Pixel density - Revision history

Xinreality at 14:18, 29 April 2025

2025-04-29T14:18:09Z

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	[[File:Low pixel density vs high pixel density.png\|thumb\|Figure 1. High Pixel Density Vs Low Pixel Density (image: teknosrc.com)]]		[[File:Low pixel density vs high pixel density.png\|thumb\|Figure 1. High Pixel Density Vs Low Pixel Density (image: teknosrc.com)]]

	Pixel density is the number of pixels in a certain amount of space and it describes the sharpness and clarity for different types of displays (i.e. computers, mobile devices, cameras, etc). Pixel density is often measured in Pixels per Inch (PPI) - the number of pixels present per inch on the display. A display's pixel density is different from its resolution, which is the total number of pixels across the display's width and height (Figure 1). <ref name=”1”>Nowell, P. (2016). Pixel Density, demystified: How pixel density works and how it affects your designs. Retrieved from https://medium.com/@pnowelldesign/pixel-density-demystified-a4db63ba2922</ref> <ref name=”2”>Raghavendar, T.S. (2013). Resolution Vs pixel density in displays – all you need to know. Retrieved from http://teknosrc.com/resolution-vs-pixel-density-in-displays-all-you-need-to-know/</ref> <ref name=”3”>Übergizmo. What is PPI: Pixels per inch, display resolution. Retrieved from http://www.ubergizmo.com/what-is/ppi-pixels-per-inch/</ref>		Pixel density is the number of pixels in a certain amount of space and it describes the sharpness and clarity for different types of displays (i.e. computers, mobile devices, cameras, etc). Pixel density is often measured in Pixels per Inch (PPI) - the number of pixels present per inch on the display. A display's pixel density is different from its resolution, which is the total number of pixels across the display's width and height (Figure 1). <ref name=”1”>Nowell, P. (2016). Pixel Density, demystified: How pixel density works and how it affects your designs. Retrieved from https://medium.com/@pnowelldesign/pixel-density-demystified-a4db63ba2922</ref> <ref name=”2”>Raghavendar, T.S. (2013). Resolution Vs pixel density in displays - all you need to know. Retrieved from http://teknosrc.com/resolution-vs-pixel-density-in-displays-all-you-need-to-know/</ref> <ref name=”3”>Übergizmo. What is PPI: Pixels per inch, display resolution. Retrieved from http://www.ubergizmo.com/what-is/ppi-pixels-per-inch/</ref>

	==Calculating pixels per inch==		==Calculating pixels per inch==

Xinreality at 08:15, 13 December 2017

2017-12-13T08:15:12Z

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	==References==		==References==
			<references />

	[[Category:Terms]]		[[Category:Terms]] [[Category:Technical Terms]]

Neo222 at 06:57, 15 October 2017

2017-10-15T06:57:46Z

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	[[File:Pixel density PPI formula.png\|left]]		[[File:Pixel density PPI formula.png\|left]]
	~~<math>\alpha</math>~~

	where Wp is the horizontal number of pixels; Hp, the vertical number of pixels; and S, the screen size. As an example, a 32 inches TV with a resolution of 1080p (1920 x 1080 pixels) will result in a pixel density of 68.84 ppi. <ref name=”2”></ref>		where Wp is the horizontal number of pixels; Hp, the vertical number of pixels; and S, the screen size. As an example, a 32 inches TV with a resolution of 1080p (1920 x 1080 pixels) will result in a pixel density of 68.84 ppi. <ref name=”2”></ref>

Neo222 at 06:57, 15 October 2017

2017-10-15T06:57:05Z

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	[[File:Pixel density PPI formula.png\|left]]		[[File:Pixel density PPI formula.png\|left]]
	<math>\~~sqrt{1-e^2}~~</math>		<math>\alpha</math>

	where Wp is the horizontal number of pixels; Hp, the vertical number of pixels; and S, the screen size. As an example, a 32 inches TV with a resolution of 1080p (1920 x 1080 pixels) will result in a pixel density of 68.84 ppi. <ref name=”2”></ref>		where Wp is the horizontal number of pixels; Hp, the vertical number of pixels; and S, the screen size. As an example, a 32 inches TV with a resolution of 1080p (1920 x 1080 pixels) will result in a pixel density of 68.84 ppi. <ref name=”2”></ref>

Neo222 at 06:35, 15 October 2017

2017-10-15T06:35:37Z

← Older revision		Revision as of 06:35, 15 October 2017
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	[[File:Pixel density PPI formula.png\|left]]		[[File:Pixel density PPI formula.png\|left]]
			<math>\sqrt{1-e^2}</math>

	where Wp is the horizontal number of pixels; Hp, the vertical number of pixels; and S, the screen size. As an example, a 32 inches TV with a resolution of 1080p (1920 x 1080 pixels) will result in a pixel density of 68.84 ppi. <ref name=”2”></ref>		where Wp is the horizontal number of pixels; Hp, the vertical number of pixels; and S, the screen size. As an example, a 32 inches TV with a resolution of 1080p (1920 x 1080 pixels) will result in a pixel density of 68.84 ppi. <ref name=”2”></ref>

Paulo Pacheco at 17:48, 14 October 2017

2017-10-14T17:48:28Z

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	{{stub}}		{{stub}}
	[[Pixel ~~density~~]] is the number of [[pixels]] in a ~~fixed distance~~. It is often measured in ~~'''~~pixels per inch~~''' or '''PPI'''~~. A display's pixel density is different from its [[resolution]], which is the total number of pixels across the display's width and height.		[[File:Low pixel density vs high pixel density.png\|thumb\|Figure 1. High Pixel Density Vs Low Pixel Density (image: teknosrc.com)]]

			Pixel density is the number of pixels in a certain amount of space and it describes the sharpness and clarity for different types of displays (i.e. computers, mobile devices, cameras, etc). Pixel density is often measured in Pixels per Inch (PPI) - the number of pixels present per inch on the display. A display's pixel density is different from its resolution, which is the total number of pixels across the display's width and height (Figure 1). <ref name=”1”>Nowell, P. (2016). Pixel Density, demystified: How pixel density works and how it affects your designs. Retrieved from https://medium.com/@pnowelldesign/pixel-density-demystified-a4db63ba2922</ref> <ref name=”2”>Raghavendar, T.S. (2013). Resolution Vs pixel density in displays – all you need to know. Retrieved from http://teknosrc.com/resolution-vs-pixel-density-in-displays-all-you-need-to-know/</ref> <ref name=”3”>Übergizmo. What is PPI: Pixels per inch, display resolution. Retrieved from http://www.ubergizmo.com/what-is/ppi-pixels-per-inch/</ref>

			==Calculating pixels per inch==
			Pixel density is calculated based on the resolution and size of the display using the following formula:

			[[File:Pixel density PPI formula.png\|left]]

			where Wp is the horizontal number of pixels; Hp, the vertical number of pixels; and S, the screen size. As an example, a 32 inches TV with a resolution of 1080p (1920 x 1080 pixels) will result in a pixel density of 68.84 ppi. <ref name=”2”></ref>

			PPI, while an important metric, cannot be used by itself as the standard for sharpness since the distance between the eyes and the display is also important. When the eyes are closer to a display, pixels may become visible; moving further away from a device that has additional pixel density may not be useful because the added pixel density will not be perceptible due to distance. Different devices are used at different ranges to the eyes: smartphones are used closer to the eyes then tablets, computer monitors are used a bit further away, and TV even farther. This means that for different devices there are distinctive PPIs to achieve the same perceived sharpness from the specific point of view of the user. <ref name=”3”></ref>

	==Pixel density in Virtual Reality==		==Pixel density in Virtual Reality==
	[[~~Virtual Reality#Devices~~\|~~Virtual~~ reality head-mounted displays]] ~~require high~~ pixel density ~~because~~ the ~~screen is very close~~ to the ~~user's eyes~~. ~~Higher PPI leads~~ to ~~clearer, sharper images with~~ more ~~details~~. An [[~~HMD~~]] with low pixel density can cause blurring of words and objects, presence of pixelation and the [[screen door effect]]. ~~PPI~~ is an ~~important parameter when considering HMDs~~.		[[File:Relation between pixels per degree and field of view.png\|thumb\|Figure 2. Relation between pixels per degree and field of view (Image: eenewseurope.com)]]

			When dealing with [[virtual reality]] or [[augmented reality]] (AR) [[head-mounted display\|head-mounted displays]] ([[HMD]]s), a more useful metric for pixel density might be Pixels per Degree (PPD). <ref name=”4”>Boger, Y. (2017). Understanding pixel density & retinal resolution, and why it’s important for AR/VR headsets. Retrieved from https://www.roadtovr.com/understanding-pixel-density-retinal-resolution-and-why-its-important-for-vr-and-ar-headsets/</ref> <ref name=”5”>Chinnock, C. (2017). What’s the definition of an immersive display? Retrieved from https://www.insightmedia.info/whats-the-definition-of-an-immersive-display/</ref>

			To calculate the HMD’s pixel density in PPD (the number of pixels per degree it presents to the eye), the number of pixels in a horizontal display line has to be divided by the horizontal [[field of view]] provided by the lens. <ref name=”4”></ref>

			As an example, the old Oculus Rift DK1 had a single 1280 x 800 display, resulting in 640 x 800 pixels per eye., and a monocular field of view of around 90 degrees. Dividing the horizontal number of pixels (640 px) by its horizontal FOV (90 degrees) results in a pixel density of 7.1 ppd. <ref name=”4”></ref>

			A higher pixel density will allow finer details to be visible and contributes to an overall more realistic image. One of the things that separated professional-grade VR HMD’s from the ones available to consumers was the higher pixel density. <ref name=”4”></ref>

			Indeed, this is is one of the elements that contribute to the sense of [[immersion]] in VR. An HMD with low pixel density can cause blurring of words and objects, presence of pixelation and the screen door effect. Also, as pixel density increases, lower [[persistence]] is needed to avoid blurring. However, in general terms, a higher PPD number will result in a sharper, more realistic image - one of the factors that influence immersion and [[presence]]. There is an inverse relationship - a trade-off - between PPD and FOV (Figure 2): a narrow FOV results in a higher pixel density and a higher FOV produces a lower pixel density. <ref name=”6”>Chinnock, C. (2017). VR headset design: Time to rethink pixel density vs wider FOV? Retrieved from http://www.eenewseurope.com/design-center/vr-headset-design-time-rethink-pixel-density-vs-wider-fov</ref>

	As pixel density ~~increases~~, ~~lower [[persistence]]~~ is ~~needed to avoid blurring~~.		Chinnock (2017) provides the following example: “If you want a 100-degree horizontal field of view and use a panel with 1080 x 1200 pixels per eye, you get 11 pixels per degree per eye if the optics are perfect and your eye is in the optimal lens-to-eye position. The PPD per eye of the HTC Vive, Oculus CV1 and PlayStation VR headsets are all in the 10 to 15 range today.” A low FOV would result in a higher pixel density, but this could also affect negatively the VR experience since a wider field of view is also important for immersion. <ref name=”6”></ref> <ref name=”7”>VR Lens Lab. Field of view for virtual reality headsets explained. Retrieved from https://vr-lens-lab.com/field-of-view-for-virtual-reality-headsets/</ref>

	~~[[GameWorks~~ VR~~]]'s [[multi-res shading]] is able~~ to ~~render different parts of the image with different resolutions~~ to ~~better match~~ the pixel density ~~of a warped image. Improving performance~~.		There is still a way to go for VR HMDs to come close to the visual acuity or retinal resolution of people’s eyes. Nevertheless, higher pixel density displays for VR headsets are coming. <ref name=”6”></ref>

	==Pixel density of various HMDs==		==Pixel density of various HMDs==

Shadowdawn at 16:34, 30 October 2015

2015-10-30T16:34:03Z

← Older revision		Revision as of 16:34, 30 October 2015
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	==Pixel density in Virtual Reality==		==Pixel density in Virtual Reality==
	[[Virtual Reality#Devices\|Virtual reality head-mounted displays]] require high pixel density because the screen is very close to the user's eyes. Higher PPI leads to clearer, sharper images with more details. An [[HMD]] with low pixel density can cause blurring of words and objects, presence of pixelation and the "screen door effect". PPI is an important parameter when considering HMDs.		[[Virtual Reality#Devices\|Virtual reality head-mounted displays]] require high pixel density because the screen is very close to the user's eyes. Higher PPI leads to clearer, sharper images with more details. An [[HMD]] with low pixel density can cause blurring of words and objects, presence of pixelation and the [[screen door effect]]. PPI is an important parameter when considering HMDs.

	As pixel density increases, lower [[persistence]] is needed to avoid blurring.		As pixel density increases, lower [[persistence]] is needed to avoid blurring.

Xinreality at 04:39, 28 August 2015

2015-08-28T04:39:18Z

← Older revision		Revision as of 04:39, 28 August 2015
Line 3:		Line 3:

	==Pixel density in Virtual Reality==		==Pixel density in Virtual Reality==
	[[Virtual Reality#Devices\|Virtual reality head-mounted displays]] require high pixel density because the screen is very close to the user's eyes. Higher PPI leads to sharper images with more details. An [[HMD]] with low pixel density can cause blurring of words and objects, presence of pixelation and the "screen door effect". PPI is an important parameter when considering HMDs.		[[Virtual Reality#Devices\|Virtual reality head-mounted displays]] require high pixel density because the screen is very close to the user's eyes. Higher PPI leads to clearer, sharper images with more details. An [[HMD]] with low pixel density can cause blurring of words and objects, presence of pixelation and the "screen door effect". PPI is an important parameter when considering HMDs.

	As pixel density increases, lower [[persistence]] is needed to avoid blurring.		As pixel density increases, lower [[persistence]] is needed to avoid blurring.

Xinreality at 02:00, 28 August 2015

2015-08-28T02:00:51Z

← Older revision		Revision as of 02:00, 28 August 2015
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	As pixel density increases, lower [[persistence]] is needed to avoid blurring.		As pixel density increases, lower [[persistence]] is needed to avoid blurring.

	[[GameWorks VR]]'s [[multi-res shading]] is able to render different parts of the image with different resolutions to better match the pixel density of a warped image.		[[GameWorks VR]]'s [[multi-res shading]] is able to render different parts of the image with different resolutions to better match the pixel density of a warped image. Improving performance.

	==Pixel density of various HMDs==		==Pixel density of various HMDs==

Xinreality at 01:59, 28 August 2015

2015-08-28T01:59:58Z

← Older revision		Revision as of 01:59, 28 August 2015
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	As pixel density increases, lower [[persistence]] is needed to avoid blurring.		As pixel density increases, lower [[persistence]] is needed to avoid blurring.

			[[GameWorks VR]]'s [[multi-res shading]] is able to render different parts of the image with different resolutions to better match the pixel density of a warped image.

	==Pixel density of various HMDs==		==Pixel density of various HMDs==