How to use PS software to add, subtract and tamper with the image identification

How to use PS software to add, subtract and tamper with the image to identify

With the popularity of digital cameras and computers, the era of universal photography. But with the photography? The first time I've seen this is when I've had a chance to see the camera in action. Events are also endless. The following is my search on how to use PS software to add or subtract tampering with the image to identify, I hope to help you! To learn more about the information please continue to pay attention to our fresh graduates training network!

Photography is divided into pre-shooting and post image production, in the era of film photography, the complex darkroom technology is only mastered by a few professionals. Entering the digital photography era, with the rapid development of computer imaging technology, digital image processing can use all kinds of software, especially Adobe Photoshop (PS) image processing software is the most widely used, the most powerful, the operation is also more convenient. Computer image processing formed by the image in the visual and real natural images almost indistinguishable from the naked eye. For the modification of the image mainly to the PS software? Mainly in the case of modified images, this paper on the use of computer image processing technology to add, delete, tamper with the image method, characteristics and how to test to make a description, to determine how to effectively distinguish and identify the real natural image and after the late modification of the image.

First, the use of PS software to add, delete, tamper with the image method

PS software synthesis function in image processing occupies an important position, the synthesis is not a simple patchwork, it requires the use of a variety of materials, through the organization, processing, modification, fusion, to get a new ? Design? works, so as to achieve the desired effect, and therefore requires a high degree of artistic cultivation and PS operation ability. From recent years, the use of computer image processing technology to modify the image of the following main methods.

1. Using PS software to add content in the picture

Add an image specifically from a picture (i.e.,? Keyboarding?) A partial, and then add it to another picture, to generate a new picture that is the use of PS composite picture. The first is to choose the right material, and then the need to replace the part of the selection with a selection, paste the material on the map, and then use the mask to control the area, and finally the overall color and detail part of the modification.

2. The use of PS software to delete, modify the content of the middle of the picture

The picture you do not want to delete the part and can not affect the integrity of the picture, there are a variety of ways to stamp repair tools and the establishment of the selection of the main. If the scene to be repaired is surrounded by white or monochrome, use a solid color brush to fill in.

3. The use of PS software on the image transformation, blurring

The modification of the image of the techniques and the use of PS software to make the image deformation and blurring. PS software can be deformed image processing methods include: free transformation, liquefaction filter, distortion filter, etc., through the command can be deformed into a special image shape. The command can deform an image into a special shape.

Second, the use of PS software to add, delete, tamper with the image characteristics

Patchwork to create an image is one of the commonly used means of using PS image processing technology. Mainly the use of PS image processing software to move, delete, cut and paste, rotate, local zoom, retouching and other various editing functions on the image processing, made into a new image.

Fake photo refers to an imaginary creation of a photo that does not actually exist, which is highlighted by the fact that the photo is not real. Counterfeit photographs are usually manifested in different parts of the real photo by editing, copying, synthesizing, reflecting a new content of the photo. Other parts are changed, the outstanding performance is that the photo is already objectively existed, is the producer of the already existing photo according to their own needs to modify, edit the formation of the photo. Alteration is generally divided into three types.

(1) additive alteration. It is to add some content on the photo screen.

(2) Deletion alteration. It is to crop or delete something from the photo frame.

(3) A combination of additive and deletive alterations. In the actual inspection of the process of non-authenticity photos, the reality is often encountered in the picture both added and deleted, and a combination of the two altered photos, which increases the difficulty of the test.

Third, the use of PS software to add, delete, tamper with the image identification method

The altered image, no matter how elaborate efforts, modified photos by careful observation will always fall out of the traces. For this kind of suspicious picture check, should use a variety of methods, from various aspects, multi-level inspection, in many cases people only with the naked eye is difficult to find the flaws, with the help of PS software can be a comprehensive assessment of the authenticity of the digital image.

1. Using PS software to view digital photo Exif?metadata?

The Exif?metadata of a digital photo is an image file format. is an image file format that currently has two versions, V2.1 and V2.2. It is added to the Jpeg file header with a variety of shooting information captured by the digital camera during the shooting process, such as camera data (e.g., camera manufacturer, model, etc.), photography parameters (e.g., shutter speed, focal length, etc.) and the thumbnail information of the photo (depending on the camera), which has a size of 2 to 6kB (depending on the camera), and is stored in the Jpeg image file after Tag encoding. To view it with the full version of PS, first open the digital photo and select it via ? File Profile? Exif? option, there are image descriptions (such as camera model, shooting time, etc.), user comments (such as Exif color space, etc.), related sound files (such as the file source, scene type, Exif label more than 30 content.

2. Using PS software to zoom in on photos

Using scientific theories of scene imaging, lighting, and color filters to observe and compare the density of light, contrast, tone, and gray value of scenes in suspected areas of forgery in the image, and to analyze the presence of contradictions with the imaging principle in order to discern whether or not the photo has been altered. Whether there are traces of alteration in the photos. In the natural image of two or more space coherent region of the probability of precise matching (including color, shape, texture, etc.) is very small, so to successfully identify the image of the copy of the tampered region, the key lies in determining the size of the image block, the characteristics. In the photo inspection, the use of PS to zoom in on the image processing, and then by observing the photo in the subject of the edge of the situation, the photo depth of field is in line with the lens imaging gauge, the difference in the noise of the image, the continuity of color, etc., you can determine whether the photo is taken in the same light conditions, so as to determine the photo's' authenticity.

(1) Check whether the edge of the subject in the photo (the edge of the fine such as hair, etc.) is blurred. Most of the fake photos are often the better subject and then put into a more ideal environment to increase the newsworthiness and beauty of the picture. Image edges can be defined as discontinuities in the local features of the image, manifested as abrupt changes in the gray level of the image, abrupt changes in the texture structure and changes in color, etc., making the edges of these subjects often not smooth. After high magnification can be found: these places have a lot of blurring.

(2) Check whether the depth of field of the photo is in line with the lens imaging laws. Whether using a wide-angle lens or a large telescope head, the performance of the depth of field is a certain law. And altered photos often can not meet these laws.

(3) Check the image noise. Digital camera noise for the image visible by the CCD / CMOS or digital signaling system caused by the error message, the visible noise in the digital image is usually affected by the temperature and ISO sensitivity, the higher the value of these two is the worse the effect. The use of different digital cameras with different background noise, different ISO sensitivity of the photographs taken under the noise is different, in the high magnification of the noise of the image after the regional statistical comparison method, you can check the originality of the digital image.　(4) Check the continuity of image color. Color is recognized as the most valuable underlying feature of an image. For complex background true images, the color features have relatively good continuity, with softer color shifts, while the RGB values of colors are different between adjacent pixels. Add images with abrupt color shifts between the edges and the background, or pixels with similarity and the same RGB value of the color between adjacent pixels.

(5) Check the reasonableness of the change of reality. The degree of clarity in the digital image with the shooting when focusing on the location of the alignment plane and the size of the depth of field, for stationary objects, when the image of the depth of field outside the range of the degree of clarity of a thing more than the depth of field within the range of the clarity of the scene, it should be added to replace or synthesize the alteration of the map, but should be excluded from the operation of improperly caused by the change in the virtual reality of the irrationality of the when there is a movement of the object. The clarity of stationary objects in the image should be higher than the clarity of moving objects, but if you use the follow method to shoot, the clarity of moving objects can be higher than the clarity of stationary objects.

3. Using PS software to measure the comparative method

The use of PS software in the measurement tool, the determination of the shooting angle of the suspicious part of the photo and the background of the shooting angle, the direction of the shadow, the direction of the light source and the relationship between the differences and similarities of perspective to determine the authenticity of the picture.

(1) Measure whether the subject and the surroundings in the photo are the same in terms of shooting angle. There? contradiction? s different shooting angles will appear different visual effects. If the subject and the surrounding environment in the shooting angle on the existence of the contradiction, you can see that this is a picture with two different shooting angle shooting pictures put together? New pictures.

(2) Measure whether the shadow direction of the object in the photo is uniform. Fake photos are often taken at different times, different locations, different environments to put them together, multi-faceted differences will appear different light, resulting in different shadows, through the shadow, you can also find out the breakage of fake news photos. Add the image and the background of the shadow in the strength, length will have a more obvious difference.

(3) Measure whether the direction of the light source in the photo is uniform. The light in an image should be uniform rather than contradictory. Consistency of light angle in the same digital image, the direction and location of the main light source is determined, the subject of the concave and convex parts of the light and dark changes and the length and direction of shadows should have the same, when the image of a scene in the image of the appearance of unexplained changes in light and dark or shadows can be judged to have a fabricated image of the possibility of digital imaging in a picture of the transition between light and dark is gradual, is natural. And synthesize a new photo, different photos of people or objects due to the shooting conditions do not, the light selection must have differences in shooting. Therefore, it is difficult to have a natural transition between the two images when splicing the light at the articulation.

(4) Measurement of photographs in the imaging perspective proportionality relationship is consistent. According to the principle of perspective, in determining the authenticity of the image test, can be used to compare the image of the size of each imaging object perspective, direction perspective, shadow perspective, and the proportion of the object ratio of the relationship between the method of measurement and analysis of the image of the existence of phenomena that violate the laws of perspective. If the violation of the laws of perspective imaging, such as not parallel to the picture of the parallel straight line did not disappear to a point, the proportion of near large and far small does not meet the effect of perspective, and the picture is not parallel to the direction of the line did not disappear in the sky point or location, the photo must have added part, then we must carefully observe and analyze the photo to determine the addition or deletion of the part.

4. Using PS software to change the tone of the image

The tone of the photo refers to the black and white tendency of the photo. The traces of modification in high or low key photos, as well as highlights or dark areas are difficult to detect, when managed to change the shadow tone of the photo, in which the traces of modification may be exposed. Use PS image processing software to adjust the image shading in the opposite direction, i.e., brighten the high key photos, darken the low key photos, and brighten and darken the middle key photos respectively. Then the photo will be enlarged to 100% to observe the brightening or darkening part, some additions, deletions and other traces of the legacy of retouching, the background area is not coordinated, the poor quality of the image, imaging irregularities will be revealed.

This article briefly introduces the method of image modification, characteristics, discusses the forged image identification easy method. With the continuous and profound development of modern digital technology, there will inevitably be more advanced means of image forgery, which will pose a higher challenge to the identification of digital images. As image forensics is an all-open research field, has been scientific research institutions, judicial organs, as well as the press and other comprehensive attention, I believe that with the gradual development of image forensics technology, the theoretical study of image authenticity will become increasingly in-depth, the digital image identification system will be increasingly perfect and standardized.