CN100414425C - Image capturing device and method for capturing non-out-of-focus image - Google Patents

Abstract

The invention relates to an image capturing device and method for capturing a non-defocusing image, wherein the non-defocusing image mode calculates the depth of field range under the aperture value according to an exposure combination determined in the image capturing device, and then uses lenses with different focal lengths to continuously shoot a plurality of photos by covering all the depth of field of a shooting subject object, and the depth of field distance range can be from the shortest focusing distance of a camera to infinity. Therefore, clear photos of at least one subject object can be obtained in the photos continuously shot.

Description

Image capture device and method for capturing out-of-focus images

technical field

The present invention relates to an image capture device and a method for capturing an image, in particular to an image capture device and a method for capturing an out-of-focus image.

Background technique

For a general auto-focus image capture device, when capturing an image of a subject object (person, building or landscape), the required exposure value (EV; exposure value) to capture images. Generally speaking, the exposure value calculated by the processor in the image capture device is fairly accurate. However, the image capture device cannot judge by itself what the image (the background or the person) needs to be captured by the user, so it can only judge the value of the focal length (focal length) with simple rules to shoot the image, but Often results in a photo where the background is clear and the subject matter in front is blurred.

As shown in FIG. 1 , it shows a flow chart of a general auto-focus image capture device when shooting. Block 101 represents that the selected local scenery or buildings are used as the background when traveling in other places; then block 102 represents asking passers-by for help, or taking a picture of the subject object to be photographed by oneself; block 103 represents that the auto-focus image capture device is shooting , will start the auto-focus function; then, after shooting, there will be two situations, one is block 104, the subject object and the background (landscape or famous building) are clear, and this is a successful photo . However, when the photo is developed, it is found that the subject image is out of focus (block 105), that is, the image presented by the photo is not clear, and the value of commemoration and preservation is lost.

Contents of the invention

In order to reduce failed images, an automatic image capture device and method for capturing images without losing focus is provided here. By taking multiple photos with partially overlapping depth-of-field ranges, the out-of-focus generated during image capture can be improved. question.

One of the objectives of the present invention is to provide a device for capturing images without losing focus. Under a fixed exposure value, multiple images can be automatically shot with different focal lengths, so that when taking important commemorative photos, you can choose this mode , and take at least one photo with the subject object clear and not out of focus.

In order to achieve the above-mentioned purpose, an embodiment of the present invention provides an automatic image capture device for capturing a non-out-of-focus image mode, comprising: an input device for inputting a non-out-of-focus image option; a storage The device is used to store the programs of several out-of-focus image options; a processor outputs a command for executing the out-of-focus image options according to the out-of-focus image options and the programs of the several out-of-focus image options, wherein The command includes: capturing several images, the several images correspond to an exposure value, any of the images includes a subject object and a background object and are based on a focus distance, each of the focus distances corresponds to a depth of field, and each of the focus distances corresponds to a depth of field. A distance range of the depth of field corresponding to the focus distance partially overlaps with a distance range of the other depth of field corresponding to the other focus distance, and connecting each distance range of the depth of field will at least cover the subject object to the background object distance range, where the position of the subject object falls within any depth of field, corresponding to the distance range of the focus distance; a capture image unit, executing the command; and a controller, receiving the command and controlling the capture according to the command image unit.

To achieve the above purpose, the present invention also provides a method for capturing an out-of-focus image, the method for capturing an out-of-focus image includes: (a) providing a subject object and a background object; (b) capturing a first an image, which includes the subject object and the background object, and has a first focus distance according to the background object, wherein the first focus distance corresponds to an exposure value and a first depth of field; (c) fixing the exposure value and using It calculates to obtain a second focus distance, wherein the second focus distance corresponds to the exposure value and a second depth of field, and the second depth of field corresponds to the distance range of the second focus distance and the first depth of field corresponds to the first focus distance (d) capture a second image including the subject object based on the second focus distance; and (e) replace the first focus distance with the second focus distance, and repeat Step (c) and step (d) are performed N integer times, so that at least one clear photo of the subject object can be obtained from the N images.

In the present invention, a non-out-of-focus image mode is added to the camera with automatic focus. The out-of-focus image mode is based on the exposure combination determined in the original image capture device with auto-focus function, calculates the depth of field under this exposure value, and then uses lenses with different focal lengths to continuously take several photos to include Including connecting all depths of field, the depth of field can be from the shortest focusing distance to the infinity focusing distance of the image capture device. Therefore, it can be guaranteed that the subject object of at least one of the photos taken continuously will be clear.

Description of drawings

FIG. 1 is a flow chart of each step of shooting a blurred image of a subject object according to a traditionally disclosed image capture device with autofocus;

FIG. 2 is a flowchart of various steps of using an image capture device with an option of an out-of-focus image mode according to an embodiment disclosed in the present invention;

FIGS. 3A to 3C are the methods for capturing and simultaneously obtaining photos with clear subject objects and background objects using the non-out-of-focus image mode in the image capture device according to an embodiment disclosed in the present invention;

FIG. 4 is a schematic block diagram of an embodiment of an image capture device according to the present invention.

Explanation of symbols in the figure

11 The user selects the background to be photographed

13 Simultaneously activate the out-of-focus image mode in the image capture device

15. Use the computing processor of the image capture device to automatically capture an image including the subject object and the background object according to the first focal length, and obtain an exposure value at the same time

17 The image capture device applies the current exposure value to calculate the second focal length and the second depth of field

19 According to the out-of-focus image mode, continuously shoot several images of the same subject subject with the same exposure value but different focal lengths

21 After photo development, at least one clear photo of the subject matter can be obtained

30 image capture device

32 themed objects

34 background objects

50 input device

52 processors

54 storage device

56 storage device

58 controllers

60 lens group

62 shutters

64 aperture

101 When traveling abroad, select local scenery or buildings as the background

102 Ask passers-by for help, or take pictures of the subject you want to shoot by yourself

103 Auto-focus image shooting device will activate the auto-focus function when shooting

104 The subject matter and background (landscape or famous buildings) are clear, this is a successful photo

105 When the photo is developed, it is found that the subject image is out of focus, that is, the image presented in the photo is not clear, and the commemorative value is lost

Detailed ways

Some embodiments of the present invention are described in detail as follows. However, the invention can be practiced broadly in other embodiments than those described in detail, and the scope of the invention is not limited, which is to be determined by the scope of the claims.

According to the current general auto-focus capture device, when shooting an object, it first passes through the processor inside the image capture device, and after calculation, an appropriate exposure value (EV; exposure value) is determined. However, the current general image capture device itself does not have software to determine the subject to be photographed, and can only manually select the subject object to be photographed. Therefore, for the shortcomings of the prior art (block 105), the present invention discloses a method to improve the out-of-focus defect in the traditional image capture device, and also discloses a non-out-of-focus image mode The image capture device, when taking a photo, selects the out-of-focus image mode to obtain at least one clear photo of the subject object.

FIG. 2 shows a flowchart of utilizing an image capture device with an out-of-focus image mode option according to an embodiment of the present invention. Block 11 represents that the user selects the object to be photographed by using an image capture device, for example, a viewfinder on an automatic camera to find a view. In one embodiment, the object to be photographed includes a subject object and a background object. In a preferred embodiment, the subject object, such as a character nearer to the camera, and the background object, such as a person closer to the automatic camera, Mountains or buildings in remote locations have a large distance between them, but the embodiment is not limited to this situation.

Block 13 represents starting the non-out-of-focus image mode, and using the image capture device to capture the image. The so-called capture here refers to making the image record on an entity. For a traditional camera, it is to make the film sensitive and record Image; in the case of a digital camera, temporarily storing or storing the image in memory. Furthermore, in this embodiment, since an automatic camera is used, the automatic camera will obtain an appropriate exposure value according to its internal light metering system and calculation. Generally speaking, the exposure value is obtained by calculating the aperture value and the shutter value, such as addition operation.

Box 15 represents using the computing processor of the image capture device itself, and according to the first object distance (that is, the distance between the lens of the image capture device and the background object), to automatically capture a picture containing the subject object and the background object. image, and the first object distance and the first depth of field (depth of field) are used corresponding to the first focal length, and the above-mentioned appropriate exposure value (EV; exposure value) is used at the same time. Block 17 represents that the image capture device applies the exposure value of the current image capture device to calculate the second focal length and the second depth of field, wherein the second depth of field of the second focal length partially overlaps with the first depth of field of the first focal length, that is , the focal length of the clear image captured with the second focal length falls within the first depth of field of the first focal length, and is partially covered by the first depth of field of the first focal length.

Next, block 19 represents that according to the non-out-of-focus image mode, several photographs with the same exposure value but different focal lengths are continuously taken on the same subject object and background object, so that the photographs covering the subject object to the background object can be obtained The entire depth of field; finally, block 21, which means that after the photo is developed, at least one photo with a clear subject object can be obtained.

3A to 3C are used to show the preferred embodiment disclosed by the present invention, to illustrate the method of taking and obtaining a clear subject object photo by using the out-of-focus image mode in the image capture device. When traveling in a scenic spot, most of the tourists will choose beautiful scenery or famous buildings as the background object 34 to take photos as a souvenir when traveling. At this time, passers-by are usually asked for help, or by Users take pictures by themselves. Taking the Tokyo Tower as the background object 34 as an example, the image capture device 30 takes a view to cover the Tokyo Tower 34 as the background object, and people as the subject object 32. At this time, the focusing point in the center of the lens is usually focused on the Tokyo Tower 34. The arithmetic processor in the device 30 is used to calculate an appropriate exposure value, for example, the aperture is 5.6 and the shutter is 1/125 second. Its shooting parameters are shown in Fig. 3A, and its b1 represents the distance between the image capture device 30 and the background object 34, which is the actual focus distance (object distance) for the first time; a1 is the lens of the image capture device 30 to the subject object The distance between 32 is the focusing distance expected by the user. However, since the actual focusing distance for the first time is b1, the depth of field D1 only covers the vicinity of the Tokyo Tower 34, and the subject object 32 that is really expected to be photographed will be blurred.

Whether the subject object 32 is expected to be clear or not is related to the depth of field range distance of the focus distance, wherein the depth of field (depth of field) refers to the clear range distance on the film after the focus is completed. Therefore, when taking any commemorative photo, especially a landscape photo, it is desirable to have a longer depth of field so that the subject object 32 and the background object 34 to be photographed can be clear. Therefore, in addition to the depth of field, the aperture (aperture), the lens focal length (the focus length of lens) and the focal length (focal length) will all affect the sharpness of the photo. Among them, the shorter the focal length of the lens used, the farther the distance from the subject is. The longer the depth of field is.

Therefore, according to the above principles, in order to solve the problem of blurring the subject object 32 to be photographed, the out-of-focus image mode in the image capture device 30 can be activated before photographing the subject object 32 . As shown in FIG. 3A, the distance between the image capture device 30 and the subject object 32 is a1, and the first focal length lens used by the image capture device 30 focuses, and calculates that under this exposure value, the focus distance at this time is, Taking the first object distance b1 from the camera lens of the device 30 to the background object Tokyo Tower 34, the depth of field covered by it is the first depth of field D1. Next, referring to FIG. 3B , under the same exposure value, the second focal length is used for calculation. At this time, the depth of field covered by the second focal distance b2 is the second depth of field D2. It should be noted that, at this time, the range covered by the second depth of field D2 corresponding to the second focus distance b2 is connected, or partially overlapped with the range covered by the first depth of field D1 corresponding to the first object distance b1.

Furthermore, in this embodiment, the second focal length of the lens used is shorter than the first focal length, that is, in this embodiment, the non-out-of-focus image mode automatically uses a shorter focal length for subsequent shooting. The large depth of field makes up for the loss of depth of field when the focusing distance of the image capture device 30 is shortened. However, the embodiments of the present invention are not limited thereto. Optionally, if the focal length of the lens used to determine the exposure value is shorter, the out-of-focus image mode will automatically use a longer focal length for subsequent shooting, and a shorter focal length can also be used together. Subsequent shooting can be performed with a shorter or longer focal length, and is not limited to the above-mentioned embodiments.

By analogy, FIG. 3C shows that according to the above methods of calculating different focal lengths and different depths of field, an appropriate focal length of the nth photo can be obtained. Continuously shoot several images with the same exposure value but with different focus distances _bn , where n is the number of continuous shots ranging from 1 to 5, and the depth of field at this time is D _n . It should be noted that, using the non-out-of-focus image mode of this embodiment, the depth of field of continuous shooting corresponds to the range covered by the focus distance covered by a1. In this way, at least one clear photo of the subject object 32 must be obtained. In this embodiment, the number of photos to be taken depends on the aperture value set at that time, and is generally about 2 to 5 photos.

Taking an actual data as an example, if the distance between the shooting subject object 32 and the image capture device 30 is 3 meters, and the distance between the background object Tokyo Tower 34 and the image capture device 30 is 40 meters, then when shooting An appropriate exposure value can be obtained through calculation by an arithmetic processor in the image capture device 30 , and the exposure value is combined with an aperture of 4.0 and a shutter speed of 1/60 second. Then according to the following depth of field calculation formula, the foreground depth ΔL ₁ and the rear depth of field ΔL ₂ can be obtained, and the addition of the two is the depth of field ΔL:

ΔL ₁ =(FδL ² )/(f ² +FδL)

ΔL ₂ =(FδL ² )/(f ² −FδL)

ΔL=ΔL ₁ +ΔL ₂ =(2f ² FδL ² )/(f ⁴ −F ² δ ² L ² )

Where ΔL ₁ is the foreground depth, ΔL ₂ is the rear depth of field, ΔL is the depth of field, F is the aperture value of the lens, f is the focal length of the lens, L is the focus distance, and δ is the diameter of the permissible circle of confusion, where, The foreground depth ΔL ₁ is a distance from the background object 34 to a near point in front of the background object 34 , and the rear depth of field ΔL ₂ is a distance from the background object 34 to a far point behind the background object 34 . The allowable diameter of the diffusion circle means that when the diameter of the diffusion circle is smaller than the ability to distinguish with the naked eye, the image within this range is blurred and indistinguishable, for example, when the lens of the image capture device is 4.35 millimeters (mm) , which allows the diameter of the diffusion circle to be approximately 0.035 mm. Therefore, according to the above formula, the foreground depth, rear depth of field and depth of field can be expressed as

ΔL _1,n =(FδL ² )/(f ² +FδL),n=1～5

ΔL _2,n =(FδL ² )/(f ² -FδL),n=1～5

ΔL _n =ΔL _1,n +ΔL _2,n =(2f ² FδL ² )/(f ⁴ −F ² δ ² L ² )

The subscript 1 represents the foreground depth, and n represents the nth continuous shooting, therefore, ΔL _{1, n} represents the nth foreground depth calculated after the nth time; the subscript 2 represents the rear depth of field, and n represents the nth consecutive Therefore, ΔL _2,n can be expressed as the nth rear depth of field calculated after n consecutive shots, and ΔL _n represents the entire depth of field obtained at the nth time of shooting.

According to the above calculation formula, it can be obtained that the first foreground depth ΔL _1,1 is 2.33 meters to 4.56 meters. However, since the focusing distance is 40 meters, the first foreground depth ΔL ₁ , 1 is 32.82 meters, the first rear depth of field is ΔL _{2, 1} is 51.2 meters, and the first depth of field is ΔL ₁ , which is 84.02 meters. Therefore, the range of the first depth of field corresponding to the first focusing distance is between 7.1 meters and 91.2 meters, because the subject object 32 to be photographed (3 meters from the image capture device 30) does not fall within this distance range, therefore, The subject matter 32 is blurred.

Therefore, according to the calculation of the above depth of field formula, the exposure value is fixed, and the second focus distance is calculated to be 4 meters. At this time, the second foreground depth ΔL _2,1 is 1.25 meters and the second rear depth of field ΔL _2,2 is 3.37 meters, and the second depth of field corresponding to the second focusing distance ranges from 2.74 meters to 7.36 meters. Wherein this distance range (2.74 meters to 7.36 meters) partly overlaps the previous distance range (7.1 meters to 91.2 meters). By analogy, the third focusing distance is 2.1 meters, the third foreground depth ΔL _3,1 is 0.41 meters and the third rear depth of field ΔL _3,2 is 0.66 meters, so the third depth of field corresponds to the range of the third focusing distance From 1.69m to 2.76m, covering the distance range of the second depth of field corresponding to the second focus distance. Therefore, according to the calculation of the above-mentioned depth of field formula, a photo is captured respectively when the focus distances are b1 (40 meters), b2 (4 meters) and b3 (2.1 meters). These three photos have the same exposure value, but use different focal length lenses, but can cover most of the depth of field between the subject object 32 and the background object 34, and it can be guaranteed that at least one is a clear photo of the subject object 32 .

In addition, it is worth mentioning that under different light conditions (sunny or rainy), the light metering system in the image capture device will use the algorithm in the image capture device to obtain the exposure under the current light conditions. At this time, according to different aperture values, calculate different depths of field under different focal lengths, and then obtain at least one clear photo of the subject object.

FIG. 4 is a schematic block diagram of an embodiment of an image capture device according to the present invention. In one embodiment, the image capture device generally includes an input device 50 , a processor 52 , a controller 58 , storage devices 54 , 56 and capture devices, such as a lens group 60 , a shutter 62 , an aperture 64 and so on. The input device 50 is a button or an option of a function or a mode. In this embodiment, the input device 50 includes a non-focus mode option. The processor 52 processes information from the input device 50 and the controller 58 to perform various calculations or settings. In this embodiment, the processor 52 includes receiving a request for an out-of-focus mode option to process the image capture operation. The controller 58 receives the capture parameter setting from the processor 52 and controls the action and time of the capture device, such as selecting the required lens group 60 , controlling the speed of the shutter 62 and controlling the size of the aperture 64 . The storage device 56, such as film or memory, is used to record the captured image information.

The storage device 54 is used to store the readable program for executing the non-out-of-focus mode. The storage device 54 can also be built in the storage device of the processor 52. With the storage device 54, the processor 52 can process calculations and execute the non-out-of-focus mode. Each parameter required by the mode is given to the controller 58 again. According to the above, once the user uses the input device 50 to select the non-out-of-focus mode, the image capture device can automatically take a plurality of photos according to the calculation, so as to capture a focused photo.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention; all other equivalent changes or modifications that do not deviate from the spirit disclosed in the present invention should be included in the claims In the range.

Claims (11)

1. the method for burnt image is not lost in an acquisition, it is characterized in that the method that burnt image is not lost in this acquisition comprises:

(a) provide a theme object and a background object;

(b) acquisition one first image, it comprises this theme object and this background object, and according to this background object have one first focusing from, wherein this first focusing is from a corresponding exposure value and one first depth of field;

(c) fix this exposure value and by its calculate to obtain one second focusing from, wherein this second focusing is to should the exposure value and one second depth of field, and this second depth of field to should second focusing from distance range and this first depth of field to should first focusing from distance range have part to overlap;

(d) acquisition one second image, its comprise this theme object with based on this second focusing from; And

(e) with this second focusing from replace this first focusing from and repeating step (c) and step (d) N integer, open at N thus and can obtain at least one theme object image clearly in the image.

2. the method for burnt image is not lost in acquisition as claimed in claim 1, wherein, above-mentioned first depth of field by this first focusing from, the depth of field and the one first back depth of field are tried to achieve before one first.

3. the method for burnt image is not lost in acquisition as claimed in claim 2, and wherein, the above-mentioned first preceding depth of field is the distance of this background object to one first near point that is positioned at this background object the place ahead.

4. the method for burnt image is not lost in acquisition as claimed in claim 2, and wherein, the above-mentioned first back depth of field is the distance of this background object to one first far point that is positioned at this background object rear.

5. the method for burnt image is not lost in acquisition as claimed in claim 1, wherein, above-mentioned second depth of field be by this second focusing from, the depth of field and the one second back depth of field are tried to achieve before one second.

6. the method for burnt image is not lost in acquisition as claimed in claim 5, and wherein, the above-mentioned second preceding depth of field is the distance of this background object to one second near point that is positioned at this background object the place ahead.

7. the method for burnt image is not lost in acquisition as claimed in claim 5, and wherein, the above-mentioned second back depth of field is the distance of this background object to one second far point that is positioned at this background object rear.

8. the method for burnt image is not lost in acquisition as claimed in claim 1, and wherein, above-mentioned N integer is two to five times.

9. the image capture unit of burnt image is not lost in an acquisition, it is characterized in that, comprises:

One input media does not lose burnt image option in order to import one;

One storage device is carried out the readable program that this does not lose burnt image option in order to store several;

One processor, according to this do not lose burnt image option and these several do not lose the program of burnt image option, an order of not losing burnt image option is carried out in output, wherein this order comprises:

Capture several images, the corresponding exposure value of these several images, arbitrary this image comprise a theme object and a background object with based on a pair of defocus distance, each this focusing is from a corresponding depth of field, wherein each this depth of field to should focusing from a distance range, with other this depth of field to should other focusing from a distance range have part to overlap, and the distance range of each this depth of field is attached to mutually I haven't seen you for ages contains the distance range of this theme object to this background object, the position of this theme object falls into arbitrary this depth of field, corresponding this focusing from distance range in;

This order is carried out in one pick-up image unit; And

One controller receives this order and controls this pick-up image unit according to this order.

10. the image capture unit of burnt image is not lost in acquisition as claimed in claim 9, wherein, this storage device, carry out the readable program that this does not lose burnt image option in order to store several, make this pick-up image unit several images of acquisition continuously, these several readable programs are controlled this pick-up image unit and are carried out the following step:

(a) fix this exposure value and calculate acquisition one first image by it, it comprises a theme object and a background object, and according to this background object have one first focusing from, wherein this first focusing is to should the exposure value and one first depth of field;

(b) obtain one second focusing from, wherein this second focusing is to should exposure value and one second depth of field, and this second depth of field to should second focusing from distance range, with this first depth of field to should first focusing from distance range the part overlapping is arranged;

(c) acquisition one second image, its comprise this theme object with based on this second focusing from; And

(d) with this second focusing from replace this first focusing from and repeating step (b) and step (c) N integer, open at N thus and can obtain at least one theme object image clearly in the image.

11. the image capture unit of burnt image is not lost in acquisition as claimed in claim 10, wherein, above-mentioned N integer is two to five times.

Images