Method and apparatus for measuring performance of a lamp

1. A light source testing method comprising:

providing a light source for generating light;

using an image capturing apparatus for capturing an image with a plurality of pixels according to the light, the image having an image center and an image edge at a distance of D 1 from the image center; and

selecting a predetermined gray level G, and defining a brightest area and the light source center as follows:

the brightest area being an area formed by pixels with gray level larger than the predetermined gray level G from the plurality of pixels of the image;

the light source center being the center of the brightest area;

defining the distance between the light source center c and the image center b as D 2 to calculate the center deviation D 2 /D 1 ;

calculating the area Q′ of the brightest area;

calculating a maximum gray level GX of the plurality of pixels of the image, and a gray level difference h′=GX−G between the predetermined gray level G and the maximum gray level GX;

calculating a product V′=h′*Q′ of the gray level difference h′ and the area Q′;

calculating a plurality of rectangles surrounding the brightest area with their four sides in contact with the brightest area;

selecting a specific rectangle having a minimum area among the plurality of rectangles, and defining the shorter side of the selected rectangle as X, the longer side as Y;

defining the ratio of side R 1 , the ratio of area R 2 , and the S value corresponding to the shape of the light source to detect the uniformity of the light source as follows:

R 1 = X/Y;

R 2 =( Q 3 /( X*Y ));

S=R 1 * R 2 ;

calculating the average gray level I according to the plurality of gray levels of the plurality of pixels; and

evaluating the brightness and uniformity of the light source by calculating a P value as follows;

P=(1−D 2 /D 1 )*V′*S*I.

2. The method of claim 1 wherein the smaller the center deviation D 2 /D 1 is, the larger the P value is, and the more uniform the light source is.

3. The method of claim 1 wherein the closer to 1 the S value is, the larger the P value is, and the more uniform the light source is.

4. The method of claim 1 wherein the larger V′ or I is, the larger the P value is, and the brighter the light source is.

5. A light source testing method comprising:

providing a light source for generating light;

using an image capturing apparatus for capturing an image with a plurality of pixels according to the light;

selecting a first predetermined gray level G 1 , and defining a first light source testing area and a light source center c as follows:

the first light source testing area being an area formed by pixels with gray level larger than the first predetermined gray level G 1 from a plurality of pixels of the image;

the light source center c being the center of the first light source testing area; and

defining the distance between the light source center c and the image center b as D 2 to calculate a center deviation D 2 /D 1 in order to detect the uniformity of the light source.

6. A light source testing method comprising:

providing a light source for generating light;

using an image capturing apparatus for capturing an image with a plurality of pixels according to the light;

selecting a second predetermined gray level G 2 , and calculating the area Q 2 of a second light source testing area formed by pixels with gray level larger than the second predetermined gray level G 2 of the image;

calculating a maximum gray level GX 1 , and a gray level difference h=GX 1 −G 2 between the second predetermined gray level G 2 and the maximum gray level GX 1 ; and

detecting the brightness of the light source by a product V=h*Q 2 of the gray level difference h and the area Q 2 .

7. A light source testing method comprising:

providing a light source for generating light;

using an image capturing apparatus for capturing an image with a plurality of pixels according to the light;

selecting a third predetermined gray level G 3 , and defining the area Q 3 of a third light source testing area formed by pixels with gray level larger than the third predetermined gray level G 3 of the image;

calculating a plurality of rectangles surrounding the third light source testing area with their four sides in contact with the third light source testing area;

selecting a specific rectangle having a minimum area among the plurality of rectangles, and defining the shorter side of the selected rectangle as X, the longer side as Y; and

defining a ratio of side R 1 , a ratio of area R 2 , and an S value corresponding to the shape of the light source to detect the uniformity of the light source as follows:

R 1 = X/Y;

R 2 =( Q 3 /( X*Y ));

S=R 1 * R 2 .