Method of adjusting video to minimise or remove PSE triggers

1. A method of adjusting video image data to reduce photosensitive epilepsy (“PSE”) triggers, the method comprising:

analysing a sequence of images to determine that a number of changes in brightness exceeding a predetermined threshold between contiguous images is greater than a predetermined value over a predetermined time or predetermined number of video images; and

applying a correction procedure to the sequence of images, wherein the correction procedure comprises:

for each image, applying a plurality of candidate brightness changes to the image;

subsequently determining which of the applied candidate brightness changes result in the number of changes in brightness exceeding the predetermined threshold between contiguous images being reduced to below the predetermined value;

selecting the determined applied candidate brightness change having a smallest brightness change; and

modifying the sequence of images by applying the determined applied candidate brightness change having the smallest brightness change.

2. A method of adjusting video image data to reduce photosensitive epilepsy (“PSE”) triggers, the method comprising:

analysing a sequence of images to determine that a number of changes in brightness exceeding a predetermined threshold between contiguous images is greater than a predetermined value over a predetermined time or predetermined number of video images;

and applying a correction procedure to the sequence of images, wherein the correction procedure comprises:

for each image, applying a plurality of candidate brightness changes to the image;

subsequently determining that none of the applied candidate brightness changes result in the number of changes in brightness exceeding the predetermined threshold between contiguous images being reduced to below the predetermined value;

subsequently determining the value of a parameter for each of the previously applied candidate brightness changes, the parameter being defined as the sum of:

a) the reduction in the number of occurrences of a change in brightness exceeding the threshold between contiguous images caused as a result in the respective applied candidate brightness change; and

b) a predetermined constant divided by the respective applied candidate brightness change;

selecting the applied candidate brightness change having a greatest parameter value; and

modifying the sequence of images by applying the applied candidate brightness change having the greatest parameter value.

3. The method of claim 1 , wherein the applied change in brightness is non-linearly applied based on the current brightness value.

4. The method of claim 1 , wherein the applied change in brightness is linearly applied based on the current brightness value.

5. The method of claim 1 , wherein the step of analysing the sequence of video images to determine that the number of changes in brightness exceeding a predetermined threshold between contiguous images is greater than the predetermined value comprises:

sub-dividing each image into a plurality of sub-areas, each sub-area in an image having corresponding sub-areas in the same location in each of the remaining images, such that the corresponding sub-areas form a set of co-located sub-areas;

for each sub-area calculating the average brightness;

for each set of co-located sub-areas, determining the number of occurrences of the average brightness changing between contiguous images by an amount greater than the predetermined threshold;

for each image, determine the number of sub-areas in which the average brightness changes by an amount greater than the threshold; and

denote the analysis result to be a “fail” if the number of determined sub-areas is greater than a predetermined threshold of the total number of sub-areas in an image.

6. The method of claim 1 , wherein the predetermined time over which it is determined if the changes in brightness exceeds the predetermined threshold comprises 1 second.

7. The method of claim 1 , wherein the predetermined number of video images over which it is determined if the changes in brightness exceeds the predetermined threshold is a number corresponding to 1 second of video data.