System and method for video quality parametric tests
A method and system for automatically evaluating the quality of a signal transmitted by an imaging device. The amount of noise in the video signal is analyzed using an algorithm that does not require comparison to a template signal. The results of the algorithm determine whether the signal meets a pre-determined threshold value for signal quality.
1. A method for measuring the amount of noise in a video image comprising:
receiving a signal comprising image data from an imaging device;
extracting a luma component from the image data;
applying a filter to compute the second derivatives of the image data;
determining from the second derivative a ratio of noise pixels to total pixels in the image data;
comparing the ratio to a pre-determined ratio; and
if the ratio exceeds the pre-determined ratio, the imaging device is determined to be faulty.
2. The method of claim 1 , wherein the filter is a Laplace filter.
3. The method of claim 1 , wherein pixels are binarized prior to determining the ratio of noise pixels to total pixels.
4. The method of claim 1 , wherein the signal comprises smooth areas in the background of images.
5. The method of claim 1 , wherein the signal comprises a color bar pattern.
6. The method of claim 1 , wherein if the ratio exceeds the pre-determined ratio the signal is rejected.
7. The method of claim 1 , wherein if the ratio is less than the pre-determined ratio the signal is accepted.
8. An apparatus for determining the functioning of an imaging device comprising;
a processor;
memory, coupled to the processor, wherein the memory is configured to allow the processor to:
obtain a video signal;
extract a luma component from the video signal;
filter the luma component to determine a ratio of noise pixels to total pixels;
compare the ratio of noise pixels to total pixels to a pre-determined ratio; and
wherein if the processor determines that the ratio of noise pixels to total pixels exceeds the pre-determined ratio, the processor emits an error code indicating that the imaging device is non-functioning.
9. The apparatus of claim 8 , wherein the filter is a Laplace filter.
10. The apparatus of claim 8 , wherein the filter is an omnidirectional filter.
11. The apparatus of claim 8 , wherein the filter recognizes small changes in contrast around pixels.
12. The apparatus of claim 8 , wherein the luma component is the Y signal of a color image.
13. A system for video quality assessment comprising:
a video imaging device;
a testing device for measuring the amount of noise in a video picture obtained from the video imaging device;
wherein the testing device comprises logic that enables determination of the amount of noise in the video picture by evaluating the contrast between neighboring pixels and calculating the ratio of noisy pixels to total pixels in the video picture; and the testing device comprises logic to control an RF attenuation of the video picture to induce noise in the video imaging device.
14. The system of claim 13 , wherein the contrast between neighboring pixels is determined by applying a Laplace filter.
15. The system of claim 13 , wherein the contrast between neighboring pixels is determined by applying an omnidirectional filter.
16. The system of claim 13 , wherein the video imaging device sends a signal to the testing device.
17. The system of claim 13 , wherein the contrast between neighboring pixels is determined in the Y signal.