ImageJ中的曲線擬合功能并不很強(qiáng)，但通過定制應(yīng)該遠(yuǎn)強(qiáng)于Excel，部分地接近少數(shù)一些專門工具，例如Logger Pro的水平。我們知道，Excel里面的曲線擬合功能沒有幾種，簡(jiǎn)單湊合還可以，稍復(fù)雜點(diǎn)的就很無力了；Tracker里的曲線擬合功能也不太行，盡管它能自定義一些函數(shù)，但也沒好哪里去。

ImageJ的不少中英文網(wǎng)頁上都建議不要直接使用ImageJ的曲線擬合功能，但也有較少的卻在建議。說明它的曲線擬合尚可一用，特別是在不太奇怪的范圍里使用，完全可以一搏的。

ImageJ的曲線擬合在Analyze/Tools/Curve Fittings菜單下，探索英文網(wǎng)站的關(guān)鍵詞ImageJ Analyze Tools CurveFittings function，會(huì)給出一大批介紹，基本夠用了。

利用Math函數(shù)集合進(jìn)行簡(jiǎn)單的自定義函數(shù)擬合：

直接線性擬合，在一個(gè)畫布上可以同時(shí)畫兩個(gè)擬合曲線：

能通過擬合曲線反向列出擬合數(shù)據(jù)表：

ImageJ默認(rèn)也存在一些數(shù)學(xué)函數(shù)、類型轉(zhuǎn)換函數(shù)等，這些函數(shù)在編寫macro時(shí)使用，但適用于曲線擬合時(shí)期：

在https://imagej./ij/developer/macro/functions.html列出的大部分?jǐn)?shù)學(xué)函數(shù)和類型轉(zhuǎn)換函數(shù)，約45個(gè)：

abs(n)：Returns the absolute value of n.

acos(n)：Returns the inverse cosine (in radians) of n.

asin(n)：Returns the inverse sine (in radians) of n.

atan(n)：Calculates the inverse tangent (arctangent) of n. Returns a value in therange -PI/2 through PI/2.

atan2(y, x)：Calculates the inverse tangent of y/x and returns an angle in the range -PIto PI, using the signs of the arguments to determine the quadrant. Multiply theresult by 180/PI to convert to degrees.

cos(angle)：Returns the cosine of an angle (in radians).

exp(n)：Returns the exponential number e (i.e., 2.718...) raised to the power of n.

floor(n)：Returns the largest value that is not greater than n and is equal to aninteger. See also: Math.ceil and round.

log(n)：Returns the natural logarithm (base e) of n. Note that log10(n) =log(n)/log(10). See also: Math.log10.

Math.abs(n)：Returns the absolute value of n.

Math.acos(n)：Returns the inverse cosine (in radians) of n.

Math.asin(n)：Returns the inverse sine (in radians) of n.

Math.atan(n)：Returns the inverse tangent (arctangent) of n, a value in the range -PI/2through PI/2.

Math.atan2(y, x)：Calculates the inverse tangent of y/x and returnsan angle in the range -PI to PI, using the signs of the arguments to determinethe quadrant. Multiply the result by 180/PI to convert to degrees.

Math.ceil(n)：Returns the smallest (closest to negative infinity) value that is greaterthan or equal to n and is an integer.

Math.cos(angle)：Returns the cosine of an angle (in radians).

Math.erf(x)：Returns an approximation of the error function.

Math.exp(n)：Returns the exponential number e (i.e., 2.718...) raised to the power of n.

Math.floor(n)：Returns the largest value that is not greater than n and is equal to aninteger.

Math.log(n)：Returns the natural logarithm (base e) of n.

Math.log10(n)：Returns the base 10 logarithm of n.

Math.min(n1, n2)：Returns the smaller of two values.

Math.max(n1, n2)：Returns the larger of two values.

Math.pow(base, exponent)：Returns the value of base raised to the power ofexponent.

Math.round(n)：Returns the closest integer to n.

Math.sin(angle)：Returns the sine of an angle (in radians).

Math.sqr(n)：Returns the square of n.

Math.sqrt(n)：Returns the square root of n, or NaN if n is less than zero.

Math.tan(n)：Returns the tangent of an angle (in radians).

Math.tan(n)：Returns the tangent of an angle (in radians).

Math.toRadians(degrees)：Converts an angle in degrees to an equivalent anglein radians. Requires 1.53f.

Math.toDegrees(radians)：Converts an angle in radians to an equivalent anglein degrees. Requires 1.53f.

Math.constrain(n, min, max)：Limits 'n' to the range 'min'-'max'. Requires1.53n.

Math.map(n, low1, high1, low2, high2)：Maps thevalue 'n' in the input range 'low1'-'high1' to the output range 'low2'-'high2'.Requires 1.53n.

maxOf(n1, n2)：Returns the greater of two values. See also: Math.max.

minOf(n1, n2)：Returns the smaller of two values. See also: Math.min.

parseFloat(string)：Converts the string argument to a number andreturns it. Returns NaN (Not a Number) if the string cannot be converted into anumber. Use the isNaN() function to test for NaN. For examples, seeParseFloatIntExamples.

parseInt(string)：Converts string to an integer and returns it.Returns NaN if the string cannot be converted into a integer.

parseInt(string, radix)：Converts string to an integer and returns it. Theoptional second argument (radix) specifies the base of the number contained inthe string. The radix must be an integer between 2 and 36. For radixes above10, the letters of the alphabet indicate numerals greater than 9. Set radix to16 to parse hexadecimal numbers. Returns NaN if the string cannot be convertedinto a integer. For examples, see ParseFloatIntExamples.

PI：Returns the constant π (3.14159265), the ratio of the circumference to thediameter of a circle.

pow(base, exponent)：Returns the value of base raised to the power ofexponent.

round(n)：Returns the closest integer to n. See also: floor.

sin(angle)：Returns the sine of an angle (in radians).

sqrt(n)：Returns the square root of n. Returns NaN if n is less than zero.

tan(angle)：Returns the tangent of an angle (in radians).