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Method for testing resolution of each imaging region of digital camera

An imaging area, digital camera technology, applied in the field of image processing

Inactive Publication Date: 2010-10-06
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] In shooting, especially in remakes, there is often such a problem, that is, whether to take a photo directly or cut out the middle part of the photo and enlarge it to the size of the original photo to make it clear

Method used

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  • Method for testing resolution of each imaging region of digital camera
  • Method for testing resolution of each imaging region of digital camera
  • Method for testing resolution of each imaging region of digital camera

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0084] Example 1 Canon EF 28-135 image quality test at F8.0 at 135mm

[0085] First prepare the resolution test board. The test board ( image 3 ) directly displayed on a monitor or a projector, or printed out and pasted on a glass or plastic plate. image 3Each white dot in is a pixel, and the interval between white dots is 5 pixels (of course, the interval can also be larger or smaller). Then if it is displayed on a 30-inch monitor (DELL 3008WFP), there are a total of 2560×1600 pixels and about 512×320 white points. The use of monitors is mainly from the perspective of cost and convenience, because there are already high-resolution monitors. In fact, if you print a 30-inch screen, the cost is relatively high, and the mounting is also troublesome. Glass or plastic boards also cost money. If a high-resolution monitor is not readily available, it can also be printed and shot for testing.

[0086] The second is to shoot. Use a tripod to set up the camera Canon 1Ds Mark III, ...

Embodiment 2

[0114] Example 2 Canon EF 100-400L imaging quality test at F8.0 at 135mm

[0115] Adopt the test method of embodiment 1.

[0116] Figure 11a and Figure 11b The results of the edge and the center are given respectively. Although there is a certain amount of astigmatism and dispersion, it is not obvious. You can compare it with Figure 5.

[0117] Figure 12 The measurement results of the astigmatism are given, and as in Example 1, the radial astigmatism is obviously greater than the tangential one, so only the radial astigmatism needs to be considered. It can be seen that the average and maximum values ​​of radial dispersion in the central part are around 5 and 7, respectively, and even at the outermost edge, the astigmatism is less than 1.5 times that in the central part. That said, the Edge is perfectly usable if the requirements aren't particularly demanding.

[0118] Figure 13 and Figure 14 The test results of relative astigmatism and resolution are given respecti...

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Abstract

The invention provides a method for testing the resolution of each imaging region of a digital camera. A camera to be tested is used for shooting resolution test plates to obtain photos, and the photos are treated according to the following steps: 1. converting into gray level images; 2. calculating the diameters of the photo images; 3. carrying out dark corner light loss correction; 4. carrying out binaryzation on the images; 5. dividing a plurality of pixel blocks to be used as foreground pixel blocks; 6. removing the foreground pixel blocks positioned at edges or corners of the photos or the foreground pixel blocks with too small area; 7. establishing a plurality of concentric circles for dividing the photo images into a plurality of annular regions; and calculating the astigmation of each annular region; and 8. calculating the relative astigmation and the resolution of each annular region in the photo images. The invention can determine the clear usable region of the photos shot by a set of camera equipment, and can also compare the resolution difference in different proportions between the whole shooting picture and the middle cut image, and the shooting method with the maximum resolution can be found, so the required shooting number is minimum on the premise that the resolution in the conversion is maximum or the resolution is ensured.

Description

technical field [0001] The invention relates to the technical field of image processing, in particular to a method for testing astigmatism and resolution (resolution) of a digital camera. It can be used for resolution evaluation of ordinary digital cameras, digital SLR cameras and digital backs. Background technique [0002] The two most important performance indicators of digital camera quality are resolution and color. The resolution, sometimes called resolution, mainly refers to the evaluation of the resolution of detail capture. For color, if there is a color cast, it can also be rescued by color correction technology. But for the resolution, it is absolutely impossible to improve it through post-correction (image processing algorithm). The details that have not been captured in the photo will not be revealed no matter how interpolated, enlarged or sharpened. For example, if a 6-megapixel photo has a resolution of 1500, then interpolating it to 24 million pixels will ...

Claims

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Application Information

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IPC IPC(8): G01M11/02
Inventor 石洗凡刁常宇鲁东明
Owner ZHEJIANG UNIV
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