JP4280363B2 - Image processing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to, for example, an image processing apparatus having an image recording and reproducing function, and in particular, an apparatus or system having a function of displaying an image on a display unit such as a viewfinder.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, a digital video camera (DVC) or the like is well known as a camera-integrated recording / reproducing apparatus that captures a subject and records and reproduces a moving image obtained thereby.
The DVC is generally provided with a viewfinder for displaying an image being photographed in real time, so that the user can shoot while confirming the image displayed on the viewfinder. Can be performed.
[0003]
Further, as represented by the above-described DVC, in a digital image recording apparatus that digitizes and records image data obtained by photographing or the like, in order to reduce the amount of image data (input image) to be recorded. The input image data is recorded after being encoded and compressed by an encoder. At this time, various compression methods are used. As a highly efficient compression method, a JPEG method for still images, an MPEG method for moving images, and the like are often used as standard methods.
[0004]
[Problems to be solved by the invention]
However, when the input image (original image) is recorded after being compressed, the reproduced image is deteriorated in image quality as compared with the original image.
For this reason, for example, when shooting is performed with the DVC as described above, images (original images) displayed on the viewfinder during shooting are sequentially compressed and recorded. In some cases, a large difference in image quality may occur between the image that is confirmed by the viewfinder at the time of shooting and the image that is reproduced. This can be frustrating for the user.
In particular, there is a DVC that can variably set the compression rate of a recorded image. In such a DVC, for example, when shooting is performed with a setting that prioritizes the recording time by increasing the compression rate, the image quality that the user has imaged is set. The above-mentioned problem appears remarkably, for example, the image may be recorded in a low image quality state different from the above.
[0005]
Therefore, the present invention has been made to eliminate the above-described drawbacks, and an object thereof is to provide an image processing apparatus that can reliably and easily record an image in a state desired by a user.
[0006]
[Means for Solving the Problems]
Under such a purpose, in the present invention, for example, in the shooting mode of the camera-integrated recording / playback device, the image quality display equivalent to the playback image has already been performed and the user confirms this, thereby grasping the image quality during playback. Configure as you can. That is, in order to confirm the deterioration of the image quality caused by the compression process, the input image (original image) is once encoded, further decoded, and displayed on the display unit.
[0007]
Specifically, with respect to a camera-integrated recording / playback apparatus that employs MPEG as an encoding method, an image obtained by shooting is processed by a camera signal processing unit in a shooting mode, and this is then processed by an MPEG encoder. In parallel with the operation of encoding and recording on the recording medium, the image data encoded by the MPEG encoder is decoded using a decoding processing function existing in the process of the MPEG encoder and displayed on the display unit. As a display form at this time, an input image (original image) from the camera and an image obtained by encoding and decoding the original image are selectively or combined and displayed.
In addition, regarding a camera-integrated recording / playback apparatus that includes both an encoder and a decoder, in the shooting mode, the camera signal processing unit performs image processing on the captured image, and then encodes this with the encoder. In parallel with the operation of recording on the recording medium, the image encoded by the encoder is acquired by another path in the previous stage of the recording process, and the acquired encoded image is decoded by the decoder and displayed on the display unit. indicate. As a display form at this time, an input image (original image) from the camera and an image obtained by encoding and decoding the original image are selectively or combined and displayed.
[0008]
That is, the first invention is encoding means for encoding the original image data by performing at least orthogonal transformation and quantization processing on the original image data, and includes an image included in the original image data, Encoding means having a motion compensated prediction unit for performing motion compensation prediction with an already encoded and decoded image, and at least inverse quanta for the encoded image data generated by the encoding means And decoding means for decoding the encoded image data and generating a local decoded image used in the motion compensated prediction unit, and a source included in the original image data At least the original image data is delayed in order to adjust the time delay from the original image until the image is generated as the local decoded image by the decoding means. Delaying means, combining the original image data adjusted in timing by the delaying means and the data of the local decoded image, and combining the images so that the images are displayed side by side on the same screen, And supplying means for supplying the display unit with the image data synthesized by the synthesizing means.
[0011]
According to a second aspect, in the first aspect, the information processing apparatus further includes selection means capable of selecting a mode for variably setting a quantization step and a mode for fixed setting in the quantization processing performed by the encoding means. Features.
[0012]
According to a third aspect of the present invention, in the first or second aspect of the present invention, an image capturing unit that captures an image of a subject and generates the original image data, and the original image data generated by the image capturing unit includes the encoding unit and the decoding unit. And recording means for recording the encoded image data subjected to image processing by operating the means on a recording medium.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0034]
(First embodiment)
The present invention is applied to, for example, an image recording / reproducing apparatus having an image recording unit 100 as shown in FIG.
The image recording unit 100 according to the present embodiment can check the image quality of the recorded image with almost the same image quality as that when the recorded image is reproduced, particularly when the input image is compressed and recorded. Yes.
[0035]
Here, FIG. 2 shows an image recording unit 500 of a general image recording / reproducing apparatus.
As shown in FIGS. 1 and 2, the image recording unit 100 according to the present embodiment performs image recording while changing the compression rate in order to give priority to time in addition to the general configuration of the image recording unit 500. Fixed quantization table 119 and switch 118 for switching between a mode to be performed (hereinafter referred to as “variable compression rate mode”) and a mode in which image recording is performed with priority on image quality (hereinafter referred to as “image quality priority mode”). And a switch 120 for switching and displaying an original image and an image (a “local decoded image” described later) decoded after the original image is compressed, and a digital / analog converter (D / A converter) 121, a display unit 122, and a display image external output terminal 123.
[0036]
In the image recording unit 100 shown in FIG. 1, components different from the configuration of the general image recording unit 500 shown in FIG. 2 are indicated by dotted lines. The compression method used here is, for example, the MPEG method.
[0037]
That is, the image recording unit 100 according to the present embodiment includes an imaging system 101 including a camera unit such as a lens and a CCD, an A / D converter 102, a camera signal processing circuit 103, and a screen rearrangement circuit as shown in FIG. 104, switch 105, subtractor 106, DCT (orthogonal transformation) circuit 107, quantization circuit 108, variable length coding circuit 109, inverse quantization circuit 110, IDCT (inverse orthogonal transformation) circuit 111, adder 112, motion compensation In addition to the prediction circuit 113, the switch 114, the buffer 115, the rate control circuit 116, and the recording medium 117, the fixed quantization table 119, the switch 118, the switch 120, the digital / analog converter (D / A converter) 121, and the display unit 122, a display image external output terminal 123, and a memory 124.
The operation of each component including the switches 105, 114, 118, and 120, the rate control circuit 116, and the variable length coding circuit 109 is controlled by a system controller (not shown). ing. In other words, this system controller controls the operation of the entire apparatus, and controls the operation of the entire apparatus in accordance with a user instruction as required from an operation unit (not shown).
Hereinafter, the image recording unit 100 in the present embodiment will be specifically described.
[0038]
[A series of operations from image encoding to recording]
[0039]
An image signal obtained by imaging with the imaging system 101 is digitally converted by the A / D converter 102 and input to the camera signal processing circuit 103.
[0040]
The camera signal processing circuit 103 determines a correction value based on the input image data, separates the input image data corrected according to the correction value into color difference data and luminance data, and supplies the data to the screen rearrangement circuit 104 in units of one frame. To do.
[0041]
The screen rearrangement circuit 104 includes a memory (not shown) capable of storing a plurality of frames of image data, and the frame order of the image data for each frame from the camera signal processing circuit 103 is switched to this memory. Store and output in that order.
[0042]
Specifically, for example, as shown in FIG. 3, image data is input to the screen rearrangement circuit 104 in the order of the first frame, the second frame, the third frame,. The screen rearrangement circuit 104 changes the frame order of the input image data (screen rearrangement), and outputs the image data in the order of the third frame, the first frame, the second frame,. .
Such screen rearrangement by the screen rearrangement circuit 104 is a process necessary for performing intra coding and inter coding as shown in FIG.
The “intra coding” described above is coding using only image data in a frame, and is coding for generating the I picture shown in FIG. On the other hand, the above “inter-coding” is coding including inter-frame prediction, and is coding for generating the P and B pictures shown in FIG.
[0043]
Hereinafter, the operation from the image rearrangement circuit 104 will be described separately for the case of intra coding and the case of inter coding.
[0044]
In the case of intra coding, the switch 105 provided at the subsequent stage of the screen rearrangement circuit 104 is switched to the A side (terminal side that outputs data from the screen rearrangement circuit 104).
As a result, the image data whose screen has been rearranged by the screen rearrangement circuit 104 is input to the DCT circuit 107 via the switch 105.
[0045]
The DCT circuit 107 orthogonally transforms the input image data and supplies it to the quantization circuit 108.
The quantization circuit 108 quantizes the image data after orthogonal transformation from the DCT circuit 107 and supplies the quantized image data to the inverse quantization circuit 110 and the variable length coding circuit 109, respectively.
[0046]
The inverse quantization circuit 110 performs inverse quantization on the quantized image data from the quantization circuit 108 to restore the image data before quantization (image data after orthogonal transformation), and supplies it to the IDCT circuit 111. To do.
The IDCT circuit 111 performs inverse orthogonal transform on the image data from the inverse quantization circuit 110 to restore the image data before the orthogonal transform.
[0047]
At this time, since the switch 114 is in an OFF state, that is, the adder 112 that is the output destination of the switch 114 is not functioning, the image data obtained by the IDCT circuit 111 is used as it is as a motion compensation prediction circuit. 113.
[0048]
Here, the image data whose screen has been rearranged by the screen rearrangement circuit 104 is also supplied to the motion compensation prediction circuit 113.
For this reason, the motion compensation prediction circuit 113 is in a state where the output of the screen rearrangement circuit 104 and the output of the IDCT circuit 111 are supplied.
[0049]
The motion compensation prediction circuit 113 generates predicted image data for the next inter coding from the image data from the screen rearrangement circuit 104 and the image data from the IDCT circuit 111.
[0050]
The variable length encoding circuit 109 performs variable length encoding on the quantized image data from the quantization circuit 108 and supplies the variable length encoded image data to the buffer 115.
The image data in the buffer 115 is recorded on the recording medium 117.
[0051]
On the other hand, in the case of inter coding, the switch 105 provided in the subsequent stage of the screen rearrangement circuit 104 is switched to the B side (the terminal side that outputs data from a subtractor 106 described later).
As a result, the subtractor 106 performs subtraction between the image data whose screen has been rearranged by the screen rearrangement circuit 104 and the predicted image data obtained by the motion compensation prediction circuit 113 described above. The subtraction result, that is, the image data from which the redundancy in the time axis direction is reduced is supplied to the DCT circuit 107 via the switch 105.
[0052]
The DCT circuit 107 orthogonally transforms the image data whose redundancy in the time axis direction is reduced by the subtractor 106 and supplies the image data to the quantization circuit 108.
The quantization circuit 108 quantizes the image data after orthogonal transformation from the DCT circuit 107 and supplies the quantized image data to the inverse quantization circuit 110 and the variable length coding circuit 109, respectively.
[0053]
The inverse quantization circuit 110 performs inverse quantization on the quantized image data from the quantization circuit 108 to restore the image data before quantization (image data after orthogonal transformation), and supplies it to the IDCT circuit 111. To do.
The IDCT circuit 111 performs inverse orthogonal transform on the image data from the inverse quantization circuit 110 to restore the image data before the orthogonal transform.
[0054]
At this time, when the switch 114 is turned off, that is, when the adder 112 at the output destination of the switch 114 is not functioning, the image data obtained by the IDCT circuit 111 is directly subjected to motion compensation prediction. This is supplied to the circuit 113. The image data whose screen has been rearranged by the screen rearrangement circuit 104 is also supplied to the motion compensation prediction circuit 113.
In such a state, the motion compensation prediction circuit 113 generates predicted image data for the next inter coding from the image data from the screen rearrangement circuit 104 and the image data from the IDCT circuit 111.
[0055]
Also , Su When the switch 114 is turned on, that is, when the adder 112 that is the output destination of the switch 114 is in a functioning state, the adder 112 performs the prediction image data generated by the motion compensation prediction circuit 113 and the IDCT. Addition with the image data obtained by the circuit 111 is performed. The addition result in the adder 112 is supplied as decoded image data to the motion compensation prediction circuit 113 for the next encoding.
[0056]
The motion compensation prediction circuit 113 generates prediction image data for the next inter coding from the decoded image data from the adder 112 and the image data from the screen rearrangement circuit 104, and detects a motion vector. .
[0057]
The variable-length encoding circuit 109 performs variable-length encoding on the quantized image data from the quantization circuit 108 based on the motion vector detected by the motion compensation prediction circuit 113, and the variable-length encoded image Data is supplied to the buffer 115.
The image data in the buffer 115 is recorded on the recording medium 117.
[0058]
[Quantization control according to the recording rate of the buffer 115]
[0059]
In general (see FIG. 2 above), the rate control circuit 116 recognizes the capacity of the buffer 115, and when the capacity is smaller than the target capacity, controls the quantization circuit 108 so that the next quantization is performed roughly. When the capacity is equal to or larger than the target capacity, the recording rate of the buffer 115 is set between one picture by controlling the quantization circuit 108 so as to perform normal quantization given as an initial value in advance. Almost constant.
At this time, if the movement of the input image is fast or the color band is wide, the quantization in the quantization circuit 108 is roughly performed by the control for keeping the recording rate constant in the rate control circuit 116. Become.
[0060]
Therefore, the control of the quantization circuit 108 by the rate control circuit 116 here (see FIG. 1 above) is performed via the switch 118.
[0061]
Specifically, first, the switch 118 includes a variable compression ratio mode (a mode in which image recording is performed while changing the compression ratio for time priority) and an image quality priority mode (a mode in which image recording is performed with priority on image quality). ) To switch the output from the A side (fixed quantization table 119 side) or the B side (rate control circuit 116 side) to the quantization circuit 108 depending on which mode is set. It is made like that.
[0062]
For example, when the compression rate variable mode is set, the switch 118 is switched to the B side.
As a result, the rate control circuit 116 recognizes the capacity of the buffer 115, and if the capacity is smaller than the target capacity, the rate control circuit 116 controls the quantization circuit 108 so that the next quantization is roughly performed, and the capacity is set to the target capacity. In the case of capacity or more, the recording rate of the buffer 115 becomes almost constant between pictures by controlling the quantization circuit 108 so as to perform normal quantization given as an initial value in advance. Perform such control. As a result, the image data is encoded according to the target time, and the image data is recorded on the recording medium 117. At this time, it is possible to lengthen the target time, but the compression rate in this case inevitably increases.
[0063]
On the other hand, when the image quality priority mode is set, the switch 118 is switched to the A side.
As a result, the quantization circuit 108 does not perform quantization according to the control in the compression rate variable mode described above from the rate control circuit 116, but performs quantization using information in the fixed quantization table 119. That is, the quantization circuit 108 reads the quantization table from the fixed quantization table 119 and performs quantization based on the read quantization table 119 so as to keep the image quality of the image data to be processed constant.
The fixed quantization table 119 includes, for example, two quantization tables for intra coding and other frame coding, and the quantization circuit 108 switches between these quantization tables as appropriate.
In such an image quality priority mode, when the input image moves fast or the color band is wide, the recording rate is high, but encoding without change in image quality can be realized. Further, when the movement of the input image is slow or the color band is narrow, the recording rate is low.
[0064]
[Configuration to make it possible to check recorded images]
[0065]
The most characteristic configuration of the present embodiment is that, as described above, when an input image is compressed and recorded, the image quality of the recorded image can be confirmed with almost the same image quality as that when the recorded image is reproduced. In the configuration.
For this reason, the image recording unit 100 operates as follows.
[0066]
First, the output of the IDCT circuit 111, that is, the input image is compressed by the DCT circuit 107 and the quantization circuit 108, and the compressed image (compressed image) is the inverse quantization circuit 110, the IDCT circuit 111, and the adder. The image (local decoded image) decoded by 112 is supplied to the display unit 122 via the memory 124, the switch 120, and the D / A converter 121 in this order.
Note that the memory 124 is used to make a blocked image a frame image.
[0067]
As described above, the compressed image is decoded by the DCT circuit 107 and the quantization circuit 108 by the inverse quantization circuit 110, the IDCT circuit 111, and the adder 112 corresponding to the DCT circuit 107 and the quantization circuit 108, respectively. By acquiring an image that has been converted back to a usable image, it is almost the same as a compressed-decompressed (encoded-decoded) image, that is, a reproduced image of a recorded image (hereinafter referred to as a “local decoded image”). The image quality of the recorded image can be confirmed with the image quality.
[0068]
Here, the output (original image) of the camera signal processing circuit 103 is also supplied to the display unit 122 via the switch 120 and the D / A converter 121 in order.
Thereby, the local decoded image and the original image can be compared on the display unit 122.
[0069]
To describe the above configuration more specifically, the output (original image) of the camera signal processing circuit 103 and the output (local decoded image) of the adder 112 are supplied to the switch 120.
The switch 120 selectively outputs the output (original image) of the camera signal processing circuit 103 and the output (local decoded image) of the adder 112 in accordance with the control from the system controller described above.
The image (digital image) output from the switch 120 is converted into an analog signal by the D / A converter 121, returned to an image signal, and displayed on the display unit 122. As a result, the user can confirm the recorded image with substantially the same image quality as the reproduced image of the recorded image.
At this time, the image selected by the switch 120 is externally output from the display image external output terminal 123 (digital interface: terminal such as DIF). This makes it possible to transmit the image data and display it on an external device such as a high-definition monitor.
[0070]
The display of the locally decoded image on the display unit 122 as described above can be executed, for example, during recording of a captured image in the shooting mode or during recording standby.
In addition, after the user confirms the image quality of the local decoded image (recorded image) on the display unit 122, the user can reset the compression rate variable mode or the image quality priority mode by an operation unit (not shown), thereby performing desired compression. It is also possible to change the rate. In this case, according to this instruction, the rate control circuit 116 performs the quantization control as described above again.
[0071]
As described above, in the present embodiment, the local decoded image is acquired from the function of the MPEG encoder and displayed on the display unit 122, so that the recorded image can be recorded without complicating the circuit configuration. Thus, it is possible to confirm with substantially the same image quality as that of the reproduced image of the recorded image.
[0072]
(Second Embodiment)
In the first embodiment described above, the original image and the local decoded image are switched and displayed on the display unit 122. However, in the present embodiment, the original image and the local decoded image are combined. The displayed composite image is displayed on the display unit 122.
For this reason, as shown in FIG. 5, the image recording unit 100 according to the present embodiment replaces the switch 120 of the image recording unit 100 according to the first embodiment described above (see FIG. 1 above). 125 and a FIFO memory 124 for delaying the original image for a predetermined time.
In the image recording unit 100 in FIG. 5, the same reference numerals are given to the portions that operate in the same manner as the image recording unit in FIG. 1, and detailed description thereof is omitted.
[0073]
In the image recording unit 100 in the present embodiment as shown in FIG. 5 described above, the output (original image) of the camera signal processing circuit 103 is supplied to the FIFO circuit 124.
The FIFO circuit 124 supplies the output (original image) of the camera signal processing circuit 103 to the image composition circuit 125 after a predetermined time delay. This is because the local decoded image supplied from the adder 112 to the image composition circuit 125 is delayed from the original image by the time required for image processing in each circuit after being captured. As a result, the timing of the original image and the local decoded image is taken, and the image composition by the image composition circuit 125 is performed.
The FIFO circuit 124 is not an essential configuration in the present embodiment, and there is no problem even if the FIFO circuit 124 is not provided.
[0074]
The image synthesizing circuit 125 synthesizes the original image via the FIFO circuit 124 and the local decoded image from the adder 112 to generate a synthesized image.
The composite image obtained by the image composition circuit 125 is supplied to the display unit 122 via the D / A converter 121 and displayed on the display unit 122.
[0075]
6 and 7 show an example of a display screen on the display unit 122, that is, a composite image generated by the image composition circuit 125.
In FIG. 6, the original image and the local decode image are combined by thinning them to a predetermined size, and a composite image that can be displayed and compared as a recording image quality confirmation mode is displayed. It is an example of a case.
FIG. 7 shows an example in which an original image is displayed in a normal size, and a local decoded image (recorded image) that has been subjected to thinning processing is combined with a small screen on the screen (large screen). Note that the local decoded image may be displayed on the large screen, and the original image may be displayed on the small screen. By displaying such a composite image on the display unit 122, the user can easily confirm the image quality of the recorded image by comparing it with the image quality of the original image.
[0076]
(Third embodiment)
In the first and second embodiments described above, the present invention is applied to an image recording / reproducing apparatus using the MPEG system as an encoding system, and a local decoded image is acquired and displayed from the function of the MPEG encoder. However, in the present embodiment, when an arbitrary method is used as an encoding method and the present invention is applied to an image recording / reproducing apparatus in which an encoder and a decoder are individually provided, and an input image is compressed and recorded, A configuration is realized in which the image quality of the recorded image can be confirmed with almost the same image quality as that when the recorded image is reproduced.
[0077]
For this reason, the image recording unit of the image recording / reproducing apparatus in the present embodiment is configured as shown in FIG. 8, for example.
That is, the image recording unit 200 according to the present embodiment includes an imaging system 201 including a lens and a CCD, an A / D converter 202, a camera signal processing circuit 203, and an encoder that encodes an original image using a predetermined compression method. 204, a recording processing circuit 205 for performing recording processing on the encoded image, a recording medium 206, a reproduction processing circuit 207 for performing reproduction processing of the recorded image, and decoding of the image by a decoding method corresponding to the compression method of the encoder 204 A decoder 208, a switch 209, a D / A converter 210, a display unit 211 such as a liquid crystal display, a display image external output terminal 212, a system controller 213 for controlling the operation of the entire apparatus, and an operation instruction input unit 214. Yes.
Hereinafter, the image recording unit 200 in the present embodiment will be specifically described.
[0078]
[A series of operations from image encoding to recording]
[0079]
First, an image signal obtained by photographing with the imaging system 201 is digitized by an A / D converter 202 and supplied to a camera signal processing circuit 203.
The camera signal processing circuit 203 performs adjustment processing of luminance and color of image data from the A / D converter 202. The image data processed by the camera signal processing circuit 203 is supplied to the encoder 204.
[0080]
The encoder 204 encodes the image data from the camera signal processing circuit 203 based on a predetermined signature algorithm. As the compression method here, for example, a DV compression method adopted as a band signature method in home digital video, other standard image compression methods such as JPEG, or a device-specific image compression method, etc. Such a compression method can also be adopted.
The image data compressed by the encoder 204 is supplied to the recording processing circuit 205.
[0081]
The recording processing circuit 205 converts the image data from the encoder 204 into a format suitable for recording (format conversion), and then uses a recording head (not shown) to record the recording medium 206 such as a disk-shaped recording medium. Are recorded in a predetermined area.
[0082]
When the image recorded on the recording medium 206 is reproduced as described above, the recorded image on the recording medium 206 is read by a reproducing head (not shown). The read recorded image data is supplied to the reproduction processing circuit 207.
The reproduction processing circuit 207 performs a conversion process for returning the recording image data read by the reproduction head to the data before the format conversion in the recording processing circuit 205. The processed image data is supplied to the decoder 208.
[0083]
The decoder 208 decompresses the image data from the reproduction processing circuit 207, that is, the compressed image data by a method corresponding to the compression method in the encoder 204. The image data expanded in this way is displayed on the display unit 211 via a switch 209 and a D / A converter 210 which will be described later.
Further, the image data output from the D / A converter 210 is also supplied to the display image external output 212. This makes it possible to transmit the image data, and an external device such as a high-definition monitor. Display with is also possible.
[0084]
[Configuration to make it possible to check recorded images]
[0085]
As in the first and second embodiments described above, the most characteristic configuration of the present embodiment is substantially the same as the image when the recorded image is reproduced when the input image is compressed and recorded. The image quality of the recorded image can be confirmed with the image quality of.
Therefore, the image recording unit 200 is configured to execute the following configuration and operation.
[0086]
First, in order to realize image quality comparison between an original image and an image (local decoded image) that has been compressed → expanded (encoded → decoded), the image recording unit 200 directly connects the encoder 204 and the decoder 208. As a result, the compressed image data obtained by the encoder 204 is supplied to the recording processing circuit 205 and simultaneously to the decoder 208. The decoder 208 decompresses the image data from the encoder 201.
As described above, the image recording unit 200 directly connects the encoder 204 and the decoder 208 to immediately expand the compressed image data and acquire a local decoded image. This local decoded image (an image having substantially the same image quality as the reproduced image of the recorded image) is acquired in real time in parallel with the original image.
[0087]
The local decoded image obtained as described above is supplied to the switch 209.
[0088]
The switch 209 selectively outputs the output (original image) of the camera signal processing circuit 203 and the output (local decoded image) of the decoder 208 in accordance with control from the system controller 213.
An image (digital image) output from the switch 209 is converted into an analog signal by the D / A converter 210, converted back to an image signal, and displayed on the display unit 211. As a result, the user can confirm the recorded image with substantially the same image quality as the reproduced image of the recorded image.
[0089]
The display of the local decoded image on the display unit 211 as described above can be executed, for example, during recording of a captured image in the shooting mode or during recording standby.
[0090]
Even with the above-described configuration, the recorded image can be confirmed with substantially the same image quality as the reproduced image of the recorded image. That is, the present invention is not limited to an image recording / reproducing apparatus using the MPEG system, but can be applied to any image recording / reproducing apparatus using an arbitrary encoding system.
[0091]
In the third embodiment described above, a configuration such as the image composition circuit 125 in the second embodiment may be provided instead of the switch 209. As a result, a synthesized image obtained by synthesizing the original image and the local decoded image can be displayed on the display unit 211, and the user can easily compare the image quality of the original image with the image quality of the recorded image.
[0092]
In the third embodiment described above, the encoder 204 (and the corresponding decoder 208) uses a variable-length encoding scheme according to the compression rate specified by the user through the operation unit 214 (encoding rate). In the same manner as in the first and second embodiments, after the user confirms the image quality of the local decoded image (recorded image) on the display unit 211, the operation unit 214 compresses the image. It is also possible to change to a desired compression rate by resetting the rate variable mode or the image quality priority mode. In this case, the system controller 213 controls the compression rate in the encoder 204 in accordance with an instruction from the operation unit 214.
[0093]
Another object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the host and terminal of each of the above-described embodiments to a system or apparatus, and the computer (or CPU) of the system or apparatus. Needless to say, this can also be achieved by reading and executing the program code stored in the storage medium.
In this case, the program code itself read from the storage medium implements the functions of the respective embodiments, and the storage medium storing the program code constitutes the present invention.
A ROM, floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, or the like can be used as a storage medium for supplying the program code.
Further, by executing the program code read by the computer, not only the functions of the respective embodiments are realized, but also the OS or the like running on the computer based on the instruction of the program code performs the actual processing. It goes without saying that a case where the functions of the respective embodiments are realized by performing part or all of the above and the processing thereof is included.
Further, after the program code read from the storage medium is written to the memory provided in the extension function board inserted in the computer or the function extension unit connected to the computer, the function extension is performed based on the instruction of the program code. It goes without saying that the case where the CPU or the like provided in the board or function expansion unit performs part or all of the actual processing and the functions of the respective embodiments are realized by the processing.
[0094]
【The invention's effect】
As described above, in the present invention, since the original image and the image restored after encoding the original image are displayed side by side, the image quality before and after encoding of the original image can be compared. .
[0095]
Therefore, according to the present invention, it is possible to reliably and easily record an image in a state desired by the user.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an image recording unit of an image recording / reproducing apparatus to which the present invention is applied in the first embodiment.
FIG. 2 is a diagram for explaining an encoding method (MPEG method) used in the image recording unit.
FIG. 3 is a diagram for explaining processing in an image rearrangement circuit of the image recording unit in the first embodiment.
FIG. 4 is a diagram for explaining the encoding order.
FIG. 5 is a block diagram showing a configuration of the image recording unit in the second embodiment.
FIG. 6 is a diagram for explaining an example (Example 1) of a display screen on the display unit of the image recording unit.
FIG. 7 is a diagram for explaining an example (Example 2) of a display screen on the display unit of the image recording unit.
FIG. 8 is a block diagram showing a configuration of an image recording unit of an image recording / reproducing apparatus to which the present invention is applied in the third embodiment.
[Explanation of symbols]
100 Image recording unit
101 Imaging system
102 A / D converter
103 Camera signal processing circuit
104 Image rearrangement circuit
105 switches
106 Subtractor
107 DCT circuit
108 Quantization circuit
109 Variable length coding circuit
110 Inverse quantization circuit
111 IDCT circuit
112 Adder
113 Motion Compensation Prediction Circuit
114 switch
115 buffers
116 Rate control circuit
117 recording media
118 switch
119 Fixed quantization table
120 switches
121 D / A converter
122 Display section
123 Display image output terminal
124 memory

Claims (3)

Encoding means for encoding the original image data by performing at least orthogonal transformation and quantization processing on the original image data, and the image included in the original image data is already encoded and decoded. Encoding means having a motion compensated prediction unit for performing motion compensated prediction between the image and
The encoded image data generated by the encoding means is subjected to at least inverse quantization processing and inverse orthogonal transform to decode the encoded image data and used in the motion compensation prediction unit. Decoding means for generating a local decoded image;
Delay means for delaying at least the original image data in order to adjust a time delay from the original image until the original image included in the original image data is generated as the local decoded image by the decoding means;
A synthesizing unit that inputs the original image data whose timing is adjusted by the delay unit and the data of the local decoded image, and synthesizes the images so as to be displayed side by side on the same screen;
Supply means for supplying image data combined by the combining means to a display unit;
An image processing apparatus comprising:   The image processing apparatus according to claim 1, further comprising a selection unit capable of selecting a mode for variably setting a quantization step in a quantization process performed by the encoding unit and a mode for fixed setting. Imaging means for imaging a subject and generating the original image data;
Recording means for recording on the recording medium the encoded image data obtained by operating the encoding means and the decoding means on the original image data generated by the imaging means;
The image processing apparatus according to claim 1, further comprising:

Images