Linear Interpolation: Formula, Methods, and Applications

The technique of determining a value between two points on a line or curve is known as linear interpolation. To assist us also to remember what it implies, consider the initial half of the term, ”inter,” as meaning’ meaning’ enter,” which reminds us to examine ”within” the data we started with. This tool, interpolation, is important not just in statistics but also in science, commerce, and any other situation where it is necessary to anticipate values that lie between two known data points.

Interpolation is a method for obtaining new values for any function using a collection of values. This formula is used to determine an unknown value on a point. If the linear interpolation formula is employed, We should use it to calculate the new value from the two provided points. In comparison to Lagrange’sLagrange’s interpolation formula, the “n” set of numbers should be accessible, and Lagrange’sLagrange’s technique should be used to determine the new value.

If you want to know more about this topic, you’re welcome here. Read on as we explore the facts about this topic.


Linear Interpolation Formula

If the two known locations are provided by the coordinates displaystyle (x 0,y 0)(x 0,y 0) and displaystyle (x 1,y 1)(x 1,y 1), the linear interpolant is the straight line between them. The value y along the straight line is provided by the equation of slopes for a value x in the interval displaystyle (x 0,x 1)(x 0,x 1).

It is mathematically derivable from the figure on the right It’sIt’s a type of polynomial interpolation with n = 1.

The formula is obtained by solving this equation for y, which is the unknown value at x.

This is the formula for linear interpolation in the interval display style (x 0,x 1)(x 0,x 1)(x 0,x 1). Outside of this range, the formula is the same as linear extrapolation.

This formula is also known as a weighted average. The weights are inversely proportional to the distance between the endpoints and the unknown location; the closer point has a greater effect than the distant point. As a result, the weights represent normalized distances between the unknown location and each of the endpoints.

                                         y= y1 + (x – x1)/(x2 – x1) x (y2 – y1)

Interpolation Formula Calculation

  1. Find the value of y at x = 8 using the interpolation formula given a series of values (2, 6), (5, 9)?
  2. x0=8, x1=2, x2=5, y1=6, y2=9y=y1+ are the known values. (x−x1)(x2−x1)×(y2−y1)

y=6+ ((8−2)(5−2)×(9−6)

y = 6 + 6 y + 6 y = 12


Determining Linear Interpolation Formula

Assume we have two known coordinates, x1,y1x1,y1 and x2,y2x2,y2.

Now we want to calculate the yy value for some xx value that is between x1x1 and x2x2. This yy value approximation is also there as an interpolated value.

There are two easy techniques for selecting yy that spring to mind. The first step is to determine if xx is closer to x1x1 or x2x2. If xx is near to x1x1, then y1y1 is used as an estimate; otherwise, y2y2 is used. This is referred to as nearest-neighbor interpolation.

The second step is to draw a straight line from x1,y1x1,y1 to x2,y2x2,y2. We check for the yy value on the line for our selected xx. This is an example of linear interpolation.


Linear Interpolation Formula 3d

To connect the source and destination color values in the lattice points of a 3D table. However, the color space transformation utilizes a 3D lookup table (LUT). The closest lattice points are used to interpolate nonlattice points. This technique has been popular recently in a variety of applications and has integrated itself into the ICC profile standard.

The 3D Lookup Table

The 3D lookup technique is divided into three steps: packing, extraction, and interpolation. 2 Packing is the process of partitioning the source space and selecting sample points for the purpose of creating a lookup table. The extraction stage seeks to locate the input pixel and extract the color values of the closest lattice points. However, interpolation is the final phase, in which the input signals and extracted lattice points are there to determine the destination color requirements for the input point.


Packing is the process of dividing the domain of the source space and populating it with sample points in order to construct the lookup table. In general, the table is a construction of sampling in equal steps along each axis of the source space.

Based on a five-level LUT, this yields (n – 1)3 cubes and n3 lattice points. The number of layers is also denoted as n. This approach has the benefit of implicitly providing information on which cell is adjacent to which. As a result, all that is required is keeping track of the beginning position and spacing for each axis.


Interpolation calculates the destination color specifications for the input point using the input signals and the extracted lattice points that hold the destination requirements. However, interpolation techniques use geometrical connections or cellular regression to do mathematical computations. Geometrical interpolations make use of the various methods to subdivide a cube. Trilinear, prism, pyramid, and tetrahedral interpolations are the four geometrical interpolations. The trilinear interpolation also got revealed in a 1974 British patent by Pugsley. Thus it was the first 3D interpolation to emerge in the literature.

I proposed the concept of linear interpolation utilizing tetrahedral segmentation of a cube in 1967. 8 Korman and Yule utilized a similar idea of linear interpolation to compute dot areas of color scanners in 1971 by searching for the nearest four neighbors that encircle the point of interest and create a tetrahedron. 9 Sakamoto and I took later patented the use of tetrahedral interpolation in color-space transformation, as well as related global patents.

Geometric Interpolation

3D interpolation is just a multiple application of linear interpolation. As a result, we begin with linear interpolation and go through 2D (bilinear) and 3D (trilinear) interpolations. Linear interpolation is critical. Interpolate the point p on the curve between the lattice points p0 and p1. However, our interpolated value pc(x) is proportional to the ratio (x x0)/(x1 x0), where (x1 x0) is the projected length of the line segment between points p0 and p1, and (x x0) is the projected distance between points p and p0.

Pyramid interpolation

The cube is also separated into three parts for pyramid interpolation. Each one also takes a face as the pyramid foundation, with its corners linked to a vertex on the opposite side as the apex. However, to find the point of interest, you must do a search. The equation includes five terms and computes the result by using the five vertices of the provided pyramid.


Linear Interpolation Formula Thermodynamics

The interpolation has been there to fill gaps in tables since antiquity. Assume you have a table with a nation’s population in 1970, 1980, 1990, and 2000, and you wish to estimate the population in 1994. Linear interpolation is a simple method for accomplishing this. However, the technique of employing linear interpolation for tabulation was there for Babylonian astronomers and mathematicians to utilize in Seleucid Mesopotamia (last three centuries BC) and Hipparchus, a Greek astronomer and mathematician (2nd century BC). Ptolemy’sPtolemy’s Almagest (2nd century AD) has a description of linear interpolation.

In computer graphics, the basic technique of linear interpolation between two variables is widely different. However, it is frequently popular as a lerp in that field’s vocabulary. For the operation, the phrase can also be there as a verb or a noun.

All current computer graphics processors have Lerp functions in their circuitry. They are frequently present as building pieces for more sophisticated processes, such as bilinear interpolation. This may also complete in three lerps. Because this process is inexpensive, it is also an excellent method to build accurate lookup tables with a rapid lookup for smooth operations that do not require a large number of table entries.


Interpolation Formula Excel

Here’s an example that will help you understand the notion of interpolation. Every other day, a gardener is also measuring and tracking the growth of a tomato plant. This gardener is inquisitive, and she wants to know how tall her plant was on the fourth day.

Her table of observations will look like this:

                             Day                                    Height

                             1                                             0

                             3                                              4

                             5                                              8

                             7                                              12

                             9                                                16

Here’s an example that will help you understand the notion of interpolation. Every other day, a gardener measured and tracked the growth of a tomato plant. This gardener is inquisitive, and she wants to know how tall her plant was on the fourth day. But what if the plant didn’t grow in a neat linear pattern? What if its development also looked more like this? What would the gardener do to make an estimate using the above curve? That’s when the interpolation formula comes in help. And it is,

The following syntax=forecast


  • x is the input value.
  • ys are the known y-values.
  • xs are the known x-values.

When the number of x-values and y-values is more than 2, the FORECAST function will not provide an interpolated y-value. Linear interpolation is based on the assumption that the change in y for a given change in x is linear. However, in most situations, linear interpolation in Excel will produce adequately accurate results. If you want even higher precision, you may want to try a more sophisticated technique such as cubic splines.