What is HSI Color Space?

The HSI color space is a very important and appealing color model for applications in image processing. The HSI variety model addresses each tone with three parts: intensity (I), saturation (H), and hue The HIS color space's color representation is depicted in the figure below. The Tone part depicts the actual variety as a point between [0,360] degrees. Zero degrees are red, 120 are green, and 240 are blue. 60 degrees is yellow, 300 degrees is maroon. The amount of white color in the color is indicated by the saturation component. The scope of the S part is [0,1].

The Force range is somewhere in the range of [0,1] and 0 methods dark, 1 method white. Hue is more important as saturation approaches 1 and less important as intensity approaches 0 or 1, as shown in the previous figure. Power additionally restricts the immersion values. To equation that believers from RGB to HSI or back is more muddled than with other variety models, consequently we won't expand on the itemized particulars engaged with this interaction.

What is Color Space?

A useful conceptual tool for comprehending a device's or digital file's color capabilities is a "color space." Color spaces can show whether shadow/highlight detail and color saturation can be retained and how much they will be compromised when trying to reproduce color on another device. A color very similar to white but actually a little bit "beige" would emerge if all of the light from the universe's gas and dust clouds, galaxies, and their stars were added together. Color space is crucial because it affects how we perceive images. A space can sometimes be applied incorrectly, resulting in a messed-up image. Sometimes, a space is applied correctly for one kind of display but makes the image look weird on another kind. That is the reason we have normalized spaces.

What is Color Model?

A method for numerically specifying or describing a color is called a color model. Normal models incorporate RGB, HSV and CMYK. A color model is a system that assists us in defining and describing colors through numerical values. For instance, in the 24-bit-deep RGB color model, the intensity of each of the model's red, green, and blue components is represented on a scale from 0 to 255. There are eight bits for each channel in the model. Although the majority of color models typically employ a combination of three or four values or color components, there are many different kinds of color models that use various mathematical systems to represent colors.

RGB Model

The RGB color model is a structured system that is used in digital devices and light-based media to create a wide range of colors from a small group of primary colors, in this case red, green, and blue. The model's name comes from the first letter of each primary color's name. It is one of the three most normal variety models, which incorporate CMYK (cyan, maroon, yellow, key [black]), principally utilized for variety printing, and RYB (red, yellow, blue), frequently utilized in the visual expressions. One illustration of the subtractive color system, the RYB color model, is depicted in this diagram, which demonstrates how colors mix. The RGB variety model is viewed as an added substance framework, since it adds frequencies of the essential tones red, green, and blue together to make an expansive scope of varieties. The cycle can be exhibited by utilizing three light projectors, every one fitted with a hued channel so one tasks a light emission light onto a white wall, one more a light emission light, and the third a light emission light. In the event that the red and green shafts were to cover on the wall, they would make yellow. In the event that the force of the green light were diminished or the immersion of the red expanded, the light on the wall would become orange. White would result from the combination of the three lights. The RYB color model is one way this additive process differs from the subtractive process. Artists primarily working in paint employ the RYB color model. Its primary colors—red, yellow, and blue—would theoretically combine to produce black. Paint's pigments selectively absorb and reflect light to produce color, which explains this. A yellow pigment, for instance, reflects yellow, green, and red wavelengths while absorbing blue and violet wavelengths. Assuming yellow and blue colors are blended, green will be created, since the main frequency isn't emphatically consumed by one or the other shade.

HSI Model (Hue, Saturation, Intensity)

It is a very important and attractive color model because it represents the colors the same way as the human eye senses colors. Hue is a color component that describes a pure color (pure yellow, orange or red).

Saturation component represents the measure of the degree to which color is mixed with white color.

0 degree – Red
120 degree – Green
240 degree – Blue
60 degree – Yellow
300 degree – Magenta

Intensity Range is [0, 1]0 
means white1 means black

The formula for conversion of RGB to HSI is quite complicated as compared to other color models.

Advantages of HSI

1. Better Image Analysis: HSI separates brightness from color. This makes it easier to analyze images, like finding edges or recognizing objects, because we can focus on brightness without worrying about color.
2. Improved Image Editing: In HSI, you can change brightness or contrast without messing up the colors. This is useful for making pictures look better or for removing noise (unwanted random pixels) from images.
3. Works Well in Different Lighting: HSI handles changes in lighting better. For example, it can recognize a face in both bright sunlight and in the shade because it separates the color information from the light information.
4. Precise Color Adjustments: You can adjust just the color without changing the brightness. For example, you can make colors more vivid or shift colors from blue to green without affecting how light or dark the image is.

Disadvantage of HSI

1. Hard to Change Between Models: Changing colors from the regular way computers show colors (RGB) to HSI and back can be hard and take time. This makes things slower, especially when you need to process many images quickly.
2. Confusing Colors: When colors are very dull or almost gray, the HSI model can get confused and not work as well. It has trouble figuring out the exact color in these cases.
3. Not Always Supported: Many software programs and tools are made to work with RGB, not HSI. This means you might have to do extra work to use HSI in some programs.

Applications of HSI

The utilizations of hyperspectral imaging are colossal and always extending. HSI has provided complete hyperspectral imaging systems for a wide range of applications, in addition to the aforementioned specialties:

1. Legal Examination
2. Compound imaging
3. Variety estimation
4. Change identification
5. Industrial quality control
6. Materials distinguishing proof
7. Clinical and drugs

Conclusion

Every color is represented by the three parts of the HSI color model: intensity (I), saturation (H), and hue The beneath figure delineates how the HIS variety space addresses tones. The Tint part depicts the actual variety as a point between [0,360] degrees. Force is all out brilliance of the variety and furthermore characterized mathematically as the normal of the same RGB values. The purity or grayness of a color is measured by its saturation. The terms "HSL" stand for "Hue, Saturation, and Luminance." Grayer colors have a saturation value closer to 0 and more pure colors have a saturation value closer to 1. Color is based on these three values. There are hue, saturation, and luminance values for every color that can be imagined. With three components, this color space represents every color: Hue (H) is how we perceive various colors, saturation (S) is how pure the color is, which means that a color with a higher saturation is brighter, and intensity (I) is how bright the color is.