CN201393267Y

CN201393267Y - High dynamic range image acquisition device

Info

Publication number: CN201393267Y
Application number: CN200920067553U
Authority: CN
Inventors: 朱建国; 江兴智
Original assignee: WUXI JINTENG INTELLIGENT TECHNOLOGY Co Ltd
Current assignee: WUXI JINTENG INTELLIGENT TECHNOLOGY Co Ltd
Priority date: 2009-02-06
Filing date: 2009-02-06
Publication date: 2010-01-27
Anticipated expiration: 2019-02-06

Abstract

The utility model provides a high dynamic range image acquisition device comprising an image collecting module, an embedded processor and a display module. The image collecting module is used for acquiring at least one picture; the embedded processor is electrically connected with the image collecting module and synthesizes a high dynamic range image according to the picture; and the display module is electrically connected with the embedded processor and displays the high dynamic range image. The high dynamic range image acquisition device can directly acquire and synthesize the high dynamic range image by utilizing the high performance embedded processor, thereby fully exerting the calculation and processing capability of the embedded processor so as to directly, rapidly and conveniently acquire the high dynamic range image, therefore, a user can see the effect of the acquired high dynamic image while directly shooting a picture.

Description

High dynamic range image acquisition device

Technical Field

The present invention relates to an image capturing device, and more particularly to a high dynamic range image capturing device.

Background

Many people use cameras and may have experienced such an experience: when a person stands in front of the window against the light, the illuminated face is dark, and if the person wants to illuminate the face clearly, the scenery outside the window may be overexposed. This is because the illumination dynamic range of the actual environment is larger than the dynamic range of the camera.

In many cases, the ratio of radiant light intensity in bright and dark portions of a scene is greater than 100000: 1. The reduced dynamic range is more than 100 db. However, the dynamic range of a common camera is only 60db, and the dynamic range of the whole scene cannot be covered, so that the irradiated image is overexposed at some bright parts or is too dark at some dark parts, and the situation causes the image to lose details, and the image content cannot be sufficiently restored for further analysis.

Another example of a high dynamic range is when there is both a direct sunlight portion and a shaded portion of the scene. The contrast of the bright and dark portions of the image is also large at this time.

The eye is the window where people feel the world, and from the viewpoint of acquiring an external image, the eye is equivalent to a camera. For human eyes, the dynamic range obtained by the system is higher than that of a common camera system due to the local automatic adjustment function of the system. Therefore, the scene directly seen by people is richer than the pictures taken by ordinary cameras, and has more details and richer colors. Whether a digital camera can be used to obtain a picture similar to the visual perception of people is a problem that many camera designers and users are concerned about when the resolution of the picture is improved.

Acquiring an image with a High Dynamic Range (HDR) is beneficial to acquiring an image with an optimal visual effect, and is of great use in medical image processing and other industrial analysis. In medical and industrial image control, high dynamic range situations are also frequently encountered. For the synthesis of high dynamic range images, some organizations have started research, but currently, mainly focus on the synthesis on computers. The current processing is mainly to shoot a group of pictures through a camera, then to synthesize the pictures on a computer through an algorithm, and to output a restored high dynamic range image. To obtain high dynamic range images, some companies design special cameras for this purpose, which increases the cost.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a high dynamic range image acquisition device to improve prior art's disappearance.

To achieve the above objective, the present invention provides a high dynamic range image capturing device, which includes an image capturing module, an embedded processor and a display module. The image acquisition module is used for capturing at least one picture; the embedded processor is electrically connected with the image acquisition module and synthesizes a high dynamic range image according to the picture; and the display module is electrically connected with the embedded processor and displays the high dynamic range image.

The utility model discloses a high dynamic range image acquisition device utilizes the embedded treater of high performance, directly carries out acquireing and synthesizing of high dynamic range image, and calculation and the throughput that can the embedded treater of full play make acquireing of high dynamic range image more direct swift, make the user can be direct when shooing, see the effect of shooting.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a schematic diagram of a high dynamic range image capturing apparatus according to an embodiment of the present invention.

Detailed Description

Fig. 1 is a schematic diagram of a high dynamic range image capturing apparatus according to an embodiment of the present invention. As shown in fig. 1, the high dynamic range image capturing apparatus 1 includes an image capturing module 11, an embedded processor 12, a display module 13, and a memory 14.

The image capturing module 11 captures a plurality of pictures of the same scene with different exposure coefficients. The embedded processor 12 is electrically connected to the image acquisition module 11, and synthesizes a high dynamic range image according to the picture. The display module 13 is electrically connected to the embedded processor 12 and displays a high dynamic range image.

In the present embodiment, the high dynamic range image capturing apparatus 1 further includes a memory 14 and a touch key 15. The storage 14 is used for storing a plurality of pictures of different exposure coefficients of the same scene and the synthesized high dynamic range image. The touch key 15 is used for inputting a shooting instruction, a processing instruction, a display instruction, and a system setting instruction of the image capturing module 11. In addition, the image capturing module 11 in this embodiment is a ccd camera, an cmos camera or an cmos camera, and the display module 13 is a touch-controlled lcd, but the present invention is not limited thereto.

Further, in the present embodiment, the embedded processor 12 is

533 a processor.

The processor is a novel 16-32 bit embedded processor designed to meet the computing requirements and power consumption constraints of current embedded audio, video and communication applications.

Processor based onThe micro-signal architecture (MSA) developed by ADI and Intel corporation combines a 32-bit RISC type instruction set and dual 16-bit multiply-accumulate (MAC) signal processing functions with the ease of use provided by general-purpose microcontrollers. The combination of such processing features enables

Processors can function well in both signal processing and control processing applications-in many cases eliminating the need to add separate heterogeneous processors, this capability greatly simplifies hardware and software design implementation tasks. At present, the number of the current day,

processors can provide performance up to 756MHz in single core products.The novel symmetric multiprocessor members of the processor family achieve performance doubling at the same frequency.

The processor family also provides industry leading power consumption performance down to 0.8V. This combination of high performance and low power consumption is essential to satisfy today's and future signal processing applications, including broadband wireless, internet appliances with audio/video capabilities, and mobile communications. Wherein,

533 is ADI Corp

The main frequency of a high-performance video processing chip in the series can reach 600MHz at most, 1200M times of multiply-add operation can be processed per second, a large number of special instructions for images are provided, and a plurality of instructions can be processed in parallel.

In the present embodiment, the image capturing moduleThe block 11 outputs pictures of different exposure coefficients of the same scene to the embedded processor 12 via the PPI interface (

533 a processor). Embedded processor 12(

533 processor) may obtain a Camera Response Function (CRF) of the image capturing module 11 according to the pictures of the same scene with different exposure coefficients. The camera response curve reflects the relationship between the gray level of the image and the exposure and illumination of each point in the scene.

The exposure of each point is recorded as X ═ E ═ T, (1)

Is the product of the illumination E and the exposure time T.

The relationship between the gray-scale value of the image and the exposure can be expressed by the following formula:

Z_ij＝f(E_iΔt_j) (2)

where Zij is expressed as a gray value of the image.

Equation (2) is the CRF curve, which is an intrinsic characteristic curve of each camera and is a non-linear function.

Debevec proposes a method of recovering the response curve of a camera, which only needs to take a group of pictures at different exposure ratios for the same scene to take a group of pictures. The corresponding response curve can be recovered by analyzing the image data, the requirement on the environment is simple, and the CRF curve can be recovered under almost any scene. In the present embodiment, the embedded processor 12(

533 processor) will calculate the CRF curve using Debevec's method.

According to the principle of sensitization of the image capturing device 11, f can beTo be regarded as a monotonically increasing function, so f has a reversible function f^-1The formula (2) is rewritten as

f^-1(Z_ij)＝E_iΔt_j (3)

Taking logarithm on two sides to obtain:

lnf^-1(Z_ij)＝lnE_i+lnΔt_j (4)

let g be lnf^-1(Z_ij) The above formula can be abbreviated as:

g(Z_ij)＝lnE_i+lnΔt_j (5)

where i represents each point and j represents the exposure of each picture.

To restore the CRF curve, the condition is Z_ijAnd Δ t_jThe illumination Ei and the function are known and unknown. We recover the illumination Ei value and the CRF function g (z) from the angle of least square error according to equation (3).

The problem may actually be converted to a solution equation, with the following quadratic equation taking the minimum.

The first term of the formula makes the solution meet the requirement of minimum variance, and the second term makes the square sum of the second reciprocal of g minimum, so that the curve meets the requirement of smoothness. By solving the system of equations defined by equation (4), the g (Z) function can be solved.

Note that Z has a finite value, and when the CRF curve is restored, only g (Z) values at finite points, such as g (0) to g (255), are restored.

When the camera response curve is determined, the illumination of the image can be restored by,

lnE_i＝g(Z_ij)-lnΔt_j (7)

where Ei is the illumination intensity of the corresponding point in the scene to be restored. Z_ijIs the pixel value at a certain exposure time, Δ t_jIs the exposure time.

Consider Zij and Δ t for each graph_jThe values may contain some errors and noise, and the recovered Ei values of each graph may be weighted and averaged to recover the lnEi values, which results in a better signal-to-noise ratio.

Thus embedded processor 12: (

533 processor) can restore the Ei value of each point to obtain the high dynamic range image.

For high dynamic range images, the Ei value of the image is obtained, and if the Ei value is directly sent to a common display, the display effect is often not good. If the simple linear mapping method is adopted, the contrast of the whole image display looks like washing, and in order to better display the high dynamic range image on a general display, the embedded processor 12(533 processor) must perform Tone Mapping processing (Tone Mapping) on the high dynamic range image so that it can realize display close to the human eye feeling on an ordinary display. At this time, the resulting image is a high dynamic range image that can be displayed on a normal display.

Although the present invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A high dynamic range image pickup apparatus characterized by comprising:

the image acquisition module is used for capturing at least one picture;

the embedded processor is electrically connected with the image acquisition module and synthesizes a high dynamic range image according to the picture; and

and the display module is electrically connected with the embedded processor and displays the high dynamic range image.

2. The device of claim 1, further comprising a storage device electrically connected to the image capture module and the embedded processor, the storage device being configured to store the image and the high dynamic range image.

3. The device of claim 1, further comprising a touch button electrically connected to the embedded processor, wherein the touch button is used for inputting a shooting command, a processing command, a display command, and a system setting command of the image capturing module.

4. The high dynamic range image capturing device of claim 1, wherein said image capturing module is a ccd camera, a cmos camera or a cmos camera.

5. The high dynamic range image capturing device of claim 1, wherein said display module is a liquid crystal display.

6. The high dynamic range image capturing device of claim 5, wherein said liquid crystal display is a touch-sensitive liquid crystal display.