US20070206102A1

US20070206102A1 - Image capturing apparatus and method thereof

Info

Publication number: US20070206102A1
Application number: US11/741,785
Authority: US
Inventors: Chih-Shih Yu; Chih-Ying Tu
Original assignee: Alpha Imaging Technology Corp
Current assignee: Alpha Imaging Technology Corp
Priority date: 2004-05-12
Filing date: 2007-04-30
Publication date: 2007-09-06
Also published as: US8233057B2; TWI314417B; TW200743366A; US20100201844A1

Abstract

An image capturing apparatus and an image capturing method. The apparatus captures and compresses a preview image, and judges an image complexity and determines a preview compressed setting value according to at least one of a set of factors consisting of a compressed setting, a resolution of the preview image and a size of a compressed preview image. Next, the apparatus captures a to-be-captured image, and determines an initial compressed setting value according to at least one of a set of factors consisting of the image complexity, and the resolution of the to-be-captured image and a compressed image target size, which is a new compressed initial value. Then, the apparatus compresses the image according to the initial compressed setting value to obtain a compressed image approaching a predetermined size or speed up a converging speed of an image compressing loop.

Description

This application claims the benefit of Taiwan application Ser. No. 95117009, filed May 12, 2006, the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates in general to an image capturing apparatus and a method thereof, and more particularly to an image capturing apparatus for compressing a preview image in a preview mode to judge an image complexity and calculate a preview compressed setting value in advance, and an image capturing method.
2. Description of the Related Art
FIG. 1 is a schematic illustration showing a first conventional image capturing apparatus 10 in a capturing mode. Referring to FIG. 1, the conventional image capturing apparatus 10 includes an image sensing unit 110, an image processing unit 120, an image storing unit 130, an image compressing unit 140 and a control unit 150. When the conventional image capturing apparatus 10 enters a capturing mode, the image sensing unit 110 captures a to-be-captured image SI and outputs a to-be-captured image signal S2 according to the to-be-captured image Si. The image processing unit 120 processes the to-be-captured image signal S2 to output to-be-captured image data S3, which is stored in the image storing unit 130 in the capturing mode. The control unit 150 controls the image compressing unit 140 to compress the to-be-captured image data S3 to make the image compressing unit 140 output a compressed image S4. The control unit 150 outputs a compressed setting value S5 according to the compressed image S4 and judges whether the compressed image S4 reaches a predetermined target or not. If not, the image compressing unit 140 compresses the to-be-captured image data S3 again according to the compressed setting value S5 until the compressed image S4 reaches the predetermined target.
FIG. 2 is a schematic illustration showing a second conventional image capturing apparatus in the capturing mode. As shown in FIG. 2, the image storing unit 130 may also store the to-be-captured image signal S2 outputted from the image sensing unit 110. The image processing unit 120 processes the to-be-captured image signal S2 in the image storing unit 130 to output the to-be-captured image data S3. Then, the control unit 150 controls the image compressing unit 140 to compress the to-be-captured image data S3 into the predetermined target.
However, the conventional image capturing apparatus cannot compress the to-be-captured image data until it enters the capturing mode. Thus, the conventional image capturing apparatus needs a longer period of time to compress the to-be-captured image data into the predetermined target.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an image capturing apparatus and an image capturing method thereof. When the image capturing apparatus is still in a preview mode, the apparatus compresses a preview image in advance and judges an image complexity according to at least one of a set of factors consisting of a compressed setting, a resolution of the preview image and a size of the compressed preview image. Thus, after entering a capturing mode, the image capturing apparatus determines an initial compressed setting value, which is a new compressed initial value, according to at least one of a set of factors consisting of the image complexity obtained in a previous step, a resolution of a to-be-captured image and a compressed image target size, and rapidly compresses captured image data to compressed data approaching the predetermined target size or speeds up the converging speed of the image compressing loop according to the initial compressed setting value.
The invention achieves the above-identified object by providing an image capturing method. The image capturing method includes the following steps. First, a preview image is captured and compressed into a compressed preview image, and an image complexity is judged and a preview compressed setting value is determined according to at least one of a set of factors consisting of a compressed setting, a resolution of the preview image and a size of the compressed preview image. The size of the compressed preview image is the size of the preview image after being compressed. Next, a to-be-captured image is captured and an initial compressed setting value, which is a new compressed initial value, is determined according to at least one of a set of factors consisting of the image complexity, a resolution of the to-be-captured image and the compressed image target size. In addition, the image is compressed to obtain a compressed image with a predetermined size according to the initial compressed setting value.
The invention also achieves the above-identified object by providing an image capturing apparatus including an image sensing unit, an image processing unit, an image compressing unit and a control unit. The image sensing unit captures a preview image and a to-be-captured image, and outputs a preview image signal and a to-be-captured image signal. The image processing unit processes the preview image signal and the to-be-captured image signal and outputs preview image data and to-be-captured image data. The image compressing unit compresses the preview image data and the to-be-captured image data.
The control unit controls an image compressing operation of the image compressing unit and performs image analysis to determine a compressed setting. The control unit controls the image compressing unit to compress the preview image data to output a compressed preview image, and judges an image complexity according to at least one of a set of factors consisting of the compressed setting, the resolution of the preview image and the size of the compressed preview image. When the image is to be captured, an initial compressed setting value, which is a new compressed initial value, is determined according to at least one of a set of factors consisting of the image complexity, the resolution of the to-be-captured image and the compressed image target size, and the image is compressed to obtain the compressed image with a predetermined size according to the initial compressed setting value.
Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (Prior Art) is a schematic illustration showing a first conventional image capturing apparatus in a capturing mode.
FIG. 2 (Prior Art) is a schematic illustration showing a second conventional image capturing apparatus in the capturing mode.
FIG. 3 is a block diagram showing an image capturing apparatus according to a preferred embodiment of the invention.
FIG. 4 is a schematic illustration showing the image capturing apparatus in a preview mode.
FIG. 5 is a schematic illustration showing the image capturing apparatus in a capturing mode.
FIG. 6 is a flow chart showing an image capturing method according to the preferred embodiment of the invention.
FIG. 7 is a flow chart showing details of step 610.
FIG. 8 is a flow chart showing details of step 620.
FIG. 9 is a schematic illustration showing another image capturing apparatus in a capturing mode.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3 is a block diagram showing an image capturing apparatus 20 according to a preferred embodiment of the invention. Referring to FIG. 3, the image capturing apparatus 20, such as a digital camera, includes an image sensing unit 210, an image processing unit 220, an image storing unit 230, an image compressing unit 240 and a control unit 250.
FIG. 4 is a schematic illustration showing the image capturing apparatus in a preview mode. Referring to FIG. 4, the image capturing apparatus 20 has two operation modes, one of which is a preview mode and the other of which is a capturing mode.
When the image capturing apparatus 20 is in the preview mode, the image sensing unit 210 captures a preview image S6 and outputs a preview image signal S7 according to the preview image S6. The image processing unit 220 processes the preview image signal S7 to output preview image data S8 by way of, for example, demosaicking, gamma correction, color reproduction and edge enhancement.
The control unit 250 controls the image compressing unit 240 to compress the preview image data S8 to generate a compressed preview image S9. In other words, the size of the compressed preview image S9 is the size of the preview image after being compressed. The control unit 250 judges an image complexity and determines a preview compressed setting value S10, which is a quantitative compression value, according to at least one of a set of factors consisting of the compressed setting, the resolution of the preview image signal S7 and the size of the compressed preview image S9.
FIG. 5 is a schematic illustration showing the image capturing apparatus in a capturing mode. As shown in FIG. 5, when the image capturing apparatus 20 enters the capturing mode from the preview mode, the image sensing unit 210 captures a to-be-captured image S11 and outputs a to-be-captured image signal S12 according to the to-be-captured image S1. The image processing unit 220 processes the to-be-captured image signal S12 to output to-be-captured image data S13, which is stored into the image storing unit 230 in the capturing mode.
Because the image capturing apparatus 20 has analyzed and judged the image complexity in the preview mode, the control unit 250 determines an initial compressed setting value S15 according to at least one of a set of factors consisting of the judged image complexity, the resolution of the to-be-captured image signal S12 and the compressed image target size. The initial compressed setting value S15 is a new compressed initial value. The control unit 250 also controls the image compressing unit 240 to compress the to-be-captured image data S13 to obtain an output image S14 with a predetermined target according to the initial compressed setting value S15. Thus, the period of working time when the image capturing apparatus 20 makes the compression in the capturing mode can be shortened.
FIG. 6 is a flow chart showing an image capturing method according to the preferred embodiment of the invention. As shown in FIG. 6. the image capturing method is used in the above-mentioned image capturing apparatus 20, and includes the following steps.
First, as shown in step 610, the image sensing unit 210 captures the preview image S6 and the image compressing unit 240 compresses the preview image data S8 when the image capturing apparatus 20 is in the preview mode. In addition, the image complexity and the preview compressed setting value S10 are analyzed and judged according to the set of factors consisting of the compressed setting, the resolution of the preview image signal S7 and the size of the compressed preview image S9.
Next, as shown in step 620, the image capturing apparatus 20 enters the capturing mode, and the image sensing unit 210 captures the to-be-captured image S11 and determines the initial compressed setting value S15 according to the set of factors consisting of the image complexity, the resolution of the to-be-captured image signal S12 and the compressed image target size. The image compressing unit 240 compresses the image according to the initial compressed setting value S15.
FIG. 7 is a flow chart showing details of step 610. The step 610 includes the following steps.
First, as shown in step 612, the image sensing unit 210 captures the preview image S6 and the image processing unit 220 processes the image to obtain the preview image data S8 when the image capturing apparatus 20 is in the preview mode.
Next, as shown in step 614, the image compressing unit 240 compresses the preview image data S8 to obtain the compressed preview image S9.
Finally, as shown in step 616, the control unit 250 judges the image complexity and obtains the preview compressed setting value S10 according to the set of factors consisting of the compressed setting, the resolution of the preview image signal S7 and the size of the compressed preview image S9.
FIG. 8 is a flow chart showing details of step 620. Referring to FIG. 8, step 620 includes the following steps.
First, as shown in step 622, the image capturing apparatus 20 enters the capturing mode, and the image sensing unit 210 captures the to-be-captured image S11 and converts the image S11 into the to-be-captured image signal S12.
Next, as shown in step 624, the image processing unit 220 processes the to-be-captured image signal S12 to obtain the to-be-captured image data S13, which is temporarily stored in the image storing unit 230.
Finally, as shown in step 626, the control unit 250 determines the initial compressed setting value S15 according to the the set of factors consisting of image complexity, the resolution of the to-be-captured image signal S12 and the compressed image target size, and controls the image compressing unit 240 to compress the to-be-captured image data S13 to obtain the output image S14 according to the initial compressed setting value S15.
FIG. 9 is a schematic illustration showing another image capturing apparatus in the capturing mode. In addition, when the image capturing apparatus 20 enters the capturing mode, the image storing unit 230 may also store the to-be-captured image signal S12 outputted from the image sensing unit 210, and then the image processing unit 220 processes the to-be-captured image signal S12. Then, the initial compressed setting value S15 is determined according to the set of factors consisting of the image complexity judged in the preview mode, the resolution of the to-be-captured image signal S12 and the compressed image target size. The image compressing unit 240 compresses the image to obtain the output image S14 according to the initial compressed setting value S15.
The image compressing unit 240 can calculate the image complexity and the preview compressed setting value S10 in advance in the preview mode when either the to-be-captured image signal S12 or the to-be-captured image data S13 is stored in the image storing unit 230. Thus, after the image capturing apparatus 20 enters the capturing mode, it can rapidly determine the initial compressed setting value S15 according to the set of factors consisting of the judged image complexity, the resolution of the to-be-captured image signal S12 and the compressed image target size. Thus, the to-be-captured image data S13 can be rapidly compressed into the predetermined target.
In the image capturing apparatus and the image capturing method according to the embodiments of the invention, the image complexity is calculated first in the preview mode. Thus, the image capturing apparatus can determine the initial compressed setting value and compress the to-be-captured image data into the predetermined target according to the set of factors consisting of the judged image complexity, the resolution of the to-be-captured image and the compressed image target size after entering the capturing mode. Consequently, the period of working time when the image capturing apparatus makes the compression in the capturing mode can be shortened.
While the invention has been described by way of example and in terms of a preferred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.

Claims

1. An image capturing method, comprising the steps of:

(a) capturing a preview image;

(b) compressing the preview image into a compressed preview image;

(c) determining an image complexity according to at least one of a set of factors consisting of a compressed setting, a resolution of the preview image and a size of the compressed preview image;

(d) capturing a to-be-captured image;

(e) determining an initial compressed setting value according to at least one of a set of factors consisting of the image complexity, a resolution of the to-be-captured image and an image compression target; and

(f) compressing the to-be-captured image according to the initial compressed setting value.

2. The method according to claim 1, wherein step (b) comprises:

(b-1) processing the preview image to obtain preview image data; and

(b-2) compressing the preview image data to obtain the compressed preview image.

3. The method according to claim 1, wherein step (e) comprises:

(e-1) processing the to-be-captured image to obtain to-be-captured image data; and

(e-2) determining the initial compressed setting value according to the set of factors consisting of the image complexity, the resolution of the to-be-captured image and the image compression target, and compressing the to-be-captured image data according to the initial compressed setting value to obtain an output image.

4. The method according to claim 3, wherein step (e-1) comprises:

(e-1-1) converting the to-be-captured image into a plurality of to-be-captured image signals, which is temporarily stored; and

(e-1-2) processing the temporarily stored to-be-captured image signals to obtain the to-be-captured image data.

5. The method according to claim 3, wherein step (e-1) comprises:

(e-1-1′) converting the to-be-captured image into a to-be-captured image signal; and

(e-1-2′) processing the to-be-captured image signal to obtain the to-be-captured image data, which is temporarily stored.

6. An image capturing apparatus, comprising:

an image sensing unit for capturing a preview image and a to-be-captured image, and outputting a preview image signal and a to-be-captured image signal;

an image processing unit for processing the preview image signal and the to-be-captured image signal and outputting preview image data and to-be-captured image data;

an image compressing unit for compressing the preview image data and the to-be-captured image data; and

a control unit for controlling an image compressing operation of the image compressing unit and performing image analysis to determine a compressed setting, wherein:

the control unit controls the image compressing unit to compress the preview image data and output a compressed preview image, and determines an image complexity according to at least one of a set of factors consisting of the compressed setting, a resolution of the preview image and a size of the compressed preview image;

the control unit determines an initial compressed setting value according to at least one of a set of factors consisting of the image complexity, a resolution of the to-be-captured image and an image compression target; and

the control unit controls the image compressing unit to compress the to-be-captured image data according to the initial compressed setting value.

7. The apparatus according to claim 6, further comprising an image storing unit for storing the to-be-captured image signal.