JP2008245237A - Image processing method and device, and image device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that image quality is deteriorated when suppressing the amount of codes. <P>SOLUTION: A correlation evaluation section 72 evaluates a correlation between a predetermined region in a target picture and a region, corresponding to a picture region different in the time direction from the target picture. A quantization control section 80 changes a quantization process to a predetermined region in the target picture adaptively in accordance with the evaluation, obtained by the correlation evaluation section 72. For an example, if the correlation is determined to be weaker than a predetermined threshold from an evaluation value obtained by the correlation evaluation section 72, the quantization step for quantizing the predetermined region is expanded. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image processing method for encoding a moving image, an image processing apparatus, and an imaging apparatus using the same.

  Digital video cameras are becoming popular. In general, a moving image captured by a digital video camera is recorded in a moving picture experts group (MPEG) format. A digital video camera that employs a recording method such as the MPEG format quantizes a captured image and then compresses and encodes the image. Quantization is a process that affects image quality and code amount. When the quantization step is increased, the code amount can be reduced, but the image quality is deteriorated. Conversely, if the quantization step is reduced, recording can be performed with high image quality, but the code amount increases.

In general, the quantization step is determined based on the buffer occupancy and the macroblock code amount.
JP-A-8-181992

  However, if the quantization step is simply determined based on the buffer occupancy etc., the code amount in the area that the viewer is paying attention to is reduced. A large amount of code may be assigned to an area where the image quality is not improved.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an image processing method, an image processing apparatus, and an imaging apparatus using the same, which can improve subjective image quality while suppressing the amount of codes. It is in.

 An image processing method according to an aspect of the present invention evaluates a correlation between a predetermined region in a target picture and a region corresponding to a region of a picture that differs from the target picture in the temporal direction, and The contents of processing are adaptively changed.

  According to the present invention, it is possible to improve the subjective image quality while suppressing the code amount.

  First, before describing the embodiments of the present invention in detail, typical embodiments will be described. An image processing method according to an aspect of the present invention evaluates a correlation between a predetermined region in a target picture and a region corresponding to a region of a picture that differs from the target picture in the temporal direction, and The contents of processing are adaptively changed. “Picture” is a unit of encoding, and the concept may include a frame, a field, a VOP (Video Object Plane), and the like. The “predetermined area” may be a macro block. The “pictures that differ in the time direction” may be past pictures or future pictures.

  According to this aspect, by encoding the predetermined area in the target picture with reference to the correlation between the predetermined area in the target picture and the corresponding area of the picture that differs from the target picture in the temporal direction, Different encoding processes can be performed for each, and encoding that improves subjective image quality while suppressing the amount of codes is also possible.

  Another embodiment of the present invention is also an image processing apparatus. According to the evaluation obtained by the correlation evaluation unit, a correlation evaluation unit that evaluates a correlation between a predetermined region in the target picture and a region corresponding to the region of the picture that differs from the picture in the temporal direction, A quantization control unit that adaptively controls quantization processing on a predetermined region in the target picture.

  According to this aspect, by referring to the correlation between a predetermined area in the target picture and the corresponding area of the picture that differs from the picture in the temporal direction, the amount of code can be changed by adaptively changing the quantization processing parameter. The subjective image quality can be improved while suppressing the above.

  When it is determined that the correlation is weaker than the predetermined threshold based on the evaluation value obtained by the correlation evaluation unit, the quantization control unit may expand the quantization step when the predetermined region is quantized. According to this, in a region where it is determined that the subjective image quality is not significantly reduced even if the code amount is reduced, the code amount can be reduced by expanding the quantization step.

  The quantization control unit may reduce the quantization step when the predetermined region is quantized when the correlation is determined to be stronger than the predetermined threshold based on the evaluation value obtained by the correlation evaluation unit. According to this, it is possible to improve the image quality by reducing the quantization step in an area that is determined as an area that is easily noticed by the viewer.

  If the correlation is determined to be weaker than a predetermined threshold based on the evaluation value obtained by the correlation evaluation unit, the quantization control unit may round off the fraction generated in the division process when quantizing the predetermined region. . According to this, in an area where it is determined that the subjective image quality is not significantly reduced even if the code amount is reduced, the image quality can be improved by rounding down the fraction generated in the division process at the time of quantization.

  The quantization control unit may round off the fraction generated in the division process when quantizing a predetermined region when the correlation is determined to be stronger than the predetermined threshold based on the evaluation value obtained by the correlation evaluation unit. Good. According to this, in a region where it is determined that the subjective image quality does not decrease so much even if the code amount is reduced, in a region where it is determined that the viewer is likely to focus attention, the fraction generated in the division process at the time of quantization is reduced. By rounding off, an image close to the original image can be recorded.

  Another embodiment of the present invention is also an image processing apparatus. This apparatus searches for a prediction area corresponding to a predetermined area in a target picture in a picture that differs in time direction from the target picture, and refers to an evaluation value of each prediction area candidate to determine a prediction area. And a quantization control unit that adaptively controls a quantization process for a predetermined region in the target picture using at least one of the evaluation values. “At least one of the evaluation values” may be an evaluation value of the prediction region determined by the motion detection unit.

  According to this aspect, the subjective image quality can be improved while suppressing the code amount by adaptively changing the quantization processing parameter using the evaluation value generated for searching the prediction region. . In addition, it is not necessary to separately calculate an evaluation value representing a correlation between pictures used for quantization processing, and the amount of calculation can be reduced.

  The motion detection unit may generate evaluation values for both the picture to be inter-coded and the picture to be intra-coded. By operating the motion detection unit also on the picture to be encoded within the picture, the evaluation value used for the quantization process can be generated regardless of the frame type.

  Another aspect of the present invention is an imaging apparatus. This apparatus includes an imaging device and the above-described image processing device, and the image processing device performs a quantization process on a picture captured from the imaging device.

  According to this aspect, it is possible to construct an imaging apparatus that can improve the subjective image quality while suppressing the code amount.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a configuration diagram of an imaging apparatus 500 according to the embodiment. The imaging device 500 includes the imaging unit 5 and the encoding device 100. The configuration of the encoding device 100 can be realized in hardware by a CPU, memory, or other LSI of an arbitrary computer, and is realized by a program having an image encoding function loaded in the memory in software. Here, however, the functional blocks realized by the cooperation are depicted. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  The imaging unit 5 includes an imaging element such as a CCD (Charge Coupled Devices) sensor or a CMOS (Complementary Metal-Oxide Semiconductor) image sensor, converts an image captured by the imaging element into an electrical signal, and encodes the encoded image as a moving image. Output to. The encoding apparatus 100 receives a moving image input in units of frames, encodes the moving image, and outputs an encoded stream CS.

  An encoding apparatus 100 according to the present embodiment includes MPEG series standards (MPEG-1, MPEG-2 and MPEG-) standardized by ISO (International Organization for Standardization) / IEC (International Electrotechnical Commission) which are international standardization organizations. 4) H.264 standardized by ITU-T (International Telecommunication Union-Telecommunication Standardization Sector) which is an international standard organization for telecommunications. 26x series standards (H.261, H.262 and H.263), or H.264, the latest video compression coding standard standardized jointly by both standards organizations. H.264 / AVC (official recommendation names in both organizations are MPEG-4 Part 10: Advanced Video Coding and H.264 respectively).

  In the MPEG series standard, an image frame for intra-frame encoding is an I (Intra) frame, an image frame for forward inter-frame predictive encoding with a past frame as a reference image, a P (Predictive) frame, and past and future An image frame that performs bidirectional inter-frame predictive coding using this frame as a reference image is referred to as a B frame.

  On the other hand, H. In H.264 / AVC, the frame that can be used as a reference image may be a past two frames as a reference image or a future two frames as a reference image regardless of the time. Further, three or more frames can be used as the reference image regardless of the number of frames that can be used as the reference image. Therefore, in MPEG-1 / 2/4, the B frame refers to a Bi-directional prediction frame. Note that in H.264 / AVC, the B frame refers to a bi-predictive prediction frame because the time of the reference image does not matter before and after.

In the specification of the present application, a frame and a picture are used in the same meaning, and an I frame, a P frame, and a B frame are also called an I picture, a P picture, and a B picture, respectively.
In this specification, a frame is used as an example of the encoding unit. However, the encoding unit may be a field. The unit of encoding may be a VOP in MPEG-4.

  The block generation unit 10 divides the input image frame into macro blocks. Macroblocks are formed in order from the upper left to the lower right of the image frame. The block generation unit 10 supplies the generated macroblock to the differentiator 12, the motion compensation unit 70, and the correlation evaluation unit 72.

  If the image frame supplied from the block generation unit 10 is an I frame, the differentiator 12 outputs it to the orthogonal transformation unit 20 as it is. However, if the image frame is a P frame or a B frame, the difference unit 12 provides a prediction supplied from the motion compensation unit 70. The difference from the image is calculated and supplied to the orthogonal transform unit 20.

  The motion compensation unit 70 uses the past or future image frame stored in the frame memory 60 as a reference image, and has the smallest error for each macroblock of the P frame or the B frame input from the block generation unit 10. A prediction area is searched from the reference image, and a motion vector indicating a deviation from the macroblock to the prediction area is obtained. The motion compensation unit 70 performs motion compensation for each macroblock using the motion vector, and generates a predicted image. The motion compensation unit 70 supplies the generated motion vector to the variable length encoding unit 90 and supplies the predicted image to the differentiator 12 and the adder 14.

  The motion compensation unit 70 can apply both bidirectional prediction and unidirectional prediction. In the unidirectional prediction, the motion compensation unit 70 generates a forward motion vector indicating the motion with respect to the forward reference frame. In the bi-directional prediction, in addition to the forward motion vector, two motion vectors of a backward motion vector indicating motion with respect to the backward reference frame are generated.

  The differentiator 12 calculates a difference between the current image output from the block generation unit 10, that is, the image to be encoded, and the predicted image output from the motion compensation unit 70, and outputs the difference to the orthogonal transform unit 20. The orthogonal transform unit 20 performs a discrete cosine transform (DCT) on the difference image given from the differentiator 12 and gives a DCT coefficient to the quantization unit 30.

  The quantization unit 30 quantizes the DCT coefficient in the quantization step set by the quantization control unit 80 and supplies the quantized DCT coefficient to the variable length coding unit 90. The variable length coding unit 90 performs variable length coding on the DCT coefficient quantized of the difference image together with the motion vector supplied from the motion compensation unit 70, and generates a coded stream CS. The buffer 92 temporarily stores the encoded stream CS, and records the encoded stream CS on a recording medium such as a memory card, a hard disk, or a DVD at a predetermined timing, or sends it to a network. The buffer 92 gives the code amount of the encoded stream CS or the buffer occupation amount by the encoded stream CS to the quantization control unit 80.

  The quantization unit 30 supplies the quantized DCT coefficient of the image frame to the inverse quantization unit 40. The inverse quantization unit 40 inversely quantizes the given quantized data and provides it to the inverse orthogonal transform unit 50. The inverse orthogonal transform unit 50 performs inverse discrete cosine transform on the given inverse quantized data. Thereby, the encoded image frame is restored. The restored image frame is input to the adder 14.

  If the image frame supplied from the inverse orthogonal transform unit 50 is an I frame, the adder 14 stores it in the frame memory 60 as it is. If the image frame supplied from the inverse orthogonal transform unit 50 is a P frame or a B frame, the adder 14 is a difference image, so the difference image supplied from the inverse orthogonal transform unit 50 and the motion compensation unit 70 By adding the supplied predicted image, the original image frame is reconstructed and stored in the frame memory 60.

  In the case of P frame or B frame encoding processing, the motion compensation unit 70 operates as described above. However, in the case of I frame encoding processing, the motion compensation unit 70 does not operate and is not shown here. The I frame is supplied to the orthogonal transform unit 20 after intra-frame prediction.

  The correlation evaluation unit 72 evaluates the correlation between the small area of the current frame and the corresponding small areas of the frame and the frame that moves back and forth in the time direction. The small area may be a macro block, an area larger than the macro block, or an area smaller than the macro block.

  The current frame and the frame that moves back and forth in the time direction may be one past frame or one future frame with respect to the current frame. Further, it may be an average value of two or more past frames or a plurality of past frames. Further, a plurality of correlations between the current frame and a plurality of past or future frames may be calculated. The frame that is to be compared with the current frame and that precedes and follows in the time direction may be a reference image that has undergone inverse quantization and inverse orthogonal transformation after quantization, or may be an original image.

  The correlation evaluation unit 72 gives an evaluation value based on the correlation to the quantization control unit 80. Details of the evaluation method will be described later. The quantization control unit 80 adaptively changes the quantization step according to the evaluation value given from the correlation evaluation unit 72 and gives the quantization step 30 to the quantization step 30. Further, according to the evaluation value given from the correlation evaluation unit 72, the rounding method of the numerical value at the time of quantization is adaptively changed and given to the quantization unit 30. Details of these processes will be described later.

  FIG. 2 is a diagram illustrating an example of correlation evaluation processing by the correlation evaluation unit 72 according to the embodiment. In FIG. 2, the correlation evaluation unit 72 evaluates the correlation between the macroblock B1 of the current frame F1 and the optimal prediction block B0 of the past frame F0. The 16 × 16 pixel optimum prediction block B0 indicates a block having the smallest error from the 16 × 16 pixel macroblock B1.

  The correlation evaluation unit 72 calculates the absolute value sum of the differences between the pixel value of the macroblock B1 and the corresponding pixel value of the optimal prediction block B0. The difference may be calculated for all the pixels between the frames F1 and F0, or may be thinned out by calculating the difference every other pixel. Further, a sum of squares of pixel value differences may be obtained.

  Further, the correlation evaluation unit 72 may obtain an absolute value sum or a square sum of coefficients obtained by orthogonally transforming the difference between the pixel value of the macroblock B1 and the corresponding pixel value of the optimal prediction block B0. In this case, since the average of the difference values is collected as one coefficient as a direct current component, it is difficult to be affected by changes in brightness. Thereby, even when only the brightness changes, the degree of correlation can be obtained correctly.

  The quantization control unit 80 determines a quantization step for quantizing the coefficient of the macroblock B1 of the current frame F1 based on the above-described evaluation. The quantization unit 30 quantizes the coefficient of the macroblock B1 of the current frame F1 in the quantization step determined by the quantization control unit 80.

  FIG. 3 is a flowchart showing an operation example 1 of the encoding apparatus 100 according to the embodiment. Note that the step width Q + ΔQ of a quantization step of a small area such as a macroblock is determined by a correlation with a frame that is temporally precedent or subtracted from the basic quantization step Q determined by the buffer occupancy and code amount. It is assumed that an additional quantization step ΔQ is added. In the following example, correlation with a past frame is used.

  As described above, the correlation evaluation unit 72 calculates the difference between the pixel value or the DCT coefficient in the corresponding small region between the frames (S10). The correlation evaluation unit 72 obtains the sum of absolute values and sum of squares of the calculated differences and uses them as evaluation values (S12).

  The quantization control unit 80 compares the evaluation value with a predetermined threshold value (S14). This threshold value is set to a value determined by the designer based on experiments and simulations. When the evaluation value is larger than the predetermined threshold (Y in S14), the quantization control unit 80 reduces the step width Q + ΔQ of the quantization step (S16). The case where the evaluation value is larger than the predetermined threshold indicates that the correlation with the past frame is strong. That is, it shows a state in which the change in the image of the region is small. There is a high possibility that the image in that area will not change in the future, and if the image has not changed, the deterioration of the image quality will be noticeable. Conversely, it can be said that if the image quality in this region is reduced, the subjective image quality is greatly reduced. Therefore, the image quality is improved by making the additional quantization step ΔQ a negative number and reducing the step width Q + ΔQ.

  In step S14, when the evaluation value is less than the predetermined threshold (N in S14), the quantization control unit 80 increases the step width Q + ΔQ of the quantization step (S18). The case where the evaluation value is less than the predetermined threshold indicates that the correlation with the past frame is small. That is, it shows a state in which the change in the image of the region is large. The image in that region is likely to change in the future, and if the image changes, the deterioration in image quality is less noticeable. Conversely, it can be said that even if the image quality in this region is reduced, the subjective image quality is not significantly affected. Therefore, the code amount is reduced by increasing the step width Q + ΔQ by making the additional quantization step ΔQ a positive number.

  As described above, according to this operation example, the code amount is suppressed by adaptively changing the step width Q + ΔQ of the quantization step in the current frame according to the correlation with the frame in the time direction. However, the subjective image quality can be improved.

  In the flowchart of FIG. 3, an example in which one threshold is used has been described in order to simplify the description. However, detailed processing may be performed using a plurality of thresholds. For example, a case where the correlation is very strong and a case where the correlation is slightly strong may be separated. An image of a region with a slightly strong correlation shows a state of moving little by little, and can be said to be a region where viewers can easily pay attention. Therefore, the step width Q + ΔQ reduced in step S18 is changed to Q + ΔQ further reduced. In addition, in the intermediate region where the correlation is strong or weak, the additional quantization step ΔQ may be set to zero. According to these, the trade-off relationship between the code amount and the subjective image quality can be further optimized.

FIG. 4 is a flowchart showing an operation example 2 of the encoding apparatus 100 according to the embodiment. The operation example 2 is a process of adaptively changing the rounding method when quantizing. When quantizing, it is necessary to divide the DCT coefficient by 2 ⁿ (n is an integer) in order from the most significant bit. At this time, if division is not possible as a result of division by the weight of each bit, it is necessary to round the divided value in preparation for the next division. As a method of rounding a numerical value, there are a method of rounding off a numerical value after the decimal point, rounding up after adding 0.25, or rounding down.

  Since the operation example 2 is the same as the process of the operation example 1 described above up to step S14, the description thereof is omitted. Different threshold values may be used. When the evaluation value calculated in step S12 is larger than the predetermined threshold (Y in S14), the quantization control unit 80 selects a rounding-down process as a rounding method for quantization (S20). As described above, it is desirable to reduce the code amount by reducing the information amount of the high-frequency component allocated to the lower bits in a region that does not significantly affect the subjective image quality even if the objective image quality is reduced. In particular, in an image region with large movement, the viewer's eyes become insensitive to small changes in brightness expressed by high-frequency components. Therefore, a truncation process that leads to code amount reduction is adopted.

  In step S14, if the evaluation value is less than the predetermined threshold value (N in S14), the quantization control unit 80 selects a rounding process as a rounding method for quantization (S22). As described above, it is necessary to maintain the image quality in a region where the subjective image quality is greatly lowered when the objective image quality is lowered. Therefore, it is necessary to accurately record the information amount of the high-frequency component assigned to the lower bits, and a rounding process that can leave an image relatively close to the original image is adopted.

  As described above, according to this operation example, the rounding method when quantizing is adaptively changed according to the correlation with the frame in the time direction, thereby suppressing the code amount and reducing the subjective image quality. Can be improved.

  The present invention has been described based on some embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. is there.

  FIG. 5 is a configuration diagram of an imaging apparatus 500 according to a modification. Compared to the imaging apparatus 500 shown in FIG. 1, the imaging apparatus 500 according to the modified example does not include the correlation evaluation unit 72 separately, and uses the action of the motion compensation unit 71. Since other configurations are the same as those in FIG. 1, the following description will focus on the motion compensation unit 71, and description of other configurations will be omitted as appropriate.

  The motion compensation unit 71 generates a motion vector based on a function as a motion detection unit that searches an optimal prediction region of a macroblock from a reference image and the determined prediction region, and generates a prediction image based on the motion vector. A function as a predicted image generation unit is provided. More specific description will be given below. The motion compensation unit 71 uses a past or future image frame stored in the frame memory 60 as a reference image, and refers to the prediction region with the smallest error for each macroblock of the frame input from the block generation unit 10. A search is performed from the image, and a motion vector indicating a deviation from the macroblock to the prediction region is obtained.

  The motion compensation unit 71 calculates the difference between the pixel value of the macroblock and the pixel value of each candidate region that should be a candidate for the prediction region in order to obtain the prediction region with the smallest error, and obtains the sum of absolute values thereof. . Note that the sum of squares may be obtained instead of the sum of absolute values. The motion compensation unit 71 determines a candidate region having the smallest absolute value sum or square sum as a prediction region.

  The motion compensation unit 71 performs motion compensation for each macroblock using a motion vector, and generates a predicted image. The motion compensation unit 71 supplies the generated motion vector to the variable length encoding unit 90 and supplies the predicted image to the differentiator 12 and the adder 14. Also, the absolute value sum or the square sum calculated in the process of determining the prediction region is supplied to the quantization control unit 80 as an evaluation value. Here, the evaluation value to be supplied may be an evaluation value of the determined prediction region, or based on at least one evaluation value among the evaluation values of each candidate region including the prediction region It may be a thing. For example, a value obtained by adding an evaluation value with the smallest prediction error and then an evaluation value with the smallest prediction error may be supplied to the quantization control unit 80 as an evaluation value.

  The motion compensator 71 determines a prediction region and needs to generate a prediction image based on the prediction region for P frames and B frames to be inter-coded. In the modified example, the above-described sum of absolute values or sum of squares is obtained for the I frame to be intra-coded to obtain the degree of correlation between frames. Of course, in the case of an I frame, it is not necessary to generate a motion vector and a predicted image.

  The quantization control unit 80 adaptively changes the quantization step according to the evaluation value given from the motion compensation unit 71 and gives the quantization step 30 to the quantization step 30. Further, according to the evaluation value given from the motion compensation unit 71, the rounding method of the numerical value at the time of quantization is adaptively changed and given to the quantization unit 30.

  As described above, according to the modification, the evaluation value used in the process of determining the prediction region for motion compensation is also used for controlling the step width and rounding method when quantizing, thereby controlling them. It is no longer necessary to separately calculate an evaluation value that should be the basis of the above, and the amount of calculation as a whole can be reduced. Therefore, it contributes to shortening of processing time and circuit scale.

  In the above-described embodiment, the MPEG system is assumed, but the present invention can also be applied to the Motion-JPEG system. In the Motion-JPEG2000 system, wavelet transformation is used instead of DCT transformation. In this case, the above-described DCT coefficients may be appropriately read as wavelet coefficients.

It is a block diagram of the imaging device which concerns on embodiment. It is a figure which shows an example of the correlation evaluation process by the correlation evaluation part which concerns on embodiment. It is a flowchart which shows the operation example 1 of the encoding apparatus which concerns on embodiment. It is a flowchart which shows the operation example 2 of the encoding apparatus which concerns on embodiment. It is a block diagram of the imaging device which concerns on a modification.

Explanation of symbols

  5 imaging units, 10 block generation units, 12 differentiators, 14 adders, 20 orthogonal transformation units, 30 quantization units, 40 inverse quantization units, 50 inverse orthogonal transformation units, 60 frame memories, 70 motion compensation units, 72 correlations Evaluation unit, 80 quantization control unit, 90 variable length coding unit, 92 buffer, 100 coding device, 500 imaging device.

Claims (8)

  Evaluate the correlation between a predetermined area in the target picture and the area corresponding to the area of the picture that differs from the target picture in the temporal direction, and adaptively change the processing content for the predetermined area in the target picture An image processing method. A correlation evaluation unit that evaluates a correlation between a predetermined region in the target picture and a region corresponding to the region of the picture that is different from the target picture in the temporal direction;
A quantization control unit that adaptively controls a quantization process for a predetermined region in the target picture according to the evaluation obtained by the correlation evaluation unit;
An image processing apparatus comprising: The quantization control unit
The quantization step for quantizing the predetermined region is expanded when the correlation is determined to be weaker than a predetermined threshold based on the evaluation value obtained by the correlation evaluation unit. The image processing apparatus according to 1. The quantization control unit
3. The quantization step for quantizing the predetermined region is reduced when the correlation is determined to be stronger than a predetermined threshold based on the evaluation value obtained by the correlation evaluation unit. The image processing apparatus according to 1. The quantization control unit
When the correlation is determined to be weaker than a predetermined threshold based on the evaluation value obtained by the correlation evaluation unit, a fraction generated in a division process when quantizing the predetermined region is rounded down. Item 3. The image processing apparatus according to Item 2. A motion detection unit that searches for a prediction area corresponding to a predetermined area in the target picture in a picture that is different in time direction from the target picture, and determines the prediction area by referring to an evaluation value of each prediction area candidate; ,
A quantization controller that adaptively controls a quantization process for a predetermined region in the target picture using at least one of the evaluation values;
An image processing apparatus comprising: The motion detector is
The image processing apparatus according to claim 6, wherein the evaluation value is generated for both a picture to be inter-picture encoded and a picture to be intra-picture encoded. An image sensor;
An image processing apparatus according to any one of claims 2 to 7,
The image processing apparatus performs the quantization process on a picture captured from the image sensor.

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