Image processing apparatus and method that may blur a background subject to highlight a main subject

An image processing apparatus and a method thereof are introduced herein. In the method, an image is divided into a plurality of blocks, and a corresponding image processing ratio is set to each of the blocks, wherein each of the blocks includes a plurality of image unit data. Next, the image processing ratios are stored in a filter table, wherein the image unit data of each of the blocks has the corresponding image processing ratio. Next, the filter table is read out and decoded to generate a plurality of filter coefficients, and the corresponding image unit data is obtained according to each of the filter coefficients. Next, filter operation is performed to the corresponding image data and the filter coefficient for outputting a filter operated image data. The image processing ratio can be a zoon ratio or a blur ratio.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 97119530, filed on May 27, 2008. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND SUBJECT OF THE INVENTION

1. Field of the Invention

The present invention relates to an image processing apparatus and a method thereof. More particularly, the present invention relates to an image processing system that may blur a background subject to highlight a main subject.

2. Description of Related Art

When a general digital camera captures pictures, a background subject blur technique is utilized to highlight a main subject, so as to avoid losing of focus of a whole image due to excessive clarity of the background subject, in which a camera lens is generally used to achieve such effect. For example, a focus region is located on the main subject, and the background subject is located on the defocus region, so as to naturally blur the background subject and highlight the main subject. Though a former shooting environment usually cannot achieve the aforementioned effect. Sometimes, the background subject is too closed to the main subject to locate it to the defocus region, or depth of field is not short enough, so that the background subject is still located at the focus region. Moreover, when the lens with a different focus range is utilized, the main subject and the background subject may have different space separations, and if the focus range of the lens cannot be changed, zoom in/out space separations of the main subject and the background subject cannot be achieved.

Since the conventional digital camera has various defects and problems, it is one of the major subjects in application of the digital cameras to provide a digital image processing system and a digital image processing method, so as to achieve different space separations of the main subject and the background subject, and perform various image processing according to different settings.

SUMMARY OF THE INVENTION

The present invention is directed to an image processing apparatus and a method thereof, which may blur a background subject to highlight a main subject.

The present invention provides an image processing apparatus including a feeder controller, a data buffer, a decoder and feeder device, a filter coefficient storing buffer, a filter operation unit. The feeder controller is used for controlling accessing of data. The data buffer is used for temporarily store image data accessed by the feeder controller, and the image data is input to the data buffer under control of the feeder controller, wherein the image data includes a plurality of row (column) image unit data. The decoder and feeder device is connected to the feeder controller for receiving a filter table request signal sent from the feeder controller, so as to read and decode a filter table to generate a plurality of filter coefficients and a control signal. The control signal is transmitted to the feeder controller for requesting the feeder controller to control the data buffer to input the corresponding plurality of row (column) image unit data. The filter coefficient storing buffer is used for temporarily storing the filter coefficients output from the decoder and feeder device. The filter operation unit is used for receiving the plurality of row (column) image unit data output from the data buffer and the filter coefficients stored in the filter coefficient storing buffer, and performing filter operation to the plurality of received row (column) image unit data, so as to output filter operated image data.

In an embodiment of the present invention, the image processing apparatus further includes a storing buffer for receiving a part of the filter operated image data, and feeding it back to the filter operation unit for accumulation operation, so as to obtain an integral image data for outputting.

In an embodiment of the present invention, the filter operation unit of the image processing apparatus further includes a plurality of multipliers and an adder. The multipliers are used for receiving the image unit data and the corresponding filter coefficients to perform a multiplication operation, and perform an accumulation operation with data fed back from the storing buffer, so as to obtain the integral image data for outputting.

In an embodiment of the present invention, the image processing apparatus further includes a shift operation unit for confining the filter operated image data within a predetermined range for outputting, under control of the feeder controller.

In an embodiment of the present invention, the image processing apparatus further includes a filter table storage unit connected to the decoder and feeder device for storing the filter table.

In an embodiment of the present invention, the filter table includes a control parameter field and a plurality of filter coefficients, wherein the control parameter field includes a first coefficient and a second coefficient. The first coefficient indicates a number of the filter coefficients required by the presently processed image unit data, and the second coefficient indicates a shifting amount for jumping to a start position of a next image unit data.

The present invention provides an image processing method. First, an image data is read and temporarily stored, wherein the image data includes a plurality of row (column) image unit data. Next, a filter table is read, and is decoded to generate a plurality of filter coefficients, and the corresponding image unit data is obtained according to each of the filter coefficients. Finally, filter operation is performed to the corresponding image unit data and the filter coefficient, so as to output a filter operated image data.

According to the image processing method, when a number of the filter coefficients exceeds a number that can be processed by filter operation, a part of the filter operated image unit data is fed back for accumulating with the other part of the non filter operated image unit data to obtain an integral image data for outputting.

According to the image processing method, a shift operation is further performed to the filter operated image data, so as to confine the filter operated image data within a predetermined range for outputting.

According to the image processing method, the filter table includes a control parameter field and a plurality of filter coefficients, wherein the control parameter field includes a first coefficient and a second coefficient. The first coefficient indicates a number of the filter coefficients required by the presently processed plurality of row (column) image unit data, and the second coefficient indicates a shifting amount for jumping to a start position of next plurality of row (column) image unit data.

The present provides an image processing method. First, an image is divided into a plurality of blocks, and a corresponding image processing ratio is set to each of the blocks, wherein each of the blocks includes a plurality of row (column) image unit data. Next, the image processing ratios are stored in a filter table, wherein the image unit data of each of the regions has the corresponding image processing ratio. Next, the filter table is read out and decoded to generate a plurality of filter coefficients, and the corresponding image unit data is obtained according to each of the filter coefficients. Next, filter operation is performed to the corresponding row (column) image data and the filter coefficients. Deduced by analogy, after the plurality of row (column) image data is processed, a filter operated image data is then output.

According to the image processing method, the image processing ratio is a zoom ratio or a blur ratio.

According to the image processing method, the filter operation performed to the corresponding image unit data and the filter coefficient includes performing a vertical zoom ratio operation and a vertical blur ratio operation to the image, and includes performing a horizontal zoom ratio operation and a horizontal blur ratio operation to the image.

The image processing apparatus and the method thereof provided by the present invention may perform various special image processing according to settings of a user, so as to blur the background subject and highlight the main subject. Accordingly, defects and problems of the conventional technique can be resolved.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, a preferred embodiment accompanied with figures is described in details below.

DESCRIPTION OF EMBODIMENTS

Embodiment of the present invention provides an image processing system and a method thereof, by which a main subject and a background subject of an image may have different space separations, and various special image processing can be performed according to settings of a user.

When a general digital camera captures pictures, a background subject blur technique is utilized to highlight a main subject, so as to avoid losing of focus of a whole image due to excessive clarity of the background subject, in which a camera lens is generally used to achieve such effect. For example, a focus region is located on the main subject, and the background subject is located on the defocus region, so as to naturally blur the background subject and highlight the main subject. Though a former shooting environment usually cannot achieve the aforementioned effect. Sometimes, the background subject is too closed to the main subject to locate it to the defocus region, or depth of field is not short enough, so that the background subject is still located at the focus region. In case that a position of the background subject cannot be changed, a digital processing method is applied to blur the background subject and highlight the main subject.

Moreover, the lens with a different focus range is utilized, the main subject and the background subject may have different space separations, and if the focus range of the lens cannot be changed, zoom in or zoom out of the main subject and the background subject can still be achieved via the digital image processing.

To achieve the aforementioned effect, the image has to be divided in to a plurality of blocks, and whether each of the blocks is belonged to the main subject, the background subject or a transitional region of the main subject and the background subject is marked, so as to perform different image processing to different marked blocks. Therefore, a structure for implementing such demand is required.

To support various types of the filter, a universal filter table is defined in the present embodiment, which is as that shown inFIG. 1A. The universal filter table is used for obtaining a corresponding line image source, and seven line image sources shown inFIG. 1Bare taken as an example.

In the filter table ofFIG. 1A, data of one byte represents a control parameter, and corresponding filter operation coefficients are attached behind. In the control parameter, the first four bits (most significant bit (MSB)) represent how many filter operation coefficients are required by the line image data for such filter operation, and the last four bits (least significant bit (LSB)) represent that after a first operation and output of the line image data, and at the beginning of a next operation and output, how many lines are jumped for a start position of the line image data.

For example, referring toFIG. 1AandFIG. 1B, there are numerals “3” and “2” in a first byte110, and filter operation coefficients “F1C1”, “F1C2” and “F1C3” with reference numerals of112,114and116are attached behind, which represents that there are 3 line image data to be processed from a start line image, and 3 coefficients112,114and116serve as filter operation coefficients of the line image data. After the filter operation is completed, at the beginning of the next operation and output, 2 lines are jumped for reading data.

For example, a presently processed line image data is a first line image data141, and the corresponding control parameters and the filter operation coefficients are “3”, “2”, “F1C1”, “F1C2” and “F1C3”, and data of a first line image data141(Line1), a second line image data142(Line2) and a third line image data143(Line3) are obtained. After the filter operation, an output thereof is:
Line Output1=(Line1*F1C1+Line2*F1C2+Line3*F1C2).

Since 2 lines are jumped for a next data to be read, the next output is started from the third line image data143, and the corresponding parameters and filter operation coefficients are “2”, “1”, “F2C1” and “F2C2”, and data of the third line image data143(Line3) and a fourth line image data144(Line4) are obtained. After the filter operation, the output thereof is:
Line Output2=(Line3*F2C1+Line4*F2C2).

Since 1 line is jumped for a next data to be read, the next output is started from the fourth line image data143, and the corresponding parameters and filter operation coefficients are “4”, “2”, “F3C1”, “F3C2”, “F3C3” and “F2C4”, and data of the fourth line image data144(Line4), a fifth line image data145(Line5), a sixth line image data146(Line6) and a seventh line image data147(Line7) are obtained. After the filter operation, the output thereof is:
Line Output3=(Line4*F3C1+Line5*F3C2+Line6*F3C3+Line7*F3C4).

In the aforementioned control parameters, the first four bits and the last four bits are used for controlling, though the present invention is not limited to such number of bits. Moreover, the adopted filter operation is performed in allusion to the line image sources, though it can also be performed in allusion to an image data with a predetermined magnitude, the reason of utilizing the line image sources is to coordinate with existing line buffers. The aforementioned content can be adjusted according to actual design requirements or the number of coefficients required by the filter operation. In the following content, an embodiment is provided for describing an image processing apparatus of the present invention.

Referring toFIG. 2, an image processing apparatus200of the present embodiment includes a decoder and feeder device210, a feeder controller220, a data buffer230, a filter coefficient storing buffer240, a filter operation unit250, a storing buffer260and a shift operation unit270.

First, a data accessing circuit202reads a strip-shape image data201, wherein the data accessing circuit202is for example, a direct memory access (DMA) circuit, the DMA circuit is a hardware structure which allows the image processing apparatus200to directly access a memory thereof, and participation of a CPU is unnecessary. The data accessing circuit202is directly controlled by the feeder controller220via a control signal222shown inFIG. 2, so as to read data. Next, the read data is temporarily stored in the data buffer230, wherein the data buffer230is for example, a buffer device composed of a plurality of line buffers, and is controlled by a signal224output from the feeder controller220, so as to output the data to the filter operation unit250for filter operation. Meanwhile, the feeder controller220outputs a signal226to the decoder and feeder device210for reading the filter table provided by the present embodiment.

A filter table storage unit205is used for storing the filter table corresponding to the strip-shape image data201. A format of the filter table is as that shown inFIG. 1A, which includes the control parameters and the filter coefficients required for processing the strip-shape image data201. The filter table is a universal filter table which may support various types of the filter.

The decoder and feeder device210decodes an internal information of the filter table storage unit205, and performs a corresponding processing according to the decoded content. For example, if the line image source is about to be processed, the required filter operation coefficients are transmitted to the filter coefficient storing buffer240in response to a multi-bit signal214for temporary storage, and are transmitted to the feeder controller220in response to a multi-bit signal212, so as to notify the feeder controller220how many lines of input image are required for a current processing, and which line image is the line image source shifted to, after the current processing and output is completed, and at the beginning of a next processing.

The image processing apparatus200may temporarily store data of intermediate processing process into the storing buffer260, and if the number of line images to be filter operated exceeds a number that can be once processed by the feeder controller220, namely, if the number of the filter operation coefficients exceeds the number that can be once processed by the feeder controller220, separate processing is required to implement an integral filter operation. Now, the data of intermediate processing process stored in the storing buffer260can be fed back to the filter operation unit250in response to a multi-bit signal262for an accumulation operation, so as to output an integral image signal, shown as an image signal264ofFIG. 2.

The shift operation unit270selectively performs the shift operation to the output image signal264to confine the output image signal264within a certain range, and outputs an adjusted image signal272. Such shift operation is selective, which can be omitted to directly output the image signal264. Whether the shift operation unit270performs the shift operation is controlled by the feeder controller220via a signal228, and the signal228is used for indicating whether the integral output image is completed, and driving the shift operation unit270only when the integral output image is completed.

During the aforementioned separate processing, the decoder and feeder device210is required to be operated correspondingly. For example, the decoder and feeder device210separately transmits the filter operation coefficients to the filter coefficient storing buffer240. The data accessing circuit202is also required to be operated correspondingly for capturing different number of line image data of the input image at an appointed position according to an actual demand. Here, the data accessing circuit202captures different number of the line image data of the input image at the appointed position according to the actual demand of the feeder controller220.

According to the aforementioned circuit structure of the image processing system and the method thereof provided by the present invention, the main subject and the background subject may have different space separations, and various special image processing can be performed according to different settings of the user. In the following content, an embodiment is provided to describe a vertical filter processing circuit and a horizontal filter processing circuit in detail with reference ofFIG. 3andFIG. 4.

Referring toFIG. 3, a vertical filter processing device300includes a vertical filter table decoder and feeder device310, a line buffer feeder controller320, a line data buffer330, a filter coefficient storing buffer340, a filter operation unit350, a storing buffer360and a shift operation unit370.

First, an output signal326of the line buffer feeder controller320is transmitted to the vertical filter table decoder and feeder device310for reading the filter table of the present embodiment.

A filter table storage unit305is used for storing the filter table corresponding to a source image data301. A format of the filter table is as that shown inFIG. 1A, which includes the control parameters and the filter coefficients required for processing the source image data301. The filter table is a universal filter table which may support various types of the filter.

The vertical filter table decoder and feeder device310decodes an internal information of the filter table storage unit305, and performs a corresponding processing according to the decoded content. For example, if the source image data301is about to be processed, the required operation coefficients are transmitted to the filter coefficient storing buffer340in response to a multi-bit signal314for temporary storage, and are transmitted to the line buffer feeder controller320in response to a multi-bit signal312, so as to notify the line buffer feeder controller320how many lines of input image are about to be processed. A DMA circuit302accesses the strip-shape source image data301with a width of W and a height of H. The DMA circuit302receives a control signal322from the line buffer feeder controller320, and performs data reading in response to the control signal322. Next, the read data is temporarily stored in the line data buffer330. The line data buffer330is for example, a buffer device composed of four line buffers, which may transmit the data to the filter operation unit350in response to a signal324output from the line buffer feeder controller320, so as to perform the filter operation. After such line image is processed and output, the start position of the line image source is shifted to a certain line image for processing a next image data.

The vertical filter processing device300may temporarily store data of intermediate processing process into the storing buffer360, and if the number of line images to be filter operated exceeds four, i.e. the number of the filter operation coefficients exceeds a number that can be once processed by the filter operation unit350, separate processing is required to implement an integral filter operation. Now, the data of intermediate processing process stored in the storing buffer360can be fed back to the filter operation unit350in response to a multi-bit signal362for an accumulation operation, so as to output an integral image signal, shown as an image signal364ofFIG. 3.

The filter operation unit350includes for example, four multipliers352and an adder354. Each of the multipliers352corresponds to a line buffer unit within the line data buffer330. The four line buffer units are disposed in parallel to transmit the line image data to the four multipliers352for performing a multiplication operation with the filter operation coefficients stored in the filter coefficient storing buffer340, and after an addition operation performed by the adder354, a result thereof is transmitted to the storing buffer360.

The shift operation unit370selectively performs the shift operation to the output image signal364to confine the output image signal364within a certain range, and outputs an adjusted image signal372. Such shift operation is selective, which can be omitted to directly output the image signal364. Whether the shift operation unit370performs the shift operation is controlled by the line buffer feeder controller320via a signal328, and the signal328is used for indicating whether the integral output image is completed, and driving the shift operation unit370only when the integral output image is completed.

Referring toFIG. 4, a horizontal filter processing device400includes a horizontal filter table decoder and feeder device410, a first in first out (FIFO) control and horizontal data feeder controller420, a FIFO buffer430, a filter coefficient storing buffer440, a filter operation unit450, a pixel buffer480and a shift operation unit470.

The horizontal filter processing device400receives a source image data403. The source image data403can be for example, a vertical adjusted signal output from the vertical filter processing device300. The source image data403is directly transmitted to the FIFO buffer430. The FIFO buffer430has a position indicator431indicating an initial position of a current processed source image, and when the processing is completed, the position indicator431is shifted to a certain pixel for a next processing. According to the number of pixels that can be once processed by the filter operation unit450, the FIFO buffer430once outputs data corresponding such number of the pixels to perform the filter operation. Data transmission of the FIFO buffer430is controlled by the FIFO control and horizontal data feeder controller420. Meanwhile, a signal426output from the FIFO control and horizontal data feeder controller420is also transmitted to the horizontal filter table decoder and feeder device410for reading the filter table of the present embodiment.

A filter table storage unit405is used for storing the filter table. A format of the filter table is as that shown inFIG. 1A, which includes the control parameters and the filter coefficients required for processing the source image data403. The filter table is a universal filter table which may support various types of the filter.

The horizontal filter table decoder and feeder device410decodes an internal information of the filter table storage unit405, and performs a corresponding processing according to the decoded content. For example, if the source image data403is about to be processed, the required filter operation coefficients are transmitted to the filter coefficient storing buffer440in response to a multi-bit signal414for temporary storage, and are transmitted to the FIFO control and horizontal data feeder controller420in response to a multi-bit signal412, so as to notify the FIFO control and horizontal data feeder controller420how many pixels of the image are about to be processed, and which pixel is the position indicator431shifted to, after image data of these pixels is processed and output, so as to perform a next processing.

The horizontal filter processing device400may temporarily store data obtained during the processing into the pixel buffer480, and if the number of the pixels to be filter operated exceeds four, i.e. the number of the filter operation coefficients exceeds a number that can be once processed by the filter operation unit450, separate processing is required to implement an integral filter operation. Now, the data stored in the storing buffer360can be fed back to the filter operation unit450in response to a multi-bit signal482for an accumulation operation, so as to output an integral image signal, shown as an image signal481ofFIG. 4.

The filter operation unit450includes for example, four multipliers452and an adder454. Each of the multipliers452corresponds to a pixel data within the FIFO buffer430, so as to perform a multiplication operation with the filter operation coefficients stored in the filter coefficient storing buffer440, and after an addition operation performed by the adder454, a result thereof is transmitted to the pixel buffer480.

The shift operation unit470selectively performs the shift operation to the output image signal481to confine the output image signal481within a certain range, and outputs an adjusted image signal472to a FIFO buffer490for temporary storage. Then, the FIFO buffer490outputs a target image with a height of h and a length of w via a signal492. Such shift operation is selective, which can be omitted to directly output the image signal481. Whether the shift operation unit470performs the shift operation is controlled by the FIFO control and horizontal data feeder controller420via a signal428, and the signal428is used for indicating whether the integral output image is completed, and driving the shift operation unit470only when the integral output image is completed.

FIG. 5Ais a schematic diagram illustrating a method of filter processing based on piecewise zoom ratios according to an embodiment of the present invention. Assuming a triangle filter510is used for processing zoom in/zoom out of the image, and a length of the triangle filter510is 4, a next equation is then obtained.
b0=(a0*F(0)+a1*F(1)+a2*F(2)+a3*F(3))/(F(1)+F(2)+F(3)+F(4))

wherein, a0represents a pixel value of a 0-th input image within the triangle filter510, and a corresponding filter coefficient value F(0) thereof is obtained according to a triangle formula. Similarly, a1, a2and a3respectively represent pixel values of a first, a second and a third input images within the triangle filter, and F(1), F(2) and F(3) represent the corresponding filter coefficients. If the aforementioned values are input to the above equation, a value of b0is then obtained, which represents a 0-th pixel value of an output image, and results thereof are shown as521,522,523and524ofFIG. 5A.

Assuming the piecewise zoom ratios are utilized to apply different zoom ratios to different sections of the input image, for example, the zoom ratio of a second pixel of the output image is 1.5, the triangle filter is then shifted for 1.5 pixel values, and a value of b1is obtained based on the second pixel of the output image. Similarly, values of the third pixel, the fourth pixel and the fifth pixel of the output image respectively represent that the zoom ratios thereof are 2, 2.5, 3 and 3.5.

According to the above deduction, the results thereof may form the filter table required by the vertical filter, or form the filter table required by the horizontal filter. The filter table records the number of pixel values of the input image, the corresponding filter coefficients, and the number of pixels jumped by the input image when a next pixel is required to be processed.

FIG. 5Bis a schematic diagram illustrating a method of processing positions of an image via different zoom ratios according to an embodiment of the present invention. According to the aforementioned method, the image can be divided into different regions, and different zoom ratios can be applied thereon. For example, regions530,532,534and536respectively have different zoom ratios 3, 2.5, 2 and 1.5. Assuming the background of the image is located at four corners of the image, and the foreground of the image is located at the center of the image, and meanwhile a relatively small magnification is applied to the background, and a relatively great magnification is applied to the center. Then, the foreground has a relatively great magnification compared to that of the background, so that the main subject can be highlighted, or a visual effect that a distance between the main subject and the background subject is elongated can be achieved.

FIG. 6Ais a schematic diagram illustrating a method for filter processing based on piecewise blur ratios according to an embodiment of the present invention. First, a blur ratio is defined, and the greater the blur ratio is, the more obvious a blur effect is. During the digital image processing, the wider a low pass filter is, the more high frequency components of the input image are filtered, and the more blurry the image is. Assuming the triangle filter is applied, and in a first case, a filter width of 6 is applied for image process, a blur effect of blur ratio=3 is then obtained. Similarly, different filter widths of 5, 4 and 3 are piecewise applied, and the image with different blur ratios 2.5, 2 and 1.5 is obtained, so that piecewise consecutive blur effects are achieved.

According to the above deduction, the results thereof may form the filter table required by the vertical filter, or form the filter table required by the horizontal filter. The filter table records the number of pixel values of the input image, the corresponding filter coefficients, and the number of pixels jumped by the input image when a next pixel is required to be processed.

FIG. 6Bis a schematic diagram illustrating a method of processing positions of an image via different zoom ratios according to an embodiment of the present invention. According to the aforementioned method, the image can be divided into different regions, and different blur ratios can be applied thereon. For example, regions630,632,634and636respectively have different blur ratios 1.5, 2, 2.5 and 3. Assuming the background of the image is located at four corners of the image, and the foreground of the image is located at the center of the image, and meanwhile relatively great blur ratio is applied to the background, and relatively small blur ratio is applied to the center. Then, the foreground is more clear compared to the background, so that the main subject can be highlighted, or a visual effect of blurring the background is achieved.

FIG. 7is a flowchart illustrating an image processing method according to an embodiment of the present invention. The image processing method can be described as follows. First, in step S710, an image is divided into a plurality of blocks, and an independent zoom ratio and blur ratio can be set to a boundary of each block. Next, in step S720, different zoom ratios and blur ratios are set to different sections of the blocks in a piecewise consecutive approach, so as to reduce a block effect. Next, steps S730to S736, and steps S740to S746are respectively executed.

For the horizontal filter processing, first, in step S730, a horizontal zoom ratio and a horizontal blur ratio are set to each of the sections. In step S732, a filter width of the filter utilized by each of the horizontal output pixels is determined according to the horizontal blur ratio. In step S734, the horizontal zoom ratio determines a center position of the filter corresponding to each of the horizontal output pixels, and the corresponding filter width is obtained according to the blur ratio, so that the filter coefficient corresponding to each of the pixels of the input image covered by such filter is obtained. In step S736, a horizontal filter table is established according to the aforementioned information, and is provided to a horizontal filter processing circuit for utilization.

For the vertical filter processing, in step S740, a vertical zoom ratio and a vertical blur ratio are set to each of the sections. In step S742, the filter width of each of the vertical output pixels is determined according to the vertical blur ratio. In step S744, the vertical zoom ratio determines a center position of the filter corresponding to each of the vertical output pixels, and the corresponding filter width is obtained according to the blur ratio, so that the filter coefficient corresponding to each of the pixels of the input image covered by such filter is obtained. In step S746, a vertical filter table is established according to the aforementioned information, and is provided to a vertical filter processing circuit for utilization.

Finally, in step S750, all of the input image is processed to obtain an output image.

The present invention further provides a vertical filter processing circuit and a horizontal filter processing circuit, and the vertical filter processing circuit and the horizontal filter processing circuit can perform various special image processing according to settings of a user.

The image processing system, the vertical filter processing circuit and the horizontal filter processing circuit provided by the present invention can be applied to an embedded system.

The image processing apparatus and the method thereof provided by the present invention may perform various special image processing according to the settings of the user, so as to blur the background subject and highlight the main subject. Accordingly, defects and problems of the conventional technique can be resolved.