Sharpness statement

Sharpness What does sharpness mean?

Sharpness is an index that reflects the sharpness of image plane and edge.

Introduction to sharpness:

If the definition is increased, the detail contrast on the image plane is also higher and looks clearer. For example, in the case of high definition, not only the wrinkles and spots on the face on the screen are clearer, but also the protrusions or depressions of facial muscles can be lifelike. On the other hand, dark lines or black lines in the vertical direction, or places where black-and-white images suddenly change, in the case of high sharpness, the edges of lines or black-and-white images suddenly change more sharply, and the overall picture appears clearer. Therefore, improving sharpness is actually improving clarity, which is the good side that people need.

However, the higher the definition, the better. If the sharpness is adjusted too high, white lines will appear on both sides of the black line, and the image will look distorted and dazzling. If this happens on a block image, the image will be seriously distorted and ugly. For example, when this happens on a small face image, not only the edges of the face will have white edges, but also the edges of black and shadow parts such as hairline, eyebrows, eyes, nose and lips will have white edges, which looks very uncomfortable. It can be seen that although the sharpness is too high, it will improve the clarity, but it will also make the graphics out of shape, which is also not a good thing. Therefore, in order to obtain a relatively clear and true image, the sharpness should be adjusted appropriately.

Definition of photography field:

In the field of photography, sharpness is used to represent the contrast of image edges. A clearer definition is that sharpness is the derivative amplitude of brightness with respect to space. Due to the characteristics of human visual system, high-definition images look clearer, but in fact, the increase in sharpness does not improve the real resolution.

What does photo sharpness mean?

Talking too much is too complicated. Let's talk about it

For example, if a square stone is placed on the ground, its edge and ground are obvious; If it is a soft soil block, its edge is blurred compared with the ground; This is the level of sharpness.

For example, writing with a pen, writing with a soft pen, the edge is softer; Write with a hard ballpoint pen with hard edges; This is also the level of sharpness.

The same is true for photos, and the main picture of photos with good clarity is clear; The definition is relatively blurred. Just like looking at a building 100 meters away, clear weather looks sharp, sharp, and high sharpness; A little foggy weather doesn't look very clear, which is low sharpness. This example may not be appropriate, but it basically means this.

If you want to explain it more clearly, you can find a PHOTOSHOP software, find a picture, and use the tools of "sharpening" and "blurring" to process the picture respectively. At this time, you can intuitively feel the change of sharpness.

Who will tell me the difference between sharpness and clarity?

Discrimination of the concepts of image clarity, resolution and sharpness (reprinted in sunose.spaces.live/blog/s! 4e 1a 1b 9d 47 b 6 ca 92！ Entrance sharpness is a common name for contrast. In the field of photography, sharpness is used to represent the contrast of image edges, and it is more clearly defined that sharpness is the derivative amplitude of brightness relative to space. Due to the characteristics of human visual system, high-definition images look clearer, but in fact, the increase in sharpness does not improve the real resolution.

Sharpness: The comprehensive expression of resolution and contrast (sharpness). Sharpness, also known as fresh sharpness and bright sharpness, is the ability of photographic lens to vividly reproduce the middle level, dark level, low contrast shadow details, weak brightness contrast and subtle color changes of the scene. The lens with high contrast has clear outline, sharp edge, normal contrast, rich layers, delicate texture, clear tone, strong texture, soft color transition and true and natural color reproduction. Resolution refers to the number of pixels expressed or captured per unit length (the number of photoelectric sensing elements of CCD sensor). Also called discrimination, discrimination, analysis, discrimination. Obviously, the higher the resolution of the lens, the clearer and more delicate the image will be. Its unit is "line pair/mm (line pair/mm) LP/ mm". Its advantage is that it can be quantified and represented by data, making the results more intuitive, scientific and rigorous.