JP2005130141A - Television and image data storing and reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a television and an image data storing and reproducing method capable of storing image data regarding a plurality of still images in the optimum data quantity every image data within a memory of a fixed capacity. <P>SOLUTION: In storing the latest image data obtained from a temporary recording domain 61 in a storage domain 62, compression processing is performed with the respective image data which have already been stored on the basis of order of storage or priority by varying degrees of compression rate. Then, the latest image data are stored with its high resolution retained within a storage domain 62 of a limited capacity and the respective image data already stored are stored in a state of smaller compression rate according as the more important they are for a user. Thus, the image data regarding the plurality of still images can be stored within the storage domain 62 without increasing the capacity in the storage domain 62 and, regarding important image data, the deterioration of the picture quality can be suppressed to the minimum. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a television and an image data storage / reproduction method, and more particularly to a television and an image data storage / reproduction method capable of storing input image data in a specific memory and displaying a still image based on the stored image data. .

  Conventionally, as this type of television, video input means for inputting an input video signal, compression means for compressing the input video signal, a compressed video buffer for temporarily storing the compressed video signal, and the compressed video Compressed video storage means capable of storing at least one buffer content, and the compressed video buffer content stored in an appropriate location of the compressed video storage means in accordance with a control signal from the instruction input means. A selection unit that reads out compressed video at an arbitrary location from the storage unit, an expansion unit that expands the content read by the selection unit, an expanded video buffer that stores the expanded video signal, and the video signal Video reproducing means for reproducing, video synthesizing means for synthesizing and outputting the output of the video reproducing means and the input video signal, and video for displaying the output from the video synthesizing means Television receiver comprising a Display means are known (e.g., see Patent Document 1.).

The television receiver stores the displayed video as a still image in the compressed video storage unit by operating the selection unit according to a user instruction, and the user wants to view the stored still image. In this case, a still image is selected from the compressed video storage means, subjected to decompression processing and synthesis processing with an input video signal, and displayed on the video display means as one video signal.
Japanese Patent Laid-Open No. 9-83928

  In the above-described television receiver, since the compression means is always operating, all the input video signals fetched from the video input means are uniformly compressed, and all the video signals stored in the compressed video storage means are all. It is in a compressed state. Therefore, even if the amount of data that the user wants to store as a still image is small and the amount of data can be sufficiently stored in the compressed video storage means without compression, each video signal is compressed. However, there is a problem that display of a still image based on the method involves unnecessary image degradation. Further, since all input video signals are uniformly compressed, the compression rate when storing the video signals cannot be changed depending on the importance of each still image for the user.

  The present invention has been made in view of the above problems, and is a television capable of storing image data of a plurality of still images in an optimum data amount for each image data in a fixed capacity memory. It is another object of the present invention to provide a method for storing and reproducing image data.

  In order to achieve the above object, according to the first aspect of the present invention, each screen constituting an image display performed by the image display means based on the image data obtained from the television broadcast signal input by the television broadcast signal input means. By performing a predetermined compression process on image data on an arbitrary screen, image data for a plurality of screens can be stored in a fixed-capacity memory, and images stored in the same memory Each screen constituting the image display in a television capable of displaying a still image based on the data and an image based on the image data obtained from the input television broadcast signal on one screen by the image display means. Image data recording means for sequentially recording the image data in the memory in the temporary recording area sequentially, and the image data A selection unit capable of selecting image data to be stored among the image data temporarily recorded by the recording unit, and assigning a priority according to the importance of the image data to the selected image data; When storing the image data selected by the selection means, if there is no unused area necessary for storing the image data at a predetermined resolution in the storage area of the memory, the storage area For other image data that has already been stored in the image data, the order of storage is the compression processing that thins out pixels at a lower extraction rate as the previous image data, or when the above priority is stored together with each image data Image data compression means for performing compression processing for thinning out pixels at a lower extraction rate based on the same priority, and image data compression means performed by the image data compression means. If an unused area necessary for storing the image data selected by the selection means at a predetermined resolution is secured in the storage area, the image data is stored in the storage area and the compression process is performed. If the unused area necessary for storing the image data at a predetermined resolution is not secured, the image data that has been compressed at a high compression rate is sequentially deleted and selected by the selection means. Image data storing means for storing an unused area necessary for storing image data at a predetermined resolution in the storage area and storing the image data in the storage area is provided.

  In the television invention according to claim 1 configured as described above, the television broadcast signal input means inputs the television broadcast signal, and the image display means applies the image data obtained from the television broadcast signal to the image data. Based on this, a predetermined image display is performed. And, by performing a predetermined compression process on the image data on any screen among the image data on each screen constituting the same image display, it is possible to store image data for a plurality of screens in a fixed capacity memory It is said. The television also displays a still image based on the image data stored in the memory and an image based on the image data obtained from the input television broadcast signal on a single screen by the image display means. Is possible. In such a configuration, the capacity of the memory is limited. Therefore, when image data for a plurality of screens is stored, the image data is usually compressed and stored in the memory. However, depending on the amount of image data stored in the memory, it may not be necessary to compress the image data. Further, even when the image data is compressed and stored, the user wants to change the degree of compression of each image data depending on the importance of the image data to be stored in view of the fact that the image is deteriorated when compressed at a high compression rate. May be considered.

  Therefore, the image data recording means temporarily records the image data relating to each screen constituting the image display sequentially in the temporary recording area of the memory, and the selection means is temporarily stored by the image data recording means. The image data to be stored is selected from the image data recorded in (1). That is, an image based on the image data obtained from the television broadcast signal is displayed by the image display means, and is sequentially recorded in the temporary recording area of the memory for each screen. When the user decides to save the image displayed by the image display means, the selection means selects the image data recorded in the temporary recording area at that time according to the user's instruction. Note that when the image data is selected, the selection unit can give priority to the image data according to the importance of the image data.

  The image data selected by the selection means is stored in the storage area of the memory. However, since the image data is the latest image data selected by the user, it is very important for the user and is not compressed as much as possible. It is desirable to store the image data with high resolution. On the other hand, depending on the amount of image data already stored in the storage area, there may be no unused area that can store the latest image data with high resolution. Therefore, the image data compression means is used for storing the storage area when there is no unused area necessary for storing the image data selected by the selection means at a predetermined resolution in the storage area of the memory. When other image data already stored in the area is compressed in the order of saving, the pixels are thinned out at a lower extraction rate as the previous image data, or when the above priority is stored together with each image data The compression processing for thinning out pixels at a lower extraction rate is performed for image data having a lower priority based on the same priority.

  In other words, it is considered that the older the image data that has already been stored, the less important it is. Therefore, the higher the compression rate, the lower the extraction order of the stored image data. Perform compression processing. Alternatively, the compression processing may be performed by thinning out pixels at a lower extraction rate for image data having a lower priority based on the priority assigned to each image data in the selection unit, instead of the order in which the data is stored. If an unused area for storing the image data selected by the selection means at a predetermined resolution remains in the storage area, the image data already stored is not compressed.

  The amount of data of each image data already stored in the storage area is compressed by the compression processing performed by the image data compression means, so that the unused area in the storage area is expanded. Here, the image data storage means stores the image data in the storage area when the unused area necessary for storing the image data selected by the selection means at a predetermined resolution is secured. Save to the save area. On the other hand, if the unused area necessary for storing the image data at a predetermined resolution is not secured even by the compression process, the image data storage means stores the image data already stored in the storage area. Among them, image data that has been compressed at a high compression rate is sequentially deleted. Since image data that has been compressed at a high compression rate is less important, there are few problems even if it is deleted. As described above, an unused area necessary for storing the image data selected by the selection unit at a predetermined resolution is secured in the storage area, and the image data is stored in the storage area.

  Through such a series of processing, the latest image data selected by the selection means can be stored as high-resolution image data in a limited capacity without increasing the capacity of the memory, and each of the already stored data Of the image data, image data that is more important to the user can be stored at a lower compression rate.

  According to a second aspect of the present invention, there is provided a television broadcast signal input means for inputting a television broadcast signal, a selection means for selecting image data to be stored among image data obtained from the television broadcast signal, and the selection When the image data selected by the means is stored, if there is no unused area necessary for storing the image data at a predetermined resolution in a specific memory, the other already stored in the memory Image data compression means for determining a compression rate of each image data for the image data of the image data and compression processing performed by the image data compression means; Image data storing means for storing the image data selected by the image data, a still image based on the image data stored in the memory, and the input text. There the image based on the image data obtained from the vision broadcast signal as configuration includes an image display unit can be displayed on one screen.

  In the television invention according to claim 2 configured as described above, the television broadcast signal input means inputs the television broadcast signal, and the selection means stores the image data obtained from the television broadcast signal. The image data to be selected is selected. Next, the image data selected by the selecting means is stored in a specific memory, but the image data compressing means leaves an unused area necessary for storing the image data at a predetermined resolution in the memory. If not, the compression rate of each image data is determined and compressed for other image data already stored in the memory. If an unused area for storing the image data at a predetermined resolution remains in the memory, the image data already stored is not compressed.

  Then, the image data storage unit stores the image data selected by the selection unit in the memory in which the unused area is expanded by the compression process. In other words, the image data selected by the selection means is stored in the memory at a predetermined resolution, and the image data related to the more important image among the already stored image data is stored at a lower compression rate. can do. The image display means can display a still image based on the image data stored in the memory on one screen together with an image based on the image data obtained from the input television broadcast signal.

  Here, it can be considered that the older the image data stored in the memory, the lower the importance for the user. Therefore, according to a third aspect of the present invention, in the television set according to the second aspect, the image data compressing means stores the image data in the first order among the other image data already stored in the memory. The image data is compressed at a higher compression rate.

  In the invention according to claim 3 configured as described above, the image data compression means has a higher compression rate as the image data stored earlier is the other image data already stored in the memory. Perform compression processing with. By compressing the older image data in the memory at a higher compression rate, the newer image data considered to be more important to the user in the limited memory, the lower the compression rate, Deterioration can be suppressed and stored.

  Although the importance of the image data may be determined based on the order in which the images are stored as described above, a priority is assigned in advance to each image data regardless of the order in which the images are stored, and compression is performed based on the priorities. The rate may be varied. Accordingly, the invention according to claim 4 is the television set according to claim 2, wherein when the selecting means selects the image data to be stored, the selected image data is added to the importance of the image data. The image data compression means assigns a higher priority to the image data having a lower priority, which is stored together with the image data, among the other image data already stored in the memory. The compression processing is performed.

  In the invention according to claim 4 configured as described above, each image data is stored in the memory together with a priority in order to give priority to the image data selected by the selection means according to importance. Will be. The image data compression means performs compression processing at a higher compression rate for lower-priority image data stored together with each image data among other image data already stored in the memory. With such a configuration, in the above-mentioned memory having a limited capacity, image data that is more important to the user among the image data can be stored with a lower compression rate and reduced image deterioration.

  Here, as a specific method of the compression processing, the invention according to claim 5 is the television set according to any one of claims 2 to 4, wherein the image data compression means is already stored in the memory. In order to change the compression rate of the other image data, the extraction rate is determined, and the compression processing is performed by performing pixel thinning processing based on the extraction rate.

  In the invention according to claim 5 configured as described above, the image data compression means determines an extraction rate when changing the compression rate of other image data already stored in the memory. Then, pixel thinning processing is performed based on the extraction rate. That is, if the pixels thinned out at a predetermined extraction rate among the pixels constituting the image data are the image data stored in the memory, the amount of data to be stored is compressed.

  According to the configuration described above, each piece of image data stored in the memory is compressed every time image data to be newly stored increases. Then, as the image data that is less important to the user increases, the compression rate increases as the number of newly stored image data increases. However, even if less important image data is compressed at a high compression rate, an unused area required for storing the latest image data at a predetermined resolution may not be secured in the memory. Accordingly, the invention according to claim 6 is the television set according to any one of claims 2 to 5, wherein the image data storage means is configured to perform the compression processing by the image data compression means. When the unused area necessary for storing the image data selected by the selection means in the memory at a predetermined resolution cannot be secured, the image data that has been compressed at a high compression rate is sequentially deleted, and In this configuration, an unused area necessary for storing the image data selected by the selection unit at a predetermined resolution is secured in the memory.

  In the invention according to claim 6 configured as described above, the image data storage means stores the image data selected by the selection means in the memory even if compression processing by the image data compression means is performed. If the unused area necessary for saving at the predetermined resolution cannot be secured, the image data already stored in the memory is erased from the image data compressed at a high compression rate. Go. Image data that has been compressed at a high compression rate is less important, so there are few problems even if it is deleted from such image data. Then, an unused area necessary for storing the latest image data at a predetermined resolution is secured in the memory, and the image data is stored in the memory. That is, even when there is almost no unused area remaining in the memory, the latest image data is not unnecessarily compressed and is stored at a predetermined resolution, and highly important image data is Saved without being erased.

  Image data that has been repeatedly subjected to compression processing and compressed at a high compression rate is less important and has a greater image degradation. Accordingly, the invention according to claim 7 is the television according to any one of claims 2 to 5, wherein the image data storage means compresses the image data among the image data stored in the memory. As a result of the compression processing performed by the means, image data whose compression rate exceeds a predetermined threshold value is erased.

  In the invention according to claim 7 configured as described above, the image data storage means has a compression ratio as a result of the compression processing performed by the image data compression means among the image data stored in the memory. Image data exceeding a predetermined threshold value is erased. With this configuration, image data relating to a deteriorated image is less important, and a certain unused area is secured in the memory.

  According to an eighth aspect of the present invention, in the television according to any one of the second to seventh aspects, the image data interpolation means performs an interpolation process on the compressed image data stored in the memory. The still image is displayed based on the image data subjected to the interpolation processing.

  In the invention according to claim 8 configured as described above, the image data interpolation means performs an interpolation process on the image data subjected to the compression process stored in the memory. Then, the image display means displays a still image based on the image data subjected to the interpolation processing. That is, even when a still image based on compressed image data is displayed, a high-quality still image can be displayed by performing interpolation processing on the image data by the image data interpolation means. .

In the above, the invention has been described as an invention relating to a substantial television. However, the technical idea according to the invention of the present application can also be established as a useful invention. Therefore, the invention according to claim 9 is a television signal input step of inputting a television broadcast signal, a selection step of selecting image data to be stored among the image data obtained from the television broadcast signal, and the above When the image data selected by the selection process is stored, if there is no unused area necessary for storing the image data at a predetermined resolution in a specific memory, it is already stored in the memory. An image data compression process for determining the compression rate of each image data with respect to other image data and performing compression processing, and the memory in which an unused area is expanded by the compression processing by the image data compression process, by the selection process An image data storage step for storing the selected image data, a still image based on the image data stored in the memory, and the input There the image based on the image data obtained from the revision broadcast signal as configuration comprising an image display step of displaying on one screen.
That is, it is not necessarily limited to a substantial television, and there is no difference that it is effective as a method for storing and reproducing image data.

As described above, according to the inventions according to claims 1 to 4, the latest selected image data is stored at a predetermined resolution and already stored in a memory having a limited capacity. It is possible to provide a television that can store an image data that is more important to the image data by performing compression processing at a lower compression rate.
According to the invention of claim 5, the data amount of the image data to be stored in the memory can be compressed by thinning out the pixels constituting the image data at a predetermined extraction rate.
Further, according to the sixth aspect of the present invention, an unused area necessary for storing the latest image data with a predetermined resolution can be surely secured in the memory.
Furthermore, according to the seventh aspect of the present invention, it is possible to secure a certain unused area in the memory by erasing image data relating to a deteriorated image with low importance.
Furthermore, according to the eighth aspect of the invention, a high-quality still image can be displayed.
Furthermore, according to the ninth aspect of the present invention, the latest selected image data is stored at a predetermined resolution in a memory of a limited capacity, and is important for image data that has already been stored. It is possible to provide an image data storage / reproduction method in which higher image data can be compressed and stored at a lower compression rate.

Embodiments of the present invention will be described in the following order.
(1) Schematic configuration of television (2) About compression processing (3) Summary

(1) Schematic Configuration of Television FIG. 1 is a diagram showing a schematic configuration of a television according to an embodiment of the present invention.
As shown in the figure, the television 100 generally includes tuners 11a and 11b, RGB signal generation units 20a and 20b, an image synthesis unit 30, a liquid crystal module 40, a microcomputer 50, and a still image storage memory 60. It consists of. In the same configuration, the microcomputer 50 is connected to each unit constituting the television 100 via the IIC bus 70, and the CPU 51 controls the entire television 100 according to each program written in a memory such as the ROM 52 and the RAM 53. . An operation panel 54 and a remote control I / F 55 are connected to the microcomputer 50, and an input signal through the operation panel 54 or an input signal from the remote control through the remote control I / F 55 is used. Various processes in the television 100 can be controlled.
In the present embodiment, a liquid crystal panel is used as the image display element, but the present invention is not limited to this, and a display element such as a plasma panel may be used.

  The television 100 has a so-called picture-in-picture function that displays a child screen in a predetermined area on the parent screen, and can display images of different channels and input systems simultaneously on one screen. Further, using the picture-in-picture function, an image based on a television broadcast signal input from the tuners 11a and 11b, a still image selected based on the user's preference and stored in the still image storage memory 60, etc. It can be displayed on the same screen as other images.

In order to realize the picture-in-picture function, the television 100 includes two processing systems for inputting an analog broadcast signal and generating image data based on the signal.
The tuners 11a and 11b can receive television broadcast signals via the antennas 10a and 10b under the control of the microcomputer 50, respectively. An intermediate frequency signal as an analog video signal based on the television broadcast signal is output from the tuner 11a and the tuner 11b to the switch circuit 13a and the switch circuit 13b, respectively. The switch circuit 13a and the switch circuit 13b are also connected to the external video input terminal 12a and the external video input terminal 12b, respectively, and can input analog video signals from the external video input terminal 12a and the external video input terminal 12b, respectively. The switch circuits 13a and 13b selectively input an intermediate frequency signal from the tuners 11a and 11b and an analog video signal from the external video input terminals 12a and 12b in accordance with a selection instruction input from the microcomputer 50, and a synchronization signal. Are output to the A / D conversion circuits 21a and 21b of the RGB signal generation units 20a and 20b, respectively.

  The A / D conversion circuits 21a and 21b convert the input video signal, which is an analog signal, into a digital signal according to the signal level. The video signal converted into a digital signal is output to the Y / C separation circuits 22a and 22b. In the Y / C separation circuits 22a and 22b, separation into a luminance signal and a chroma signal is performed based on the digitized video signal. The separated luminance signals are input to the image quality adjustment circuits 23a and 23b. After the image quality adjustment circuits 23a and 23b perform predetermined image quality adjustment such as contrast adjustment, they are output to the matrix circuits 25a and 25b. On the other hand, the separated chroma signals are demodulated into RY and BY color difference signals in the color demodulation circuits 24a and 24b, and then output to the matrix circuits 25a and 25b. In the matrix circuits 25a and 25b, matrix conversion processing is performed based on the input luminance signal and color difference signal to generate RGB signals as image data. The image data output from the matrix circuit 25a is referred to as first image data, and the image data output from the matrix circuit 25b is referred to as second image data.

  In order to simultaneously display an image based on the first and second image data generated by the above-described two systems on one screen, the first and second image data are input to the image composition unit 30 and predetermined composition processing is performed. It is necessary to do. In order to display an image based on the first or second image data and a still image based on the image data stored in the storage area 62 of the still image storage memory 60 on one screen, first or second It is necessary to input the image data and the image data to the image composition unit 30 and perform a predetermined composition process. The processing for storing the image data in the storage area 62 of the still image storage memory 60 will be described in detail later.

  Here, as an example, an image based on the first image data is used as a main screen, a still image based on the image data stored in the storage area 62 is used as a sub screen, and the two images are displayed on one screen as an example. Processing in the synthesis unit 30 and the like will be described. First, the pixel number conversion circuit 31 inputs the first image data and the same image data, and performs a predetermined scaling process. For example, the number of pixels of the first image data is converted into horizontal 640 × vertical 480 pixels, and the number of pixels of the image data is converted into horizontal 150 × vertical 120. Information for determining the number of pixels and coordinates of the display area of the small screen is recorded in the memory 33 in advance, and the number of pixels of the image data for the small screen is converted based on such information. Each image data after converting the number of pixels is written in the memory 33.

  The image synthesis circuit 32 performs a process of synthesizing the first image data with the converted number of pixels and the same image data. Information for determining the coordinates of the display area of the child screen is acquired from the memory 33, the coordinates of the display area of the child screen are made to correspond to the same image data converted in the number of pixels. Image data with 0 gradation is generated. On the other hand, each RGB component for the display area of the small screen in the first image data converted in the number of pixels is set to 0 gradation, and the other areas are image data in which the gradation values are the same as the original first image data. Generate. By superimposing the generated image data, a still image based on the image data stored in the storage area 62 is displayed in the display area of the child screen, and the first image data is displayed as the parent screen in the other areas. Composite image data in which an image based on the image is displayed is generated.

  The composite image data generated by the above processing is output to the liquid crystal module 40 after being subjected to processing such as luminance adjustment, contrast adjustment, saturation correction, and OSD signal superposition by an image quality adjustment circuit (not shown). The liquid crystal module 40 includes a liquid crystal driving circuit 41, a liquid crystal panel 42, and a backlight 43. The liquid crystal driving circuit 41 generates a voltage for driving the panel corresponding to each RGB of the liquid crystal panel 42. The backlight 43 is turned on by receiving a high voltage from an inverter (not shown), and irradiates the liquid crystal panel 42 from the back side. As a result, the liquid crystal module 40 displays an image based on the composite image data on the liquid crystal panel 42.

  The television 100 is an ordinary television receiver that not only displays two images simultaneously on the parent screen and the child screen as described above but also displays an image based on image data input from one input system. Also works naturally. In the case of functioning as a normal television receiver, the image data output from one of the RGB signal generation unit 20a or the RGB signal generation unit 20b to the image synthesis unit 30 is not subjected to synthesis processing with other image data. The image is output to the module 40 and an image based on the image data is displayed on the liquid crystal panel 42.

(2) About compression processing Here, the image data output from the image composition unit 30 is input to the liquid crystal module 40 to display a predetermined image on the liquid crystal panel 42, and in accordance with an instruction from the microcomputer 50. Data is sequentially recorded in the temporary recording area 61 of the still image storage memory 60 for each data amount of one screen. That is, the image data constituting the image displayed on the liquid crystal panel 42 is simultaneously recorded in the temporary recording area 61 for each screen. In the temporary recording area 61, every time the displayed screen changes, the image data relating to the latest image is overwritten and recorded. The recording operation of the image data in the temporary recording area 61 may be always performed while the image display is being performed on the liquid crystal panel 42, or the user may store the image data in the temporary recording area 61. The recording operation may be performed only for a certain period of time when it is desired to perform the recording operation.

Next, a series of processes for saving the image data for one screen recorded in the temporary recording area 61 in the saving area 62 will be described.
FIG. 2 is a flowchart showing the contents of the processing performed by the microcomputer 50 to store the image data recorded in the temporary recording area 61 in the storage area 62.
First, the microcomputer 50 determines whether or not there is an instruction signal for instructing storage of a still image from the user via the operation panel 54 or the remote control I / F 55 (step S100). That is, when the user who is viewing the image displayed on the liquid crystal panel 42 wants to store the image currently viewed as a still image, the microcomputer 50 stores the still image via the remote control or the operation panel 54. To direct. When receiving the instruction signal, the microcomputer 50 acquires the recorded image data from the temporary recording area 61 (step S110).

  The microcomputer 50 that has acquired the image data from the temporary recording area 61 determines whether or not an unused area necessary for storing the acquired image data (hereinafter, the latest image data) remains in the storage area 62. Judgment is made (step S120). This is because other image data may already be acquired and stored in the storage area 62 from the temporary recording area 61. Here, the unused area necessary for storing the latest image data is a recording area necessary for storing the data amount as it is without compressing the latest image data at all, or when it is compressed. However, it is a recording area required for processing at a low compression rate and storing the data amount after the compression. The latest image data is data related to the latest image that the user wants to save, and is considered to be highly important. The latest image data is saved as high resolution without performing compression as much as possible.

In the case where an unused area necessary for storing the latest image data remains in the storage area 62, without compressing other image data stored in the storage area 62, The latest image data is stored in the unused area (step S180). However, if the unused area is insufficient, the microcomputer 50 performs a predetermined compression process on the other image data.
The microcomputer 50 determines whether the other image data stored in the storage area 62 has data indicating the priority of the image data (step S130). The priority is given based on the importance of each corresponding image data every time the user sends the instruction signal to the microcomputer 50. The priority given to each image data is each image data as data. At the same time, it is stored in the storage area 62. Whether the image data is stored with priority or whether the image data is stored without priority can be changed according to user preference.

  If no priority is given to the other image data, compression processing is performed so that the higher the compression rate is, the higher the order of the data stored in the storage area 62 is (step S140). For example, each time the latest image data is acquired from the temporary recording area 61, the compression processing is performed on each image data stored in the storage area 62 based on the same compression ratio. As a result, the image data stored in the first order is overlapped with the number of times of compression in one step and two steps each time the newly stored image data increases. In addition, an area that can be used to store other image data in the storage area 62 is assigned to each data based on a ratio corresponding to the order in which the other image data is saved, and the area is allocated to each assigned area. Each other image data may be compressed so as to be stored.

  If priority is given to other image data, compression processing is performed so that the other image data with lower priority has a higher compression rate based on the same priority (step S150). For example, among the other image data stored in the storage area 62, the image data with the highest priority is compressed one step at a predetermined compression rate α, and the image data with the second highest priority is Two-stage compression is performed based on the same compression ratio α, and the third highest-priority image data is compressed in three stages based on the same compression ratio α. Increase the number of times. In addition, an area that can be used to store other image data in the storage area 62 is allocated to each data based on a ratio corresponding to the priority of each other image data, and is stored in each allocated area. Each other image data may be compressed as described above.

The microcomputer 50 determines whether or not an unused area necessary for storing the latest image data in the storage area 62 has been secured by the processing in S140 or S150 (step S160). Although the unused area is expanded to some extent by the processing in S140 or S150, an unused area necessary for storing the latest image data is secured even if the compression process is performed, depending on the number of stored still images. This is because there are cases where it is not possible. If the microcomputer 50 determines that an unused area necessary for storing the latest image data cannot be secured in the storage area 62, the microcomputer 50 stores the unused area 62 until the necessary unused area is secured. The other image data stored in is deleted in the order of compression processing at a high compression rate (step S170). If it is compressed at a high compression rate, it is less important for the user and there are few problems even if it is deleted. As a result, an unused area for storing the latest image data can be secured in the still image storage memory 60 having a limited capacity, and highly important image data can be stored without being erased.
The latest image data is stored in the unused area secured in the storage area 62 by the above processing (step S180).

In FIG. 2, after the compression process in S140 or S150, it is determined in S160 whether or not an unused area for storing the latest image data can be secured in the storage area 62. Instead of this determination, it may be configured to determine whether or not there is image data whose compression rate exceeds a predetermined threshold as a result of the compression processing.
FIG. 3 is a flowchart showing the contents of processing performed by the microcomputer 50 to store the image data recorded in the temporary recording area 61 in the storage area 62, and shows an example different from FIG. Yes. In the figure, S200 to S250 are the same as the processing contents from S100 to S150 in FIG.

  In step S260 in the figure, the microcomputer 50 determines whether or not image data whose compression rate exceeds a predetermined threshold Th exists in the storage area 62 as a result of the compression processing in S240 or S250. to decide. Then, as a result of the determination, image data for which it is determined that the compression rate exceeds the predetermined threshold Th is deleted (step S270). In S240 and S250, based on the stored order and the priority assigned to each image data, the compression processing is performed so that the compression rate of the image data that is less important to the user is higher. Therefore, by adding such processing, it is possible to automatically erase image data that has become less important and image deterioration has been increased due to the high compression rate. Finally, the latest image data is stored in an unused area secured in the storage area 62 (step S280). Here, the threshold value is higher than the compression ratio of the image data to be erased when the unused area for storing the latest image data cannot be secured in the storage area 62 even by the compression process described in FIG. Is set to a low value, an unused area for storing the latest image data can be secured in the storage area 62, and image data that has become less important to some extent can be automatically deleted.

Next, the contents and results of the compression processing performed in S140, S150, S240, and S250 of FIGS.
FIG. 4 shows an example of the relationship between the amount of data before compression and the amount of data after compression when compression processing is performed so that the earlier image data has a higher compression rate as the image data is stored.
As described above, every time the microcomputer 50 receives an instruction signal from the user, the microcomputer 50 stores the image data for one screen recorded in the temporary recording area 61 in the storage area 62. Here, it is assumed that the image data for one screen to be stored is D1, D2, D3,. The amount of data before compression processing of each image data is assumed to be q1, q2, q3,. Since each image data is data constituting an image for one screen, the data amount is the same, but the numbers are distinguished for convenience. Further, it is assumed that the capacity of the storage area 62 is C, and image data for three screens can be stored without being compressed. Under this premise, the description after FIG. 4 will be made.

The left column in the figure is the latest image data at that time, which is acquired from the temporary recording area 61 and stored in the storage area 62. The middle column is the data amount of each image data stored in the storage region 62 before compression processing, and the right column is the data amount stored in the storage region 62 after compression processing. is there.
Since the image data D1 is data acquired from the temporary recording area 61 first, the amount of data in the storage area 62 is 0 at the time when D1 is acquired. In addition, since the storage area 62 can store image data for three screens without compression processing, compression processing is not performed until D3 is acquired and stored in the storage area 62. Then, compression processing is performed from the stage where D4 is acquired from the temporary recording area 61. That is, in the state in which the data amounts q1, q2, and q3 are stored in the storage area 62, there is no unused area for storing D4, so the compression processing is performed on the image data D1 to D3. I do.

For example, when the compression ratio is α (0 <α <1), the first stored D1 is compressed in three stages, and the data amount is q1 × α ** 3. However, ** represents a power. The D2 with the second oldest stored order is compressed in two stages, the data amount is compressed to q2 × α ** 2, the D3 with the newest stored order is compressed in one step, and the data amount is q3 × α. To do. As a result, the data amount in the storage area 62 is compressed from q1, q2, and q3 to q1 × α ** 3, q2 × α ** 2, and q3 × α, respectively. When D5 is acquired, one-stage compression processing is performed on each of the image data D1 to D4, and the amount of data in the storage area 62 is set to q1 × α ** 3, q2 × α ** 2, q3. The compression is performed from × α, q4 to q1 × α ** 4, q2 × α ** 3, q3 × α ** 2, q4 × α. Thereafter, each time the latest image data Dx to be acquired increases, each stored image data is compressed step by step at the same compression rate α.
As another method, a table associated with compression ratio α1 = 90%, α2 = 80%, α3 = 70%, etc. is stored in a predetermined storage area in advance, and compression processing is performed on certain image data. Each time it is performed, the compression rate may be read from the same table in the order of α1, α2,... That is, when the latest image data is acquired for certain image data stored in the storage area 62, JPEG compression is first performed based on the compression rate α1, and then the latest image data is acquired, α2 Based on this, JPEG compression is performed, and so on.
As a result, the earlier the image data is stored, the more the number of times compression processing is performed, so the image data is compressed at a high compression rate.

FIG. 5 shows the relationship between the amount of data before compression and the amount of data after compression when compression processing is performed so that the earlier image data has a higher compression rate, and is different from FIG. An example is shown.
In the figure, an area that can be used to store other image data in the storage area 62 is assigned to each data based on a ratio corresponding to the order in which the other image data is stored. A case where each other image data is compressed so as to be stored in the area is shown. 4 is the same as the process in FIG. 4 in that the compression process is not performed until D3 is acquired and stored in the storage area 62.

The compression process is performed when the microcomputer 50 acquires D4 from the temporary recording area 61 as the latest image data. Here, when the acquired D4 is stored in the storage area 62, the area that can be used to store D1 to D3 is Cq4. Therefore, D1 to D3 are respectively compressed so as to be stored in the areas allocated based on the ratio corresponding to the stored order of each of D1 to D3 among the usable areas C-q4. The ratio corresponding to the stored order can be expressed as, for example, the stored order of the image data / the sum of the stored order of each image data.
According to this example, as shown in the figure, D1 is assigned an area of 1/6 (the order in which D1 is saved / the sum of the order in which D1 to D3 are saved) in the area C-q4. The data amount q1 is compressed at a compression rate necessary to be stored in the area. Similarly, the data amount q2 of D2 is compressed at a compression rate necessary to be stored in 2/6 of the regions C-q4, and the data amount q3 of D3 is compressed in the region C-q4. Of these, compression is performed at a compression rate necessary to be stored in an area of 3/6. Further, when the microcomputer 50 acquires the image data D5 from the temporary recording area 61, the data amount of each of the image data D1 to D4 is stored for each of the D1 to D4 in the usable area C-q5. Each of the images is compressed so as to be stored in the area allocated based on the ratio corresponding to the order.

In FIGS. 4 and 5, the case where the compression processing is performed so that the order of saving is higher in the earlier image data is described, but in FIGS. 6 and 7, the image data is attached to the image data. A description will be given of a case where compression processing is performed so that image data with a lower priority has a higher compression rate based on the priority. This processing is performed when the microcomputer 50 determines in S130 and S230 that each image data stored in the storage area 62 has data indicating its priority.
FIG. 6 shows the amount of data before compression and the amount of data after compression when compression processing is performed so that image data with lower priority is based on the priority assigned to stored image data so that the compression rate is higher. An example of the relationship is shown. For example, the priorities are 3, 2, and 1 in descending order of priority.

  In the left column of the figure, each image data D1, D2, D3, Dn acquired from the temporary recording area 61 is displayed and the priority given to each image data is shown in parentheses. . Also in this figure, compression processing is not performed until D3 is acquired and stored in the storage area 62. When D4 is acquired from the temporary recording area 61, compression processing is performed. According to the figure, the priority of the image data D1 is 3, the priority of D2 is 1, and the priority of D3 is 2. Therefore, as an example of compressing each image data D1, D2, D3 based on priority, when the compression rate is α (0 <α <1), D2 having the lowest priority is compressed in three stages. The data amount is changed from q2 to q2 × α ** 3. D3 with the second lowest priority is compressed in two steps, the data amount is compressed from q3 to q3 × α ** 2, and D1 with the highest priority is compressed in one step, and the data amount is reduced from q1 to q1 × α. To do.

  When D5 is acquired, the image data D1 to D4 stored in the storage area 62 are subjected to compression processing. In this case, the previous temporary recording area 61 is newly compressed. Only the image data D4 acquired from the storage area 62 and stored in the storage area 62. Since D4 has the lowest priority of 1, the data amount is compressed from q4 to q4 × α ** 3. Similarly, when D6 is acquired, the data amount q5 of the image data D5 is compressed at a compression rate corresponding to the priority. In other words, the compression processing is performed based on the priority assigned to each image data regardless of the order in which the images are stored in the storage area 62. Therefore, even in the case of old image data stored for a long time, the priority is high. If it is high, it is stored at a lower compression rate than later-stored low-priority image data.

FIG. 7 shows the amount of data before compression and the amount of data after compression when compression processing is performed so that image data with a lower priority has a higher compression rate based on the priority assigned to stored image data. An example different from FIG. 6 is shown.
In the figure, an area that can be used for storing other image data in the storage area 62 is allocated to each data based on a ratio corresponding to the priority of each other image data, and the area within each allocated area is stored. The case where each other image data was compressed so that it may be preserve | saved is shown.

Here, consider a case where the image data D4 is acquired from the temporary recording area 61 and stored in the storage area 62. An area that can be used to store the image data D1 to D3 is C-q4. Accordingly, D1 to D3 are respectively compressed so as to be stored in the areas allocated based on the ratios corresponding to the priorities assigned to the respective D1 to D3 among the usable areas C-q4. . The ratio corresponding to the priority can be expressed as, for example, the priority of the image data / the sum of the priorities of the image data.
According to this example, as shown in the figure, D1 is assigned an area of 3/6 (priority of D1 / sum of priorities of D1 to D3) out of the area C-q4. The data amount q1 is compressed at a compression rate necessary for storing the data. Similarly, the data amount q2 of D2 is compressed at a compression rate necessary to be stored in 1/6 of the region C-q4, and the data amount q3 of D3 is compressed in the region C-q4. Of these, compression is performed at a compression rate necessary for storage within 2/6 of the area. When the microcomputer 50 acquires the image data D5 from the temporary recording area 61, the data amount of each of the image data D1 to D4 is the priority of each D1 to D4 in the usable area C-q5. Are compressed so as to be stored in the area allocated based on the ratio corresponding to.

As a specific method of the compression processing performed by the microcomputer 50, a case where thinning processing of pixels constituting image data is performed can be considered. That is, among the pixels constituting the image data, the pixels thinned out based on a predetermined extraction rate are used as the image data to be stored, thereby compressing the data amount to be stored in the storage area 62.
Here, a thinning process when the image data described in FIGS. 4 and 6 is compressed in a plurality of stages at a predetermined compression rate α will be described. When image data is compressed by thinning out pixels based on a certain extraction rate, a value obtained by dividing the image data amount after the thinning process by the image data amount before the thinning process is the compression rate. Therefore, a table 80 in which a predetermined compression rate and an extraction rate for thinning out image data so as to be the same compression rate are stored in a predetermined storage area in advance.

  FIG. 8 shows the table 80. A plurality of compression rates α1 to αn are written in the left column of the table 80, and extraction rates β1 to βn for realizing the corresponding compression rates are written in the right column. For example, when β1 is 1/2, the image data is thinned out every other pixel in both the vertical and horizontal directions. Since the number of pixels of the image data to be compressed is ½ in both the vertical and horizontal directions, the data amount after the thinning process is ¼ of the original. Therefore, the compression ratio α1 corresponding to β1 is ¼. A plurality of values are prepared for the compression rate αx, and the user selects and sets a desired compression rate αx via the operation panel 54 or the like. Then, when performing the thinning process of the image data, the microcomputer 50 reads out the extraction rate βx corresponding to the set compression rate αx from the table 80, and performs the thinning process of the image data based on the extraction rate βx. , Compress the amount of data.

Next, as described with reference to FIGS. 5 and 7, the storage area 62 is allocated to each image data based on a predetermined ratio, and the thinning is performed when each image data is compressed so as to be stored in each allocated area. Processing will be described.
5 and 7, the size of the area stored after each image data is compressed is determined for each image data. Since the compression rate of each image data is a value obtained by dividing the amount of data after compression by the amount of data before compression, in the case of the figure, the compression rate of each image data is after the image data is compressed. This is a value obtained by dividing the data amount of the area to be saved by the data amount before compression. To explain with an example, in FIG. 5, the compression rate of the compression process for the image data D1 performed when the image data D4 is acquired as the latest image data from the temporary recording area 61 is the data amount C after compression. The value obtained by dividing −q4 × 1/6 by the data amount q1 before compression is C−q4 / 6q1. In this way, the compression rate of each image data is determined.

When the microcomputer 50 obtains the compression rate of the image data as described above, the microcomputer 50 obtains an extraction rate for regularly thinning out pixels so that the ratio between the data amount before compression and the data amount after compression becomes the same compression rate. A thinning process is performed based on the extraction rate. As another method of pixel thinning processing, averaging processing may be performed in which data of a plurality of adjacent pixels is averaged to be one pixel.
FIG. 9 shows image data to be averaged. For example, consider a case where the compression ratio is 1/9. An average gradation value R′G′B ′ is taken from the gradation value data (RGB data) of 3 × 3 pixels in the vertical and horizontal directions, and one pixel composed of the average gradation value data is obtained. As a result of this thinning processing, the image data amount is compressed to 1/9 of the original image data amount.

The process from when the latest image data is acquired from the temporary recording area 61 until it is stored in the storage area 62 has been described. Next, a process performed by the microcomputer 50 when the user views a still image based on each image data stored in the storage area 62 will be described.
FIG. 10 is a flowchart showing the processing contents until the microcomputer 50 acquires the image data stored in the storage area 62 and outputs it to the image composition unit 30.
First, the microcomputer 50 determines whether or not there is an instruction signal for instructing acquisition of the image data stored in the storage area 62 from the user via the operation panel 54 or the remote control I / F 55 (step). S300). In other words, when the user wants to view a still image based on the stored image data, the desired image data is acquired from the image data stored in the storage area 62 via the remote controller or the operation panel 54. Is instructed to the microcomputer 50.

  When receiving the instruction signal, the microcomputer 50 acquires image data from the storage area 62 based on the instruction signal (step S310). Here, the microcomputer 50 determines whether or not to perform interpolation processing on the acquired image data (step S320). This is because the image data stored in the storage area 62 may be subjected to compression processing, and if a still image is displayed as it is based on the image data, a low-resolution image is displayed. . In the present embodiment, the user can select and set a mode in which interpolation processing is performed on image data acquired from the storage area 62 and a mode in which interpolation processing is not performed. If it is determined that the mode for performing the interpolation process on the image data acquired from the storage area 62 is set, the microcomputer 50 performs a predetermined interpolation process on the image data (step S330). That is, new gradation value data is generated between the gradation value data of adjacent pixels, and the vertical and horizontal resolutions of the image data are increased. As the interpolation processing method, various known interpolation processing methods such as a near neighbor method and a spline interpolation method can be employed.

  Then, the same image data having a high resolution by the interpolation processing is output to the image composition unit 30. Alternatively, if it is determined in step S320 that the mode for performing the interpolation process is not set, the image data is output to the image composition unit 30 without being subjected to the interpolation process (step S340). Thereafter, the image data is combined with the first image data input from another input system and output to the liquid crystal module 40, and a still image based on the image data is displayed on the liquid crystal panel 42. It is displayed on one screen together with an image based on the first image data.

(3) Summary As described above, when the latest image data acquired from the temporary recording area 61 is stored in the storage area 62, the order in which the image data has already been stored, The compression processing is performed with a difference in the degree of compression rate based on the priority. Then, the latest image data is stored at a high resolution in the storage area 62 with a limited capacity, and each image data that has already been stored is in a low compression rate state as the importance to the user increases. save. Therefore, image data relating to a plurality of still images can be stored in the storage area 62 without increasing the capacity of the storage area 62, and image degradation is minimized for important image data. Can do.

It is a schematic block diagram of the television concerning one Embodiment of this invention. It is the flowchart which showed the processing content performed until it preserve | saves the image data recorded on the area | region for temporary recording in the area | region for a preservation | save. It is the flowchart which showed the content of the processing performed before preserve | saving to the storage area | region the image data recorded on the area | region for temporary recording, and showed the other example. It is the figure which showed an example of the relationship between the data amount before compression, and the data amount after compression in the case of performing a compression process so that the order of preserve | saved image data may become a high compression rate. It is the figure which showed an example of the relationship between the data amount before compression, and the data amount after compression in the case of performing a compression process so that the order of preserve | saved image data may become a high compression rate. An example of the relationship between the amount of data before compression and the amount of data after compression when compression processing is performed so that image data with a lower priority has a higher compression rate based on the priority assigned to stored image data FIG. An example of the relationship between the amount of data before compression and the amount of data after compression when compression processing is performed so that image data with a lower priority has a higher compression rate based on the priority assigned to stored image data FIG. It is the figure which showed the table. It is the figure which showed the state which performed the averaging process with respect to image data. It is the flowchart which showed the processing content until it acquires the image data preserve | saved at the area | region for preservation | save, and outputs it to an image synthetic | combination part.

Explanation of symbols

11a, 11b ... tuners 13a, 13b ... switch circuits 20a, 20b ... RGB signal generators 21a, 21b ... A / D conversion circuits 22a, 22b ... Y / C separation circuits 23a, 23b ... image quality adjustment circuits 24a, 24b ... color demodulation Circuits 25a, 25b ... Matrix circuit 30 ... Image composition unit 31 ... Pixel number conversion circuit 32 ... Image composition circuit 33 ... Memory 40 ... Liquid crystal module 41 ... Liquid crystal drive circuit 42 ... Liquid crystal panel 43 ... Backlight 50 ... Microcomputer 51 ... CPU
52 ... ROM
53 ... RAM
54 ... Operation panel 55 ... Remote control I / F
60 ... Still image storage memory 61 ... Temporary recording area 62 ... Storage area 80 ... Table 100 ... Television

Claims (9)

Among the image data relating to each screen constituting the image display performed by the image display means based on the image data obtained from the television broadcast signal input by the television broadcast signal input means, the image data relating to an arbitrary screen On the other hand, by performing a predetermined compression process, it is possible to store image data for a plurality of screens in a fixed-capacity memory, and from a still image based on the image data stored in the memory and the input television broadcast signal. In a television that can display an image based on the obtained image data on one screen by the image display means,
Image data recording means for temporarily recording the image data applied to each screen constituting the image display sequentially in the temporary recording area of the memory;
A selection capable of selecting image data to be saved from among the image data temporarily recorded by the image data recording means and assigning a priority according to the importance of the image data to the selected image data Means,
When storing the image data selected by the selection means, if there is no unused area necessary for storing the image data at a predetermined resolution in the storage area of the memory, the storage area For other image data that has already been stored in the image data, the order of storage is the compression processing that thins out pixels at a lower extraction rate as the previous image data, or when the above priority is stored together with each image data Image data compression means for performing compression processing for thinning out pixels at a lower extraction rate for image data having a lower priority based on the same priority;
If an unused area necessary for storing the image data selected by the selection means at a predetermined resolution is secured in the storage area by the compression processing performed by the image data compression means, the image data is stored in the storage area. If the unused area necessary for storing the image data at a predetermined resolution is not secured by the compression process, the image data that has been compressed at a high compression rate is stored in the storage area. Image data for erasing sequentially and securing the unused area necessary for storing the image data selected by the selection means at a predetermined resolution in the storage area and storing the image data in the storage area And a storage means. A television broadcast signal input means for inputting a television broadcast signal;
Selecting means for selecting image data to be stored among the image data obtained from the television broadcast signal;
When saving the image data selected by the selection means, if there is no unused area necessary for saving the image data at a predetermined resolution in a specific memory, the image data is already saved in the memory. Image data compression means for determining the compression rate of each image data with respect to the other image data and performing compression processing;
Image data storage means for storing the image data selected by the selection means in the memory in which the unused area is expanded by the compression processing performed by the image data compression means;
Image display means capable of displaying a still image based on the image data stored in the memory and an image based on the image data obtained from the input television broadcast signal on one screen. TV. 3. The image data compression unit performs compression processing at a higher compression rate as the image data stored in the earlier image data is stored in the other image data already stored in the memory. Television. When selecting the image data to be stored, the selection unit attaches a priority according to the importance of the image data to the selected image data,
The image data compression means is characterized in that among other image data already stored in the memory, the lower priority image data stored with each image data is compressed at a higher compression rate. The television according to claim 2. The image data compression means determines an extraction rate when changing the compression rate of other image data already stored in the memory, and performs compression processing by performing pixel thinning processing based on the extraction rate The television according to any one of claims 2 to 4, wherein The image data storage means reserves an unused area necessary for storing the image data selected by the selection means at a predetermined resolution in the memory even if the compression processing by the image data compression means is performed. If this is not possible, the image data that has been compressed at a high compression rate is sequentially deleted, and an unused area necessary for storing the image data selected by the selection means at a predetermined resolution is secured in the memory. The television according to any one of claims 2 to 5, wherein: The image data storage means deletes image data whose compression rate has exceeded a predetermined threshold as a result of the compression processing by the image data compression means from among the image data stored in the memory. The television according to any one of claims 2 to 5, characterized in that The image data interpolating means performs an interpolation process on the compressed image data stored in the memory, and a still image is displayed based on the image data subjected to the interpolation process. The television according to any one of claims 2 to 7. A television signal input process for inputting a television broadcast signal;
A selection step of selecting image data to be stored among the image data obtained from the television broadcast signal;
When saving the image data selected in the selection step, if there is no unused area necessary for saving the image data at a predetermined resolution in a specific memory, the image data is already saved in the memory. An image data compression process for determining the compression rate of each image data with respect to the other image data and performing compression processing;
An image data storage step for storing the image data selected in the selection step in the memory in which an unused area is expanded by the compression processing in the image data compression step;
An image display step of displaying, on a single screen, a still image based on the image data stored in the memory and an image based on the image data obtained from the input television broadcast signal. Image data storage and playback method.

Images