayed by a smartphone. The aspect ratio of video data captured by an imaging device is usually 16:9. Smartphones often have small displays and do not have an aspect ratio of 16:9. Smartphones may also display the delivered video data on a vertically long display.

In order to improve visibility on smartphone displays, it is conceivable to cut out a portion of each frame of video data with a superimposed watermark image for distribution on a smartphone display. However, when a portion of each frame of video data is cut out to generate video data for distribution, the watermark image may be partially missing or lost entirely. Here, distribution of video data is used as an example, but the same applies when distributing still image data.

The present invention aims to provide an imaging device and a control method for an imaging device that can output image data with a watermark image superimposed thereon without losing part of the watermark image or losing it entirely, even when outputting image data that is a cut-out portion of a frame of image data captured by an imaging unit.

The present invention provides an imaging device comprising an imaging unit that photographs a subject and generates first photographed image data composed of frames having a first angle of view, an image data storage unit that stores the first photographed image data, a photographed image processing unit that performs a clipping process to cut out a portion of each frame of the first photographed image data read from the image data storage unit to generate second photographed image data, a first watermark image superimposition unit that superimposes a watermark image on frames of the second photographed image data to generate photographed image data for output, an output unit that outputs the photographed image data for output to an external device, a second watermark image superimposition unit that superimposes the watermark image on frames of the first photographed image data read from the image data storage unit to generate photographed image data for recording, and a recording processing unit that processes the photographed image data for recording to a recording medium .

The present invention provides a control method for an imaging device in which an imaging unit photographs a subject to generate first photographed image data composed of frames having a first angle of view, an image data holding unit holds the first photographed image data, a photographed image processing unit performs a clipping process to cut out a portion of each frame of the first photographed image data read from the image data holding unit to generate second photographed image data, a watermark image superimposition unit superimposes a watermark image on a frame of the second photographed image data to generate photographed image data for output, an output unit outputs the photographed image data for output to an external device, a second watermark image superimposition unit superimposes the watermark image on a frame of the first photographed image data read from the image data holding unit to generate photographed image data for recording, and a recording processing unit processes the photographed image data for recording to a recording medium .

According to the imaging device and imaging device control method of the present invention, even when outputting image data that is a part of a frame of image data captured by an imaging unit, it is possible to output image data on which a watermark image is superimposed without losing part of the watermark image or losing the entire image.

1 is a block diagram showing an imaging apparatus according to an embodiment; FIG. 13 is a diagram conceptually illustrating an alpha channel set for a watermark image. 2 is a diagram showing one frame of photographed image data D12 read out from an image data holding unit 12 in FIG. 1. 2 is a diagram showing one frame of the recordable photographed image data D22 on which the watermark image Wm has been superimposed by the watermark image superimposing section 220 in FIG. 1. FIG. 1. FIG. 4 is a diagram showing a clipping process in which the distribution captured image processing unit 31 in FIG. 1 cuts out a part of each frame of the captured image data D12. 6 is a diagram showing one frame of photographed image data D31 for distribution obtained as a result of the clipping process shown in FIG. 5. 2 is a diagram showing one frame of the photographed image data D32 for distribution on which the watermark image Wm has been superimposed by the watermark image superimposing unit 32 in FIG. 1. FIG. FIG. 13 is a partial enlarged view showing an example in which the difference in brightness between the background of the frame on which the watermark image Wm is superimposed and the mark Wm01 is smaller than a predetermined value. FIG. 13 is a partial enlarged view showing a state in which the luminance of the mark Wm01 is inverted when the luminance difference between the background of the frame on which the watermark image Wm is superimposed and the mark Wm01 is smaller than a predetermined value.

The imaging device and the control method for the imaging device according to one embodiment will be described below with reference to the attached drawings.

In FIG. 1, the imaging unit 11 includes an imaging element and multiple lenses, and captures an image of a subject with an angle of view (first angle of view) of, for example, an aspect ratio of 16:9 to generate captured image data (first captured image data). The imaging element may be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The image data storage unit 12 temporarily stores the captured image data output from the imaging unit 11. The image data storage unit 12 is a frame memory, and may be an SDRAM (Synchronous Dynamic Random Access Memory) or a DDR (Double-Data-Rate SDRAM).

The watermark image storage unit 21 stores watermark image data to be superimposed on the captured image data. The watermark image storage unit 21 is composed of a non-volatile memory. The watermark image data is composed of image data in a format that includes auxiliary data called an alpha channel that sets the opacity of the image. As an example, the watermark image data is in PNG format.

Figure 2 conceptually shows the alpha channel set for the watermark image Wm indicated by the watermark image data. As an example, the background Wm00 within a rectangular area is set to an opacity of 0% (i.e., a transparency of 100%), and the mark Wm01 is set to an opacity of 100% (i.e., a transparency of 0%). In the example shown in Figure 2, the mark Wm01 is the letters "W.MK."

The recording image processing unit 22 performs at least one of scaling and noise reduction processing on the captured image data D12 read from the image data storage unit 12 for recording the captured image. Figure 3 shows one frame of the captured image data D12 read from the image data storage unit 12.

As an example of scaling processing, when the captured image data output from the imaging unit 11 has a horizontal pixel count x vertical pixel count of 3840 x 2160, called 4K, the recording captured image processing unit 22 reduces it to full HD pixel count of 1920 x 1080. When the capacity of the recording medium 24 is sufficiently large, the recording captured image processing unit 22 does not need to reduce the captured image data.

The photographed image processing unit for recording 22 includes a watermark image superimposing unit 220 (second watermark image superimposing unit) that superimposes watermark image data on the photographed image data D12. The watermark image superimposing unit 220 superimposes the watermark image data read from the watermark image storage unit 21 on the photographed image data D12. FIG. 4 shows one frame of the photographed image data for recording D22 on which the watermark image Wm has been superimposed by the watermark image superimposing unit 220.

Because the background Wm00 is set to 0% opacity by the alpha channel, only the mark Wm01 with 100% opacity appears to be superimposed on the captured image data D12. The watermark image superimposition unit 220 may automatically determine the position at which to superimpose the watermark image Wm on the captured image data D12, or may set the position at which to superimpose the watermark image Wm based on instruction data specified by the user.

The recording processing unit 23 encodes the recording image data D22 and creates a file as necessary in order to record the recording image data D22 on the recording medium 24. The recording processing unit 23 records the encoded recording image data D22 on the recording medium 24. The recording medium 24 is any recording medium, and may be a memory card made up of a flash memory or a hard disk drive.

The distribution-purpose captured image processing unit 31 performs clipping processing to cut out a portion of each frame of the captured image data D12 read out from the image data storage unit 12, to generate distribution-purpose captured image data D31 (second captured image data). As shown in FIG. 5, when the distribution-purpose captured image processing unit 31 performs clipping processing to cut out a rectangular area indicated by a dashed dotted line in a frame of the captured image data D12, a frame of distribution-purpose captured image data D31 having the angle of view (second angle of view) shown in FIG. 6 is generated.

The angle of view of the photographed image data for distribution D31 has an aspect ratio that is different from the aspect ratio of 16:9. However, the angle of view of the photographed image data for distribution D31 may also have an aspect ratio of 16:9.

In addition to clipping, the distribution-purpose captured image processing unit 31 may also perform scaling to reduce the number of lines and pixels. The degree of reduction in the number of lines and pixels in the scaling process by the distribution-purpose captured image processing unit 31 may be greater than the degree of reduction in the number of lines and pixels in the scaling process by the recording-purpose captured image processing unit 22.

The watermark image storage unit 33 stores watermark image data to be superimposed on the captured image data for distribution D31. The watermark image storage unit 33 is composed of a non-volatile memory. Like the watermark image data stored in the watermark image storage unit 21, the watermark image data stored in the watermark image storage unit 33 is also composed of image data in a format having an alpha channel.

In FIG. 1, the watermark image storage unit 21 and the watermark image storage unit 33 are separate entities, but the watermark image storage unit 21 and the watermark image storage unit 33 may be configured as a single common watermark image storage unit. The watermark image data superimposed on the photographed image data D12 and the watermark image data superimposed on the photographed image data for distribution D31 may be the same image data. The watermark image Wm superimposed on the photographed image data for distribution D31 may be smaller than the watermark image Wm superimposed on the photographed image data D12.

The watermark image superimposing unit 32 (first watermark image superimposing unit) superimposes the watermark image data read from the watermark image storage unit 33 onto the photographed image data for distribution D31. Figure 7 shows one frame of the photographed image data for distribution D32 (photographed image data for output) on which the watermark image Wm has been superimposed by the watermark image superimposing unit 32.

Similarly, the watermark image Wm superimposed on the photographed image data for distribution D31 has the background Wm00 set to 0% opacity by the alpha channel, so that only the mark Wm01 with 100% opacity appears to be superimposed on the photographed image data for distribution D31. The watermark image superimposition unit 32 may automatically determine the position at which to superimpose the watermark image data on the photographed image data for distribution D31, or may set the position at which to superimpose the watermark image data based on instruction data specified by the user.

The output processing unit 34 encodes the photographed image data for distribution D32, performs packetization processing for a protocol and serialization processing for SDI (Serial Digital Interface) as necessary, and supplies the data to the output unit 35. The output unit 35 outputs the encoded photographed image data for distribution D32 supplied from the output processing unit 34 to a network external to the imaging device. The image data distributed via the network is equivalent to the photographed image data for distribution D32 shown in FIG. 7.

However, when the watermark image superimposition unit 220 superimposes watermark image data on the captured image data D12, depending on the relationship between the brightness of the background on which the watermark image Wm is superimposed and the brightness of the mark Wm01, it may be difficult to see the mark Wm01. For example, suppose that the captured image data D12 is 8 bits, the background on which the watermark image Wm is superimposed has a gradation value of 255, which is the maximum brightness, and the mark Wm01 has a gradation value of 0, which is the minimum brightness. In this case, the mark Wm01 is easily visible.

As shown in FIG. 8, the background on which the watermark image Wm is superimposed has a low gradation, for example a gradation value of 30, and the mark Wm01 has a gradation value of 0, which is the lowest brightness. In this case, the difference in brightness between the background and the mark Wm01 is small, so the mark Wm01 cannot be clearly seen.

The watermark image superimposing unit 220 therefore inverts the luminance (black and white) of the mark Wm01 when the luminance difference between the background on which the watermark image Wm is superimposed and the mark Wm01 is smaller than a predetermined value in each frame of the captured image data D12. As shown in FIG. 9, when the mark Wm01 has a gradation value of 0, the watermark image superimposing unit 220 superimposes the watermark image Wm converted to a gradation value of 255 onto the frame of the captured image data D12.

The same applies when the watermark image superimposing unit 32 superimposes the watermark image data on the photographed image data for distribution D31. When the difference in brightness between the background on which the watermark image Wm is superimposed and the mark Wm01 is smaller than a predetermined value in each frame of the photographed image data for distribution D31, the watermark image superimposing unit 32 inverts the brightness (black and white) of the mark Wm01.

There are cases where the color of the watermark image Wm (mark Wm01) is strictly specified, such as a company logo, and it is not possible to invert the brightness of the mark Wm01. In this case, the watermark image superimposition units 220 and 32 may set in advance that inversion of the brightness of the mark Wm01 is not possible, or may set a flag indicating whether or not inversion is possible in the watermark image data, and decide whether or not to invert it depending on whether or not the flag indicates whether or not inversion is possible. The watermark image superimposition units 220 and 32 may set whether or not to invert the brightness of the mark Wm01 based on instruction data specified by the user.

The present invention is not limited to the embodiment described above, and various modifications are possible without departing from the spirit of the present invention.

REFERENCE SIGNS LIST 11 imaging section 12 image data storage section 21 watermark image storage section 22 photographed image processing section for recording 23 recording processing section 24 recording medium 31 photographed image processing section for distribution 32 watermark image superimposing section 33 watermark image storage section 34 output processing section 35 output section 220 watermark image superimposing section

Claims (4)

an imaging unit that captures an image of a subject and generates first captured image data configured of a frame having a first angle of view;
an image data storage unit that stores the first captured image data;
a captured image processing unit that performs clipping processing to cut out a part of each frame of the first captured image data read from the image data storage unit, to generate second captured image data;
a first watermark image superimposing unit for generating output photographed image data by superimposing a watermark image on a frame of the second photographed image data;
an output unit that outputs the captured image data for output to an external device;
a second watermark image superimposing unit that generates recording photographic image data by superimposing the watermark image on a frame of the first photographic image data read from the image data storage unit;
a recording processing unit that processes the photographed image data for recording so as to record the photographed image data on a recording medium;
An imaging device comprising: 2. The imaging device according to claim 1, wherein the first watermark image superimposing unit inverts a luminance of the watermark image when a luminance difference between the background and the watermark image in a frame of the second captured image data on which the watermark image is superimposed is smaller than a predetermined value. 3. The imaging device according to claim 1, wherein the second watermark image superimposition unit inverts a luminance of the watermark image when a luminance difference between the background in a frame of the first captured image data on which the watermark image is superimposed and the watermark image is smaller than a predetermined value. an imaging unit captures an image of a subject and generates first captured image data configured of a frame having a first angle of view;
an image data storage unit stores the first captured image data;
a captured image processing unit performs a clipping process to cut out a part of each frame of the first captured image data read from the image data storage unit, thereby generating second captured image data;
a watermark image superimposing unit superimposing a watermark image on a frame of the second captured image data to generate captured image data for output;
An output unit outputs the captured image data for output to an outside .
a second watermark image superimposing unit superimposing the watermark image on a frame of the first photographed image data read from the image data storage unit to generate photographed image data for recording;
A recording processing unit processes the recording photographic image data so as to record the data on a recording medium.
A method for controlling an imaging device.

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